SYN1 and obesity due to melanocortin 4 receptor deficiency: Recently, we reported that synapsin 1-Cre-mediated neuronal ablation of GHS-R totally prevents high-fat diet-induced obesity [15]; we further reported that specific deletion of GHS-R in Agouti-related protein (AgRP) neurons mitigates diet induced obesity, at least in part, through activation of thermogenesis [16].