Myeloperoxidase mutants lead to impaired ROS production, making the host susceptible to infection, and thus, both MPO and NADPH oxidase mutants are unable to eradicate fungal threats like chronic granulomatous disease (CGD) and IA (Lehrer and Cline, 1969; Aratani et al., 2004; Segal and Romani, 2009; Ren et al., 2012). The gene discussed is MPO; the disease is chronic granulomatous disease.