FMO5 and sickle cell disease: Studying the oxidative stress in sickle cell disease, George and collaborators demonstrated the presence not only of NOX1 and NOX5, but also catalytic subunits that are necessary to the NADPH oxidase complex in both normal and sickle erythrocytes, suggesting that these may be the primary active isoforms of NADPH oxidase-mediated ROS generation in erythrocytes [27].