LRRK2 and Parkinson disease: Mutations in PTEN-induced putative kinase 1 (PINK1), Parkin, DJ-1, leucine-rich repeat kinase 2 (LRRK2) and vacuolar protein sorting-associated protein 35 (VPS35) highlight the relevance of mitochondrial dysfunction as a primary cause of neuronal death in PD (Court and Coleman, 2012; Park et al., 2014; Tang et al., 2015a,b).