In agreement with these findings, several previous studies in European populations have reported that the risk variant(s) of TCF7L2 can be associated with lower BMI [35]–[37], whereas a few studies (involving<5,000 participants) have not detected significant association between measures of fatness and genetic variants of type 2 diabetes risk loci except FTO and MC4R; here, the risk variants of these 2 loci increase both type 2 diabetes susceptibility and BMI [38], [39] (Figure 6A). Here, FTO is linked to type 2 diabetes mellitus.