Three TCF7L2 SNPs (rs7901695, rs7903146, and rs12255372) have shown a strong association with impaired insulin secretion, susceptibility to T2DM, and some T2DM complications (i.e., diabetic retinopathy, CVD, and CAD), both at the genotypic and allelic levels (27). This evidence concerns the gene TCF7L2 and type 2 diabetes mellitus.