[Application value of CNV-seq for the prenatal diagnosis of women with high-risk pregnancies].

Objective: To assess the application value of copy number variation sequencing (CNV-seq) for women with a high risk for fetal anomalies.

Methods: Based on the results of non-invasive prenatal testing (NIPT), 271 high-risk pregnant women were divided into NIPT positive group (n = 83) and other anomaly group (advanced age, high risk by serological screening, repeated NIPT failure, adverse pregnancy history, abnormal ultrasound finding, and abnormal phenotype) (n = 188). CNV-seq was carried out to detect copy number variations (CNVs) in amniocytic DNA from the two groups of pregnant women, and karyotyping analysis of the amniotic cells was carried out for verification and comparison.

Results: The amniocytes from 271 pregnant women were detected. The detection rate was 20.66% (56/271) for pathogenic CNVs by CNV-seq and 19.19% (52/271) for pathogenic karyotypes by karyotyping analysis. The difference was statistically significant (P < 0.05). CNV-seq had shown that, compared with NIPT positive group, the detection rates for likely pathogenic CNVs and variants of unknown significance (VUS) in other abnormality group were significantly higher [2.41%(2/83) vs. 5.32%(10/188)](P < 0.05).

Conclusion: CNV-seq can well suit the first-tier diagnosis for pregnant women suspected for fetal abnormality. In prenatal diagnosis settings, CNV-seq can identify additional and clinically significant cytogenetic abnormalities. In those with other abnormalities, the detection rates for likely pathogenic CNVs and VUS are higher than with the NIPT positive cases.