The excess production of mitochondrial reactive oxygen species (ROS), including superoxide (O2−), hydrogen peroxide (H2O2), and the hydroxyl radical (OH), and decreased activity of antioxidant defences, such as catalase, glutathione peroxidases, and peroxiredoxins, have been postulated to contribute to obesity-induced metabolic perturbations [10,11,12,13]. The gene discussed is CAT; the disease is obesity disorder.