FTO and obesity due to melanocortin 4 receptor deficiency: These GWAS approaches have revealed that loci associated with obesity carry genes involved in pathways influencing neuro-circuits of appetite and satiety regulation (BDNF, MC4R, NEGR, POMC) (69–73), insulin secretion and action (TCF7L2, IRS1) (69, 74), adipogenesis (75) and energy and lipid metabolism [FTO, RPTOR, MAP2K5 (69, 74, 76)].