GBA1 and lysosomal storage disease: Variants in the glucocerebrosidase (GBA1) gene, causing the lysosomal storage disorder Gaucher disease (GD) when present on both alleles, and leucine-rich repeat kinase 2 (LRRK2) gene are found in 10–15% and 1–2% of sporadic PD cases, respectively [4, 5], constituting the most important genetic risk factor for PD.