LRRK2 encodes the 51-exon, multidomain protein, leucine-rich repeat kinase 2 (LRRK2); mutations in LRRK2 cause an autosomal dominant PD that, in most patients, produces a α-synuclein-type neuropathology.2, 3, 4. This evidence concerns the gene LRRK2 and Parkinson disease.