Previous research has identified over 20 PD causal mutations in SNCA, LRRK2, VPS35, PINK1, DJ-1, Parkin, FBXO7, DNAJC6, ATP13A2, DCTN1, and SYNJ1 (for review, see ref. 1 and MDS Taskforce database: www.mdsgene.org). This evidence concerns the gene LRRK2 and Parkinson disease.