CYP2R1 and type 2 diabetes mellitus: These results might differ in other population from other ethnic backgrounds as ethnicity has a possible impact on the association of VitD with genetic variation.11 Moreover, including more number of SNPs in the genes GC and CYP2R1 and DHCR7 in future studies when investigating the association between VitD genes and T2DM might give a stronger support whether these VitD related genes have a vital role and involvement in T2DM.