PINK1 and Parkinson disease: PINK1 facilitates axonal transport and degradation of damaged mitochondrias (Valente et al., 2004a; Liu, 2014), and this PINK1 activity is altered in both the PD (Valente et al., 2004b; Albanese et al., 2005; Gelmetti et al., 2008) and aging (Wood-Kaczmar et al., 2008; Vincow et al., 2013) brain.