Polypoid Change of the Glomerular Basement Membrane in a Child with Steroid Resistant Nephrotic Syndrome and ARHGAP24 Mutation: A Case Report

Steroid resistant nephrotic syndrome (SRNS) is increasingly recognised to have a genetic basis following the identification of a number of mutations within genes encoding podocyte and basement membrane proteins. The ARHGAP24 gene product is a recently recognised important player in podocyte interaction with the glomerular basement membrane. The ARHGAP24 gene encodes a protein involved in regulating cell motility, membrane structure and polarity. Mutations in the gene have been shown in vitro to cause cell membrane ruffling.

We report a novel missense mutation in exon 4 (c.[284G>A]; p.[Arg95Gln]) of the ARHGAP24 gene in a child that presented with SRNS at four years of age. Renal biopsy demonstrated unusual polypoid changes of the glomerular basement membrane (GBM).

We propose this novel ARHGAP24 mutation as causative for SRNS associated with unusual polypoid basement membrane changes. These biopsy findings, in association with ARHGAP24 mutation and clinical nephrotic syndrome are a novel finding. This finding may advance the understanding of ARHGAP24 gene product function.