FTO and obesity due to melanocortin 4 receptor deficiency: To further investigate the functions/roles of the FTO gene and their related pathways, we examined in the present study the metabolite profiles according to the FTO genotype, based on the rs9939609 SNP, which have been clearly shown in a number of previous studies to be associated with obesity (Ali, Shkurat & Abbas, 2021; Tanofsky-Kraff et al., 2009), using a targeted metabolomic approach.