TCF7L2 and type 2 diabetes mellitus: An association between the SNPs investigated and T2DM was definitely confirmed, but their effect was relatively mild, with the odds ratios for most variants ranging from 1.10 to 1.20, with a maximum of about 1.4 for TCF7L2 rs7903146 T. TCF7L2 rs7903146 T is the most prominent of all T2DM-associated common polymorphisms identified to date [13, 22].