The obesity phenotype in POMC mutation carriers resulting in β-MSH deficiency (Tyr5Cys, Tyr221Cys, and Arg236Gly) implies a significant effect of β-MSH on body weight [66,67,68], underscoring the importance of β-MSH as a physiologically relevant melanocortin ligand. This evidence concerns the gene POMC and obesity due to melanocortin 4 receptor deficiency.