LRRK2 and Parkinson disease: Among these, mutations in the leucine-rich repeat kinase 2 gene (LRRK2) [4] or in the α-synuclein gene [5] are causes of PD autosomal dominant forms, whereas genes involved in autosomal recessive PD include parkin [6], PTEN-induced putative kinase 1 (PINK1) [7], DJ-1 [8] and ATP13A2 [9].