X-linked variations inSHROOM4are implicated in congenital anomalies of the urinary tract and the anorectal, cardiovascular and central nervous systems

Abstract

BackgroundSHROOM4is 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) inSHROOM4have 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.MethodsHere, exome sequencing and CNV analyses besides expression studies in zebrafish and mouse andknockdown(KD) experiments using a splice blocking morpholino in zebrafish were performed to study the role ofSHROOM4during embryonic development.ResultsIn this study, we identified putative disease-causing SNVs and CNVs inSHROOM4in 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 showedShroom4expression 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-typeSHROOM4mRNA and morpholino.ConclusionThe 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 suggestSHROOM4as a developmental gene for different organ systems.

Modelling human lower urinary tract malformations in zebrafish

“…Similarly, phalloidin staining can be employed to visualize cytoskeleton actin filaments and by this to analyze cloaca morphogenesis (Fig. 2 E) [ 14 , 19 , 31 ]. This allows the evaluation of cellular organization of the cloacal epithelium and size of the lumen of the distal pronephros and hindgut inserting into the cloaca (Fig.…”

“…As a useful functional assessment to determine the in vivo functionality of the hindgut and cloaca, a sulforhodamine excretion-assay can be applied [ 17 , 31 ]. Here, zfl are bathed in sulforhodamine, a red fluorescent dye, for several hours at day 5 post-fertilization.…”