Uromodulin rs4293393 T>C variation is associated with kidney disease in patients with type 2 diabetes.

Background & objectives: Uromodulin, a UMOD gene encoded glycoprotein is synthesized exclusively in renal tubular cells and released into urine. Mutations lead to uromodulin misfolding and retention in the kidney, where it might stimulate cells of immune system to cause inflammation and progression of kidney disease. Genome-wide association studies (GWAS) have identified UMOD locus to be associated with hypertension and diabetic nephropathy (DN). In this study, we investigated the association between rs4293393 variation in UMOD gene and susceptibility to kidney disease in individuals with type 2 diabetes mellitus (T2DM). Methods: A total of 646 individuals, 208 with T2DM without evidence of kidney disease (DM), 221 with DN and 217 healthy controls (HC) were genotyped for UMOD variant rs4293393T>C by restriction fragment length polymorphism. Serum uromodulin levels were quantified by enzyme-linked immunosorbent assay. Results: A significant difference was found in genotype and allelic frequency among DM, DN and HC. TC+CC genotype and C allele were found more frequently in DN compared to HC (33.9 vs 23.0%, P=0.011 and 20.1 vs 12.9%, P=0.004, respectively). Compared to DM, C allele was found to be more frequent in individuals with DN (20.1 vs 14.7%, P=0.034). Those with DN had higher serum uromodulin levels compared to those with DM (P=0.001). Serum uromodulin levels showed a positive correlation with serum creatinine (r=0.431; P<0.001) and negative correlation with estimated glomerular filtration rate (r=-0.423; P<0.001). Interpretation & conclusions: The frequency of UMOD rs4293393 variant with C allele was significantly higher in individuals with DN. UMOD rs4293393 T>C variation might have a bearing on susceptibility to nephropathy in north Indian individuals with type 2 diabetes.