For example, several genes [e.g., α-synuclein, parkin, PTEN-induced putative kinase 1 (PINK1), DJ-1, and leucine-rich repeat kinase 2 (LRRK2)] associated with PD are involved in the generation of reactive oxygen species (ROS) and proteolysis in the mitochondrial outer membrane4. Here, PINK1 is linked to Parkinson disease.