Browsing by Author "Levy, Brynn"

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    Reliable detection of subchromosomal deletions and duplications using cell-based noninvasive prenatal testing
    (Wiley, 2018-10-25) Vossaert, Liesbeth; Wang, Qun; Salman, Roseen; Zhuo, Xinming; Qu, Chunjing; Henke, David; Seubert, Ron; Chow, Jennifer; U'ren, Lance; Enright, Brennan; Stilwell, Jackie; Kaldjian, Eric; Yang, Yaping; Shaw, Chad; Levy, Brynn; Wapner, Ronald; Breman, Amy; Veyver, Ignatia Van den; Beaudet, Arthur; Medical and Molecular Genetics, School of Medicine
    Objective To gather additional data on the ability to detect subchromosomal abnormalities of various sizes in single fetal cells isolated from maternal blood, using low-coverage shotgun next-generation sequencing for cell-based noninvasive prenatal testing (NIPT). Method Fetal trophoblasts were recovered from approximately 30 mL of maternal blood using maternal white blood cell depletion, density-based cell separation, immunofluorescence staining, and high-resolution scanning. These trophoblastic cells were picked as single cells and underwent whole genome amplification for subsequent genome-wide copy number analysis and genotyping to confirm the fetal origin of the cells. Results Applying our fetal cell isolation method to a series of 125 maternal blood samples, we detected on average 4.17 putative fetal cells/sample. The series included 15 cases with clinically diagnosed fetal aneuploidies and five cases with subchromosomal abnormalities. This method was capable of detecting findings that were 1 to 2 Mb in size, and all were concordant with the microarray or karyotype data obtained on a fetal sample. A minority of fetal cells showed evidence of genome degradation likely related to apoptosis. Conclusion We demonstrate that this cell-based NIPT method has the capacity to reliably diagnose fetal chromosomal abnormalities down to 1 to 2 Mb in size.
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    Systematic evaluation of genome sequencing for the diagnostic assessment of autism spectrum disorder and fetal structural anomalies
    (Elsevier, 2023) Lowther, Chelsea; Valkanas, Elise; Giordano, Jessica L.; Wang, Harold Z.; Currall, Benjamin B.; O'Keefe, Kathryn; Pierce-Hoffman, Emma; Kurtas, Nehir E.; Whelan, Christopher W.; Hao, Stephanie P.; Weisburd, Ben; Jalili, Vahid; Fu, Jack; Wong, Isaac; Collins, Ryan L.; Zhao, Xuefang; Austin-Tse, Christina A.; Evangelista, Emily; Lemire, Gabrielle; Aggarwal, Vimla S.; Lucente, Diane; Gauthier, Laura D.; Tolonen, Charlotte; Sahakian, Nareh; Stevens, Christine; An, Joon-Yong; Dong, Shan; Norton, Mary E.; MacKenzie, Tippi C.; Devlin, Bernie; Gilmore, Kelly; Powell, Bradford C.; Brandt, Alicia; Vetrini, Francesco; DiVito, Michelle; Sanders, Stephan J.; MacArthur, Daniel G.; Hodge, Jennelle C.; O'Donnell-Luria, Anne; Rehm, Heidi L.; Vora, Neeta L.; Levy, Brynn; Brand, Harrison; Wapner, Ronald J.; Talkowski, Michael E.; Medical and Molecular Genetics, School of Medicine
    Short-read genome sequencing (GS) holds the promise of becoming the primary diagnostic approach for the assessment of autism spectrum disorder (ASD) and fetal structural anomalies (FSAs). However, few studies have comprehensively evaluated its performance against current standard-of-care diagnostic tests: karyotype, chromosomal microarray (CMA), and exome sequencing (ES). To assess the clinical utility of GS, we compared its diagnostic yield against these three tests in 1,612 quartet families including an individual with ASD and in 295 prenatal families. Our GS analytic framework identified a diagnostic variant in 7.8% of ASD probands, almost 2-fold more than CMA (4.3%) and 3-fold more than ES (2.7%). However, when we systematically captured copy-number variants (CNVs) from the exome data, the diagnostic yield of ES (7.4%) was brought much closer to, but did not surpass, GS. Similarly, we estimated that GS could achieve an overall diagnostic yield of 46.1% in unselected FSAs, representing a 17.2% increased yield over karyotype, 14.1% over CMA, and 4.1% over ES with CNV calling or 36.1% increase without CNV discovery. Overall, GS provided an added diagnostic yield of 0.4% and 0.8% beyond the combination of all three standard-of-care tests in ASD and FSAs, respectively. This corresponded to nine GS unique diagnostic variants, including sequence variants in exons not captured by ES, structural variants (SVs) inaccessible to existing standard-of-care tests, and SVs where the resolution of GS changed variant classification. Overall, this large-scale evaluation demonstrated that GS significantly outperforms each individual standard-of-care test while also outperforming the combination of all three tests, thus warranting consideration as the first-tier diagnostic approach for the assessment of ASD and FSAs.
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    Validation Studies for Single Circulating Trophoblast Genetic Testing as a Form of Noninvasive Prenatal Diagnosis
    (Elsevier, 2019-12-05) Vossaert, Liesbeth; Wang, Qun; Salman, Roseen; McCombs, Anne K.; Patel, Vipulkumar; Qu, Chunjing; Mancini, Michael A.; Edwards, Dean P.; Malovannaya, Anna; Liu, Pengfei; Shaw, Chad A.; Levy, Brynn; Wapner, Ronald J.; Bi, Weimin; Breman, Amy M.; Van den Veyver, Ignatia B.; Beaudet, Arthur L.; Medical and Molecular Genetics, School of Medicine
    It has long been appreciated that genetic analysis of fetal or trophoblast cells in maternal blood could revolutionize prenatal diagnosis. We implemented a protocol for single circulating trophoblast (SCT) testing using positive selection by magnetic-activated cell sorting and single-cell low-coverage whole-genome sequencing to detect fetal aneuploidies and copy-number variants (CNVs) at ∼1 Mb resolution. In 95 validation cases, we identified on average 0.20 putative trophoblasts/mL, of which 55% were of high quality and scorable for both aneuploidy and CNVs. We emphasize the importance of analyzing individual cells because some cells are apoptotic, in S-phase, or otherwise of poor quality. When two or more high-quality trophoblast cells were available for singleton pregnancies, there was complete concordance between all trophoblasts unless there was evidence of confined placental mosaicism. SCT results were highly concordant with available clinical data from chorionic villus sampling (CVS) or amniocentesis procedures. Although determining the exact sensitivity and specificity will require more data, this study further supports the potential for SCT testing to become a diagnostic prenatal test.