Chromosomal microarray analysis in fetuses with congenital anomalies of the kidney and urinary tract: A prospective cohort study and meta‐analysis

Objective To evaluate the usefulness and incremental diagnostic yield of chromosomal microarray analysis (CMA) compared with standard karyotyping in fetuses with congenital anomalies of the kidney and urinary tract (CAKUT). Methods A prospective cohort study and systematic review of the literature were conducted. In the prospective cohort study, 123 fetuses with CAKUT, as detected by prenatal ultrasound at our center, were enrolled and evaluated using karyotyping and CMA. In the meta‐analysis, articles in PubMed and ISI Web of Knowledge databases describing copy number variations (CNVs) in prenatal cases of CAKUT were included. Results Among the 123 fetuses in our prospective cohort study, 13 fetuses were detected with chromosomal abnormalities or submicroscopic chromosomal abnormalities by both karyotyping and CMA. In the remaining 110 fetuses, four pathogenic CNVs in four fetuses were only detected by CMA, indicating an excess diagnostic yield of 3.6%. Six publications and our own study met the inclusion criteria for the meta‐analysis. In total, 615 fetuses with CAKUT were included. The pooled data from all of the reviewed studies indicate that the incremental yield of CMA over karyotyping was 3.8%. Conclusion The use of CMA provides a 3.8% incremental yield of detecting pathogenic CNVs in fetuses with CAKUT and normal karyotype. What's already known about this topic? Congenital anomalies of kidney and urinary tract (CAKUT) are one of the most common birth defects in human. To date, the usefulness and diagnostic yield of chromosomal microarray analysis (CMA) in the prenatal cases of CAKUT was unclear. What does this study add? In this study, our data show that CMA revealed incremental diagnostic yields of 3.8% over karyotyping in fetuses with CAKUT. The most common pathogenic CNVs reported were 17q12 deletion and 22q11.2 deletion. The additional yield of variant of unknown significance was 2.0% in the meta‐analysis. It is reasonable to perform CMA when CAKUT are identified prenatally.