Fetal Nucleic Acids in Maternal Plasma Toward the Development of Noninvasive Prenatal Diagnosis of Fetal Chromosomal Aneuploidies

Centre for Research into Circulating Fetal Nucleic Acids, Li Ka Shing Institute of Health Sciences, Department of Chemical Pathology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR.
Annals of the New York Academy of Sciences (Impact Factor: 4.31). 01/2008; 1137(1). DOI: 10.1196/annals.1448.004

ABSTRACT The discovery of cell-free fetal nucleic acids in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis. Over the last few years, a number of approaches have been demonstrated to allow such circulating fetal nucleic acids to be used for the prenatal detection of chromosomal aneuploidies. One such approach involves the enrichment of fetal DNA, such as by size fractionation or by the contro- versial formaldehyde treatment technique. A second approach involves the targeting of fetal-specific nucleic acid molecules, including fetal-specific epigenetic markers and placenta-specific mRNA markers. A third approach involves the development of highly discriminatory quantitative methods for chromosome dosage analysis using digital polymerase chain reaction technology. It is likely that these and other methods yet to be developed would allow noninvasive prenatal diagnosis of chromosomal aneuploidies by maternal plasma nucleic acids to be realized in the near future.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of prenatal diagnosis is to provide information on chromosomal abnormalities, in order to allow parents an informed choice on the course of pregnancy. Karyotyping is the diagnostic test used to detect chromosomal abnormalities. It is highly accurate, but labour-intense, costly and slow. Karyotyping detects chromosomal abnormalities with no, mild, or unclear clinical consequences. Rapid aneuploidy detection (RAD) techniques can detect the most common chromosomal abnormalities (trisomies 13, 18, 21, X and Y). Multiplex Ligation-dependent Probe Amplification (MLPA) is a RAD test. Its diagnostic accuracy, tested on 4585 amniotic fluid samples in routine clinical practice, is comparable to that of karyotyping (P<0.001) and it reduces waiting time with 14.5 days at lower costs (-€240 per sample). Patient quality of life does not differ significantly. While caregivers prefer RAD, experts prefer a test detecting all severe chromosomal abnormalities. Patients&apos; preferences are equally divided; they value the detection of severe chromosomal abnormalities most. Since RAD and karyotyping both detect the most common chromosomal abnormalities with severe consequences, both tests are appropriate for prenatal diagnosis. Based on decision analytic considerations and our study results, women should be offered a choice, since they will bear the responsibility of raising the child.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Free fetal nucleic acids, found in the plasma of every pregnant woman, have made a substantial impact on prenatal diagnosis. The past decade has seen the introduction of routine noninvasive prenatal diagnosis (NIPD) using DNA extracted from maternal plasma for a number of clinical complications of pregnancy, notably feto-maternal blood group incompatibility, fetal sexing and exclusion/detection of single-gene disorders. It appears that mass-scale analysis of all RhD-negative pregnant women will be adopted to conserve stocks of prophylactic anti-D and avoid the administration of a blood product unnecessarily. For the majority of prenatal diagnostic procedures, the assessment of trisomy, particularly trisomy 21, is the highest priority. Because RHD genotyping, fetal sexing and analysis of single-gene disorders all depend on the detection of paternally inherited alleles, they were relatively simple to adapt on the basis of PCR analysis of DNA obtained from maternal plasma. However, for assessment of chromosome copy number, this is not so straightforward. The assessment of polymorphisms among placentally expressed mRNAs found in maternal plasma has enabled the detection of trisomy 21 fetuses using a combination of reverse transcriptase PCR and mass spectrometry to define allelic ratios of maternally and paternally inherited single nucleotide polymorphisms. Interesting recent developments also include the finding that direct sequence analysis of maternal plasma extracted DNA using 'next-generation' DNA sequencers can differentiate between normal and trisomy fetuses. NIPD using nucleic acids obtained from maternal plasma and serum is now a clinical reality, particularly in the management of hemolytic disease of the fetus and newborn. Recent advances signal that NIPD for common aneuploidies will soon be possible.
    Current opinion in obstetrics & gynecology 05/2009; 21(2):175-9. DOI:10.1097/GCO.0b013e3283294798 · 2.37 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We describe a novel microarray-based approach for the high-throughput discovery of epigenetic biomarkers for use in the noninvasive detection of fetal genetic disease. We combined a 215 060-probe custom oligonucleotide microarray with a comprehensive library preparation method and novel statistical tools to compare DNA methylation patterns in chorionic villus samples (CVS) with gestational age-matched maternal blood cell (MBC) samples. Our custom microarray was designed to provide high-resolution coverage across human chromosomes 13, 18 and 21. We identified 6311 MspI/HpaII sites across all three chromosomes that displayed tissue-specific differential CpG methylation patterns. To maximize the probability of identifying biomarkers that have clinical utility we filtered our data to identify MspI/HpaII sites that are within 150 bp of a highly polymorphic single nucleotide polymorphism (SNP) so that its allelic ratio may be determined for the detection of fetal aneuploidy. Our microarray design and the computational tools used for data analysis are available for download as is the entire data set. This high-resolution analysis of DNA methylation patterns in the human placenta during the first trimester of pregnancy identifies numerous potential biomarkers for the diagnosis of fetal aneuploidy on chromosomes 13, 18 and 21.
    Prenatal Diagnosis 11/2009; 29(11):1020-30. DOI:10.1002/pd.2335 · 2.51 Impact Factor


Available from