Genetic diagnosis of common fetal renal abnormalities detected on prenatal ultrasound.

Objectives: This retrospective study aimed to investigate the correlations between phenotypes of fetal renal abnormalities on prenatal ultrasound and genetic aetiologies detected using chromosomal microarray analysis (CMA) and whole-exome sequencing (WES).

Methods: Fetuses with renal abnormalities were subjected to CMA and were further analysed by WES when CMA-negative. The detection rates for chromosomal abnormalities and monogenic variants among different types of isolated renal abnormalities and those with extrarenal abnormalities (non-isolated cases) were determined and compared.

Results: CMA detected chromosomal abnormalities in 78 of 577 fetuses (13.52%). WES detected monogenic variants in 31 of 160 fetuses (19.38%) that had non-diagnostic CMA results. In cases of isolated hyperechogenic kidney, polycystic kidney disease, and multicystic dysplastic kidney, the detection rates of copy number variants (CNVs) by CMA and monogenic variants by WES were not significantly different (p > 0.05). However, monogenic variants were more frequently detected than CNVs when kidney abnormalities were accompanied by reduced amniotic fluid (p < 0.05). Other renal abnormalities identified on prenatal ultrasound had different detection rates.

Conclusions: Our findings contribute to the overall knowledge of genetic variants associated with prenatally identified renal anomalies and may aid in decision making regarding prenatal genetic testing options for affected pregnancies.