HO-1 has drawn much attention as a molecule with potent antioxidant, antiinflammatory, and anti-proliferative effects and several studies suggest that HO could be the target for drugs aimed to treat a high variety of diseases from cardiovascular disease to obesity [28–30], from organ transplantation to gastrointestinal affections [31–34]. Here, HMOX1 is linked to obesity due to melanocortin 4 receptor deficiency.