FTO and obesity due to melanocortin 4 receptor deficiency: The most studied variant from FTO is the SNP rs9939609 (g.87653T>A), in which carriers of the risk allele A (homozygous or heterozygous) have increased odds for obesity and higher calorie, fat, and carbohydrate intake (Daya et al., 2019; Mehrdad et al., 2020).