Specific mutations in genes that participate in the leptin-melanocortin pathway, such as those encoding leptin, leptin receptor (LepR), melanocortin-4 receptor (MC4R), and pro-opiomelanocortin (POMC), are recognized to cause monogenic forms of obesity (Butler, 2016). This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.