Noninvasive prenatal screening for fetal common sex chromosome aneuploidies from maternal blood

OBJECTIVE: To explore the feasibility of high-throughput massively parallel genomic DNA sequencing technology for the noninvasive prenatal detection of fetal sex chromosome aneuploidies (SCAs). METHODS: The study enrolled pregnant women who were prepared to undergo noninvasive prenatal testing (NIPT) in the second trimester. Cell-free fetal DNA (cffDNA) was extracted from the mother’s peripheral venous blood and a high-throughput sequencing procedure was undertaken. Patients identified as having pregnancies associated with SCAs were offered prenatal fetal chromosomal karyotyping. RESULTS: The study enrolled 10 275 pregnant women who were prepared to undergo NIPT. Of these, 57 pregnant women (0.55%) showed fetal SCA, including 27 with Turner syndrome (45,X), eight with Triple X syndrome (47,XXX), 12 with Klinefelter syndrome (47,XXY) and three with 47,XYY. Thirty-three pregnant women agreed to undergo fetal karyotyping and 18 had results consistent with NIPT, while 15 patients received a normal karyotype result. The overall positive predictive value of NIPT for detecting SCAs was 54.54% (18/33) and for detecting Turner syndrome (45,X) was 29.41% (5/17). CONCLUSION: NIPT can be used to identify fetal SCAs by analysing cffDNA using massively parallel genomic sequencing, although the accuracy needs to be improved particularly for Turner syndrome (45,X).