Increasing evidence supports a contribution of impaired energy metabolism and mitochondrial dynamics to the pathogenesis of monogenic and sporadic PD, that is, for at least seven established PD genes (PINK1, Parkin, DJ-1, LRRK2, ATP13A2, SNCA, and VPS35), a role in mitochondrial homeostasis and clearance has been described (24). The gene discussed is LRRK2; the disease is Parkinson disease.