PRKN and Parkinson disease: Aberrantly increased ROS/RNS levels, as shown in the majority of sporadic cases in PD brains, phenocopied the effects of rare mutations in the gene encoding Parkin (PARK2) via the S-nitrosylation of Parkin-mediated mitochondrial dysfunction, protein misfolding and ubiquitin–proteasome system (UPS) impairment [150,211,212] (Figure 7).