TCF7L2 and type 2 diabetes mellitus: This large meta-analysis summarizes the strong evidence for an association between TCF7L2 gene and T2DM both overall and in Caucasians, North Europeans, East Asians, Indians, and Africans, and suggested a potential multiplicative genetic model for all the four polymorphisms of TCF7L2 gene among different ethnic populations except for Africans, where additive genetic mode is suggested for IVS3C>T polymorphism.