The first round of European GWAS confirmed 8 T2D susceptibility loci across multiple ethnic groups: TCF7L2, SLC30A8, HHEX, CDKAL1, IGF2BP2, CDKN2A/B, PPARG, and KCNJ11. In addition to these 8 loci, the WTCCC/UKT2D study identified a strong association between FTO variants and T2D, although the effect of FTO variants on conferring susceptibility to T2D was mostly mediated through increase in body weight [55]. Here, TCF7L2 is linked to type 2 diabetes mellitus.