LRRK2 and Parkinson disease: This function is impaired by CD-linked LRRK2 mutation in CD cases, presumably due to the nonsense RNA decay of LRRK2. Our recent study of the occurrence of CD with PD cohort identified only 2 cases of co-occurrence out 876 PD patients (0.2%), which is within the known prevalence of CD (26.0–198.5 cases per 100,000 persons) (Fujioka et al. 2017).