Cell-free DNA screening for sex chromosome aneuploidies by non-invasive prenatal testing in maternal plasma

BACKGROUND: Non-invasive prenatal testing (NIPT) has been confirmed as the most accurate screening test for trisomies 21, 18, and 13. However, reports on NIPT performance in sex chromosome aneuploidies (SCA) based on real clinical data are still limited. METHODS: High-throughput massively parallel genomic sequencing (MPS) technique was used to screen for fetal SCAs as part of the research to determine the potential value of NIPT in detecting fetal SCAs in the second trimester. A number of 12,243 consecutive cases from a single center were included in this study. RESULTS: The positive predictive value (PPV) of NIPT in the present study was 57.6%, which was divided and categorized by individual SCAs as follows: 21.4% for Turner syndrome (45,X), 75.0% for Triple X syndrome (47,XXX), 90.9% for Klinefelter syndrome (47,XXY), and 75.0% for XYY syndrome (47,XYY). CONCLUSION: The NIPT-based SCA test cannot be used as a diagnostic method, and performing an invasive confirmation test on NIPT-based SCA-positive cases is strongly recommended.