LRRK2 and Parkinson disease: Risk factors of idiopathic PD, most common in late-onset PD cases, include a combination of genetic (e.g. mutations in leucine rich repeat kinase 2” (LRRK2) or glucosylceramidase-β) and environmental factors (e.g. pesticide exposure, prior head injury, rural living, and intensive use of β-blockers).