The involvement of UCP1 in adrenergically induced thermogenesis demonstrates that UCP1 plays a significant role in the control of energy expenditure; its dysfunction contributes to the development and maintenance of obesity (Feldmann et al., 2009; Inokuma et al., 2006; Ricquier and Bouillaud, 2000). The gene discussed is UCP1; the disease is obesity due to melanocortin 4 receptor deficiency.