Is the G2019S LRRK2 mutation common in all southern European populations?

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene, especially the G2019S mutation, have been identified as a common cause of Parkinson's disease in southern European and other Mediterranean populations (Iberians, Ashkenazi Jews and North African Arabs). Owing to the geographic and historic vicinity of Greece with areas of high prevalence of LRRK2 mutations we studied the frequency of the G2019S mutation in a well characterized cohort of familial and sporadic Parkinson's disease patients of Greek origin from mainland Greece. The prevalence of the LRRK2 R1441C mutation and the G2385R Asian polymorphism was also determined. We identified no patients with any of the studied mutations/polymorphisms. Very low prevalence of the LRRK2 G2019S mutation has been reported in other southern European populations. LRRK2 mutations appear to be limited in certain populations and differing ancestry and founder effects may explain the reported variability. Accurate estimations of the frequency and penetrance of different LRRK2 mutations are essential for correct and cost-efficient use of genetic testing and proper genetic counseling of patients with Parkinson's disease.