Numerous genes have unequivocally been tied to familial PD, including SNCA, PRKN, PINK1, DJ1, LRRK2, ATP13A2, and PLA2G6. 4, 5 This “familial form” of PD, however, accounts for only a small percentage of overall PD diagnoses. Here, LRRK2 is linked to Parkinson disease.