Association of 18bp insertion/deletion polymorphism, at −2549 position of VEGF gene, with diabetic nephropathy in type 2 diabetes mellitus patients of North Indian population

BACKGROUND Vascular endothelial growth factor (VEGF) is a potent multifunctional cytokine which plays a key role in the pathogenesis of diabetic micro-vascular complications. Human VEGF gene is said to be highly polymorphic. Insertion/deletion (I/D) polymorphism of the 18 bp fragment at -2549 position of the promoter region in VEGF gene is said to be of particular interest. The study was aimed to evaluate association of Insertion/deletion (I/D) polymorphism of the 18 bp fragment at -2549 position of the promoter region in VEGF gene, with diabetic nephropathy in type 2 diabetes mellitus. METHODS This cross sectional study enrolled 40 subjects each of diabetic nephropathy (DN), diabetes mellitus without nephropathy (DM) and normal control subjects. DNA was isolated from peripheral blood leukocytes. Genotyping of the VEGF gene insertion/ deletion (I/D) polymorphism was done by the polymerase chain reaction (PCR) methods. The frequency of VEGF alleles and genotype distribution were compared in diabetic nephropathy, uncomplicated diabetic and control groups. RESULTS DD genotype and D allele were found to be significantly associated with DN group (p = 0.009 and 0.02 respectively) in comparison to DM group. Also DD genotype conferred significant risk of diabetic nephropathy in DM group (OR = 4.2) (against combined frequency of ID and II genotype) so does D allele 2.09 (against I allele). CONCLUSION DD genotype and D allele in I/D polymorphism at -2549 position of VEGF gene is associated with increased susceptibility to diabetic nephropathy in north Indian population.