Abstract:

Objective: To explore the clinical significance of noninvasive prenatal screening (NIPS) in screening the rare autosomal trisomies (RAT) and chromosome copy number variation (CNV). Methods: The amniotic fluid karyotype analysis and single nucleotide polymorphism array were performed at the Prenatal Diagnostic Center of Quanzhou Women′s and Children′s Hospital from March 2017 to July 2023, in 108 cases that NIPS suggested high risk of RAT and (or) CNV. Results: In the 83 cases of NIPS suggesting high risk of RAT, 15 abnormal RAT were found by prenatal diagnosis, with a positive predictive value of 18.07%. There were 1 pathogenic copy number variants (pCNV), 9 variants of uncertain significance (VOUS), 4 loss of heterozygosity (LOH) and 1 VOUS+LOH. In 25 cases of NIPS suggesting high risk of CNV, 16 abnormal CNV were indicated by prenatal diagnosis, with a positive predictive value of 64.00%. There were 11 pCNV, 1 likely pathogenic copy number variants (lpCNV) and 4 VOUS. Conclusions: The positive predictive value of NIPS is not high in RAT, but the high risk of RAT is associated with the increasing adverse pregnancy outcomes. NIPS has a certain application value for the high risk screening of CNV. When NIPS suggested high risk of RAT and CNV, fetal prognosis should be evaluated in the combination of prenatal diagnosis with ultrasound follow-up, and monitoring and management of pregnancy should be strengthened.

Key words: Noninvasive prenatal testing, Prenatal diagnosis, DNA copy number variations, Trisomy, Polymorphism, single nucleotide, Rare autosomal trisomies