Missense mutations in the LRRK2 gene (dardarin), which are linked to changes in the coding region of the PARK8 locus [6]–[8], represent the most common cause of familial (up to 10% overall; up to 40% in certain ethnic populations) and sporadic (1–2%) late-onset forms of PD [7]–[14]. The gene discussed is LRRK2; the disease is Parkinson disease.