FTO and obesity due to melanocortin 4 receptor deficiency: In 2007, the GWAS study identified FTO as an obesity sensitivity gene, and multiple SNPs in the intron 1 region were strongly associated with BMI, body fat rate, waist circumference, hip circumference, and energy intake (Dina et al., 2007; Frayling et al., 2007; Scuteri et al., 2007).