LRRK2 G2019S mutation does not contribute to Parkinson's disease in South India

Background: The frequency of leucine-rich repeat kinase 2 (LRRK2) G2019S mutation, the most common genetic cause of Parkinson's disease (PD), shows significant variation based on ethnicity. Earlier reports suggest a very low frequency or absence of this mutation in Asians. Objective: To analyze the frequency of LRRK2 G2019S mutation in sporadic and familial cases of PD and normal controls of common ethnicity from South India. Patients and Methods: We used direct sequencing technique of all DNA samples in a clinic-based study of sporadic (n = 100) and familial PD patients (n = 86 index cases) and normal controls (n = 100) of common ethnicity from South India. Results: None among the patients or controls had the G2019S mutation. Conclusion: The founding events that influenced a number of other populations/ethnicities had no impact on the genetic makeup of PD patients from South India. Our findings support the current view that G2019S-associated PD may be population-specific. This has implications in genetic testing for PD and selection of subjects for potential future gene-based therapeutic trials for G2019S carriers in such populations.