X-linked variations in <i>SHROOM4</i> are implicated in congenital anomalies of the urinary tract and the anorectal, cardiovascular and central nervous systems.

Abstract

<i>SHROOM4</i> is thought to play an important role in cytoskeletal modification and development of the early nervous system. Previously, single-nucleotide variants (SNVs) or copy number variations (CNVs) in <i>SHROOM4</i> have been associated with the neurodevelopmental disorder Stocco dos Santos syndrome, but not with congenital anomalies of the urinary tract and the visceral or the cardiovascular system. Here, exome sequencing and CNV analyses besides expression studies in zebrafish and mouse and <i>knockdown</i> (KD) experiments using a splice blocking morpholino in zebrafish were performed to study the role of <i>SHROOM4</i> during embryonic development. In this study, we identified putative disease-causing SNVs and CNVs in <i>SHROOM4</i> in six individuals from four families with congenital anomalies of the urinary tract and the anorectal, cardiovascular and central nervous systems (CNS). Embryonic mouse and zebrafish expression studies showed <i>Shroom4</i> expression in the upper and lower urinary tract, the developing cloaca, the heart and the cerebral CNS. KD studies in zebrafish larvae revealed pronephric cysts, anomalies of the cloaca and the heart, decreased eye-to-head ratio and higher mortality compared with controls. These phenotypes could be rescued by co-injection of human wild-type <i>SHROOM4</i> mRNA and morpholino. The identified SNVs and CNVs in affected individuals with congenital anomalies of the urinary tract, the anorectal, the cardiovascular and the central nervous systems, and subsequent embryonic mouse and zebrafish studies suggest <i>SHROOM4</i> as a developmental gene for different organ systems.