With data pointing to the PVN and MC4R as the key to unraveling the obesity phenotype in MRAP2 deficient mice and because all existing mouse models to date involve developmental deletion of MRAP2, we undertook this study to assess the effect of postnatal overexpression of MRAP2 in MC4R neurons of the PVN. The gene discussed is MC4R; the disease is obesity due to melanocortin 4 receptor deficiency.