Vitamin D receptor (FokI, BsmI and TaqI) gene polymorphisms and type 2 diabetes mellitus : A North Indian study

BACKGROUND: The vitamin D receptor (VDR) gene is a candidate gene for susceptibility to several diseases. Studies on association between VDR polymorphisms and risk of type 2 diabetes (T2DM) in different ethnic populations are yet inconclusive. AIMS: This study was conducted to evaluate association between VDR polymorphisms and genetic susceptibility to T2DM in the north Indian population. SETTINGS AND DESIGN: One hundred clinically diagnosed T2DM patients and 160 healthy controls from the north Indian population were recruited for genetic association study. MATERIALS AND METHODS: Genomic DNA was extracted from blood and genotyped for the single nucleotide polymorphism SNPs of FokI (T/C) [rs2228570], BsmI (A/G) [rs1544410] and TaqI (C/T) [rs731236] by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. STATISTICAL ANALYSIS USED: Genotype distribution and allelic frequencies were compared between patients and controls. Mean values and odds ratios (ORs) with 95% confidence interval (CI) were calculated using SPSS software (version 15.0). RESULTS: The genotype distribution, allele and haplotype frequencies of VDR polymorphism did not differ significantly between patients and controls. Mean age and waist-hip ratio of patients were found to be associated with VDR polymorphism. Combination studies showed FFBbtt increased the risk of T2DM in north Indians. CONCLUSIONS: Our data suggest that VDR gene polymorphism in combination of genotypes is associated with the risk of T2DM and thus requires further studies as a probable genetic risk marker for T2DM.