TCF7L2 and type 2 diabetes mellitus: Thus, the significant genetic contribution to the development of T2D, substantial ethnic differentiation, contradictory results of previous studies in assessing the strength of associations between the rs7903146 polymorphism of the TCF7L2 gene and the risk of T2D, and the absence of similar studies on prediabetes, indicate the need for replicative associative studies of this polymorphism in cases of prediabetes within the Kazakh population.