TCF7L2 and type 2 diabetes mellitus: By comparing patients with either lean or obese BMI to the full set of normal glycemic controls in the DMS, the present study identified that genetic variants in or near CDKAL1, CDKN2BAS, KCNQ1, TCF7L2, CDC123/CAMK1D, HHEX, and TCF2 were associated with the risk for lean T2D, and genetic variants in or near KCNQ1 and FTO were associated with the risk for obese T2D in Chinese Han patients.