In addition, the brain-derived neurotrophic factor (BDNF) as well as its neurotrophic receptor kinase 2 (NTRK2) receptor are also strongly expressed in the VMN, and the deletion of BDNF and its receptor leads to hyperphagia and obesity in humans and mice (45, 46). The gene discussed is BDNF; the disease is obesity due to melanocortin 4 receptor deficiency.