The distribution and risk effect of GBA variants in a large cohort of PD patients from Colombia and Peru

Background: Mutations in the glucocerebrosidase (GBA) gene are an important risk factor for Parkinson's disease (PD). However, most GBA genetic studies in PD have been performed in patients of European origin and very few data are available in other populations. Methods: We sequenced the entire GBA coding region in 602 PD patients and 319 controls from Colombia and Peru enrolled as part of the Latin American Research Consortium on the Genetics of Parkinson's disease (LARGE PD). Results: We observed a significantly higher proportion of GM mutation carriers in patients compared to healthy controls (5.5% vs 1.6%; OR = 4.3, p = 0.004). Interestingly, the frequency of mutations in Colombian patients (9.9%) was more than two-fold greater than in Peruvian patients (4.2%) and other European-derived populations reported in the literature (4-5%). This was primarily due to the presence of a population-specific mutation (p.K198E) found only in the Colombian cohort. We also observed that the age at onset was significantly earlier in GBA carriers when compared to non-carriers (47.1 +/- 14.2 y vs. 55.9 +/- 14.2 y; p = 0.0004). Conclusion: These findings suggest that GBA mutations are strongly associated with PD risk and earlier age at onset in Peru and Colombia. The high frequency of GBA carriers among Colombian PD patients (similar to 10%) makes this population especially well-suited for novel therapeutic approaches that target GBA-related PD.