Only approximately 10% are familial, arising through mutations in mitochondria-associated genes, including SNCA (α-synuclein), LRRK2 (leucine-rich repeat kinase 2), Parkin (PARK2), PINK1 (phosphatase and tensin homolog induced putative kinase 1), PARK7 (protein deglycase DJ-1), and ATP13A2 (ATPase type 13A), pointing to the important role of mitochondrial dysfunction in the pathogenesis of PD [74]. The gene discussed is LRRK2; the disease is Parkinson disease.