Prenatal BACs-on-BeadsTM: The prospective experience of five prenatal diagnosis laboratories

Department of Cytogenetics, Obstetrics and Gynecology, CHI Poissy St Germain, Poissy, France.
Prenatal Diagnosis (Impact Factor: 3.27). 04/2012; 32(4):329-35. DOI: 10.1002/pd.2934
Source: PubMed


We previously reported on the validation of Prenatal BACs-on-Beads™ on retrospectively selected and prospective prenatal samples. This bead-based multiplex assay detects chromosome 13, 18, 21 and X/Y aneuploidies and the nine most frequent microdeletion syndromes. We demonstrated that Prenatal BACs-on-Beads(TM) is a new-generation, prenatal screening tool. Here, we describe the experience of five European prenatal diagnosis laboratories concerning the ongoing use of Prenatal BACs-on-Beads™ .
Some 1653 samples were analyzed. All results were confirmed by conventional karyotyping or another appropriate technique. All indications for invasive prenatal diagnosis were included. Amniotic fluid and chorionic villus samples were analyzed in equivalent proportions.
The failure rate was 3.3% and the overall abnormality detection rate was ~1/10. Eighty-five percent of the detected abnormalities were common aneuploidies. Eleven microdeletions and duplications were identified, thus giving an overall yield for microdeletion and microduplication detection of 1/145. Compared with QF-PCR, Prenatal BACs-on-Beads™ provides an additional detection rate of ~1/250 for low-risk pregnancies. The false positive and negative rates were both <1%.
When associated with conventional karyotyping, the Prenatal BACs-on-Beads™ assay combines a short turnaround time (typical of rapid aneuploidy detection tests) with valuable detection of the most frequent microdeletion syndromes that cannot be detected in cytogenetic analyses.

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    • "Each bead is coupled to DNA amplified from BACs (a total of 83 different PCR-amplified BAC clones) and analyzed using a Luminex cytometric acquisition system with two separate lasers (Luminex Corp., Austin, Texas) equipped with xPonent 3.1 software (Perkin Elmer, Turku, Finland). Experiments with acceptable quality control parameters had more than 50 beads/BACs analyzed alongside both male and female samples which were included as reference DNAs [19]. Prenatal-BoBs assesses 75 chromosomal regions involving chromosomes 13, 18, 21, X, and Y as well as the nine previously mentioned microdeletion syndromes. "
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    ABSTRACT: The risk of fetal aneuploidies is usually estimated based on high resolution ultrasound combined with biochemical determination of criterion in maternal blood, with invasive procedures offered to the population at risk. The purpose of this study was to investigate the effectiveness of a new rapid aneuploidy screening test on amniotic fluid (AF) or chorionic villus (CV) samples based on BACs-on-Beads (BoBs) technology and to compare the results with classical karyotyping by Giemsa banding (G-banding) of cultured cells in metaphase as the gold standard technique. The prenatal-BoBs kit was used to study aneuploidies involving chromosomes 13, 18, 21, X, and Y as well as nine microdeletion syndromes in 321 AF and 43 CV samples. G-banding of metaphase cultured cells was performed concomitantly for all prenatal samples. A microarray-based comparative genomic hybridization (aCGH) was also carried out in a subset of samples. Prenatal-BoBs results were widely confirmed by classical karyotyping. Only six karyotype findings were not identified by Prenatal-BoBs, all of them due to the known limitations of the technique. In summary, the BACs-on-Beads technology was an accurate, robust, and efficient method for the rapid diagnosis of common aneuploidies and microdeletion syndromes in prenatal samples.
    Full-text · Article · Mar 2014
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    Preview · Article · Apr 2012 · Prenatal Diagnosis
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    ABSTRACT: Duplication 17p11.2 (Potocki-Lupski syndrome (PTLS) MIM# 610883) is a genomic disorder with an estimated incidence of 1 in 25,000 births. As for other genomic disorders this duplication is typically de novo and is not associated with advanced maternal age or advanced paternal age. Herein we describe a prenatal diagnosis of duplication 17p11.2. This diagnosis was not suspected as the prenatal ultrasound findings were non-specific; however, BACs-on-Beads™ technology and array comparative genomic hybridization (aCGH) confirmed the common ∼3.7 Mb duplication. Evaluation of the foetus following termination of pregnancy revealed mildly dysmorphic features as well as congenital anomalies not previously reported in PTLS, specifically left pulmonary isomerism, an abnormally positioned left coronary orifice and nodular cerebellar heterotopia. This report exemplifies the utility of prenatal testing using new genomic technologies even when there are no multiple anomalies on foetal ultrasound. This report also exemplifies the utility of foetal autopsy in the identification of "occult" congenital anomalies.
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