The successful use of setmelanotide has opened doors for clinical trials of treatments for other monogenic deficiencies of the leptin–melanocortin pathway, such as MC4R-deficiency (which occurs in a far larger cohort than POMC deficiency) and leptin receptor deficiency the sufferers of which, for obvious reasons, are resistant to leptin treatment. This evidence concerns the gene LEP and hyperinsulinemic hypoglycemia, familial, 4.