Briefly, the terms “melanocortin 4 receptor,” “MC4R,” “leptin receptor,” “LEPR,” “proopiomelanocortin,” “POMC,” “Bardet-Biedl syndrome,” “BBS,” and/or “PCSK1” were used in combination with “obesity” with the case reports filter applied to identify studies reporting on patients with hyperphagia in populations of interest. Here, PCSK1 is linked to obesity due to melanocortin 4 receptor deficiency.