A large number of studies have shown significant link of certain SNPs in VDR and impaired insulin secretion and sensitivity as well as increased risk of T2DM.7,8 Only a few studies investigated SNPs in GC (the main carrier of VitD) in T2DM and found that these SNPs increase the risk of T2DM.9 In regards with CYP2R1, only a single recent study conducted in Chinese population by Wang et al.10 Has found an association between two SNPs in CYP2R1 and T2DM risk. This evidence concerns the gene CYP2R1 and type 2 diabetes mellitus.