Analysis of the Detection Status of Non-Invasive Prenatal Testing in Sex Chromosome Abnormalities

Abstract

Objective: To analyze the detection efficiency of non-invasive prenatal tests (NIPT) in single fetus sex chromosome abnormalities and explore the application value of NIPT in sex chromosome diseases. Method: A total of 47,770 singleton pregnant women received free NIPT at Dongguan Maternity and Infant Clinic. Pregnant women with NIPT results indicating sex chromosome abnormalities provided informed consent for amniocentesis and subsequent karyotype analysis and/or multiplex ligation probe amplification (MLPA) technology. The study also involved telephone follow-ups on test results and pregnancy outcomes, along with a retrospective analysis of the positive detection rate of sex chromosome abnormalities by NIPT. Results: Among the 47,770 pregnant women, NIPT identified sex chromosome abnormalities in 158 cases, resulting in a detection rate of 0.33%. Of these cases, 113 pregnant women opted for amniocentesis, while 36 declined. One newborn, whose parents refused puncture, was later diagnosed with cryptorchidism. 8 cases failed to follow up. Among the 113 cases undergoing amniocentesis, 55 were diagnosed with sex chromosome abnormalities. These included 7 cases of X monosomy, 24 cases of sex chromosome trisomy (14 cases of Klinefelter syndrome; 5 cases of Jacobs syndrome; 5 cases of trisomy X), and 24 cases with sex chromosome microdeletions and microduplications. Meanwhile, 58 cases had no abnormalities. The overall positive predictive value (PPV) of NIPT testing for sex chromosome abnormalities was 48.67%, with specific PPVs for monosomy X, Klinefelter syndrome, Jacobs syndrome, trisomy X, and sex chromosome microdeletions and microduplications being 6.19%, 12.39%, 4.42%, 4.42%, and 21.24% respectively. Conclusion: NIPT demonstrates high detection efficiency in sex chromosome diseases. However, the efficiency varies significantly across different chromosomal abnormalities. Pregnant women with NIPT results indicating sex chromosome abnormalities should undergo amniocentesis for karyotype analysis and MLPA.