[CNV-seq analysis of copy number variations in 217 fetuses with nasal bone dysplasia]

To assess the diagnostic value of copy number variation sequencing (CNV-seq) in the genetic etiology of fetuses with nasal bone dysplasia (NBD).

A total of 217 fetuses discovered with NBD from December 2017 to December 2020 were divided into the isolated NBD group and NBD combined with other anomalies group, for which copy number variations (CNVs) were analyzed.

A total of 40 fetal abnormalities were detected in 217 cases, with an overall abnormal rate of 18.4%. These included 31 cases with aneuploidies (14.3%, 31/217) and 9 cases with genomic CNVs (4.1%, 9/217). Five cases of trisomy 21 (3.5%, 5/144) and two CNVs cases with unknown clinical significance (1.4%, 2/144) were detected in the isolated group. As for the combined NBD group, 26 aneuploidies (35.6%, 26/73), including 19 cases with trisomy 21, 6 cases with trisomy 18, 1 case with trisomy 13, 5 cases with pathogenic CNVs (6.8%, 5/73), and 2 cases with CNVs of unknown clinical significance (2.7%, 2/73) were detected. A significant difference was detected between the two groups (P < 0.01).

The detection rate of CNV-seq is high for chromosomal aneuploidies and pathogenic CNVs in fetuses with NBD, particularly in those combined with other ultrasonic abnormalities.