Whole‐exome sequencing in the evaluation of fetal congenital anomalies of the kidney and urinary tract detected by ultrasonography

OBJECTIVE: We aimed to investigate the value of whole-exome sequencing (WES) in fetuses with congenital anomalies of the kidney and urinary tract (CAKUT) with/without other structural anomalies but with normal findings upon karyotyping and chromosome microarray analysis (CMA). METHODS: Cases with CAKUT with/without other structural anomalies were screened for eligibility. Fetuses with abnormal karyotyping or CMA results were excluded. We performed WES on DNA samples from eligible fetus-parental trios and identified diagnostic genetic variants based on ultrasonographic features. RESULTS: A total of 163 eligible fetus-parental trios were successfully analyzed by WES. We found 26 likely pathogenic or pathogenic variants in 18 genes from 20 fetuses, with a total proportion of diagnostic genetic variants of 12.3% (20/163). Genetic variants were significantly more frequently detected in fetuses with multisystem anomalies (27.0%, 10/37), enlarged kidney/echogenic kidney (20%, 4/20) and multicystic dysplastic kidney (11.1%, 4/36). Pregnancy outcome data showed that 88 (94.6%, 88/93) of the surviving cases with negative WES results had a good prognosis in early childhood. CONCLUSIONS: Our study is the largest to use WES prenatally for CAKUT and shows that WES can be used diagnostically to define the molecular defects that underlie unexplained CAKUT.