Conclusions
Even in pregnancies without ultrasonography-identified anomalies, a positive NIPT screen for CNVs must be interpreted with caution and validated by additional diagnostic study.
Methods
A total of 135,981
Objective
To evaluate the clinical value of positive copy number variations (CNVs)
Results
A total of 44 (50.6%) cases underwent invasive prenatal diagnosis, of which six cases were detected with abnormal karyotype. CMA/CNV-Seq revealed 11 fetuses with positive results for CNVs, among whom eight were consistent with NIPT results, two were partially consistent, one was inconsistent, and positive predictive value (PPV) was 22.7% (10/44). For known CNVs, PPVs were 20% (15q11.2-q13 microdeletion) and 33.3% (5p end deletions). Among 11 pregnant women with positive prenatal diagnosis, seven were confirmed to have pathogenic CNVs in their fetuses; four had CNVs of unknown clinical significance. Conclusions: Even in pregnancies without ultrasonography-identified anomalies, a positive NIPT screen for CNVs must be interpreted with caution and validated by additional diagnostic study.