TCF7L2 and type 2 diabetes mellitus: And that, this meta-analysis of the association between TCF7L2 gene and T2DM, only summarized IVS3C>T polymorphism by just analyze allele frequency [77], the authors did not generalize the association between other important variations such as IVS4G>T, IVS3T>C and IVS4G>C polymorphisms and T2DM.