BSMI single nucleotide polymorphism in vitamin D receptor gene is associated with decreased circulatory levels of serum 25-hydroxyvitamin D among micro and macrovascular complications of type 2 diabetes mellitus.

Vitamin D Receptor (VDR) gene single nucleotide polymorphism (SNP) in the intron 8 is a well characterized SNP which has previously been linked to various diseases including Type 2 Diabetes Mellitus (T2DM). However, the association of this SNP with micro and macrovascular complications of T2DM remains poorly studied. Hence, the present study was designed to investigate the association of VDR gene SNP with complications of T2DM (disease phenotype) and correlated it with the serum levels of (25[OH]D) (intermediate phenotype) along with other clinical risk factors of T2DM. Genotyping was carried out in a total of 866 subjects, in which Group-I had Control subjects (n = 252), Group-II with T2DM without complications (n = 200); Group-III and Group-IV had subjects with micro (n = 216) and macrovascular (n = 198) complications respectively by PCR -RFLP. The 'G' allele of the VDR gene SNP is associated with a significant risk for T2DM, Diabetic Neuropathy (DN) and Coronary Artery Disease (CAD). In addition, subjects with mutant GG genotype had lower levels of (25[OH]D) in both T2DM and micro-macrovascular complications than AA genotype. Thus, VDR (rs1544410) SNP was found to be associated with decreased serum (25[OH]D) levels in both micro-macrovascular complications of T2DM among South Indian Population.