Genetic etiology of ventriculomegaly in 73 fetuses identified by High-Throughput sequencing

To investigate the genetic etiology of ventriculomegaly (VM) in fetuses by analyzing chromosomal aberrations and genetic variations through high-throughput sequencing. Clinical data and samples (amniotic fluid or miscarriage tissue) were collected from fetuses with ventricular width >10 mm, diagnosed at Shanxi Children's Hospital between 2020 and 2023. All samples underwent copy number variation sequencing (CNV-seq), and those with negative CNV-seq result were further analyzed by whole exome sequencing (WES) to identify single-gene variants. Chromosomal abnormalities and monogenic variants were classified according to the American College of Medical Genetics and Genomics guidelines. Statistical analysis was performed using SPSS 26.0, and pregnancy outcomes were tracked. Among 73 VM fetuses, 23 (31.5%) cases exhibited chromosomal aberrations via CNV-seq, including 4 aneuploidies, 12 pathogenic CNVs, 2 likely pathogenic CNVs, and 8 variants of unknown significance. The incidence of chromosomal abnormalities was significantly higher in non-isolated VM fetuses compared to isolated VM (p < 0.05). WES analysis of 33 CNV-negative cases identified single-gene defects in 16 (48.5%) fetuses, including SPATA5, PDHA1, TRIM71, PIK3R2, TUBB, CRB2, PIDD1, RTTN, FGFR3, AIMP1, POGZ, MYH7, CNOT3, MACF1, and PURA gene, with 10 novel variants reported. Fetal VM is associated with heterogeneous neurodevelopmental outcomes, and genetic etiology plays an important role in its pathogenesis. WES enhances the efficiency of diagnosis, particularly for VM fetuses without detectable aneuploidy or CNVs. Identifying the genetic etiology of fetal VM is is crucial for informing birth defect prevention strategies and improving the overall health of the newborn population.