PRKN and Parkinson disease: Aging represents the greatest risk factor for idiopathic PD, and while impairments in PINK1–Parkin-dependent mitophagy might be difficult to detect experimentally under basal conditions, cumulative oxidative cellular damage associated with long-term deficits in the removal of damaged mitochondrial components fits mechanistically with observations of age-related dopaminergic neurodegeneration in PD.