LRRK2 and Parkinson disease: The cohort included individuals diagnosed with PD (N = 149), the at-risk group (N = 158) which consists of individuals identified based on specific genetic (GBA, LRRK2, SNCA) and/or prodromal (polysomnography-proven RBD, hyposmia) markers, and unaffected controls (N = 35) (Tables 2 and 6).