Monogenic forms of obesity are estimated to account for 4% to 6% of severe obesity before age 6, with LEPR and MC4R genes being the most common etiologies [21, 23].An estimated 5% to 6% of children and adults with obesity have a MC4R germline pathogenic [23, 24]. Here, MC4R is linked to obesity due to melanocortin 4 receptor deficiency.