At a genetic level, the population frequency of mutations in both genes, especially in specific populations such as the Ashkenazim and Imazighen, has resulted in a number of individuals harboring PD-associated mutations in LRRK2 and GBA1, and there is evidence from the literature that supports an interaction at a clinical level between the impact of mutations in the two genes [14,15]. This evidence concerns the gene GBA1 and Parkinson disease.