Considering that the prevalence of metabolic syndrome, type 2 diabetes, obesity, coronary artery disease and hypertension increases as individuals get older, it is possible that BDNF functions as a protective factor against metabolic and cardiovascular disorders, and that decreased peripheral BDNF synthesis, secondary to aging, renders individuals more susceptible to these conditions. The gene discussed is BDNF; the disease is obesity due to melanocortin 4 receptor deficiency.