[Application of high-throughput sequencing technology for the detection of fetal copy number variations]

To assess the value of non-invasive prenatal testing (NIPT) for the detection of fetal copy number variations (CNVs) in addition to trisomies 21, 18, and 13.

A total of 37 306 pregnant women underwent the NIPT test. For those with fetal CNVs indicated by NIPT and accepted invasive prenatal diagnosis, amniotic fluid samples were obtained for chromosomal karyotyping analysis and chromosome microarray analysis (CMA). All cases were followed up.

Among the 37 306 cases, 78 (0.209%) were predicted to have fetal CNVs. Among these, 52 pregnant women accepted invasive prenatal diagnosis, and 15 of them (28.85%) obtained a consistent result. Follow up of 26 women who refused invasive prenatal diagnosis have found 2 cases with spontaneous abortion, 2 with induced labor for fetal malformation indicated by ultrasonography, and 1 had multiple malformations and a consistent result by CMA, which yielded an abnormal rate of 19.23%.

NIPT can signal fetal chromosomal abnormalities through detection of gain and/or loss of fetal DNA copies. Combined chromosomal karyotyping and CMA can increase the detection rate for common chromosomal aneuploidies and CNVs, thereby provide a basis for genetic counseling for the affected families.