Variants of the single nucleotide polymorphism (SNP) rs9939609 of fat mass and obesity associated (FTO) gene are linked to obesity (Yang et al., 2012; Loos and Yeo, 2014), with the AA and AT genotypes considered at-risk compared to the TT genotype (Frayling et al., 2007; Jacobsson et al., 2012; Sällman Almén et al., 2013). The gene discussed is FTO; the disease is obesity due to melanocortin 4 receptor deficiency.