UCP2 and obesity due to melanocortin 4 receptor deficiency: On the other hand, reduced expression of Pomc (Bjorbaek and Hollenberg, 2002) and Ucp2 (Coppola et al., 2007) as well as hyperphagia would predict, together with the slight decrease in leptin receptor expression, a positive energy balance and obesity, possibly due to partial leptin resistance.