FMO5 and Parkinson disease: Apart from that, the mitochondrial complex I inhibition and other bioenergetic impairment, autoxidation or enzymatic oxidation of dopamine, and activation of microglial NADPH oxidase are also responsible for increased ROS formation in the PD brain (Jana et al., 2011; Bisaglia et al., 2014; Ganguly et al., 2017; Puspita et al., 2017; Guo et al., 2018).