[Application of chromosomal microarray analysis for fetuses with ventricular septal defects].

OBJECTIVE: To explore the genetic etiology of fetuses with ventricular septal defects (VSD) using chromosomal microarray analysis (CMA).

METHODS: A total of 248 fetuses were divided into isolated VSD group, VSD with other cardiac and/or great vessels malformation group, VSD with extra-cardiac anomalies group (including malformation and sonographic soft markers), and VSD with both cardiac and extra-cardiac anomalies group. Standard karyotyping was carried out for all fetuses, and CMA was performed for 6 fetuses with an abnormal karyotype and a proportion of fetuses with a normal karyotype. All cases were followed up, and neonates were followed up until 1 year of age.

RESULTS: Chromosomal abnormalities were identified in 60 (24.2%) of the 248 fetuses. For 6 of the fetuses subjected to further CMA analysis, the origin of abnormal chromosomes were clarified, among which 2 have overlapped with the critical region of Wolf-Hirschhorn syndrome. Candidate genes for VSD included WHSC1, LBX1, LDB3 and BBS10. For 143 fetuses with a normal karyotype, CMA has identified pathogenic copy number variations (CNVs) in 11 cases (7.7%). These included 9 well-known microdeletion or microduplication syndromes, including 22q11.2 microdeletion, 17p11.2 microdeletion (Smith-Magenis syndrome), 17p13.3 microdeletion (Miller-Dieker syndrome), 1p36 microdeletion, 1q21.1 microduplication and 4q deletion. Candidate genes for VSD included TBX1, LZTR1, FAT1, AKAP10, SKI, PRDM26, GJA5, ERCC4 and YWHAE. For 48.7% of the fetuses with benign CNVs, spontaneously closure has occurred within the first year of life.

CONCLUSION: CMA may increase the detection rate of submicroscopic imbalances by 7.7%. No significant correlation between different groups of VSD and the pathogenic CNVs was observed. Whole-genome CMA should be recommended to the fetuses with VSD but a normal karyotype. Nearly half of VSDs with benign CNVs may close spontaneously within the first year of life.