High levels of ROS can occur by: (1) high production of ROS from the cellular oxidative metabolism in mitochondria; (2) a low level of antioxidant compounds or enzymes (i.e., superoxide dismutase (SOD), catalase, or glutathione in the system [5]; or (3) hyperglycemia in bloodstream promoting the release of interleukin-1 (IL-1), excessive glucose autoxidation, and lipid peroxidation [34]. The gene discussed is CAT; the disease is Hyperglycemia.