Mutations in GBA1 and LRRK2 each increase the risk of PD and both GBA1 and LRRK2 are important for lysosomal function as GBA1 encodes the lysosomal enzyme β-glucocerebrosidase [18] and LRRK2 may control lysosome levels within the cell [74]. This evidence concerns the gene GBA1 and Parkinson disease.