In patients with obesity, intracellular targets such as the deacetylating enzyme sirtuin-1 (SIRT-1), adenosine monophosphate-activated protein kinase (AMPK), and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) are altered [67]. The gene discussed is SIRT1; the disease is obesity due to melanocortin 4 receptor deficiency.