The classic BMI-related FTO SNPs were rs9939609 (T/A), and compared with those who did not carry the risk allele, 16% of adults who carried the homozygous risk allele gained nearly 3 kg in weight, and the risk of obesity increased by 1.67 times (Frayling et al., 2007). The gene discussed is FTO; the disease is obesity due to melanocortin 4 receptor deficiency.