SNCA and Parkinson disease: Mutations in the genes LRRK2 (enriched with leucine repeats kinase 2) and SNCA (alpha-sinuclein) are well-known causes of autosomal dominant Parkinson's disease, mutations in the Parkin, PINK1 and DJ-1 genes, mediate autosomal recessive and early forms of PD (Bonifati et al. 2003a; Annesi et al. 2005).