NOX2-containing NADPH oxidases have emerged as a major source of OS in PD (Gao et al., 2003a; Qin et al., 2004; Wu et al., 2005; Kim et al., 2007; Gao et al., 2012; Marrali et al., 2018; Sun et al., 2020) (Figure 5). Here, FMO5 is linked to Parkinson disease.