Previous reports have found that NADPH oxidase can be activated and produce a large amount of related ROS in the brain of a PD model and that it plays a key role in chronic neuroinflammation and related dopaminergic neurodegeneration in PD (Peterson and Flood, 2012; Qin et al., 2013; Wang et al., 2015; Hou et al., 2017a). Here, FMO5 is linked to Parkinson disease.