Melanocortin 4 Receptor (MC4R)

Melanocortin receptor 4 is a protein that in humans is encoded by the MC4R gene. It encodes the MC₄ protein, a G-protein coupled receptor that binds α-melanocyte stimulating hormone (α-MSH). In murine models MC₄ receptors have been found to be involved in feeding behaviour, the regulation of metabolism, sexual behaviour, and male erectile function. In 1998, it was reported that MC4R mutations were associated with inherited human obesity. They were found in heterozygotes, suggesting an autosomal dominant inheritance pattern. However, based on other research and observations, these mutations seem to have an incomplete penetrance and some degree of codominance. It has a prevalence of 1-2.5% in people with BMIs of greater than 30, making it the most commonly known genetic defect predisposing people to obesity.