My coauthors and I thank Gutti and colleagues for their interest in our study on GBA mutations in PD. We fully agree with them that the 2.4% frequency of GBA mutations that we found in our Chinese population is likely to be an underestimate, and direct sequencing of the entire gene would have been the preferred screening method because additional mutations could be uncovered, as Gutti and colleagues have highlighted.
Differences in ethnicity, sample size, inclusion criteria of the patients, and mutational screening techniques may partly explain the contradictory results of the association between GBA mutations and PD reported in the literature. We have studied only L444P and N370S mutations because these 2 mutations are the most extensively examined by various investigators, thus allowing our findings to be appropriately compared with others.
Tan E. The Need for Appropriate Genotyping Strategies for Glucocerebrosidase Mutations in Cohorts With Parkinson Disease—Reply. Arch Neurol. 2008;65(6):849-852. doi:10.1001/archneur.65.6.851-a