Background:Shroom family member 3 (SHROOM3) encodes an actin-associated protein that regulates epithelial morphology during development. Several genome-wide association studies (GWAS) have identified genetic variances primarily in the 5’ region of SHROOM3, associated with chronic kidney disease (CKD) and poor transplant outcomes. These genetic variants are associated with alterations in Shroom3 expression.Objective:Characterize the phenotypic abnormalities associated with reducedShroom3expression in postnatal day 3-, 1-month and 3-month-old mice.Methods:The Shroom3 protein expression pattern was determined by immunofluorescence. We generatedShroom3heterozygous null mice (Shroom3Gt/+) and performed comparative analyses withwild typelittermates based on somatic and kidney growth, gross renal anatomy, renal histology, renal function at postnatal day 3, 1 month, and 3 months.Results:The Shroom3 protein expression localized to the apical regions of medullary and cortical tubular epithelium in postnatalwild typekidneys. Co-immunofluorescence studies confirmed protein expression localized to the apical side of the tubular epithelium in proximal convoluted tubules, distal convoluted tubules, and collecting ducts. WhileShroom3heterozygous null mice exhibited reduced Shroom3 protein expression, no differences in somatic and kidney growth were observed when compared towild typemice. Although, rare cases of unilateral hypoplasia of the right kidney were observed at postnatal 1 month inShroom3heterozygotes. Yet renal histological analysis did not reveal any overt abnormalities in overall kidney structure or in glomerular and tubular organization inShroom3heterozygous null mice when compared towild typemice. Analysis of the apical-basolateral orientation of the tubule epithelium demonstrated alterations in the proximal convoluted tubules and modest disorganization in the distal convoluted tubules at 3 months inShroom3heterozygotes. Additionally, these modest abnormalities were not accompanied by tubular injury or physiological defects in renal and cardiovascular function.Conclusion:Taken together, our results describe a mild kidney disease phenotype in adultShroom3heterozygous null mice, suggesting that Shroom3 expression and function may be required for proper structure and maintenance of the various tubular epithelial parenchyma of the kidney.