This study was approved by the institutional review boards of the Chinese University of Hong Kong and Jinan University. Pregnant women requesting a prenatal diagnostic test referred to the two prenatal diagnosis centers were enrolled with written informed consent obtained from each participant. Prenatal samples including chorionic villi, amniotic fluid and cord blood were collected for DNA extraction and quality control (QC), while parental peripheral blood samples were collected whenever available either concurrently or after identification of a putative disease-associated variant for assessment of inheritance.
Genomic DNA was extracted with DNeasy Blood & Tissue Kit (cat. number/ID: 69506, Qiagen, Hilden, Germany) and treated with RNase (Qiagen, Hilden, Germany). DNA was subsequently quantified with the Qubit dsDNA HS Assay Kit (Invitrogen, Carlsbad, CA, USA) and DNA integrity was assessed by gel electrophoresis. Quantitative fluorescence polymerase chain reaction (QF-PCR) was conducted with 100 ng DNA and two panels of short tandem repeat (STR) markers (P1 and XY) located on chromosomes 18, X, and Y for exclusion of maternal cell admixture and polyploidy16 (link). Subsequently, after exclusion, each DNA sample was subjected for routine CMA and low-pass GS in parallel.
Genomic DNA was extracted with DNeasy Blood & Tissue Kit (cat. number/ID: 69506, Qiagen, Hilden, Germany) and treated with RNase (Qiagen, Hilden, Germany). DNA was subsequently quantified with the Qubit dsDNA HS Assay Kit (Invitrogen, Carlsbad, CA, USA) and DNA integrity was assessed by gel electrophoresis. Quantitative fluorescence polymerase chain reaction (QF-PCR) was conducted with 100 ng DNA and two panels of short tandem repeat (STR) markers (P1 and XY) located on chromosomes 18, X, and Y for exclusion of maternal cell admixture and polyploidy16 (link). Subsequently, after exclusion, each DNA sample was subjected for routine CMA and low-pass GS in parallel.
