MC4R and obesity due to melanocortin 4 receptor deficiency: Another encouraging therapeutic approach is the use of a selective MC4R agonist, which has been proven successful in the treatment of POMC-deficient obesity (Kuhnen et al., 2016) as well as in humans with non-genetic obesity (Chen et al., 2015a) and in non-human primates (Kievit et al., 2013).