Although multiple melanocortin receptor agonists have been investigated, setmelanotide is currently the only MC4R agonist approved by the FDA for the treatment of specific genetic forms of obesity, including deficiencies in POMC, PCSK1, and LepR, as well as Bardet-Biedl syndrome (BBS) (135, 136). The gene discussed is PCSK1; the disease is Bardet-Biedl syndrome.