Familial PD is characterized by autosomal dominant and recessive mutations in several genes such as α-synuclein (SNCA), ubiquitin C-terminal hydrolase L1 (UCHL-1), phosphatase and tensin homolog-induced putative kinase 1 (PINK1), PARKIN (PRKN), protein deglycase (DJ-1), and leucine-rich repeat kinase 2 (LRRK2) [33]. Here, LRRK2 is linked to Parkinson disease.