- Browse by Author
Browsing by Author "Breman, Amy"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Chromosomal microarray analysis on uncultured chorionic villus sampling can be complicated by confined placental mosaicism for aneuploidy and microdeletions(Wiley, 2018) Gu, Shen; Jernegan, Madison; Van den Veyver, Ignatia B.; Peacock, Sandra; Smith, Janice; Breman, Amy; Medical and Molecular Genetics, School of MedicineObjective This study aims to establish the incidence and implications of confined placental mosaicism (CPM) in the context of prenatal chromosomal microarray analysis (CMA). Methods We retrospectively reviewed prenatal array data on 1382 consecutive chorionic villus sampling (CVS) specimens spanning the past 6 years, focusing on those for which whole CVS biopsy (both cytotrophoblast and mesenchymal cells) was used for CMA and cultured cells (primarily mesenchyme) was also analyzed or amniotic fluid (AF)/newborn blood was used for confirmation, to determine the frequency of mosaic abnormal findings that were the result of CPM. Results Out of a total of 1382 consecutive CVS cases, we identified 42 (42/1382 = 3.0%) cases with abnormal array findings suggestive of mosaicism. Among them, 10 cases were unequivocally interpreted as CPM based on a normal AF/newborn blood confirmatory result. In addition, another 10 cases were interpreted as provisional CPM based on normal results on cultured cells. Notably, 40% (8/20) of the cases revealed complex findings, including multiple mosaic aneuploidies, mosaic submicroscopic copy number variation (CNV), and mosaic aneuploidy plus mosaic CNV. Conclusion Abnormal CMA results from CVS specimens should be interpreted with caution when mosaicism is evident or suspected. Furthermore, confirmatory testing on amniotic fluid, which contains cells derived from the fetus, is recommended in these cases.Item 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 MedicineObjective 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.Item Use of amplicon-based sequencing for testing fetal identity and monogenic traits with Single Circulating Trophoblast (SCT) as one form of cell-based NIPT(PLOS, 2021-04-15) Zhuo, Xinming; Wang, Qun; Vossaert, Liesbeth; Salman, Roseen; Kim, Adriel; Van den Veyver, Ignatia; Breman, Amy; Beaudet, Arthur; Medical and Molecular Genetics, School of MedicineA major challenge for cell-based non-invasive prenatal testing (NIPT) is to distinguish individual presumptive fetal cells from maternal cells in female pregnancies. We have sought a rapid, robust, versatile, and low-cost next-generation sequencing method to facilitate this process. Toward this goal, single isolated cells underwent whole genome amplification prior to genotyping. Multiple highly polymorphic genomic regions (including HLA-A and HLA-B) with 10-20 very informative single nucleotide polymorphisms (SNPs) within a 200 bp interval were amplified with a modified method based on other publications. To enhance the power of cell identification, approximately 40 Human Identification SNP (Applied Biosystems) test amplicons were also utilized. Using SNP results to compare to sex chromosome data from NGS as a reliable standard, the true positive rate for genotyping was 83.4%, true negative 6.6%, false positive 3.3%, and false negative 6.6%. These results would not be sufficient for clinical diagnosis, but they demonstrate the general validity of the approach and suggest that deeper genotyping of single cells could be completely reliable. A paternal DNA sample is not required using this method. The assay also successfully detected pathogenic variants causing Tay Sachs disease, cystic fibrosis, and hemoglobinopathies in single lymphoblastoid cells, and disease-causing variants in three cell-based NIPT cases. This method could be applicable for any monogenic diagnosis.