Six genes have been identified so far that cause autosomal dominant forms of PD (SNCA, LRRK2, VPS35, EIF4G1, DNAJC13 and CHCHD2), while three genes (Parkin, PINK1 and DJ-1) are associated with autosomal recessive forms of PD. The gene discussed is LRRK2; the disease is Parkinson disease.