Chronic Granulomatous Disease (CGD) is an inherited primary immunodeficiency in which the NADPH oxidase complex loses some or all function, resulting in the inability of neutrophils and other phagocytic cells to generate sufficient reactive oxygen species (ROS) necessary to kill pathogens after engulfment.1,2 As a result, patients experience recurrent and often life-threatening bacterial and fungal infections and suffer from inflammatory complications. The gene discussed is FMO5; the disease is chronic granulomatous disease.