Researchers Eye Extending NIPT for Subchromosomal Analysis

Non-invasive prenatal testing (NIPT) is rapidly being adopted as an aneuploidy screening test in high-risk pregnancies. Its benefits include its high sensitivity and its ability to reduce the need for invasive testing. NIPT uses massively parallel sequencing of cell-free DNA in maternal plasma to detect fetal trisomies in chromosomes 13, 18, and 21. While some are working towards evaluating the benefits of screening wider populations of women with NIPT, others are interested in expanding the scope of testing to include selected subchromosomal abnormalities. But, the evidence base remains limited for this use. There are no serum-based tests that specifically screen for subchromosomal abnormalities. Individually, these rearrangements are rare, but combined have an estimated, combined incidence close to Down syndrome, researchers say. There are some concerns that widespread NIPT use could actually decrease detection of other pathogenic rearrangements—detectable with microarray analysis from invasively derived samples—given the declining numbers of invasive procedures performed. A few previous studies demonstrated the potential of extending NIPT to detect fetal deletion and duplication syndromes, but questions remain about the fetal DNA fraction and the depth of sequencing needed for accurate results. Two recent studies provide additional data to fill this gap. Rearrangements Less than 6 Mb […]