TCF7L2 and type 2 diabetes mellitus: The transcription factor 7-like 2 (TCF7L2) gene is a downstream effector of the canonical Wnt/β-catenin signaling pathway and represents the most potent locus known for T2DM risk (13–17), linking the pathogenesis of T2DM to altered Wnt/β-catenin/TCF7L2 signaling.