Previously, both in vitro and rodent studies demonstrated that the gene products of CDKAL1, CDKN2BAS, and KCNQ1 are expressed in pancreatic β-cells and have critical roles in β-cell survival and function.[38–42] Moreover, SNPs in or near TCF7L2, CDC123/CAMK1D, HHEX, and TCF2 showed robust associations with the risk for lean T2D, but not with the risk for obese T2D. Here, TCF7L2 is linked to type 2 diabetes mellitus.