Vicennati et al. [15] observed a lower ghrelin/obestatin ratio in the blood plasma of obese women and suggested that disparate changes in circulating ghrelin and obestatin level represent adaptive modifications to obesity development rather than primary defects and that their alteration in circulating blood levels reflects an imbalance of regulatory factors or mechanisms responsible, in turn, for their metabolic processes and action. The gene discussed is GHRL; the disease is obesity due to melanocortin 4 receptor deficiency.