TCF7L2 and type 2 diabetes mellitus: TCF7L2 and KCNQ1 were previously considered to be the strongest type 2 diabetes susceptible genes in Caucansians and East Asians [9], [12]–[15], [17]–[20], [40]–[43], both of which were well replicated in Han Chinese [25], [35], [40], [41], [44], [45].