LEP and obesity due to melanocortin 4 receptor deficiency: The variants selected were linked to low serum leptin (p.L72S, p.N103K, p.R105W, p.C117Y, and p.P23R) (12, 25, 26, 27, 28) and/or those associated with obesity with a less clear or debated mechanism-of-action (p.H118L, p.S141C, p.D100N) (29, 30, 31) (Table 1).