TCF7L2 and type 2 diabetes mellitus: First, the exact underlying molecular mechanisms of our positive findings remains to be explored, but we speculated that TCF7L2 rs7903146 polymorphism may lead to alternations in gene expression or changes in protein structure, which may subsequently affect biological functions of TCF7L2, impact insulin secretion or decrease sensitivity to insulin, and ultimately affect individual susceptibility to T2DM.