TCF7L2 and type 2 diabetes mellitus: In another study, SNPs in twelve candidate loci (TCF7L2, IDE/KIF11/HHEX, SLC30A8, CDKAL1, PKN2, IGF2BP2, FLJ39370, and EXT/ALX4) were genotyped in 993 African American patients with T2D, and 1,054 control patients without T2D.