MC4R and obesity due to melanocortin 4 receptor deficiency: In particular, common variants within the fat-mass and obesity associated (FTO) and melanocoritin 4 receptor (MC4R) genes are associated with modest effects on BMI (0.2–0.4 kg/m2 per allele) which translate into increased odds of obesity of 1.1–1.3 in adults [24], [26], [27], [28], [29].