However, persistent hyperlipidemia can provoke ROS and generate peroxynitrite (OONO–) which ultimately lead to tissue oxidative stress by increasing the activities of three primary oxidant producing enzyme systems; NADPH oxidases, xanthine oxidase (XO), and myeloperoxidase (Cai and Harrison 2000; Balkan et al. The gene discussed is FMO5; the disease is hyperlipidemia.