NADPH oxidase-dependent production of superoxide is involved in the increase in oxidative stress that is observed in a variety of brain disorders, including cerebral ischemia (Sugawara and Chan, 2003; Suh et al., 2008; Yoshioka et al., 2011), traumatic brain injury (Dohi et al., 2010), sepsis-associated encephalopathy (Hernandes et al., 2014), and psychiatric disorders as well as Alzheimer’s disease, Parkinson’s disease and other neurodegenerative diseases (Sorce and Krause, 2009). Here, FMO5 is linked to Parkinson disease.