Alongside NGF and BDNF alterations, hyperleptinemia and an increased number of mast cells in subcutaneous abdominal adipose tissue are also reported (Sornelli et al., 2007; Tore et al., 2008), shedding light on the role of these metabotrophins in the pathogenesis of obesity and related diseases. Here, NGF is linked to obesity due to melanocortin 4 receptor deficiency.