MC4R and obesity due to melanocortin 4 receptor deficiency: The observation that UM0130866 acute treatment restored the anorexigenic response of R165W-hMC4R-KI mice to MTII provides a proof of principle that the PC approach represents a promising therapeutic avenue for the treatment of obesity resulting from misfolded MC4R and demonstrates that this potentially new MC4R mouse model is a valid in vivo tool to test PC activity.