It's behind a paywall, but read [1]:
"in a cohort of 876 patients with Parkinson's disease, based on the observation that LRRK2 is a shared genetic risk factor. We identified 2 patients with Crohn's diseases; this number was consistent with the number of cases expected in the general population."
Reference:
"Occurrence of Crohn's disease with Parkinson's disease"
Shinsuke Fujioka et al.
Parkinsonism & Related Disorders, April 2017.
Occurrence of Crohn's disease with Parkinson’s disease - ScienceDirect
John