LRRK2 and Parkinson disease: In familial PD cases, pathological mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common genetic cause, reaching up to 40% in some ethnic groups, such as Ashkenazi Jewish and North African Arab Berbers and, in addition, LRRK2 is also found mutated in approximately 1–3% of idiopathic PD cases [2,3].