LRRK2 and Parkinson disease: In 2002, Funayama et al. described a locus on chromosome 12 linked to PD in a family from the Sagamihara region of Japan (Funayama et al. 2002), and, in 2004, two independent groups identified autosomal dominant mutations in the LRRK2 gene (Paisán-Ruíz et al. 2004; Zimprich et al. 2004).