Genetic Investigation of Fetuses With Isolated Unilateral Renal Agenesis Identified on Second Trimester Ultrasound: A Single Referral Center Experience

ABSTRACT Objective The objective of this paper is to explore genetic syndromes in fetuses with isolated unilateral renal agenesis (URA). Methods This was a retrospective study of 121 cases with isolated URA diagnosed on second trimester anatomy ultrasound. All cases underwent invasive prenatal diagnosis for copy number variant (CNV) detection by chromosomal microarray analysis (CMA). For those with a negative CNV, exome sequencing (ES) is an option. Clinical and laboratory data were collected and reviewed for these cases, including maternal demographics, prenatal sonographic findings, molecular sequencing results, and pregnancy outcomes. Results In total, 121 cases underwent CMA testing, which identified one case of trisomy X and two instances of pathogenic deletional CNVs, and specifically one deletion at 7q11.23 and another at 22q11.21. Among the cases that yielded negative results from CMA, 40 proceeded to trio ES. Notably, only one disease‐causing variant, c.2437 G > T (p.Glu813Ter) in the CHD8 gene, was detected in a single case. Conclusion The diagnostic yield of 2.48% for CNVs warrants the use of CMA during pregnancies complicated by URA. Monogenic conditions appear to be rarely involved in the pathology of isolated fetal URA.