TCF7L2 and type 2 diabetes mellitus: TCF7L2, highly expressed in white adipose tissue, also has a fundamental role in adipogenesis by directly regulating the expression of genes implicated in lipid and glucose metabolism, while the loss of TCF7L2 in adipocytes leads to reduced glucose tolerance, increased insulin resistance, weight gain, and increased amount of subcutaneous adipose tissue in mice fed with high-fat diet, predisposing animals to develop T2D [40,50].