Studies showed that the estimates of the heritability of T2D range from 30% to 70%, depending on the age of diabetes onset and the glycemic status of cases.7 For now, more than 100 T2D-susceptibility genes have been mapped in human including TCF7L2, GCK, KCNJ11, PPARG.7 Here, GCK is linked to type 2 diabetes mellitus.