... in the case of Parkinson’s disease, the most common genetic risk factor identified to date came about from an unanticipated clinical finding made in the genetics clinic during studies of patients with the rare lysosomal storage disorder Gaucher's disease. In most populations with Parkinson’s disease, mutations in the glucocerebrosidase (GBA) gene are more frequent than in other implicated genes including dardarin (LRKK2),α-synuclein (SNCA), and parkin (PARK2).

The link between the GBA gene and parkinsonism