Leptin and adiponectin, hormones produced primarily by adipocytes, are involved not only in glucose and lipid metabolism, controlling energy homeostasis, but also in the modulation of inflammation, appearing to play a role in the relationship between obesity and neuronal/glial function (Minokoshi et al., 2002; Yamauchi et al., 2002). The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.