POMC and obesity due to melanocortin 4 receptor deficiency: However, studies of humans with POMC mutations resulting in aberrant forms of β-MSH (due to disruption of the receptor binding site; Lee et al., 2006; or production of an aberrant β-MSH/β-endorphin fusion protein; Challis et al., 2002) have suggested that β-MSH is important in controlling appetite and obesity development in man, with hyperphagia notable in patients with both mutations.