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Genomics-based non-invasive prenatal testing for detection of fetal chromosomal aneuploidy in pregnant women
Abstract
Background
Common fetal aneuploidies include Down syndrome (trisomy 21 or T21), Edward syndrome (trisomy 18 or T18), Patau syndrome (trisomy 13 or T13), Turner syndrome (45,X), Klinefelter syndrome (47,XXY), Triple X syndrome (47,XXX) and 47,XYY syndrome (47,XYY). Prenatal screening for fetal aneuploidies is standard care in many countries, but current biochemical and ultrasound tests have high false negative and false positive rates. The discovery of fetal circulating cell-free DNA (ccfDNA) in maternal blood offers the potential for genomics-based non-invasive prenatal testing (gNIPT) as a more accurate screening method. Two approaches used for gNIPT are massively parallel shotgun sequencing (MPSS) and targeted massively parallel sequencing (TMPS).
Objectives
To evaluate and compare the diagnostic accuracy of MPSS and TMPS for gNIPT as a first-tier test in unselected populations of pregnant women undergoing aneuploidy screening or as a second-tier test in pregnant women considered to be high risk after first-tier screening for common fetal aneuploidies. The gNIPT results were confirmed by a reference standard such as fetal karyotype or neonatal clinical examination.
Search methods
We searched 13 databases (including MEDLINE, Embase and Web of Science) from 1 January 2007 to 12 July 2016 without any language, search filter or publication type restrictions. We also screened reference lists of relevant full-text articles, websites of private prenatal diagnosis companies and conference abstracts.
Selection criteria
Studies could include pregnant women of any age, ethnicity and gestational age with singleton or multifetal pregnancy. The women must have had a screening test for fetal aneuploidy by MPSS or TMPS and a reference standard such as fetal karyotype or medical records from birth.
Data collection and analysis
Two review authors independently carried out study selection, data extraction and quality assessment (using the QUADAS-2 tool). Where possible, hierarchical models or simpler alternatives were used for meta-analysis.
Main results
Sixty-five studies of 86,139 pregnant women (3141 aneuploids and 82,998 euploids) were included. No study was judged to be at low risk of bias across the four domains of the QUADAS-2 tool but applicability concerns were generally low. Of the 65 studies, 42 enrolled pregnant women at high risk, five recruited an unselected population and 18 recruited cohorts with a mix of prior risk of fetal aneuploidy. Among the 65 studies, 44 evaluated MPSS and 21 evaluated TMPS; of these, five studies also compared gNIPT with a traditional screening test (biochemical, ultrasound or both). Forty-six out of 65 studies (71%) reported gNIPT assay failure rate, which ranged between 0% and 25% for MPSS, and between 0.8% and 7.5% for TMPS.
In the population of unselected pregnant women, MPSS was evaluated by only one study; the study assessed T21, T18 and T13. TMPS was assessed for T21 in four studies involving unselected cohorts; three of the studies also assessed T18 and 13. In pooled analyses (88 T21 cases, 22 T18 cases, eight T13 cases and 20,649 unaffected pregnancies (non T21, T18 and T13)), the clinical sensitivity (95% confidence interval (CI)) of TMPS was 99.2% (78.2% to 100%), 90.9% (70.0% to 97.7%) and 65.1% (9.16% to 97.2%) for T21, T18 and T13, respectively. The corresponding clinical specificity was above 99.9% for T21, T18 and T13.
In high-risk populations, MPSS was assessed for T21, T18, T13 and 45,X in 30, 28, 20 and 12 studies, respectively. In pooled analyses (1048 T21 cases, 332 T18 cases, 128 T13 cases and 15,797 unaffected pregnancies), the clinical sensitivity (95% confidence interval (CI)) of MPSS was 99.7% (98.0% to 100%), 97.8% (92.5% to 99.4%), 95.8% (86.1% to 98.9%) and 91.7% (78.3% to 97.1%) for T21, T18, T13 and 45,X, respectively. The corresponding clinical specificities (95% CI) were 99.9% (99.8% to 100%), 99.9% (99.8% to 100%), 99.8% (99.8% to 99.9%) and 99.6% (98.9% to 99.8%). In this risk group, TMPS was assessed for T21, T18, T13 and 45,X in six, five, two and four studies. In pooled analyses (246 T21 cases, 112 T18 cases, 20 T13 cases and 4282 unaffected pregnancies), the clinical sensitivity (95% CI) of TMPS was 99.2% (96.8% to 99.8%), 98.2% (93.1% to 99.6%), 100% (83.9% to 100%) and 92.4% (84.1% to 96.5%) for T21, T18, T13 and 45,X respectively. The clinical specificities were above 100% for T21, T18 and T13 and 99.8% (98.3% to 100%) for 45,X. Indirect comparisons of MPSS and TMPS for T21, T18 and 45,X showed no statistical difference in clinical sensitivity, clinical specificity or both. Due to limited data, comparative meta-analysis of MPSS and TMPS was not possible for T13.
We were unable to perform meta-analyses of gNIPT for 47,XXX, 47,XXY and 47,XYY because there were very few or no studies in one or more risk groups.
Authors' conclusions
These results show that MPSS and TMPS perform similarly in terms of clinical sensitivity and specificity for the detection of fetal T31, T18, T13 and sex chromosome aneuploidy (SCA). However, no study compared the two approaches head-to-head in the same cohort of patients. The accuracy of gNIPT as a prenatal screening test has been mainly evaluated as a second-tier screening test to identify pregnancies at very low risk of fetal aneuploidies (T21, T18 and T13), thus avoiding invasive procedures. Genomics-based non-invasive prenatal testing methods appear to be sensitive and highly specific for detection of fetal trisomies 21, 18 and 13 in high-risk populations. There is paucity of data on the accuracy of gNIPT as a first-tier aneuploidy screening test in a population of unselected pregnant women. With respect to the replacement of invasive tests, the performance of gNIPT observed in this review is not sufficient to replace current invasive diagnostic tests.
We conclude that given the current data on the performance of gNIPT, invasive fetal karyotyping is still the required diagnostic approach to confirm the presence of a chromosomal abnormality prior to making irreversible decisions relative to the pregnancy outcome. However, most of the gNIPT studies were prone to bias, especially in terms of the selection of participants.
... For NIPT, the occurrence of false positive and false negative cases is inevitable [6,27,28], and our study also shows a low number of three false positives and one false negative case. Unlike conventional screening, false positives in NIPT are due to biological factors rather than technical errors [11]. ...
... There is also a Cochrane review that evaluated the accuracy of genomics-based noninvasive prenatal testing (gNIPT) for detecting common foetal aneuploidies in pregnant women based on their prior risk levels [6]. Specifically, the authors compared the diagnostic performance of two next-generation sequencing methods: massively parallel shotgun sequencing and targeted massively parallel sequencing, both of which analyse cffDNA in maternal plasma. ...
... Specifically, the authors compared the diagnostic performance of two next-generation sequencing methods: massively parallel shotgun sequencing and targeted massively parallel sequencing, both of which analyse cffDNA in maternal plasma. The results indicate that these two techniques have similar clinical sensitivity and specificity for detecting foetal T21, T18, T13, and sex chromosome aneuploidy [6]. Furthermore, in high-risk pregnancies, these gNIPT methods demonstrated high accuracy for detecting the three major trisomies (i.e., T21, T18, and T13), with sensitivities ranging from 95.8% to 99.7% (depending on the specific trisomy), and specificities exceeding 99% [6]. ...
Background: Chromosomal numerical and structural alterations are significant causes of various developmental disorders in foetuses. Non-invasive prenatal testing (NIPT) has emerged as an effective screening tool for detecting common aneuploidies, aiding in the identification of individuals who may require further diagnostic work-up. Methods: This retrospective, monocentric observational study evaluates the usage patterns, test choices, turnaround times (TAT), and outcomes of NIPT between 2013 and 2023 on a sample of 2431 pregnant women at a special hospital offering outpatient services and comprehensive gynaecological/obstetric inpatient care. We analysed the trends in NIPT usage, high-risk results, prior screening procedures, as well as factors such as age, gestational age and in vitro fertilisation (IVF) status. NIPT was performed using cell-free foetal DNA (cffDNA) extracted from maternal plasma, followed by library construction, sequencing and result analysis. The sequencing results were aligned with reference genomes, and z-scores were calculated to assess the likelihood of aneuploidy. Statistical significance was set at p < 0.05. Results: The average age of women undergoing NIPT decreased from 36.1 years in 2013 to 33.01 years in 2023 (p = 0.0287), and mean TAT dropped from 12.44 days in 2013 to 7.08 days in 2023 (p = 0.0121), with the most substantial reduction occurring between 2013 and 2019. The study identified a stable rate of women who underwent IVF seeking prenatal testing, with no statistically significant difference between the first half and the second half of the analysed period (p = 0.2659). Among high-risk results, there were 39 chromosomal abnormalities detected, most of them belonging to trisomy 21 (59%). Conclusions: Our findings demonstrate the increasing efficiency and accessibility of NIPT in prenatal care in Croatia, while the significant reduction in TAT and the decreasing age of women undergoing NIPT reflect enhanced operational practices and broader acceptance. Introducing NIPT into the public healthcare system in the Republic of Croatia could improve equitable access to advanced prenatal care and enhance pregnancy outcomes. Future advancements in technology and genetic counselling will further enhance its role, requiring careful attention to ethical and regulatory considerations.
... Traditionally, prenatal diagnosis has been performed using invasive methods such as amniocentesis and chorionic villus sampling. However, these methods are associated with a small risk of miscarriage [2,3]. In recent years, noninvasive prenatal testing (NIPT) has emerged as a safe and effective alternative to invasive methods. ...
... In recent years, noninvasive prenatal testing (NIPT) has emerged as a safe and effective alternative to invasive methods. NIPT is based on the analysis of cell-free DNA (cfDNA) in the maternal blood [3]. cfDNA is released into the maternal blood by the placenta and contains genetic material from both the mother and the fetus. ...
... cfDNA is released into the maternal blood by the placenta and contains genetic material from both the mother and the fetus. This advent of NIPT has revolutionized prenatal diagnosis [3]. While NIPT has emerged as a powerful tool for detecting common chromosomal abnormalities such as Down syndrome, its accessibility and potential for broader application through internet-based platforms remain relatively unexplored. ...
Background
Chromosomal abnormalities are genetic disorders caused by chromosome errors, leading to developmental delays, birth defects, and miscarriages. Currently, invasive procedures such as amniocentesis or chorionic villus sampling are mostly used, which carry a risk of miscarriage. This has led to the need for a noninvasive and innovative approach to detect and prevent chromosomal abnormalities during pregnancy.
Objective
This review aims to describe and appraise the potential of internet-based abnormal chromosomal preventive measures as a noninvasive approach to detecting and preventing chromosomal abnormalities during pregnancy.
Methods
A thorough review of existing literature and research on chromosomal abnormalities and noninvasive approaches to prenatal diagnosis and therapy was conducted. Electronic databases such as PubMed, Google Scholar, ScienceDirect, CENTRAL, CINAHL, Embase, OVID MEDLINE, OVID PsycINFO, Scopus, ACM, and IEEE Xplore were searched for relevant studies and articles published in the last 5 years. The keywords used included chromosomal abnormalities, prenatal diagnosis, noninvasive, and internet-based, and diagnosis.
Results
The review of literature revealed that internet-based abnormal chromosomal diagnosis is a potential noninvasive approach to detecting and preventing chromosomal abnormalities during pregnancy. This innovative approach involves the use of advanced technology, including high-resolution ultrasound, cell-free DNA testing, and bioinformatics, to analyze fetal DNA from maternal blood samples. It allows early detection of chromosomal abnormalities, enabling timely interventions and treatment to prevent adverse outcomes. Furthermore, with the advancement of technology, internet-based abnormal chromosomal diagnosis has emerged as a safe alternative with benefits including its cost-effectiveness, increased accessibility and convenience, potential for earlier detection and intervention, and ethical considerations.
Conclusions
Internet-based abnormal chromosomal diagnosis has the potential to revolutionize prenatal care by offering a safe and noninvasive alternative to invasive procedures. It has the potential to improve the detection of chromosomal abnormalities, leading to better pregnancy outcomes and reduced risk of miscarriage. Further research and development in this field is needed to make this approach more accessible and affordable for pregnant women.
... Non-invasive prenatal testing (NIPT) has become the most widely adopted clinical approach for screening fetal aneuploidies and is now a standard healthcare practice in many countries. 11 NIPT offers high sensitivity and speci city for detecting common chromosomal abnormalities. Speci cally, recent studies indicate that the sensitivity for T21 and T18 is over 98%, for T13 is approximately 100%, all with a speci city exceeding 99%. ...
... However, its e cacy in detecting SCAs is less optimal, with widely varying sensitivities reported. 11 For instance, the sensitivity for X-monosomy ranges from 83.2-98.8%, while for other SCAs, it varies between 76.3% and 100%. ...
... while for other SCAs, it varies between 76.3% and 100%. 11,[23][24][25] Furthermore, the PPV of NIPT for SCAs is reported to be less than 50%, substantially lower than the PPV of 91.8% for T21. 12 Despite its high accuracy, NIPT is not universally offered to all pregnant women but is typically reserved for those at high risk. This underscores the limitations of prenatal screening in fully guaranteeing newborn health. ...
The application of next-generation sequencing (NGS) technology is increasingly used in newborn screening (NBS) to detect monogenic disorders. However, its capability to identify chromosomal aneuploidies and its potential clinical value have not been fully explored. This study investigates the feasibility of using an NGS panel for aneuploidy screening and examines the incidence of aneuploidies in newborns. We designed an NBS panel targeting 142 genes associated with 128 disorders and conducted chromosomal copy number analysis on 29,601 newborns across eight hospitals in China. The presence of chromosomal aneuploidies was confirmed through karyotyping or genome sequencing, and follow-up visits were conducted to assess prenatal screening outcomes and postnatal phenotypes. Among the 29,601 newborns, 47 were identified with various aneuploidies. Further investigation confirmed 30 of these cases, yielding a positive predictive value (PPV) of 100%. The estimated incidence of aneuploidies among live births was 0.16%, with significant regional discrepancies ranging from 0.04–0.23%. Sex chromosome aneuploidy (SCA) was the most prevalent at 0.15%, while trisomy 21 occurred at a lower rate of 0.01%. The NBS panel demonstrated potential effectiveness and accuracy in detecting chromosomal aneuploidies, suggesting it could play a valuable role in future genetic NBS clinical practice.
... 10 where chromosomal abnormalities are concerned (i.e., it is not considered diagnostic), NIPS is the preferred method. 4,5,11 As sequencing technologies have advanced since 2011, so has the accuracy of NIPS. Although the previously noted maternal factors (e.g., maternal mosaicism) and test characteristics (e.g., sufficient ...
... T18, and T13, respectively.11 A similarly powered meta-analysis by Gil et al., incorporating 35 studies and in excess of 223,000 pregnancies, suggests that NIPS is at least 99.7%, 97.9%, 99.0%, 95.8%, and 100% sensitive for T21, T18, T13, 45X, and non-45X SCAs, respectively. ...
... decision-making (CVS is performed at weeks[10][11][12].25 A further two states are implementing 15-week prohibitions, similarly excluding diagnostic amniocentesis, which is performed at weeks 15-18. 25 It is not difficult to imagine a patient confronted with a positive NIPS result at 10 week's gestation, which suggests that their foetus may be carrying a life-limiting or otherwise life-altering condition, who then has to choose between potentially altering the course of the pregnancy in the absence of a confirmatory diagnosis, or facing legal sanctions if doing so later with more complete diagnostic information. ...
... On the other hand, systematic reviews and meta-analysis on NIPT have reported higher sensitivities of more than 99 % for trisomy 21 and more than 97 % for trisomies 18 and 13, with specificities > 99 % for the three trisomies in singleton pregnancies, and slightly lower sensitivities for twin pregnancies [16][17][18][19]. NIPT, therefore, serves as a reasonable measure to further triage women following high chance CST to avoid unnecessary exposure of all these women to the higher risk of invasive testing [20]. Some countries, including the United States, offer the option of the NIPT both as a first-line screening for all pregnant women in their first trimester or as the second line for those with high chance CST [11]. ...
... Given that NIPT can result in false positives, positive results should be confirmed with invasive testing before any irreversible procedure is performed [20]. It also further stresses the fact that NIPT is a screening test and extensive counseling about this, and the possibilities of false-negative and false-positive results is important for a patient to make an informed decision before and after the result, and guide against medico-legal issues if there is a discrepancy at birth. ...
... The care provider should at the very least provide some information when discussing the alternatives for prenatal invasive testing during the pretesting counseling. This should include the fact that NIPT is a screening test, thus more testing is necessary to confirm a diagnosis before making an irreversible choice; genetic testing is discretionary, the choice to undertake or avoid it should be based on the individual patient's beliefs and desires; the significance of a report of abnormality and options of follow-up; limitations and risks of the various diagnostic testing; accessibility to genetic counseling to offer more information and risk evaluation to help with making a decision and follow-up plan; and the possibility of detecting other genetic problems not detectable by NIPT [1,2,20,46]. ...
The non-invasive prenatal testing (NIPT) analyses cell-free DNA (cfDNA) derived from the placental tissue in the maternal circulation. Though highly sensitive and specific, a major limitation is in cases of confined placental mosaicism (CPM). Whether to perform chorionic villus sampling (CVS) or amniocentesis to confirm a positive NIPT result is controversial. One major drawback of CVS is that cytogenetic diagnosis may not always reflect the true chromosomal make-up of the fetus. This work, therefore, proposes the use of amniocentesis in the presence of normal ultrasound findings, and the option of either CVS or amniocentesis when there are abnormal USS findings.
... 10 There are several methods utilized by different laboratories (see Table 2); however, the predictive value between techniques is comparable. 7,11 Selective methods target specific chromosomes or genes and can evaluate for common trisomies, fetal sex, sex chromosome aneuploidies, and specific microdeletions or duplications. Whole genome sequencing allows for more extensive screening for subchromosomal imbalances, rare autosomal trisomies, and single gene disorders. ...
... 4,54 Legislative restrictions may compel some families to seek early termination; however, a recent Cochrane review and an US Food and Drug Administration safety communication caution against using cfDNA alone to make permanent pregnancy-related decisions and encourage confirmatory invasive testing before pursuing termination due to the possibility of inaccurate results. 11,55 Prenatal care practitioners, regardless of personal beliefs, are professionally obligated to provide comprehensive family planning counseling when faced with abnormal genetic testing (ie, cfDNA) results. ...
Advances in technology have correlated with expanding prenatal genetic testing options for pregnant people. Leading medical organizations recommend cell‐free DNA as the most sensitive screening test for trisomies 13, 18, and 21, as well as for fetal sex chromosome aneuploidies. The commercially available testing options go beyond these recommended tests, and prenatal care professionals should be familiar with the tests that their patients may choose despite being beyond the scope of current medical recommendations. This article explains updates in cell‐free DNA technology and clinical considerations for prenatal care professionals, recognizing that this is a rapidly changing field of science and health care.
... Nonetheless, some babies have reasonably normal lives despite the symptoms, which range from mild to severe. Although the degree of dysfunction in the various trisomy or SCA disorders varies, the likelihood of a newborn being impacted is far lower [1]. When it comes to identifying Down syndrome, NIPT has a sensitivity greater than 99%and a falsepositive rate of less than 0.1%. ...
... The discovery that placental cells constantly produce measurable quantities of fetal ccfDNA in mother blood is the foundation for non-invasive prenatal diagnostics based on genomics. This ccfDNA from fetus is mostly composed of relatively small pieces, less than Three hundred base pairs and comes from the placenta's normal cell death [1]. One crucial factor in accurately detecting the fetal fraction of gNIPT is an aneuploid fetus, or the portion of total ccfDNA of fetal origin in the bloodstream of mothers. ...
This article provides an overview of Non-Invasive Prenatal Testing (NIPT), also known as noninvasive prenatal screening. It is a technique for estimating the likelihood that the fetus will have specific genetic defects at birth for pregnant women. The content is specifically tailored for pregnant women and ncompasses a detailed exploration of topics such as Genomics-based noninvasive prenatal tests, sample details for noninvasive prenatal testing, factors influencing test results, the interpretation of test results, limitations associated with the test, and the content included in the Declaration of Consent Form for Noninvasive Prenatal Testing.
... 7 There are different NIPS methods, massively parallel shotgun sequencing (MPSS) analyses all fetal DNA randomly, and targeted massively parallel sequencing (TMPS) analyses the target fetal DNA. 8 Compared with the conventional screening approaches, NIPS is found to be a more accurate and costeffective method to screen for the three most common aneuploidies, when used as a second-tier test in high-risk pregnancies. [8][9][10] The decreasing cost of NIPS, which is expected to decrease further over the next few years, provides the opportunity to include other chromosomal anomalies in a screening programme efficiently and allows the consideration of NIPS as a first-tier test. ...
... 8 Compared with the conventional screening approaches, NIPS is found to be a more accurate and costeffective method to screen for the three most common aneuploidies, when used as a second-tier test in high-risk pregnancies. [8][9][10] The decreasing cost of NIPS, which is expected to decrease further over the next few years, provides the opportunity to include other chromosomal anomalies in a screening programme efficiently and allows the consideration of NIPS as a first-tier test. 9 This project aimed at measuring the expected costeffectiveness of expanding a Canadian prenatal screening programme for the detection of fetal sex chromosome aneuploidies (SCAs), rare autosomal aneuploidies (RATs) and/or microdeletions in addition to the common chromosomal anomalies. ...
Objectives
To determine the cost-effectiveness of the addition of chromosomal anomalies detectable by non-invasive prenatal screening (NIPS), in a prenatal screening programme targeting common aneuploidies.
Design, setting and participants
A simulation study was conducted to study the addition of chromosomal anomalies detectable by NIPS (sex chromosome aneuploidies, 22q11.2 deletion syndrome, large deletion/duplication >7 Mb and rare autosomal trisomies) to five basic strategies currently aiming the common trisomies: three strategies currently offered by the public healthcare systems in Canada, whose first-tier test is performed with biochemical markers, and two programmes whose first-tier test consists of NIPS-based methods.
Outcome measures
The total number of cases of chromosomal anomalies detected and the costs related to the consumption of medical services.
Results
The most effective and the most cost-effective option in almost all prenatal screening strategies is the option that includes all targeted additional conditions. In the strategies where NIPS is used as first-tier testing, the cost per additional case detected by adding all possible additional anomalies to a programme that currently targets only common trisomies is C25 489 to C57 711 (95% CI C58 292) for targeted massively parallel sequencing, respectively. The acceptability curves show that at a willingness-to-pay of $C50 000 per one additional case detected, the expansion of NIPS-based methods for the detection of all possible additional conditions has a 90% probability of being cost-effective.
Conclusion
From an economic perspective, in strategies that use NIPS as a first-tier screening test, expanding the programmes to detect any considered chromosomal anomalies other than the three common trisomies would be cost-effective. However, the potential expansion of prenatal screening programmes also requires consideration of societal issues, including ethical ones.
... In recent years, noninvasive prenatal testing (NIPT), a new test to identify fetal chromosomal abnormalities, has been developed to detect fetal cell-free DNA (cfDNA) in maternal plasma [10], and it can be performed from nine weeks gestational age up to delivery. A metaanalysis of the accuracy of universal NIPT yielded a detection rate of more than 99% for T21, 90% for T18, and 60% for T13 [11]. ...
... This study's NIPT performance had excellent results since there were no false positives or false negatives. An earlier meta-analysis about NIPT showed pool sensitivity in unselected pregnant women to be 99%, 90.9%, and 65.1% for T21, T18, and T13, respectively, and the specificity of all trisomy was 99.9% [11]. In Thailand, the sensitivity of T13, 18 and 21 was 100%, and the specificity was 99.9% [30]. ...
This study evaluated prenatal screening test performance and the prevalence of common aneuploidies at Siriraj Hospital, Thailand. We collected data from screening tests which are first-trimester test, quadruple test, and noninvasive prenatal tests (NIPT) between January 2016 and December 2020. Thirty percent (7,860/25,736) of pregnancies received prenatal screening tests for aneuploidies disorders, and 17.8% underwent prenatal diagnosis tests without screening. The highest percentage of screening tests was first-trimester test (64.5%). The high-risk results were 4% for first-trimester test, 6.6% for quadruple test, and 1.3% for NIPT. The serum screening tests for trisomy 13 and 18 had no true positives; therefore, we could not calculate sensitivity. For the first-trimester test, the sensitivity for trisomy 21 was 71.4% (95% confidence intervals (CI) 30.3–94.9); specificity for trisomy 13 and 18 was 99.9% (95% CI 99.8–99.9); and for trisomy 21 was 96.1% (95% CI 95.6–96.7). For the quadruple test, the specificity for trisomy 18 was 99.6% (95% CI 98.9–99.8), while the sensitivity and specificity for trisomy 21 were 50% (95% CI 26.7–97.3) and 93.9% (95% CI 92.2–95.3), respectively. NIPT had 100% sensitivity and specificity for trisomy 13, 18 and 21, and there were neither false negatives nor false positives. For pregnant women < 35 years, the prevalence of trisomy 13, 18, and 21 per 1,000 births was 0.28 (95% CI 0.12–0.67), 0.28 (95% CI 0.12–0.67), and 0.89 (95% CI 0.54–1.45), respectively. For pregnant women ≥35 years, the prevalence of trisomy 13, 18, and 21 per 1,000 births was 0.26 (95% CI 0.06–1.03), 2.59 (95% CI 1.67–4.01), and 7.25 (95% CI 5.58–9.41), respectively. For all pregnancies, the prevalence of trisomy 13, 18, and 21 per 1,000 births was 0.27 (95% CI 0.13–0.57), 0.97 (95% CI 0.66–1.44), 2.80 (95% CI 2.22–3.52), respectively.
... This finding was prevalent in studies focused on NIPT, which made up 36% of studies in this review. NIPT may be viewed favourably because of its high sensitivity and specificity [74]. However, its limitations include the possibility of false-positive and falsenegative results, and the need for diagnostic confirmation via invasive methods following a positive result [75]. ...
Background
Several studies have explored parent and public perspectives on screening and diagnostic genetic testing during pregnancy (prenatal testing). Little is known about how much people from Black communities have contributed to this research.
Objective
To examine whether Black people's views on prenatal testing are proportionately represented in UK and US studies.
Search Strategy
Searches were conducted in Medline (Ovid), PsycINFO (Ovid), CINAHL Complete (EBSCOhost), and Emcare (Ovid).
Selection Criteria
Primary experimental UK and US studies examining parental and public perspectives on prenatal testing, published between 2014 and 2024.
Data Collection and Analysis
After duplicate removal, titles and abstracts were independently screened by two reviewers. Full texts were then obtained, and data were extracted for analysis.
Main Results
Seventy‐six studies were included. 83% (n = 63) included Black participants; only 39% (n = 30) reported a sample meeting the respective national Black population. More studies in which Black participants met the population were from the UK (UK: 69% vs. US: 42%), though this difference did not reach significance (OR = 1.53; 95% CI: 0.52, 4.48; p = 0.431). Black participants were better represented in studies exploring views on prenatal testing for sickle cell than those on non‐invasive prenatal testing and genomic technologies.
Conclusions
Whilst important for our understanding, efforts to include Black participants in studies examining views on prenatal testing should not be limited to those where the condition primarily impacts this population. Improved representation of Black people across a wider range of studies is essential for supporting health equity and minimising health disparities.
... Such a pragmatic information remains limited in current publication domain. The performance of for detection of T21 and T18 in our laboratory during an initial phase of implementation seemed comparable to previous reports [17,18]. Because of all of the prenatal cf-DNA screenings in this study were performed by our own not-for-profit laboratory, price barriers were much lower than that of the sent-out tests, and thus we did not suspect for a significant selection bias. ...
Objectives
We reported a performance during an implementation of prenatal cell-free (cf) DNA screening using single nucleotide polymorphism (SNP) approach in our accredited laboratory.
Methods
Prospective audit with prompt intervention was set for the processing of 2,502 samples from singleton pregnancy from August 2017 to July 2019. Risks of trisomy 21 (T21), T18, T13, monosomy X (XO), and other sex chromosome aneuploidies (SCAs) were clarified by a proprietary bioinformatics algorithm.
Results
Laboratory failure occurred in 192 samples (7.7 %) as a result of inadequate sequencing (n=144), fundamental limitation of the testing (n=19), and obvious human error (n=29). Faulty setting of the calibration curve was the most common human error (n=22/29). After a redraw (n=110), 79 (71.8 %) were settled. Overall, 2,389/2,502 samples (95.5 %) were reportable. Thirty-five samples were high-risk for T21 (n=19), T18 (n=5), T13 (n=1), XO (n=3), and other SCAs (n=7), respectively. Positive predictive values calculated from either prenatal confirmatory tests or postnatal findings were 93.8 % (n=16), 100 % (n=4), 50 % (n=2), and 83.3 % (n=6) for T21, T18, XO, and other SCAs, respectively, with high sensitivity and specificity (>99.9 %). Vanishing twin was detected from 1 out of 4 samples with detected additional haplotypes.
Conclusions
An overall performance of SNP-based prenatal cf-DNA screening during our initial implementation can be optimized with proactive approach. The technical know-how was a significant limiting factor for adopting the technology. The lessons learnt may be of interest to the academic laboratory considering adopting their own test instead of sending blood to a testing service of a supplier.
... 19,20 Studies have reported that fetal ultrasound abnormalities are caused by about 12.4-35% chromosomal aberrations, about 25% by chromosomal karyotype structure or number abnormalities, and about 10% by chromosomal microstructure abnormalities. 21 When the fetal ultrasound is abnormal, genetic examination should be performed. Chromosomal karyotype analysis of fetal specimens has always been the gold standard for prenatal analysis of chromosomal defects in pregnant women, which can detect balanced translocation, inversion, deletion, insertion, and rearrangement of large fragments. ...
Objective
Chromosomal microarray analysis (CMA) is a first-line test to assess the genetic etiology of fetal ultrasound abnormalities. The aim of this study was to evaluate the effectiveness of CMA in detecting chromosomal abnormalities in fetuses with ultrasound abnormalities, including structural abnormalities and non-structural abnormalities.
Methods
A retrospective study was conducted on 368 fetuses with abnormal ultrasound who received interventional prenatal diagnosis at Meizhou People’s Hospital from October 2022 to December 2023. Samples of villi, amniotic fluid, and umbilical cord blood were collected according to different gestational weeks, and karyotype and CMA analyses were performed. The detection rate of chromosomal abnormalities in different ultrasonic abnormalities was analyzed.
Results
There were 368 fetuses with abnormal ultrasound, including 114 (31.0%) with structural abnormalities, 225 (61.1%) with non-structural abnormalities, and 29 (7.9%) with structural combined with non-structural abnormalities. The detection rate of aneuploidy and pathogenic (P)/likely pathogenic (LP) copy number variations (CNVs) of CMA in fetuses with structural abnormalities was 5.26% (6/114), the detection rate of karyotype was 2.63% (3/114), and the additional diagnosis rate of CMA was 2.63%. In the fetuses with ultrasonic non-structural abnormalities, the detection rate of karyotype was 6.22% (14/225), the detection rate of aneuploidy and P/LP CNVs in fetuses with ultrasonic structural abnormalities was 9.33% (21/225), and the additional diagnosis rate of CMA was 3.11%. There was no significant difference in chromosome abnormality detection rate of CMA among structural abnormality, non-structural abnormality, and structural abnormality combined with non-structural abnormality groups (5.3%, 9.3%, and 13.8%, p = 0.241), also among multiple ultrasonic abnormality and single ultrasonic abnormality groups (14.8%, and 7.3%, p = 0.105).
Conclusion
CMA can significantly improve the detection rate of genetic abnormalities in prenatal diagnosis of ultrasonic abnormal fetuses compared with karyotype analysis. CMA is a more effective tool than karyotyping alone in detecting chromosomal abnormalities in fetuses with ultrasound abnormalities.
... It has been over a decade since the clinical introduction of cell-free (cf.) DNA screening into the prenatal space, with numerous publications demonstrating the high accuracy of this screening test in the detection of common fetal trisomies (trisomies 21, 18, and 13) [1][2][3][4]. The use of cfDNA screening to test for the presence of common fetal trisomies is now recommended by many professional medical societies for all pregnant patients [5][6][7][8][9], however, professional societies note that more data is needed for cfDNA screening beyond the common trisomies. ...
Trisomy 20 has been shown to be one of the most frequent rare autosomal trisomies in patients that undergo genome-wide noninvasive prenatal testing. Here, we describe the clinical outcomes of cases that screened positive for trisomy 20 following prenatal genome-wide cell-free (cf.) DNA screening. These cases are part of a larger cohort of previously published cases. Members of the Global Expanded NIPT Consortium were invited to submit details on their cases with a single rare autosomal aneuploidy following genome-wide cfDNA screening for retrospective analysis. Clinical details including patient demographics, test indications, diagnostic testing, and obstetric pregnancy outcomes were collected. Genome-wide cfDNA screening was conducted following site-specific laboratory procedures. Cases which screened positive for trisomy 20 (n = 10) were reviewed. Clinical outcome information was available for 90% (9/10) of our screen-positive trisomy 20 cases; the case without diagnostic testing ended in a fetal demise. Of the nine cases with outcome information, one was found to have a mosaic partial duplication (duplication at 20p13), rather than a full trisomy 20. Only one case in the study cohort had placental testing; therefore, confined placental mosaicism could not be ruled out in most cases. Adverse pregnancy outcomes were seen in half of the cases, which could suggest the presence of underlying confined placental mosaicism or mosaic/full fetal trisomy 20. Based on our limited series, the likelihood of true fetal aneuploidy is low but pregnancies may be at increased risk for adverse obstetric outcomes and may benefit from additional surveillance.
... Besides, for transformation from scienti c research to clinical, it owns advantages of less harm to patients, such as infertility persons whose endometrial uids were extracted transfer cycle and whose pregnancy outcomes were not worse [3,4]. Therefore, it can be used in the diagnosis of disease and exploration of the mechanism of molecular, which parallels the trends that Non-invasive testing has been pursued in many medical disciplines because of fewer risks and more comfortable feelings [5]. ...
Background: Endometrial fluid represents the condition of the endometrium and testing it brings less harm to patients. Thus, we overviewed the domain of endometrium fluid by bibliometric analysis, the results of which are comprehended by researchers more easily and rapidly.
Method: The publications were retrieved with the terms on endometrial fluid from the Web of Science Core Collection on October 30, 2023. Data were analyzed by VOSviwer, CiteSpace, and Excel.
Results: The analyzed data include 5024 articles and 769 reviews. Both the USA and Texas A&M Universityown the most publications, the quantity of which are 1508 and 68 respectively. Researchers published most often in Human Reproduction. The most productive author is Roberto Romero, who publishes 37 articles and owns a higher value of citations per document with 171. Besides, this article clustered keywords, analyzed them at the timeline level, and discovered the hotspot that will become the future development trend.
Conclusions: This research gives a new perspective to people who just stepped into the field and more intuitive and comprehensive choices for them and sophisticated persons to study in suitable institutions and to collaborate with appropriate authors, which will accelerate the advancement of the domain.
... Increasing technical and biologic understanding of cell-free DNA (cfDNA) in human health and disease has heralded the era of the liquid biopsy-adjunct analysis of cfDNA, typically from patient plasma, to inform clinical decision making. 1,2 Liquid biopsy has the advantage of being reliant on minimally invasive collection techniques (e.g., routine blood draw) while providing valuable information in a growing array of clinical scenarios, such as prenatal genetic screening 3 and minimal residual disease monitoring in multiple cancer types. [4][5][6] Although plasma remains the most frequently used substrate for liquid biopsy, other body fluids that are routinely collected during clinical care have emerged as valuable resources for assessing cfDNA, particularly in the setting of cancer. ...
Background
Leptomeningeal metastases occur across multiple solid and lymphoid cancers, and patients typically undergo cytopathologic assessment of cerebrospinal fluid (CSF) in this setting. For patients diagnosed with metastatic cancer, the detection of actionable somatic mutations in CSF can provide clinically valuable information for treatment without the need for additional tissue collection.
Methods
The authors validated a targeted next‐generation sequencing assay for the detection of somatic variants in cancer (OncoPanel) on cell‐free DNA (cfDNA) isolated from archival CSF specimens in a cohort of 25 patients who had undergone molecular testing of a prior tumor specimen.
Results
CSF storage time and volume had no impact on cfDNA concentration or mean target coverage of the assay. Previously identified somatic variants in CSF cfDNA were detected in 88%, 50%, and 27% of specimens diagnosed cytologically as positive, suspicious/atypical, and negative for malignancy, respectively. Somatic variants were identified in 81% of CSF specimens from patients who had leptomeningeal enhancement on magnetic resonance imaging compared with 31% from patients without such enhancement.
Conclusions
These data highlight the stability of cfDNA in CSF, which allows for cytopathologic evaluation before triage for next‐generation sequencing assays. For a subset of cases in which clinical suspicion is high but cytologic or radiographic studies are inconclusive, the detection of pathogenic somatic variants in CSF cfDNA may aid in the diagnosis of leptomeningeal metastases.
... The probabilities related to trisomy incidence, miscarriage, rate of pregnancy termination, uptake rate of screening test, uptake rate of diagnostic test following a high-risk result of screening test, failure rate of NIPT, and procedure-related miscarriage were retrieved from Siriraj hospital's databases and published articles [25,30,35]. The sensitivity and specificity of Cost of food per visit Gamma 1.5 0.3 [31] The opportunity cost of pregnant women per visit Gamma 2.2 0.4 [31] The opportunity cost of a caregiver per visit Gamma 2.7 0.5 [31] (Continued ) these tests were determined based on a study conducted by Badeau et al. [23] and Manotaya et al. [34]. ...
Historically, there has been a lack of cost-effectiveness data regarding the inclusion of universal non-invasive prenatal testing (NIPT) for trisomy 21, 18, and 13 in the benefit package of the Universal Health Coverage (UHC) in Thailand. Therefore, this study aimed to perform the cost-benefit analysis of prenatal screening tests and calculate the budget impact that would result from the implementation of a universal NIPT program. A decision-tree model was employed to evaluate cost and benefit of different prenatal chromosomal abnormalities screenings: 1) first-trimester screening (FTS), 2) NIPT, and 3) definitive diagnostic (amniocentesis). The comparison was made between these screenings and no screening in three groups of pregnant women: all ages, < 35 years, and ≥ 35 years. The analysis was conducted from societal and governmental perspectives. The costs comprised direct medical, direct non-medical, and indirect costs, while the benefit was cost-avoidance associated with caring for children with trisomy and the loss of productivity for caregivers. Parameter uncertainties were evaluated through one-way and probabilistic sensitivity analyses. From a governmental perspective, all three methods were found to be cost-beneficial. Among them, FTS was identified as the most cost-beneficial, especially for pregnant women aged ≥ 35 years. From a societal perspective, the definitive diagnostic test was not cost-effective, but the other two screening tests were. The most sensitive parameters for FTS and NIPT strategies were the productivity loss of caregivers and the incidence of trisomy 21. Our study suggested that NIPT was the most cost-effective strategy in Thailand, if the cost was reduced to 47 USD. This evidence-based information can serve as a crucial resource for policymakers when making informed decisions regarding the allocation of resources for prenatal care in Thailand and similar context.
... Дослідження крові плода засвідчили ознаки апластичного кризу. За допомогою аналізу ДНК ПВ19 шляхом полімеразної ланцюгової реакції у зразках тканин плода виявлено ознаки зараження парвовірусом людини [3]. ...
Background. Intrauterine infection remains the main problem of perinatology. Early diagnosis of such infection causes enough difficulties and requires improvement. This study is devoted to the problem of predicting non-immune fetal hydrops if a woman is infected with parvovirus B19 in the II trimester of pregnancy.Objectives: to improve the diagnosis of non-immune fetal hydrops on the basis of changes in the α-fetoprotein (AFP) value in maternal blood during parvovirus B19 infection .Materials and methods. Serial AFP determination in blood serum of pregnant women infected with parvovirus B19 (n = 16) at 18–20–22 weeks of pregnancy was carried out. Biochemical analysis of AFP in amniotic fluid was performed after prenatal invasive examination in fetuses with non-immune hydrops. The obtained data were compared with similar indicators of pregnant women from the control group (n = 16) with a normal course of pregnancy in the II trimester. Transabdominal amniocentesis was performed under ultrasound control at 16–20 weeks of gestation for fetuses with non-immune hydrops. Determination of the AFP value in the blood serum of pregnant women in the II trimester was performed with a chemiluminescence immunoassay analyzer.Results. It was established that the AFP level in maternal blood reaches and exceeds threshold values (2.6 ± 0.05 MoM) on average 2.5 ± 0.5 weeks before the manifestation of severe fetal anemia in infected fetus with non-immune hydrops (r = 0.768, p < 0.001). That is, a sharp AFP increase in the blood of a pregnant woman infected with parvovirus B19 is a predictor of the development of non-immune fetal hydrops due to parvovirus B19 infection.Conclusions. The described method has proven to be highly effective, it is allows reducing the frequency of ultrasound examinations for infected women, because the fetus is not always infected from an infected mother. This technique can be used as a predictor of intrauterine parvovirus B19 infection in the II trimester, which will allow the development of new approaches to the early diagnosis of non-immune fetal hydrops, as well as contribute to timely intrauterine hemotransfusion.
... improved cytogenetic and molecular diagnostic techniques have paved the way for more than 90% prenatal identification of aneuploidies and a large proportion of sex chromosome anomalies (SCA) [11][12][13]. There is also a well-established association between risk for aneuploids and advanced maternal age [1], which partially explains the elevated prevalence of CA worldwide [2,8]. ...
Background
To investigate the prevalence and prenatal diagnosis rate of chromosomal abnormalities (CA) in Zhejiang Province, China.
Methods
We estimated the annual changes in the detected prevalence of CA and prenatal diagnosis rate among 681,590 births in Zhejiang Province, China, between 2014 and 2020. Data were derived from the provincial birth defects surveillance system, which represents 30% of annual births in Zhejiang Province. The effect of maternal age was also evaluated.
Results
The detected prevalence of sex chromosomal abnormalities (1.70–7.30 per 10,000 births, P trend < 0.001) and microdeletion and microduplication (0.30–6.81 per 10,000 births, P trend < 0.001) gradually increased, contributing to an upward trend in overall CA (12.09–39.22 per 10,000 births). The diagnosis rate before 22 gestational weeks constantly increased from 20.8 to 70.1% for trisomy 21 ( P trend = 0.003). The prevalence rate ratio for maternal age of ≥ 35 years was higher than that for maternal age of 25–29 years for trisomy 21 (5.40, 95% confidence interval [CI] 4.59–6.35) and sex chromosomal abnormalities (3.28, 95% CI 2.48–4.33).
Conclusions
The rising prevalence of CA in China may be attributable to the elevated maternal age and the innovation of prenatal diagnosis tools, Thus, studies should pay attention to the rare CA that were previously ignored, and select rational screening tools.
... This is explained by companies providing NIPT performed on high-risk populations [15]. Although the specificity of NIPT is high for trisomies 21, 18, and 13, the positive predictive values vary widely across studies and range from 40% to 100% [16][17][18][19]. Our study showed that the positive predictive value of the NIPT in the high-risk population was 21.9%. ...
Background: Non-invasive prenatal testing (NIPT) is being applied more widely in Vietnam. However, the effects of NIPT on prenatal diagnosis have not been studied much in our country. This study aims to analyze the impact of NIPT on the changes in the number of routine screening tests for chromosomal abnormalities 21, 18, and 13 and the impact of NIPT on invasive prenatal diagnostic procedures and propose strategies to screen for fetal aneuploidy. Results: NIPT did not change the number of routine screening tests for chromosomal abnormalities 21, 18, and 13. The rate of amniocentesis used to confirm the diagnosis of aneuploidy was decreased by 6,32 (p < 0,0001, 95% CI: 3,99 – 10,45). Among the strategies to detect aneuploidy 21, 18, and 13 suitable for socio-economic conditions in Vietnam, a 2-step screening method can be applied. Conclusions: NIPT did not change the number of routine screening tests. NIPT reduced the number of invasive prenatal procedures. The screening strategy for fetal aneuploidy should follow a two-step approach.
... Several studies have reported this test to be more sensitive and accurate compared to biochemical and ultrasound tests for the detection of fetal aneuploidies, specifically trisomy 21, trisomy 18, and trisomy 13, and for screening for SCAs in early pregnancy. [1][2][3][4] Since the first introduction of NIPT into clinical practice in Hong Kong and the USA in 2011, 5 NIPT has become widely used in the detection of fetal chromosomal aneuploidies on the basis that it reduces the need for invasive testing methods, such as amniocentesis and chorionic villus sampling. 6,7 Over the past few years, public healthcare systems have been implementing NIPT often as a contingent (second-tier) test after a high-risk assessment from the first-trimester test or integrated serum screening combined across the first and second trimester. ...
In recent years, as the implementation and use of NIPT have increased, the cost of the test has been decreasing. The cost of NIPT is expected to fall further in the upcoming years. As a result of the decreasing cost of NIPT, many jurisdictions may change their prenatal screening policies towards abandoning serum‐based screening and instead, implement and support NIPT as the first‐tier screening for all women. There are several concerns in replacing first‐trimester screening with NIPT. In this scoping review, we aimed to map the existing knowledge about possible issues in the systematic implementation of NIPT as the primary method of first‐tier screening, and to assess if any jurisdiction has altered its policy and discontinued serum based prenatal screening in exchange for NIPT. The Medline database (Ovid) and Google Scholar was searched and all the studies discussing, investigating, or reporting on the systematic implementation of NIPT as the primary method of first‐tier screening were included. All the studies went through a two‐stage screening process and included full‐text articles were reviewed and charted, and the data is summarized narratively and put in tables. Findings from this scoping review may be informative for stakeholders and policymakers regarding recent changes in NIPT implementation policies around the world and may aid with developing policy for NIPT implementation with a broader perspective. This article is protected by copyright. All rights reserved.
... 90 Currently, genome-wide cfDNA screening and single gene cfDNA screening are not available for twin pregnancies or other higher order multiple pregnancies. 91 Although cfDNA analysis has created an exciting new frontier of prenatal testing, it may not be available for all patients under all circumstances. ...
First-trimester septated cystic hygroma occurs in approximately 1 in 268 pregnancies and has long been associated with a markedly increased risk of fetal aneuploidy and, among euploid fetuses, an increased risk of structural anomalies primarily affecting the cardiac and skeletal systems. Invasive prenatal diagnosis – chorionic villus sampling and/or amniocentesis – encompasses the time-honored clinical tools for the next step in management following prenatal sonographic diagnosis of first-trimester septated cystic hygroma. Currently, prenatal cell-free DNA (cfDNA) screening for fetal aneuploidy with select microdeletions is gradually replacing the considerably less sensitive, and labor-intensive combined first-trimester screening. These new technologies have opened potential new venues in the clinical management of this ominous late first-trimester sonographic diagnosis. Advances in cfDNA technologies are now permitting detection of chromosomal copy number variants (CNV) larger than 7Mb across genome and select serious single-gene disorders (mainly impacting skeletal and neurological development), affecting quality of life and may benefit from medical and/or surgical management. This commentary will address the available non-invasive prenatal screening technologies, which clearly enhance immediate genetic analysis modalities applicable in the presence of the complex sonographic finding of first-trimester septated cystic hygroma.
Background/Objectives: Non-invasive prenatal testing (NIPT) has become a widely used method for screening common fetal aneuploidies due to its high sensitivity and specificity compared to traditional screening methods. With various NIPT technologies available, such as whole-genome sequencing (WGS), single nucleotide polymorphisms (SNPs), microarray, and rolling circle amplification (RCA), understanding the accuracy and reliability of each method is critical for clinical decision-making. However, comprehensive evaluations comparing the performance of these NIPT methods, especially in terms of predictive values for trisomy detection, remain limited. A systematic review of the difference in accuracy of the different NIPT methods used for common aneuploidy screening. Methods: A systematic review of former clinical studies using different NIPT methods, such as whole-genome sequencing (WGS), a targeted method of single nucleotide polymorphisms (SNPs), microarray and rolling circle amplification (RCA). We collected data from the PubMed, Embase, Web of Science, Scopus, clinicaltrials.gov, and Cochrane library from the last 20 years, between 2003 January and 2023 October, without any language, search filter or publication type restrictions. Results: Two authors selected twenty articles including twenty-one studies to perform the systematic review. In these studies, altogether 92,164 pregnant women were tested by genomics-based non-invasive prenatal testing (NIPT). We extracted data on true positive, false positive, false negative, and true negative values from each study, and calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) from them. We collected data regarding trisomy 21 (T21), trisomy 18 (T18) and trisomy 13 (T13) detection from all studies. Conclusions: As a conclusion, for the detection of common fetal trisomies, different methods of NIPT perform similarly in terms of clinical sensitivity, specificity and NPV. However, the tests utilizing SNP and RCA had lower PPV values than other NIPT methods. Our research indicates all NIPT methods showed greater sensitivity for the detection of T21, above 97%, than traditional screening tests. For T18 detection, the targeted method with the microarray had a lower sensitivity compared to other tests. The SNP and the microarray-based test had high PPV, whilst the other tests, utilizing WGS, and the test with RCA had quite low PPV. Regarding T13 detection, all of the tests performed similarly in terms of clinical sensitivity, specificity, PPV, and NPV (with one exception—one of the tests using WGS had lower PPV). According to these results, there was no significant difference between the methods of NIPT, such as WGS, SNPs, microarray, and RCA, used to detect common trisomies, but the variation in PPV underlines the importance of invasive tests to derive positive NIPT results. We suggest that NIPT combined with US screening for structural abnormalities could further improve the utility of the non-invasive tests in pregnancy. This is the first independent systematic review into the efficacy of the different NIPT methods.
Background
Klinefelter syndrome (KS) is an uncommonly recognised condition typified by gynaecomastia, small testes and aspermatogenesis. It is caused by a supernumerary X chromosome, resulting in a 47 XXY karyotype. Since its first description, the phenotype of KS has evolved and there is a much greater appreciation of the subtle features of the condition.
Method
In this review, we explore the phenotype of the KS with particular consideration to patients with pre‐natal and early infancy diagnosis, given that this is becoming increasingly common. The current understanding of the genetic mechanisms of KS, caused by supernumerary X chromosome are explored and the genotype‐phenotype correlation are discussed.
Results
The implications of the condition both in childhood and later development are explored in detail, with particular focus on social and educational implications. Potential treatments, with emphasis on preservation of fertility are discussed. We highlight the optimal therapeutic conditions in which fertility preservation is most likely to be achieved, compared to those which can be more challenging. Finally, we discuss the other health challenges which can be associated with KS. These include poor bone health, diabetes, cardiovascular complications, and malignancy. The challenges in managing these co‐morbid conditions and most up‐to‐date management recommendations are also explored.
Introduction
This Clinical Practical Guideline provides recommendations based on a systematic review of the evidence to address critical decision points in the management of pregnancy. The guideline is intended to improve patient outcomes and local management of patients who are pregnant. This CPG is based on a systematic review of both clinical and epidemiological evidence and was developed by a panel of multidisciplinary experts. The Work Group provides clear and comprehensive evidence-based recommendations incorporating current information and practices targeting practitioners throughout the DoD and VA Health Care systems. The guideline is intended to improve patient outcomes and local management of patients who are pregnant. This CPG does not address every aspect of routine pregnancy care and is not intended to be a comprehensive guide to all care needed in pregnancy. It also addresses some clinically important and generally accepted standards of pregnancy care interventions that do not have sufficient high-quality evidence to support standalone recommendations. Additionally, it highlights emerging topics that have the potential to impact pregnancy care in the future and identifies gaps in the literature that warrant further research.
Materials and Methods
The development of all VA/DoD guidelines is directed by the Evidence-Based Practice Guideline Work Group and adheres to the standards for trustworthy guidelines that were set by the National Academy of Medicine. A patient focus group was convened to assess important aspects of treatment for patients and to gain information about patient values and preferences. The Lewin Group, a contracted third party with expertise in CPG development, facilitated meetings and the development of key questions using the population, intervention, comparison, outcome, timing, and setting format. Consensus was achieved among the Work Group through an iterative process involving discussions on conference calls and in person during the recommendation development meeting. An independent third party, ECRI, conducted the systematic evidence review, which the guideline Work Group then used to develop recommendations using the Grading of Recommendations Assessment, Development and Evaluation system (7-9). The search methods and results are detailed in the full guideline.
Results
This CPG provides 28 clinical practice recommendations that cover selected topics that the Work Group deemed had high priority need for evidence-based standards. The recommendations are divided into 3 main categories: routine care, complicated obstetrics, and mental health. An algorithm delineating recommended interventions and appropriate timing of these interventions over the course of the pregnancy and postpartum period was also created.
Conclusion
The CPG is not intended to define standards of care nor address all care needed in pregnancy; it does provide comprehensive guidance for routine pregnancy care. It aligns with the VA and DOD’s goal of providing care that is consistent in quality and utilization of resources in efforts to reduce errors and inappropriate variations in practices. In total, the Work Group identified 71 items needing further study, including areas requiring stronger evidence to support current recommendations and newer topics that will guide future guideline development.
Sequencing technology enables prenatal screening by noninvasive detection of fetal health through cell-free fetal DNA in the mother’s circulation. This approach offers early diagnosis of genetic anomalies without invasive procedures, reducing risks to both mother and fetus. Noninvasive prenatal testing using sequencing has become a routine screening tool globally, facilitating accurate identification of chromosomal abnormalities. Ongoing research explores sequencing’s potential to detect a broader spectrum of genetic conditions, including rare diseases and structural abnormalities. Despite its promise, challenges remain, including standardization of protocols, quality control measures, and ethical considerations. Understanding the advantages and limitations of prenatal sequencing is crucial for individualized screening based on risk profiles. Continued innovation in sequencing technology holds the potential to enhance prenatal care, leading to improved outcomes for expectant parents and their babies.
Background:
Prenatal ultrasound is widely used to screen for structural anomalies before birth. While this is traditionally done in the second trimester, there is an increasing use of first-trimester ultrasound for early detection of lethal and certain severe structural anomalies.
Objectives:
To evaluate the diagnostic accuracy of ultrasound in detecting fetal structural anomalies before 14 and 24 weeks' gestation in low-risk and unselected pregnant women and to compare the current two main prenatal screening approaches: a single second-trimester scan (single-stage screening) and a first- and second-trimester scan combined (two-stage screening) in terms of anomaly detection before 24 weeks' gestation.
Search methods:
We searched MEDLINE, EMBASE, Science Citation Index Expanded (Web of Science), Social Sciences Citation Index (Web of Science), Arts & Humanities Citation Index and Emerging Sources Citation Index (Web of Science) from 1 January 1997 to 22 July 2022. We limited our search to studies published after 1997 and excluded animal studies, reviews and case reports. No further restrictions were applied. We also screened reference lists and citing articles of each of the included studies.
Selection criteria:
Studies were eligible if they included low-risk or unselected pregnant women undergoing a first- and/or second-trimester fetal anomaly scan, conducted at 11 to 14 or 18 to 24 weeks' gestation, respectively. The reference standard was detection of anomalies at birth or postmortem.
Data collection and analysis:
Two review authors independently undertook study selection, quality assessment (QUADAS-2), data extraction and evaluation of the certainty of evidence (GRADE approach). We used univariate random-effects logistic regression models for the meta-analysis of sensitivity and specificity.
Main results:
Eighty-seven studies covering 7,057,859 fetuses (including 25,202 with structural anomalies) were included. No study was deemed low risk across all QUADAS-2 domains. Main methodological concerns included risk of bias in the reference standard domain and risk of partial verification. Applicability concerns were common in studies evaluating first-trimester scans and two-stage screening in terms of patient selection due to frequent recruitment from single tertiary centres without exclusion of referrals. We reported ultrasound accuracy for fetal structural anomalies overall, by severity, affected organ system and for 46 specific anomalies. Detection rates varied widely across categories, with the highest estimates of sensitivity for thoracic and abdominal wall anomalies and the lowest for gastrointestinal anomalies across all tests. The summary sensitivity of a first-trimester scan was 37.5% for detection of structural anomalies overall (95% confidence interval (CI) 31.1 to 44.3; low-certainty evidence) and 91.3% for lethal anomalies (95% CI 83.9 to 95.5; moderate-certainty evidence), with an overall specificity of 99.9% (95% CI 99.9 to 100; low-certainty evidence). Two-stage screening had a combined sensitivity of 83.8% (95% CI 74.7 to 90.1; low-certainty evidence), while single-stage screening had a sensitivity of 50.5% (95% CI 38.5 to 62.4; very low-certainty evidence). The specificity of two-stage screening was 99.9% (95% CI 99.7 to 100; low-certainty evidence) and for single-stage screening, it was 99.8% (95% CI 99.2 to 100; moderate-certainty evidence). Indirect comparisons suggested superiority of two-stage screening across all analyses regarding sensitivity, with no significant difference in specificity. However, the certainty of the evidence is very low due to the absence of direct comparisons.
Authors' conclusions:
A first-trimester scan has the potential to detect lethal and certain severe anomalies with high accuracy before 14 weeks' gestation, despite its limited overall sensitivity. Conversely, two-stage screening shows high accuracy in detecting most fetal structural anomalies before 24 weeks' gestation with high sensitivity and specificity. In a hypothetical cohort of 100,000 fetuses, the first-trimester scan is expected to correctly identify 113 out of 124 fetuses with lethal anomalies (91.3%) and 665 out of 1776 fetuses with any anomaly (37.5%). However, 79 false-positive diagnoses are anticipated among 98,224 fetuses (0.08%). Two-stage screening is expected to correctly identify 1448 out of 1776 cases of structural anomalies overall (83.8%), with 118 false positives (0.1%). In contrast, single-stage screening is expected to correctly identify 896 out of 1776 cases before 24 weeks' gestation (50.5%), with 205 false-positive diagnoses (0.2%). This represents a difference of 592 fewer correct identifications and 88 more false positives compared to two-stage screening. However, it is crucial to acknowledge the uncertainty surrounding the additional benefits of two-stage versus single-stage screening, as there are no studies directly comparing them. Moreover, the evidence supporting the accuracy of first-trimester ultrasound and two-stage screening approaches primarily originates from studies conducted in single tertiary care facilities, which restricts the generalisability of the results of this meta-analysis to the broader population.
Background:
Noninvasive prenatal screening (NIPS) has shown good performance in screening common aneuploidies. However, its performance in detecting fetal sex chromosome aneuploidies (SCAs) needs to be evaluated in a large cohort.
Research design and methods:
In this retrospective observation, a total of 116,862 women underwent NIPS based on DNA nanoball sequencing from 2015 to 2022. SCAs were diagnosed based on karyotyping or chromosomal microarray analysis (CMA). Among them, 2,084 singleton pregnancies received karyotyping and/or CMA. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of NIPS for fetal SCAs were evaluated.
Results:
The sensitivity was 97.7% (95%CI, 87.7-99.9), 87.3% (95% CI, 76.5-94.4), 96.1% (95%CI, 86.5-99.5), and 95.7% (95% CI, 78.1-99.9), the PPV was 25.8% (95%CI, 19.2-33.2), 80.9% (95%CI, 69.5-89.4), 79.0% (95%CI, 66.8-88.3), and 53.7% (95%CI, 37.4-69.3) for 45,X, 47,XXY, 47,XXX, and 47,XYY, respectively. The specificity was 94.1% (95%CI, 93.0-95.1) for 45,X, and more than 99.0% for sex chromosome trisomy (SCT). The NPV was over 99.0% for all.
Conclusions:
NIPS screening for fetal SCAs has high sensitivity, specificity and NPV. The PPV of SCAs was moderate, but that of 45,X was lower than that of SCTs. Invasive prenatal diagnosis should be recommended for high-risk patients.
Неинвазивный пренатальный тест (НИПТ) – современный молекулярно-генетический метод, применяемый для скрининга хромосомной патологии у плода путем выделения и секвенирования свободно циркулирующих фрагментов ДНК плода и плаценты в крови матери (внеклеточная фетоплацентарная ДНК). НИПТ стал активно применяться в клинической практике сравнительно недавно – с начала прошлого десятилетия, в связи с чем нет единого мнения и решений этических вопросов, связанных с тестированием. Селекция пола, формирование спектра выявляемых рисков, медико-генетическое консультирование, дискриминация детей с хромосомными аномалиями и их родителей, «рутинизация» метода – основные этические проблемы, с которыми сталкиваются врачи различных специальностей и пациенты. Влияние результата НИПТ на репродуктивный выбор семейных пар сложно недооценить, поэтому применение теста в системе пренатального скрининга требует особого внимания, консультирования и участия специалистов разных областей медицины и не только.
Non-invasive prenatal testing (NIPT) is a molecular genetic method of assessing the risks of fetal chromosomal abnormalities from cell-free fetal DNA by isolating and sequencing cell-free fetal and placental DNA fragments in maternal blood (cell-free fetoplacental DNA). NIPT has been in use for the past decade, so as a consequence, there is still no consensus or solution regarding the ethical issues surrounding the testing. Gender selection, the range of risks assessed, genetic counseling, discrimination against children with chromosomal abnormalities and their parents, and the «routinization» of the method are the main ethical problems physicians of different specialties and patients face. The impact of NIPT results on the reproductive choices of couples is hard to underestimate, so the involvement of various medical and other specialists in the system of prenatal screening requires particular consultative attention and assistance.
This article provides an overview of Non-Invasive Prenatal Testing (NIPT), also known as noninvasive prenatal screening. It is a method of determining the risk that the fetus will be born with certain genetic abnormalities for pregnant women. The content is specifically tailored for pregnant women and encompasses a detailed exploration of topics such as Genomics-based noninvasive prenatal tests, sample details for noninvasive prenatal testing, factors influencing test results, the interpretation of test results, limitations associated with the test, and the content included in the Declaration of Consent Form for Noninvasive Prenatal Testing.
The purpose of this study was to determine direct and indirect costs of patients with trisomy (T) 13, 18, and 21 in Thailand. Direct medical costs were obtained from Siriraj Informatics and Data Innovation Center (SiData+), Faculty of Medicine, Siriraj Hospital, and indirect costs were estimated using a human capital approach. About 241 patients with T21 had outpatient care visits and 124 patients received inpatient care. For T13 and T18, five and seven patients were analyzed for outpatient and inpatient cares, respectively. For patients with T13, T18, and T21 receiving outpatient care, total annual mean direct medical costs ranged from 183.2 USD to 655.2 USD. For inpatient care, average yearly direct medical costs varied between 2,507 USD to 14,790 USD. The mean and median increased with age. In outpatient care, costs associated with drugs and medical devices were a major factor for both T13 and T21 patients, whereas laboratory costs were substantial for T18 patients. For inpatient care, costs of drug and medical devices were the greatest for T13 patients, while service fee and operation costs were the highest for T18 and T21 patients, respectively. For outpatient care, adult patients with congenital heart disease (CHD) had significantly higher mean annual direct medical costs than those without CHD. However, all adult and pediatric patients with CHD receiving inpatient care had significantly higher costs. Patients with T13, T18, and T21 had relative lifetime costs of 22,715 USD, 11,924 USD, and 1,022,830 USD, respectively.
Purpose
This study aimed to investigate the performance, cost-effectiveness and additional findings of combined detailed ultrasound and biochemical screening for risks of major fetal trisomies in the first-trimester.
Methods
This is a retrospective analysis study, we estimated the risk of trisomies 21, 18 and 13 based on maternal age, fetal nuchal translucency thickness, nasal bone, ductus venosus pulsatility index velocity, tricuspid regurgitation, fetal heart rate, free beta-human chorionic gonadotropin, and pregnancy-associated plasma protein A in singleton pregnant women, and performed non-invasive prenatal testing for women with risks of trisomy 21 between 1:500 and 1:300. Invasive diagnostic testing was performed for women with positive or failed non-invasive prenatal testing result and in the high-risk group of this screening method. The direct costs were compared between this strategy and the non-invasive prenatal testing which alone used as first-line screening for all pregnant women.
Results
Among 25,155 singleton pregnant women who underwent screening, 24,361 were available for analysis, of these, 194 cases underwent non-invasive prenatal testing. Among the 24,361 women, 39, 19, and 7 had trisomies 21, 18 and 13, respectively. The use of this strategy could potentially detect approximately 94.87% of trisomy 21 cases, 100% of trisomy 18 cases, and 100% of trisomy 13 cases, with false-positive rates of 2.49%, 0.41%, and 0.49%, respectively. The overall detection rate and overall false-positive rates were 96.92% and 2.52%, respectively. The detection rate was 100% in the advanced age group and 94.12% in the general age group. Additionally, structural abnormalities were detected in 137 fetuses, and 44 fetuses had other chromosomal abnormalities. The total cost of this strategy was 153.15. The total cost of using non-invasive prenatal testing as the first-line strategy would be 279.68.
Conclusions
Our strategy is an efficient and cost-effective approach for detecting major trisomies and identifying more fetuses with a potential abnormality. Therefore, this strategy is a valuable screening method and highly feasible in the clinical setting.
Every pregnant woman in the Spanish national health system is offered the option of controlling her pregnancy by means of prenatal screening. For women in a high-risk situation, non-invasive techniques for the detection of chromosomal aneuploidies are now available, which have the advantage of not endangering the life of the fetus, facilitating subsequent prenatal genetic diagnosis. However, despite the potential medical benefits for both pregnant women and fetuses, the widespread implementation of non-invasive prenatal testing (NIPT) raises a number of ethical issues. The objective of this work is to explore the ethical aspects derived from the implementation of the NIPT from the perspective of the main philosophical currents in bioethics and their implications for the health professional. In particular, it focus on the ethical aspects raised by the NIPT according to the major bioethical currents, the possible ethical dilemmas that the clinical advisor faces based on these currents and the requirements that genetic counseling for an ethical implementation of NIPT in clinical practice taking advantage of its advantages without violate human dignity.
Amaç: Cff-DNA’nın non-invazif tanı uygulamaları dışında, bu biyobelirtecin preeklampsi, IUGR, preterm doğum gibi önemli obstetrik komplikasyonları belirlemede yerini araştırmak. Yöntemler: Çalışmamız eylül 2019-mart 2020 tarihleri arasında, kliniğimize başvuran 10-24. Gebelik haftaları arasında kendi isteği, ileri anne yaşı olan (≥40) ve ikili testte artmış trizomi 13, 18 ve 21 riski nedeniyle serbest fetal DNA analizi (HarmonyTM Prenatal Test; Ariosa Diagnostics Inc., San Jose, Calif., USA) yapılan 131 hastalarda tek merkezli retrospektif çalışma olarak planlandı. Bulgular: Çalışmamızda hastaların 10’ unda (%8,1) oligohidramnios, 10’ unda (%8,1) gestasyonel diyabet, 7’ sinde de (%8,6) preeklampsi gözlenmiştir. 2 hastada da (%1,2) dekolman plasenta izlenmiştir. 10-24. gebelik haftaları arası ölçülen hücre dışı fetal DNA fraksiyonlarının artmış düzeyleri IUGR ile sonuçlanan gebelikleri öngörmede anlamlı bulunmuştur (p< 0.01). Diğer gebelik sonuçları ( preeklampsi, GDM, preterm eylem, oligohidroamnios, dekolman plasenta ) ve hücre dışı fetal DNA fraksiyon düzeyleri ile anlamlı ilişki bulunamamıştır. Sonuç: Cff-DNA’nın prenatal taramada bir dizi değerli uygulamaya sahiptir ancak gebelik komplikasyonlarını öngörmede cff-DNA’nın düzeyleri ile ilişkisi klinik uygulamada henüz yeri netleşmemiştir. Bu nedenle çalışmalar, cff-DNA’nın potansiyel öngörüsü ve tanısal uygulamalarını belirlemek için gebelikteki patolojik koşullar altındaki düzeylerinin belirlemesini amaçlamalıdır.
Linked article: This Correspondence comments on Maya et al. Click here to view the article.
Objective:
The screening performance of non-invasive prenatal testing (NIPT) in vanishing twin pregnancies is relatively unknown. To close this knowledge gap, we conducted a systematic review of available literature.
Method:
Studies describing the test performance of NIPT for trisomy 21, 18, 13, sex chromosomes and additional findings in pregnancies with a vanishing twin were retrieved from a literature search with a publication date until October 4th , 2022. The methodological quality of the studies was assessed with the quality assessment tool for diagnostic accuracy studies-2 (QUADAS- 2). The screen positive rate of the pooled data and the pooled positive predictive value (PPV) were calculated using a random effects model.
Results:
Seven studies, with cohort sizes ranging from 5 to 767, were included. The screen positive rate of the pooled data for trisomy 21 was 35/1592(2.2%), with a PPV of 20%(confirmation in 7/35 cases[95%CI 9.8%-36%]). For trisomy 18, the screen positive rate was 13/1592(0.91%) and the pooled PPV 25%[95%CI 1.3%-90%]. The screen positive rate for trisomy 13 was 7/1592(0.44%) and confirmed in 0/7 cases(pooled PPV 0%[95%CI 0%-100%]). The screen positive rate for additional findings as 23/767(2.9%), of which none could be confirmed. No discordant negative results were reported.
Conclusion:
There is insufficient data to fully evaluate NIPT performance in pregnancies with a vanishing twin. However, existing studies suggest that NIPT can successfully detect common autosomal aneuploidies in pregnancies affected by a vanishing twin, but with a higher false positive rate. Further studies are needed to determine the optimal timing of NIPT in vanishing twin pregnancies. This article is protected by copyright. All rights reserved.
Objective:
A rolling circle amplification (RCA) based commercial methodology using cell-free (cf)DNA to screen for common trisomies became available in 2018. Relevant publications documented high detection but with a higher than expected 1% false positive rate. Preliminary evidence suggested assay variability was an issue. A multi-center collaboration was created to explore this further and examine whether subsequent manufacturer changes were effective.
Methods:
Three academic (four devices) and two commercial (two devices) laboratories provided run date, chromosome 21, 18, and 13 run-specific standard deviations, number of samples run, and reagent lot identifications. Temporal trends and between-site/device consistency were explored. Proportions of run standard deviations exceeding pre-specified caps of 0.4%, 0.4% and 0.6% were computed.
Results:
Overall, 661 RCA runs between April 2019 and July 30, 2022 tested 39,756 samples. In the first 24, subsequent 9, and final 7 months, proportions of capped chromosome 21 runs dropped from 39% to 22% to 6.0%; for chromosome 18, rates were 76%, 36%, and 4.0%. Few chromosome 13 runs were capped using the original 0.60%, but capping at 0.50%, rates were 28%, 16%, and 7.6%. Final rates occurred after reformulated reagents and imaging software modifications were fully implemented across all devices. Revised detection and false positive rates are estimated at 98.4% and 0.3%, respectively. After repeat testing, failure rates may be as low as 0.3%.
Conclusion:
Current RCA-based screening performance estimates are equivalent to those reported for other methods, but with a lower test failure rate after repeat testing.
Noninvasive prenatal testing (NIPT) has revolutionized the screening methods for fetal chromosomal aneuploidies with high utility for aneuploidies for common chromosomes 13,18, 21, X and Y. Trisomy 13 is often associated with major and minor fetal malformations and can be screened by antenatal fetal scan and first- and second-trimester biochemical screening. We describe a case with high risk for trisomy 13 on NIPT, but without any fetal abnormalities on fetal scan. As recommended, follow-up invasive testing of amniotic fluid by chromosomal microarray detected a microduplication on chromosome 13, which has been associated with congenital microcoria. This case demonstrates the high sensitivity and clinical utility of NIPT in detecting rare copy number variations, which can assist families in making informed reproductive decisions. This also emphasizes that all screen positive NIPT cases should be confirmed with an appropriate diagnostic test by an invasive method.
Key points
What is already known about this topic?
In 2015, the International Society for Prenatal Diagnosis (ISPD) published its first position statement on the use of non‐invasive prenatal testing (NIPT) to screen for aneuploidy. Widespread uptake across the globe and subsequent published research has shed new light on test performance and implementation issues.
What does this study add?
This new position statement replaces the 2015 statement with updated information on the current technologies, clinical experience, and implementation practices.
As an international organization, ISPD recognizes that there are important population‐specific considerations in the organization of prenatal screening and diagnosis. These opinions are designed to apply to high income settings where prenatal screening for aneuploidy is an established part of antenatal care.
This position statement is not a clinical practice guideline but represents the consensus opinion of the current ISPD Board based on the current state of knowledge and clinical practice.
Noninvasive prenatal screening (NIPS), using placental cell-free DNA from a maternal blood sample, is currently the most sensitive and specific screening tool for detecting common fetal aneuploidies. The aim of this study was to compare the rates of "atypical" single nucleotide polymorphism (SNP)-based NIPS results and subsequent pregnancy outcomes between Arab American and non-Arab American patients. We conducted a retrospective cohort study of pregnant Arab and non-Arab American patients who had SNP-based NIPS performed between September 2018 and January 2021 at an urban health system in Michigan. The rate of "atypical" results and other perinatal outcomes were compared between groups using descriptive statistics. "Atypical" results due to multifetal gestations, either undisclosed or unknown at time of ordering, were excluded. Five thousand eight hundred and seventy-three patients underwent SNP-based NIPS: 771 (13.1%) were identified as Arab American, 5102 (86.9%) were non-Arab American, and 49 (0.8%) patients received "atypical" results. Arab patients represented only 13.1% of patients screened (771/5873) but had a significantly higher rate of "atypical" results than non-Arab American patients (17/771 [2.2%] vs. 32/5102 [0.6%]; p < 0.001). Of the 17 Arab patients with "atypical" results, 9 (52.9%) were in known consanguineous relationships. No major congenital anomalies or chromosomal aberrations were identified for any patients who had "atypical" results, and no significant differences in other perinatal outcomes were observed between Arab and non-Arab American patients. A better understanding of the association between consanguinity and "atypical" SNP-based NIPS results would aid in appropriate test selection and interpretation and may help physicians and genetic counselors provide better perinatal counseling and follow-up care for patients in consanguineous relationships.
Background:
Non-invasive prenatal testing (NIPT) using cell-free DNA (cfDNA) circulating in maternal blood provides a sensitive and specific screening technique for common fetal aneuploidies, but the high cost and workflow complexity of conventional methodologies limit its widespread implementation. A unique rolling circle amplification methodology reduces cost and complexity, providing a promising alternative for increased global accessibility as a first-tier test.
Methods:
In this clinical study, 8160 pregnant women were screened on the Vanadis system for trisomies 13, 18, and 21, and positive results were compared to clinical outcomes where available.
Results:
The Vanadis system yielded a 0.07% no-call rate, a 98% overall sensitivity, and a specificity of over 99% based on available outcomes.
Conclusion:
The Vanadis system provided a sensitive, specific, and cost-effective cfDNA assay for trisomies 13, 18, and 21, with good performance characteristics and low no-call rate, and it eliminated the need for either next-generation sequencing or polymerase chain reaction amplification.
The purpose of this study was to evaluate and identify the health-seeking behaviors, its associated factors, and the relationship between these factors to the health seeking behavior of young adults in Barangay Quiot Pardo, Cebu City. A sample size 332 respondents participated in the study. All the respondents were able to meet the inclusion criteria. The respondents were given likert-scale questionnaires online. Data were analyzed using SPSS. The findings of this study show that out of the 332 respondents, only 116 of those have sought treatment for their disease in the past 12 months. From the 332 young adults who participated in this study, the results showed that psychological, individual, and socio-cultural and familial factors have a significant relationship to the individual's decision to seek treatment during the period of disease while situational and marketing factors show no relationship to young adults' overall health-seeking behavior. The researchers conclude that psychological, individual, sociocultural and familial factors influence the health-seeking behaviors among young adults aging 20 to 24 years old residing in Barangay Quiot Pardo, Cebu City. The situational and marketing factors are less likely to affect the respondents' behavior.
Background:
Non-invasive prenatal testing (NIPT) has good screening performance for common chromosomes, but it may have false positive (FP) and false negative (FN) results for various reasons. For abnormal NIPT results, the combination of fetal ultrasound phenotypes will provide more fetal information for prenatal diagnosis. The aim of this study was to combine NIPT and ultrasound phenotypes to analyze their complementary roles in prenatal screening of fetal chromosome abnormalities.
Methods:
From January 2018 to December 2021, 12,803 pregnant women with singleton who successfully underwent NIPT/expanded NIPT (NIPT-Plus) at Xiangya Hospital of Central South University, of which 111 cases were positive results and one case was FN result. We retrospectively collected the clinical features, ultrasonographic findings, prenatal diagnosis, and pregnancy outcomes of these 112 pregnant women and analyzed the ultrasonic manifestations of different chromosomal abnormalities in detail.
Results:
The positive predictive values (PPVs) of NIPT/NIPT-Plus for trisomy (T)21, T18, sex chromosome abnormality (SCA), microdeletion/microduplication syndrome (MMS), T13, and rare autosomal trisomy (RAT) were 100.0%, 85.7%, 57.1%, 44.4%, 40.0%, and 7.7%, respectively. The total termination rates of pregnancy for T21, T18, T13, SCA, pathogenic MMS, and RAT were 93.5%, 100.0%, 100.0%, 66.7%, 100.0%, and 100.0%, respectively. From the karyotypes of SCA live-born fetuses, 47,XYY and 47,XXX were more likely to be selected for continued pregnancy. The ultrasound phenotypes of T21 were diverse, including normal, soft marker, and structural malformation. Both T18 and T13 had structural malformations as the main phenotypes. Most ultrasound phenotypes of FP T21, T18, and T13 were normal but occasionally manifested as fetal growth restriction (FGR). The ultrasound phenotypes of SCA, MMS, and RAT were relatively mild and manifested as normal, soft marker, FGR, or polyhydramnios, and the ultrasound phenotypes were similar between FP and true positive (TP) cases.
Conclusions:
Ultrasound phenotypes are helpful in identifying FP NIPT/NIPT-Plus results, especially for T18 and T13. Given its mild ultrasound phenotypes, NIPT-Plus has important clinical significance in reducing the missed diagnosis of SCA, MMS, and RAT, but its screening performance needs to be further improved.
The discovery of cell-free fetal DNA (cffDNA) in maternal blood and the rapid development of massively parallel sequencing have revolutionized prenatal testing from invasive to noninvasive. Noninvasive prenatal screening (NIPS) based on cffDNA enables the detection of fetal trisomy through sequencing, comparison, and bioassays. Its accuracy is better than that of traditional screening methods, and it is the most advanced clinical application of high-throughput sequencing technologies. However, the existing sequencing methods are limited by high costs and complex sequencing procedures. These limitations restrict the availability of NIPS for pregnant women. Many amplification methods have been developed to overcome the limitations of sequencing methods. The rapid development of non-sequencing methods has not been accompanied by reviews to summarize them. In this review, we initially describe the detection principles for sequencing-based NIPS. We summarize the rapidly evolving amplification technologies, focusing on the need to reduce costs and simplify the procedures. To ensure that the testing systems are feasible and that the testing processes are reliable, we expand our vision to the clinic. We evaluate the clinical validity of NIPS in terms of sensitivity, specificity, and positive predictive value. Finally, we summarize the application guidelines and discuss the corresponding quality control methods for NIPS. In addition to cffDNA, extracellular vesicle DNA, RNA, protein/peptide, and fetal cells can also be detected as biomarkers of NIPS. With the development of prenatal testing, NIPS has become increasingly important. Notably, NIPS is a screening test instead of a diagnostic test. The testing methods and procedures used in the NIPS process require standardization.
Objectives:
The aim was to determine the accuracy of cell free DNA testing (cfDNA) for detecting sex chromosome aneuploidies (SCA) in singleton pregnancies.
Methods:
A systematic review and meta-analysis was performed to assess cfDNA accuracy for prenatal detection of 45,X, 47,XXY, 47,XXX and 47,XYY. Inclusion was restricted to studies published between January 2010 and December 2021 reporting both cfDNA and confirmatory diagnostic test results.
Results:
For 45,X the sensitivity was 98.8% (95%CI 94.6%-100%), specificity 99.4% (95%CI 98.7%-99.9%), and positive predictive value (PPV) 14.5% (95%CI 7.0%-43.8%). For 47,XXY the sensitivity was 100% (95%CI 99.6%-100%), specificity 100% (95%CI 99.9%-100%), and PPV 97.7% (95%CI 78.6%-100%) . For 47,XXX the sensitivity was 100% (95%CI 96.9%-100%), specificity 99.9% (95%CI 99.7%-100%), and PPV 61.6% (95%CI 37.6%-95.4%). For 47,XYY the sensitivity was 100% (95%CI 91.3%-100%), specificity 100% (95% CI 100%-100%), and PPV 100% (95%CI 76.5%-100%) . All four SCAs had estimated negative predictive values (NPV) exceeding 99.99%, though false negatives were reported.
Conclusions:
This analysis suggests cfDNA is a reliable screening test for SCA, though both false negatives and false positives were reported. These estimates of test performance are derived from pregnancies at high pretest risk for aneuploidy, limiting the generalizability to average risk pregnancies. This article is protected by copyright. All rights reserved.
Recent data suggest that chromosome mosaicism is a possible mechanism for intrauterine and postnatal survival in cases of trisomy 18 and Turner syndrome (45X). The aim of this study was to evaluate if chromosomal mosaicism is a possible mechanism of survival in Down syndrome (DS) (trisomy 21) individuals. Mosaicism was studied by interphase fluorescence in-situ hybridization (FISH), using a specific probe for chromosome 21 (21q22.13–21q22.2) in 78 cases suspected of DS. To rule out tissue specific mosaicism, buccal cells or amniocytes were analysed in addition to blood in 20 DS cases. Thirty-three per cent of the cases studied by FISH in only peripheral blood were mosaics. In 20 cases of trisomy 21, two tissues were studied and mosaicism was not detected in either of the two tissues in 15 cases. The remaining five cases were mosaics in both the tissues analysed. Clinical comparisons in 17 DS mosaics showed a direct relationship between the percentage of trisomic cells and the degree of phenotypic manifestations. These results suggest that mechanism(s) other than mosaicism may exist for the intrauterine and postnatal survival of DS cases.
Background:
Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive and false negative screening tests (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have.
Objectives:
To estimate and compare the accuracy of first trimester ultrasound markers alone, and in combination with first trimester serum tests for the detection of Down's syndrome.
Search methods:
We carried out extensive literature searches including MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), and The Database of Abstracts of Reviews of Effects (the Cochrane Library 2011, Issue 7). We checked reference lists and published review articles for additional potentially relevant studies.
Selection criteria:
Studies evaluating tests of first trimester ultrasound screening, alone or in combination with first trimester serum tests (up to 14 weeks' gestation) for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.
Data collection and analysis:
Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses.
Main results:
We included 126 studies (152 publications) involving 1,604,040 fetuses (including 8454 Down's syndrome cases). Studies were generally good quality, although differential verification was common with invasive testing of only high-risk pregnancies. Sixty test combinations were evaluated formed from combinations of 11 different ultrasound markers (nuchal translucency (NT), nasal bone, ductus venosus Doppler, maxillary bone length, fetal heart rate, aberrant right subclavian artery, frontomaxillary facial angle, presence of mitral gap, tricuspid regurgitation, tricuspid blood flow and iliac angle 90 degrees); 12 serum tests (inhibin A, alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (ßhCG), total hCG, pregnancy-associated plasma protein A (PAPP-A), unconjugated oestriol (uE3), disintegrin and metalloprotease 12 (ADAM 12), placental growth factor (PlGF), placental growth hormone (PGH), invasive trophoblast antigen (ITA) (synonymous with hyperglycosylated hCG), growth hormone binding protein (GHBP) and placental protein 13 (PP13)); and maternal age. The most frequently evaluated serum markers in combination with ultrasound markers were PAPP-A and free ßhCG.Comparisons of the 10 most frequently evaluated test strategies showed that a combined NT, PAPP-A, free ßhCG and maternal age test strategy significantly outperformed ultrasound markers alone (with or without maternal age) except nasal bone, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). In both direct and indirect comparisons, the combined NT, PAPP-A, free ßhCG and maternal age test strategy showed superior diagnostic accuracy to an NT and maternal age test strategy (P < 0.0001). Based on the indirect comparison of all available studies for the two tests, the sensitivity (95% confidence interval) estimated at a 5% FPR for the combined NT, PAPP-A, free ßhCG and maternal age test strategy (69 studies; 1,173,853 fetuses including 6010 with Down's syndrome) was 87% (86 to 89) and for the NT and maternal age test strategy (50 studies; 530,874 fetuses including 2701 Down's syndrome pregnancies) was 71% (66 to 75). Combinations of NT with other ultrasound markers, PAPP-A and free ßhCG were evaluated in one or two studies and showed sensitivities of more than 90% and specificities of more than 95%.High-risk populations (defined before screening was done, mainly due to advanced maternal age of 35 years or more, or previous pregnancies affected with Down's syndrome) showed lower detection rates compared to routine screening populations at a 5% FPR. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under-ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting test sensitivity. Conversely, for the NT, PAPP-A, free ßhCG and maternal age test strategy, detection rates and false positive rates increased with maternal age in the five studies that provided data separately for the subset of women aged 35 years or more.
Authors' conclusions:
Test strategies that combine ultrasound markers with serum markers, especially PAPP-A and free ßhCG, and maternal age were significantly better than those involving only ultrasound markers (with or without maternal age) except nasal bone. They detect about nine out of 10 Down's affected pregnancies for a fixed 5% FPR. Although the absence of nasal bone appeared to have a high diagnostic accuracy, only five out of 10 affected Down's pregnancies were detected at a 1% FPR.
Background:
Down's syndrome occurs when a person has three copies of chromosome 21 (or the specific area of chromosome 21 implicated in causing Down's syndrome) rather than two. It is the commonest congenital cause of mental disability. Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing. Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal) and false negative screening tests (i.e. a fetus with Down's syndrome will be missed). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have.
Objectives:
To estimate and compare the accuracy of first and second trimester serum markers with and without first trimester ultrasound markers for the detection of Down's syndrome in the antenatal period, as combinations of markers.
Search methods:
We conducted a sensitive and comprehensive literature search of MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), the Database of Abstracts of Reviews of Effectiveness (the Cochrane Library 25 August 2011), MEDION (25 August 2011), the Database of Systematic Reviews and Meta-Analyses in Laboratory Medicine (25 August 2011), the National Research Register (Archived 2007), and Health Services Research Projects in Progress database (25 August 2011). We did not apply a diagnostic test search filter. We did forward citation searching in ISI citation indices, Google Scholar and PubMed 'related articles'. We also searched reference lists of retrieved articles SELECTION CRITERIA: Studies evaluating tests of combining first and second trimester maternal serum markers in women up to 24 weeks of gestation for Down's syndrome, with or without first trimester ultrasound markers, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.
Data collection and analysis:
Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses.
Main results:
Twenty-two studies (reported in 25 publications) involving 228,615 pregnancies (including 1067 with Down's syndrome) were included. Studies were generally high quality, although differential verification was common with invasive testing of only high risk pregnancies. Ten studies made direct comparisons between tests. Thirty-two different test combinations were evaluated formed from combinations of eight different tests and maternal age; first trimester nuchal translucency (NT) and the serum markers AFP, uE3, total hCG, free βhCG, Inhibin A, PAPP-A and ADAM 12. We looked at tests combining first and second trimester markers with or without ultrasound as complete tests, and we also examined stepwise and contingent strategies.Meta-analysis of the six most frequently evaluated test combinations showed that a test strategy involving maternal age and a combination of first trimester NT and PAPP-A, and second trimester total hCG, uE3, AFP and Inhibin A significantly outperformed other test combinations that involved only one serum marker or NT in the first trimester, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate. However, the evidence was limited in terms of the number of studies evaluating this strategy, and we therefore cannot recommend one single screening strategy.
Authors' conclusions:
Tests involving first trimester ultrasound with first and second trimester serum markers in combination with maternal age are significantly better than those without ultrasound, or those evaluating first trimester ultrasound in combination with second trimester serum markers, without first trimester serum markers. We cannot make recommendations about a specific strategy on the basis of the small number of studies available.
We evaluated performance characteristics of a laboratory-developed, non-invasive prenatal screening (NIPS) assay for fetal aneuploidies. This assay employs massively parallel shotgun sequencing with full automation. GC sequencing bias correction and statistical smoothing were performed to enhance discrimination of affected and unaffected pregnancies. Maternal plasma samples from pregnancies with known aneuploidy status were used for assay development, verification, and validation. Assay verification studies using 2,085 known samples (1873 unaffected, 69 trisomy 21, 20 trisomy 18, 17 trisomy 13) demonstrated complete discrimination between autosomal trisomy (Z scores >8) and unaffected (Z scores <4) singleton pregnancies. A validation study using 552 known samples (21 trisomy 21, 10 trisomy 18, 1 trisomy 13) confirmed complete discrimination. Twin pregnancies showed similar results. Follow-up of abnormal results from the first 10,000 clinical samples demonstrated PPVs of 98% (41/42) for trisomy 21, 92% (23/25) for trisomy 18, and 69% (9/13) for trisomy 13. Adjustment for causes of false-positive results identified during clinical testing (eg, maternal duplications) improved PPVs to 100% for trisomy 21 and 96% for trisomy 18. This NIPS test demonstrates excellent discrimination between trisomic and unaffected pregnancies. The PPVs obtained in initial clinical testing are substantially higher than previously reported NIPS methods.
Purpose:
Cell-free DNA (cfDNA) testing for fetal aneuploidies was broadly implemented for common trisomies and sex-chromosome anomalies (SCAs). However, such an approach identifies only 75 to 85% of clinically relevant aneuploidies.
Methods:
We present a consecutive series of 6,388 cases, thus uncovering a broader array of aneuploidies, including the rare autosomal trisomies (RATs) and the maternally inherited deletion and duplication copy-number variations (CNVs), with complete and stratified follow-up by amniocentesis. Combined measurements of z-scores and the fetal fraction, in conjunction with fetal cfDNA enrichment, were used to stratify the likelihood of true and false results.
Results:
We obtained an incremental diagnostic yield of 50%; RATs and CNVs were found to be significant causes of fetal pathology. Scrutinizing z-scores and the fetal fraction made it possible to distinguish the sources of false-negative results; predict the likelihood of false-positive results for major trisomies and SCAs; classify maternal mosaic SCAs and CNVs, preventing false-positive results; and robustly identify maternally inherited CNVs and detect recurrent genomic disorders as a standardized function of the fetal fraction.
Conclusion:
With the clinical pertinence of this broader detection scheme confirmed, we offer recommendations for its implementation.Genet Med advance online publication 30 June 2016Genetics in Medicine (2016); doi:10.1038/gim.2016.72.
Background:
Since its commercial release in 2011 cell-free DNA screening has been rapidly adopted as a routine prenatal genetic test. However, little is known about its performance in actual clinical practice.
Objective:
To investigate factors associated with the accuracy of abnormal autosomal cell- free DNA results.
STUDY DESIGN: Retrospective cohort study of 121 patients with abnormal cell-free DNA results from a referral maternal-fetal medicine practice from March 2013 to July 2015. Patients were included if cell-free DNA results for trisomy 21, trisomy 18, trisomy 13 , or microdeletions (if reported by the laboratory) were positive or non-reportable. The primary outcome was confirmed aneuploidy or microarray abnormality on either prenatal or postnatal karyotype or microarray. Secondary outcomes were identifiable associations with in vitro fertilization, twins, ultrasound findings, testing platform, and testing laboratory. Kruskal-Wallis or Fisher's exact tests were used as appropriate.
Results:
121 patients had abnormal cell-free DNA results for for trisomy 21, trisomy 18, trisomy 13, and/or microdeletions. 105 patients had abnormal cell-free DNA results for for trisomy 21, trisomy 18, trisomy 13. Of these, 92 (87.6%) were positive and 13 (12.4%) were non-reportable. The results of the 92 positive cell-free DNA were for trisomy 21 (48, 52.2%), trisomy 18 (22, 23.9%), trisomy 13 (17, 18.5%), triploidy (2, 2.2%), and positive for >1 parameter (3, 3.3%). Overall, the positive predictive value of cell-free DNA was 73.5% (61/83, 95% confidence interval (CI) 63% to 82%) for all trisomies (by chromosome: trisomy 21, 83.0% (39/47, CI 69% to 92%, trisomy 18, 65.0% (13/20, CI 41% to 84%), and trisomy 13, 43.8% (7/16, CI 21% to 70%). Abnormal cell-free DNA results were associated with positive serum screening (by group: trisomy 21 17/48, 70.8%; trisomy 18 7/22, 77.8%; trisomy 13 3/17, 37.5%; non-reportable 2/13, 16.7%; p=0.004), and abnormal first trimester ultrasound (trisomy 21 25/45, 55.6%; trisomy 18 13/20, 65%; trisomy 13 6/14, 42.9%; non-reportable 1/13, 7.7%; p=0.003). There was no association between false positive rates and testing platform, but there was a difference between the four laboratories (p=0.018). Twenty-six patients had positive (n=9) or non-reportable (n=17) microdeletion results. Seven of nine screens positive for microdeletions underwent confirmatory testing; all were false positives.
CONCLUSIONS: The positive predictive value of 73.5% for cell-free DNA screening for autosomal aneuploidy is lower than reported. The positive predictive value for microdeletion testing was 0%. Diagnostic testing is needed to confirm abnormal cell-free DNA results for aneuploidy and microdeletions.
Objective:
The aim of this study was to validate noninvasive prenatal testing (NIPT) for fetal aneuploidies by whole-genome massively parallel sequencing (MPS).
Methods:
MPS was performed on cell-free DNA (cfDNA) isolated from maternal plasma in two groups: a first set of 186 euploid samples and a second set of 195 samples enriched of aneuploid cases (n = 69); digital PCR for fetal fraction (FF) assessment was performed on 178/381 samples. Cases with <10 × 10(6) reads (n = 54) were excluded for downstream data analysis. Follow-up data (invasive testing results or neonatal information) were available for all samples. Performances in terms of specificity/sensitivity and Z-score distributions were evaluated.
Results:
All positive samples for trisomy 21 (T21) (n = 43), trisomy 18 (T18) (n = 6) and trisomy 13 (T13) (n = 7) were correctly identified (sensitivity: 99.9%); 5 false positive results were reported: 3 for T21 (specificity = 98.9%) and 2 for T13 (specificity = 99.4%). Besides FF, total cfDNA concentration seems another important parameter for MPS, since it influences the number of reads.
Conclusions:
The overall test accuracy allowed us introducing NIPT for T21, T18 and T13 as a clinical service for pregnant women after 10 + 4 weeks of gestation. Sex chromosome aneuploidy assessment needs further validation due to the limited number of aneuploid cases in this study.
Objective:
To report the performance of noninvasive prenatal testing (NIPT) in twin pregnancies after the treatment of assisted reproductive technology (ART).
Method:
In two years period, 565 pregnant women with ART twin pregnancies were prospectively tested by NIPT for screening for trisomy 21 (T21), 18 (T18) and 13 (T13) by sequencing cell-free DNA in maternal plasma. Positive NIPT results were confirmed by karyotyping, while negative results were interviewed after delivery. Pregnant decision based on NIPT and confirmation results was discussed during post-test counseling.
Results:
In total of 565 cases, NIPT had a failure rate of 0.9% (5/565). Four cases of T21 were identified by NIPT and confirmed by karyotyping, resulting in 100% (95%CI 39.8%-100%) positive predictive value (PPV). Among 556 cases with NIPT negative results, 506 cases (91.0%) were confirmed by follow-up of postnatal phenotypes, while 33 cases (5.9%) had adverse pregnant outcomes with unconfirmed reasons due to the lack of cytogenetic samples. The remaining 17 cases (3.1%) refused follow-up. No false negative result was reported.
Conclusion:
With apparently high PPV and low false positive rate, NIPT has the potential to be used as a good alternative approach of conventional prenatal screening at the first trimester in ART twin pregnancy. This article is protected by copyright. All rights reserved.
Background:
Noninvasive prenatal testing (NIPT) to detect fetal aneuploidy using next-generation sequencing on ion semiconductor platforms has become common. There are several sequencers that can generate sufficient DNA reads for NIPT. However, the approval criteria vary among platforms and countries. This can delay the introduction of such devices and systems to clinics. A comparison of the sensitivity and specificity of two different platforms using the same sequencing chemistry could be useful in NIPT for fetal chromosomal aneuploidies. This would improve healthcare authorities' confidence in decision-making on sequencing-based tests.
Methods:
One hundred and one pregnant women who were predicted at high risk of fetal defects using conventional prenatal screening tests, and who underwent definitive diagnosis by full karyotyping, were enrolled from three hospitals in Korea. Most of the pregnant women (69.79 %) received NIPT during weeks 11-13 of gestation and 30.21 % during weeks 14-18. We used Ion Torrent PGM and Proton semi-conductor-based sequencers with 0.3× sequencing coverage depth. The average total reads of 101 samples were approximately 4.5 and 7.6 M for PGM and Proton, respectively. A Burrows-Wheeler Aligner (BWA) algorithm was used for the alignment, and a z-score was used to decide fetal trisomy 21. Interactive dot diagrams from the sequencing data showed minimal z-score values of 2.07 and 2.10 to discriminate negative versus positive cases of fetal trisomy 21 for the two different sequencing systems.
Results:
Our z-score-based discrimination method resulted in 100 % positive and negative prediction values for both ion semiconductor PGM and Proton sequencers, regardless of their sequencing chip and chemistry differences. Both platforms performed well at an early stage (11-13 weeks of gestation) compared with previous studies.
Conclusions:
These results suggested that, using two different sequencers, NIPT to detect fetal trisomy 21 in early pregnancy is accurate and platform-independent. The data suggested that the amount of sequencing and the application of common, simple, and robust statistical analyses are more important than sequencing chemistry and platform types. This result has practical implications in countries where PGM is approved for NIPT but the Proton system is not.
Objective:
The aim of this study was to evaluate clinical use of NIPT at gestational ages of 23 weeks and above.
Methods:
A cohort of 5579 clinical patients with singleton gestations of 23 weeks or greater submitting a blood sample for NIPT in an 18-month period were selected for this study. Clinical outcomes were requested for samples with NIPT results indicating fetal aneuploidy and compared with NIPT findings to confirm concordance or discordance.
Results:
A review of clinical indications revealed that a significantly (p < 0.0001) larger proportion of late-gestation samples indicated abnormal ultrasound findings with or without other indications, 6.2% and 42.1%, compared with early-gestation samples, 1.8% and 6.0%, respectively. Of 5372 reported late-gestation samples, 151 (2.8%) were reported as aneuploidy detected or suspected. In late-gestation samples, the overall observed positive predictive value (PPV) for NIPT was 64.7%, with an observed PPV of 100% in the subset of cases with multiple clinical indications including abnormal ultrasound findings.
Conclusions:
NIPT is a highly accurate prenatal screening option for women after 23 weeks of gestation. Women who presented for NIPT in the latter stages of pregnancy more frequently specified clinical indications of abnormal ultrasound findings than women who entered screening earlier in pregnancy.
Background:
There is great need for the development of highly accurate cost effective technologies that could facilitate the widespread adoption of noninvasive prenatal testing (NIPT).
Methods:
We developed an assay based on the targeted analysis of cell-free DNA for the detection of fetal aneuploidies of chromosomes 21, 18, and 13. This method enabled the capture and analysis of selected genomic regions of interest. An advanced fetal fraction estimation and aneuploidy determination algorithm was also developed. This assay allowed for accurate counting and assessment of chromosomal regions of interest. The analytical performance of the assay was evaluated in a blind study of 631 samples derived from pregnancies of at least 10 weeks of gestation that had also undergone invasive testing.
Results:
Our blind study exhibited 100% diagnostic sensitivity and specificity and correctly classified 52/52 (95% CI, 93.2%-100%) cases of trisomy 21, 16/16 (95% CI, 79.4%-100%) cases of trisomy 18, 5/5 (95% CI, 47.8%-100%) cases of trisomy 13, and 538/538 (95% CI, 99.3%-100%) normal cases. The test also correctly identified fetal sex in all cases (95% CI, 99.4%-100%). One sample failed prespecified assay quality control criteria, and 19 samples were nonreportable because of low fetal fraction.
Conclusions:
The extent to which free fetal DNA testing can be applied as a universal screening tool for trisomy 21, 18, and 13 depends mainly on assay accuracy and cost. Cell-free DNA analysis of targeted genomic regions in maternal plasma enables accurate and cost-effective noninvasive fetal aneuploidy detection, which is critical for widespread adoption of NIPT.
Objective:
To validate an updated version (Version 2) of a single-nucleotide polymorphism (SNP)-based noninvasive prenatal test (NIPT) and to determine the likelihood of success when testing for fetal aneuploidies following a redraw.
Methods:
Version 2 was analytically validated using 587 plasma samples with known genotype (184 trisomy 21, 37 trisomy 18, 15 trisomy 13, 9 monosomy X, 4 triploidy and 338 euploid). Sensitivity, specificity and no-call rate were calculated, and a fetal-fraction adjustment was applied to enable projection of these values in a commercial distribution. Likelihood of success of a second blood draw was computed based on fetal fraction and maternal weight from the first draw.
Results:
Validation of this methodology yielded high sensitivities (≥99.4%) and specificities (100%) for all conditions tested with an observed no-call rate of 2.3%. The no-call threshold for sample calling was reduced to 2.8% fetal fraction. The redraw success rate was driven by higher initial fetal fractions and lower maternal weights, with the fetal fraction being the more significant variable.
Conclusions:
The enhanced version of this SNP-based NIPT method showed a reduced no-call rate and a reduced fetal-fraction threshold for sample calling in comparison to the earlier version, while maintaining high sensitivity and specificity.
Background:
Current cell-free DNA assessment of fetal chromosomes does not analyze and report on all chromosomes. Hence, a significant proportion of fetal chromosomal abnormalities are not detectable by current noninvasive methods. Here we report the clinical validation of a novel noninvasive prenatal test (NIPT) designed to detect genomewide gains and losses of chromosomal material ≥7 Mb and losses associated with specific deletions <7 Mb.
Objective:
The objective of this study is to provide a clinical validation of the sensitivity and specificity of a novel NIPT for detection of genomewide abnormalities.
Study design:
This retrospective, blinded study included maternal plasma collected from 1222 study subjects with pregnancies at increased risk for fetal chromosomal abnormalities that were assessed for trisomy 21 (T21), trisomy 18 (T18), trisomy 13 (T13), sex chromosome aneuploidies (SCAs), fetal sex, genomewide copy number variants (CNVs) ≥7 Mb, and select deletions <7 Mb. Performance was assessed by comparing test results with findings from G-band karyotyping, microarray data, or high coverage sequencing.
Results:
Clinical sensitivity within this study was determined to be 100% for T21 (95% confidence interval [CI], 94.6-100%), T18 (95% CI, 84.4-100%), T13 (95% CI, 74.7-100%), and SCAs (95% CI, 84-100%), and 97.7% for genomewide CNVs (95% CI, 86.2-99.9%). Clinical specificity within this study was determined to be 100% for T21 (95% CI, 99.6-100%), T18 (95% CI, 99.6-100%), and T13 (95% CI, 99.6-100%), and 99.9% for SCAs and CNVs (95% CI, 99.4-100% for both). Fetal sex classification had an accuracy of 99.6% (95% CI, 98.9-99.8%).
Conclusion:
This study has demonstrated that genomewide NIPT for fetal chromosomal abnormalities can provide high resolution, sensitive, and specific detection of a wide range of subchromosomal and whole chromosomal abnormalities that were previously only detectable by invasive karyotype analysis. In some instances, this NIPT also provided additional clarification about the origin of genetic material that had not been identified by invasive karyotype analysis.
Noninvasive prenatal testing (NIPT) has marked a revolution in aneuploidy screening because it allows a simple maternal blood test to detect trisomy 21, 18 and 13 in a foetus with a very high level of accuracy. After one year of NIPT utilisation with 683 samples, we analyzed retrospectively the performance of the test for 2014 : 3 positive samples (2 trisomies 21 and 1 trisomy 18) were correctly detected (100% sensitivity) and no foetal aneuploidy was missed for the pregnancies having already resulted in delivery by decembre 2014 (280 true negatif, 100% specificity). However, the additionnally available analysis of the sex chromosomes resulted in 2 erronous results: 1 uncorrect sex determination (1 male resulting in a female phenotype at birth) and 1 result suggesting a Turner syndrome was not confirmed by amniocentesis. The failure rate leading to a resampling was at 1.46% (10/683). The test used was the NIFTY of the BGI laboratory in Hong-Kong. By comparison to the year 2013, the utilisation of NIPT lead to a significant diminution of invasive samples performed by amniocentesis or choriocentesis 144 vs. 239 (- 63%). We confirmed that NIPT is a high-performance tool for the screening of the main foetal aneuploidies and report that during its first year of utilisation, 63% of invasive samples collected could be avoided. The test is expensive, not reimboursed by Luxembourg social security and therefore prohibitive for a number of women and their families.
Several existing unconditional methods for setting confidence intervals for the difference between binomial proportions are evaluated. Computationally simpler methods are prone to a variety of aberrations and poor coverage properties. The closely interrelated methods of Mee and Miettinen and Nurminen perform well but require a computer program. Two new approaches which also avoid aberrations are developed and evaluated. A tail area profile likelihood based method produces the best coverage properties, but is difficult to calculate for large denominators. A method combining Wilson score intervals for the two proportions to be compared also performs well, and is readily implemented irrespective of sample size. © 1998 John Wiley & Sons, Ltd.
Objective:
To review clinical validation or implementation studies of maternal blood cell-free (cf) DNA analysis and define the performance of screening for fetal trisomies 21, 18 and 13 and sex chromosome aneuploidies.
Methods:
Searches of PubMed, EMBASE and The Cochrane Library were performed to identify all peer-reviewed articles on cfDNA testing in screening for aneuploidies between January 2011, when the first such study was published, and 4 January 2015.
Results:
In total, 37 relevant studies were identified and these were used for the meta-analysis on the performance of cfDNA testing in screening for aneuploidies. These studies reported cfDNA results in relation to fetal karyotype from invasive testing or clinical outcome. Weighted pooled detection rates (DR) and false-positive rates (FPR) in singleton pregnancies were 99.2% (95% CI, 98.5-99.6%) and 0.09% (95% CI, 0.05-0.14%), respectively, for trisomy 21, 96.3% (95% CI, 94.3-97.9%) and 0.13% (95% CI, 0.07-0.20) for trisomy 18, 91.0% (95% CI, 85.0-95.6%) and 0.13% (95% CI, 0.05-0.26%) for trisomy 13, 90.3% (95% CI, 85.7-94.2%) and 0.23% (95% CI, 0.14-0.34%) for monosomy X and 93.0% (95% CI, 85.8-97.8%) and 0.14% (95% CI, 0.06-0.24%) for sex chromosome aneuploidies other than monosomy X. For twin pregnancies, the DR for trisomy 21 was 93.7% (95% CI, 83.6-99.2%) and the FPR was 0.23% (95% CI, 0.00-0.92%).
Conclusion:
Screening for trisomy 21 by analysis of cfDNA in maternal blood is superior to that of all other traditional methods of screening, with higher DR and lower FPR. The performance of screening for trisomies 18 and 13 and sex chromosome aneuploidies is considerably worse than that for trisomy 21.
Unlabelled:
Prenatal screening by definition is a way of identifying pregnancies, with a high enough risk to specific fetal damage as to justify the subsequent invasive diagnosis among the seemingly normal pregnancies. [1] The aim of the prenatal screening test is to reach the high diagnostic frequency (DR > 95%), with low false-positive rate (FPR < 1%). Several non-invasive prenatal tests (NIPT) are widely adopted and use in clinical practice: 1st Trimester Combined screening (First trimester Combined Screening) and 2nd trimester biochemical screening (Second trimester biochemical screening) and in the last few years through screening Fetal DNA in Maternal serum (cfDNA screening). Since the introduction of the sfDNA test were examined and discussed the results of several ways of application: (1) as a primary screening method without preceding the result of 1st trimester combined screening for chromosomal abnormalities, (2) as a contingent test after 1st trimester combined screening in high risk pregnancies (> 1:100) (3) as a contingent test after 1st trimester combined screening, when the calculated risk is between ( 1:10 to 1:2500). The purpose of the study: to compare the results of different ways of application screening through cfDNA: detection rate (DR) for Tri21, Tri18 and Tri13, procentage of invasive diagnostics and cost-effectiveness ratio of cfDNA test in comparison with the 1st trimester combined screening. To establish the most suitable algorithm for application of cfDNA test.
Methods and materials:
Analyzed were the results of several randomized multi-center clinical studies whose data are processed through a meta-analysis.
Results:
cfDNA-test has a higher DR for Tri21 for lower FPR, compared to the combined screening in 1st trimester (cfDNA-DR 99%, 1st trimester screening-DR 96% and 0.4%FPR, respectively FPR 5%), but although it is with better results and reduces the incidence of invasive tests, does not justify the significant difference in price-performance ratio. On the other hand cfDNA-test is with a lower detection rate for Tri 18 or 13 (93-95%), which makes it worse for a primary screening test instead of combined screening in the 1st trimester.
Conclusions:
The performance of cfDNA-test in terms of the three most common Trisomies: 21,18 and 13 is highest when used after (contingent to) 1st trimester screening and only for patients with an intermediate risk from 1-st trimester screening (risk > 1:10 and 1:2500, around 27% of all pregnancies), as it increases the diagnostic rate of combined screening for Down syndrome (from 90% to 98%), and significantly reduces the percentage of invasive diagnostics (from 3% to 0.7-1%) and that way we are able to achieve optimal result in price-performance result.
(Abstracted from Prenat Diagn 2017;37:515–520)
Noninvasive prenatal testing (NIPT) using cell-free DNA (cfDNA) technology has been shown to accurately detect trisomy 21, as well as fetal sex in the first trimester. The predictive values of NIPT for other aneuploidies such as sex chromosome aneuploidy (SCA) are not as well understood.
(Abstracted from Am J Obstet Gynecol 2016;214:727.e1–727.e6)
Cell-free DNA (cfDNA) screening has shown high sensitivities and specificities for trisomy 21 and other common aneuploidies, thereby leading to a consideration for its use as a primary screening test. However, it has limitations, including the limited range of targeted aneuploidies and the failure to always provide a result.
Objective:
To evaluate the impact of ovarian stimulation on the outcome of intrauterine insemination (IUI).
Design:
Retrospective analysis.
Setting:
A single university-based centre.
Population:
A total of 5109 couples with 8893 cycles.
Methods:
The outcome of IUI with different protocols for ovarian stimulation was examined.
Main outcome measures:
The live birth rate (LBR), twin pregnancy rate and ovarian hyperstimulation syndrome (OHSS).
Results:
In ovulatory women without ovarian stimulation, the LBR was 7.6%. Stimulation with clomifene citrate (CC), letrozole (LE), human menopausal gonadotrophin (HMG), CC or LE combined with HMG achieved LBRs of 6.1, 5, 7.9, 8 and 12.2%, respectively. LE combined with HMG achieved a significantly improved LBR compared with no stimulation. HMG stimulation was associated with a higher rate of twins (7.4%) than no stimulation (0%, P < 0.01). In ovulatory women, the LBR appeared lower in CC and LE compared with no stimulation (P > 0.05). In anovulatory women, ovarian stimulation with CC, LE, HMG, CC or LE combined with HMG achieved LBRs of 11.3, 5.1, 11.8, 12.6 and 13.6%, respectively. No significant difference was observed. There were no triplet pregnancies or OHSS in stimulated cycles.
Conclusions:
In ovulatory women, ovarian stimulation with LE combined with HMG achieved a significantly improved live birth rate. HMG stimulation resulted in a high risk for twins.
Tweetable abstract:
In ovulatory women, ovarian stimulation with letrozole and HMG resulted in a significantly improved LBR.
Background Harmony™ Prenatal Test uses an assay method, Digital Analysis of Selected Regions (DANSR™), for analysis of chromosomes 13, 18, 21, X and Y as well as other chromosomes to measure fetal fraction (FF). Products from the DANSR assay are then analysed with Fetal fraction Optimised Risk of Trisomy Evaluation (FORTE™) algorithm to assess patient-specific risk of trisomy. Alternative tests, such as those using massively parallel shotgun sequencing, use a Z-statistic or Normalised Chromosome Value (NCV) to discriminate between normal and abnormal chromosomal counts without accounting for FF.
Methods A general pregnancy population cohort of 15,841 women between 10.0 to 14.3 weeks gestation were followed to pregnancy outcome. Z-statistics were computed using previously described standard Z-test of proportions and compared to FORTE risk scores generated by Harmony. A Z-statistic of ≥3 was ‘Positive’ for trisomy and a FORTE risk score of ≥1% was ‘High Risk’ for trisomy.
Results See Table 1. Cumulative test discordant rate for non-trisomies with FORTE was 0.08% compared to 1.07% with Z-statistic.
Conclusion Analysis using FORTE to incorporate FF in cfDNA testing yields >10 fold reduction in discordant results This will become increasingly relevant as cfDNA testing gets more broadly used in the general pregnancy population.
Objective:
To evaluate a new ultrahigh throughout NIPT method based on combinatorial probe-anchor ligation sequencing (cPAL) of cell-free fetal DNA (cffDNA) for clinical validity using a centralized testing mode.
Methods:
To ensure the stable and reproducible performance of centralized cPAL-based NIPT in detecting trisomy 21/18/13, series of quality control system including two sets of artificial samples were employed and evaluated. 10594 singleton pregnancies were enrolled from 20 centers in China, including 8155 retrospective and 2439 prospective cases from high-risk populations. Fetal outcome data and karyotyping results were documented as gold standard and double blind during NIPT testing. The clinical performance of this ultra-high throughout sequencer for NIPT was validated by sensitivity, specificity, and positive predictive rate (PPV) in detecting trisomy 21/18/13 as a centralized testing mode in the reference laboratory.
Results:
Ten cases were excluded from the study because of incomplete clinical information. Four cases in prospective samples failed to generate NIPT results due to assay failure, presenting a failure rate of 0.16% (4/2429). A total of 168 and 47 NIPT positive cases were identified in retrospective and prospective group, giving a positive rate of 2.06% and 1.94%, respectively. Four false positive cases and no false positive case were observed in the retrospective and prospective group, resulting in PPV of 98.14% (95%CI, 96.33-99.95%) and 100 % (95%CI, 92.45-100%), respectively. In retrospective group, sensitivity and specificity were 100% (95%CI, 97.07%-100%) and 99.98%(95%CI, 99.94%-100%), respectively, for T21, 100%(95%CI, 97.75%-100%) and 99.98%(95%CI, 99.94%-100%) for T18, 100%(95%CI, 15.81%-100%) and 100%(95%CI, 99.95%-100%) for T13. In prospective group, sensitivity and specificity were 100% (95%CI, 90.75%-100%) and 100%(95%CI, 99.85%-100%), respectively, for T21, 100%(95%CI, 63.06%-100%) and 100%(95%CI, 99.85%-100%) for T18, 100%(95%CI, 2.50%-100%) and 100%(95%CI, 99.85%-100%) for T13.
Conclusions:
In this multicenter study, with full quality control system, sample centralized testing using cPAL-based NIPT showed high stability and comparable performance to previous validation studies in high-risk population.
Non-invasive prenatal testing (NIPT) based on cell-free DNA in maternal plasma is being expanded to include additional chromosome abnormalities beyond those involving chromosomes 21, 18, 13, X and Y. Review of population cytogenetic data provides insight into the likely number of additional abnormalities detectable. Additional clinically significant and cytogenetically recognizable abnormalities are present in less than 0.1% of newborns but clinically significant, or potentially significant, sub-microscopic imbalances are expected to be present in 1.7%. Cytogenetic studies on chorionic villus samples suggests that after excluding abnormalities involving chromosomes 21, 18, 13, X and Y, approximately 0.6% of NIPT results may be positive for an unbalanced abnormality attributable to mosaicism but most of these will not be confirmed at amniocentesis or in newborns. NIPT has also been developed for specific microdeletion syndromes and initial experience is now available. Laboratory procedures such as deeper sequencing and additional data analytics are rapidly evolving but even with existing protocols, it is already clear that NIPT does not necessarily need to be limited to trisomies 21, 18, 13 and the sex chromosome abnormalities. Patient educational materials and genetic counselling services need to be available for women offered expanded NIPT.
Objectives:
First, to examine in twin pregnancies the performance of first-trimester screening for fetal trisomies 21, 18 and 13 by cell-free (cf) DNA testing of maternal blood and, second, to compare twin and singleton pregnancies regarding the distribution of fetal fraction of cfDNA and rate of failure to obtain a result.
Methods:
This was a prospective study in 438 twin and 10 698 singleton pregnancies undergoing screening for fetal trisomies by cfDNA testing at 10 + 0 to 13 + 6 weeks' gestation. Chromosome-selective sequencing of cfDNA was used and, in twin pregnancies, an algorithm was applied that relies on the lower fetal fraction contributed by the two fetuses. Multivariate regression analysis was used to determine significant predictors of fetal fraction and a failed result.
Results:
In twin pregnancies, the median fetal fraction was lower (8.0% (interquartile range (IQR), 6.0-10.4%) vs 11.0% (IQR, 8.3-14.4%); P < 0.0001) and failure rate after first sampling was higher (9.4% vs 2.9%; P < 0.0001) compared to in singletons. Multivariate logistic regression analysis demonstrated that the risk of test failure increased with increasing maternal age and body mass index and decreased with fetal crown-rump length. The risk was increased in women of South Asian racial origin and in pregnancies conceived by in-vitro fertilization (IVF). The main contributor to the higher rate of failure in twins was conception by IVF which was observed in 9.5% of singletons and 56.2% of twins. In the 417 twin pregnancies with a cfDNA result after first or second sampling, the detection rate was 100% (8/8) for trisomy 21 and 60% (3/5) for trisomies 18 or 13, at a false-positive rate (FPR) of 0.25% (1/404). In the 10 530 singleton pregnancies with a cfDNA result after first or second sampling, the detection rate was 98.7% (156/158) for trisomy 21 and 80.3% (49/61) for trisomies 18 or 13, at a FPR of 0.22% (23/10 311).
Conclusions:
In twin pregnancies undergoing first-trimester screening for trisomies by cfDNA testing, the fetal fraction is lower and failure rate higher compared to in singletons. The number of trisomic twin pregnancies examined was too small for an accurate assessment of performance of screening, but it may be similar to that in singleton pregnancies. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
Background:
Cell-free fetal DNA (cffDNA) non-invasive prenatal testing (NIPT) is rapidly expanding, and is being introduced at varying rates depending on country and condition.
Objectives:
Determine accuracy of cffDNA-based NIPT for all conditions. Evaluate influence of other factors on test performance.
Search strategy:
Medline, Embase, CINAHL, Cochrane Library, from 1997 to April 2015.
Selection criteria:
Cohort studies reporting cffDNA-based NIPT performance in singleton pregnancies.
Data collection and analysis:
Bivariate or univariate meta-analysis and subgroup analysis performed to explore influence of test type and population risk.
Main results:
A total of 117 studies were included that analysed 18 conditions. Bivariate meta-analysis demonstrated sensitivities and specificities, respectively, for: fetal sex, 0.989 (95% CI 0.980-0.994) and 0.996 (95% CI 0.989-0.998), 11 179 tests; rhesus D, 0.993 (95% CI 0.982-0.997) and 0.984 (95% CI 0.964-0.993), 10 290 tests; trisomy 21, 0.994 (95% CI 0.983-0.998) and 0.999 (95% CI 0.999-1.000), 148 344 tests; trisomy 18, 0.977 (95% CI 0.952-0.989) and 0.999 (95% CI 0.998-1.000), 146 940 tests; monosomy X, 0.929 (95% CI 0.741-0.984) and 0.999 (95% CI 0.995-0.999), 6712 tests. Trisomy 13 was analysed by univariate meta-analysis, with a summary sensitivity of 0.906 (95% CI 0.823-0.958) and specificity of 1.00 (95% CI 0.999-0.100), from 134 691 tests. False and inconclusive results were poorly reported across all conditions. Although the test type affected both sensitivity and specificity, there was no evidence that population risk had any effect.
Conclusion:
Performance of cffDNA-based NIPT is affected by condition under investigation. For fetal sex and rhesus D status, NIPT can be considered diagnostic. For trisomy 21, 18, and 13, the lower sensitivity, specificity, and disease prevalence, combined with the biological influence of confined placental mosaicism, designates it a screening test. These factors must be considered when counselling patients and assessing the cost of introduction into routine care.
Tweetable abstract:
cffDNA NIPT accuracy high, can be diagnostic for fetal sex and rhesus D, but only screening test in aneuploidy.
Background
Many published studies have demonstrated the high sensitivity and specificity of noninvasive prenatal tests (NIPT) analyzing cell-free fetal DNA (cffDNA) from maternal blood to detect the most common fetal aneuploidies.
Objectives
However, there are also reports demonstrating discordance between the NIPT results and the results of subsequent conventional cytogenetic analyses following invasive prenatal procedures.
Results
These discordances result from different technical and biological factors. The most important factor is the chorionic origin of the cffDNA. The cffDNA originates mainly from cells from the cytotrophoblast. Therefore, NIPT results can only achieve the diagnostic accuracy of results from chorionic villi short-term cultures.
Conclusions
These findings suggest the need for careful interpretation of NIPT results in the general clinical context. NIPT results do not have the high diagnostic power in comparison to results from invasive prenatal diagnosis, and NIPT cannot replace invasive procedures. Amniocentesis is still the gold standard in prenatal genetic diagnosis.
Abstracted from Ultrasound Obstet Gynecol 2016;47:45–52 Although detection of trisomies 21, 18, and 13 by cell-free DNA (cfDNA) analysis of maternal blood is superior to other methods of screening, it is expensive. To maximize performance at reduced cost, a strategy that can be used is to offer cfDNA testing contingent on the results of the first-trimester combined test that is used currently.
Objective:
To demonstrate the decrease in intrauterine invasive procedures through analysis of DNA fetoplacental free circulating in maternal blood: Non Invasive Prenatal Test (NIPT), in Prenatal Diagnosis Center of American Hospital of Paris (AHP).
Materials and methods:
Retrospective descriptive study of 8821 patients in Prenatal Diagnosis Center at the AHP between 01/01/2012 and 09/25/2014. The NIPT is available to patients since 1st January 2013.
Results:
The number of invasive procedures decreased significantly (P<0.0001) between 2012 (n=1177, i.e. 42 % of the global activity of the Prenatal Diagnosis Center at the AHP in 2012) and 2013 (n=987 or 28.5 %) and between 2013 and 2014 (n=599 or 23.4 %). The NIPT calculated performance statistics are: sensitivity≥99.9 %; specificity=99.8 %; Positive Predictive Value=90.4 %; Negative Predictive Value≥99.9 %; False Positives=3. While the actual screening statistic values are: sensitivity≥95.4 %; specificity=82.5 %; Positive Predictive Value=6.5 %; Negative Predictive Value=99.9 %; False Positives=1197. The NIPT has reduced the number of invasive procedures at the Prenatal Diagnosis Center at the AHP. The NIPT performances are superior to those of the actual screening.
The aim of the present study was to evaluate the efficacy of using non-invasive DNA testing technology in screening Down's syndrome among women of advanced maternal age (AMA) and to provide evidence for prenatal screening of Down's syndrome. With a double-blind design, 8 ml of peripheral venous blood samples were collected from 87 women aged ≥35 years after 12 weeks of pregnancy. All cases were recorded with unique identification cards with clinical details and followed up until delivery. All the non-invasive prenatal testing results were confirmed by amniotic fluid fetal karyotyping (the gold standard of aneuploidy test), follow-up examination by neonatologists or neonatal blood karyotyping. The sensitivity, specificity and other indicators of non-invasive DNA testing technology were calculated based on the data of 87 women of AMA. Among the 87 women of AMA, 5 were cases with abnormal numbers of chromosomes (3 cases of trisomy 21, 1 case of trisomy 18 and 1 case of 47, XXX). The sensitivity and specificity reached 100% for trisomy 21, trisomy 18 and 47, XXX. The present study supports that non-invasive DNA testing is a useful method of AMA screening of Down's syndrome with 100% accuracy. Therefore, it can be used as an important alternative screening method for Down's syndrome in women of AMA.
Objective:
To introduce NIPT for fetal autosomal trisomies and gender in a Danish public health setting, using semi-conductor sequencing and published open source scripts for analysis.
Methods:
Plasma derived DNA from a total of 375 pregnant women (divided into 3 datasets) was whole-genome sequenced on the Ion Proton™ platform and analyzed using a pipeline based on WISECONDOR for fetal autosomal aneuploidy detection and SeqFF for fetal DNA fraction estimation. We furthermore validated a fetal sex determination analysis.
Results:
The pipeline correctly detected 27/27 trisomy 21, 4/4 trisomy 18 and 3/3 trisomy 13 fetuses. Neither false negatives nor false positives (chromosomes 13, 18 and 21) were observed in our validation dataset. Fetal sex was identified correctly in all but one triploid fetus (172/173). SeqFF showed a strong correlation (R(2) = 0.72) to Y-chromosomal content of the male fetus samples.
Discussion:
We have implemented NIPT into Danish health care using published open source scripts for autosomal aneuploidy detection and fetal DNA fraction estimation showing excellent false negative and false positive rates. SeqFF provides a good estimation of fetal DNA fraction. This coupled with an analysis of fetal sex provides a complete NIPT workflow, which may easily be adapted for implementation in other public health laboratories.
Objective:
Non-invasive prenatal testing (NIPT) is increasingly being used in prenatal aneuploidy screening. The objective of this study was to assess the positive predictive value in our cohort of 68 cases with positive NIPT result. In addition, we wondered if the use of NIPT in cases with ultrasound abnormalities is appropriate, given the limited number of chromosomes investigated.
Design:
We performed confirmative invasive testing using karyotyping, fluorescence in situ hybridization (FISH) and/or high-resolution chromosomal microarray analysis.
Results:
In line with the published data, the positive NIPT result was confirmed in 64.7% of cases. Inconclusive and negative NIPT results followed by cytogenetically pathologic findings were encountered in three and in five cases, respectively. Four of the five fetuses with negative NIPT but pathologic cytogenetic findings were born with several malformations and diagnosed right after birth with severe genetic conditions. Of note, in all of those four cases, NIPT was offered despite the finding of major fetal ultrasound abnormalities and despite the fact that the family would not have opposed invasive testing or pregnancy termination.
Conclusion:
More education of health care providers and caution in counseling and interpretation of test results are needed in order to meet the challenges that this new test, which enriches our diagnostic options in prenatal testing, poses.
Chromosomal aberration mostly occurs in chromosome 21, 18 and 13, with an incidence approximately 1 out of 160 live births in humans, therefore making prenatal diagnosis necessary in clinics. Current methods have drawbacks such as time consuming, high cost, complicated operations and low sensitivity. In this paper, a novel method for rapid and accurate prenatal diagnosis of aneuploidy is proposed based on pyrosequencing, which quantitatively detects the peak height ratio of different bases of segmental duplication. A direct PCR approach was undertaken where a small volume of amniotic fluid was used as the starting material without DNA extraction. Single-stranded DNA was prepared from PCR products and subsequently analyzed using pyrosequencing. The peak height ratio between target and reference chromosome of 2.2 for euploid and 3:2 for a trisomy fetus were used as reference. The reference intervals and z scores were calculated for discrimination of aneuploidy. A total of 132 samples were collected, within trisomy 21 (n = 11), trisomy 18 (n = 3), trisomy 13 (n = 2), and unaffected controls (n = 116). A set of six segmental duplications were chosen for analysis. This method had consistent results with karyotyping analysis, a correct diagnosis with 100% sensitivity and 99.9% specificity.
Objective:
Evaluate patient choices and outcomes following positive cfDNA.
Method:
Retrospective cohort study of women with positive cfDNA through two academic centers between March 2012 and December 2014. Patients were screened based on ACOG indications. Medical records reviewed for counseling, ultrasound findings, diagnostic testing, karyotype and outcome.
Results:
CfDNA was positive in 114 women;105 singletons and 9 twin pairs. CfDNAwas positive for autosomal trisomy (21,18,13) in 96 (84.2%) and sex chromosome aneuploidy in 18 (15.8%). Certified Genetic Counselors performed 95% of post-cfDNA counseling. Prenatal diagnostic testing was pursued by 71/114 (62%). Karyotype was available in 91/105 (86.7%) singletons and confirmed aneuploidy in 75/91 (82.4%); The PPV of cfDNA with any ultrasound finding was 93.6% versus 58.6% without a finding. An abnormal sonographic finding was seen in 4/16 (25%) singletons with false positive cfDNA. Fetal termination occurred in 53/79 (67%) singletons and 3/5 (60%) twins with prenatal abnormal or unknown karyotype for autosomal trisomy. Eleven fetuses (11/56, 19.6%) terminated for suspected autosomal trisomy without karyotype confirmation.
Conclusion:
Patient choices following positive cfDNA are varied. Ultrasound modifies the PPV of cfDNA. Termination rates for aneuploidy are not higher than historical controls. Recommendation for karyotype confirmation prior to termination is not universally followed This article is protected by copyright. All rights reserved.
Introduction:
Non-invasive prenatal testing (NIPT) using cell-free DNA in maternal blood is a relatively new screening modality for the common trisomies of chromosomes 21, 18 & 13 and sex chromosome aneuploidies (SCAs). For some patients however, results are not reported due to laboratory technical issues such as low fetal fraction and sequencing failures. In this review the clinical implications of NIPT test failures are discussed.
Methods:
A Medline search was performed for all studies on NIPT that include >1000 samples. The failure rates were assessed by technology.
Results:
Methods based on massive parallel sequencing (MPS) have been found to have the lowest failure rate (1.58%) while tests based on single nucleotide polymorphism (SNP) analysis have the highest failure rate (6.39%).
Conclusions:
Recent publications suggest that patients who receive a " no call" result are at increased risk of aneuploidy. Some professional societies have therefore recommended that these patients undergo genetic counseling and be offered invasive diagnostic testing. NIPT technology that has a high failure rate may increase the false positive rates, decrease the positive predictive value and increase the procedure-related pregnancy loss. This article is protected by copyright. All rights reserved.
To summarize for obstetrical care providers the current literature on array genomic hybridization in prenatal diagnosis and to outline the recommendations of the Canadian College of Medical Geneticists regarding the use of this new technology with respect to prenatal diagnosis.
To determine the postprocedure loss rate for mid-trimester genetic amniocentesis.
To develop a Canadian consensus document withrecommendations on maternal screening for fetal aneuploidy(e.g., Down syndrome and trisomy 18) in pregnancy.
To provide Canadian health care providers with current information on the use of quantitative fluorescent polymerase chain reaction (QF-PCR) or equivalent technology in the prenatal diagnosis of fetal chromosomal abnormalities.
To develop a Canadian consensus document on maternal screening for fetal aneuploidy (e.g., Down syndrome and trisomy 18) in singleton pregnancies.
