Mutations of the glucocerebrosidase (GBA) gene are the most important risk factor yet
discovered for Parkinson disease (PD). Homozygous GBA mutations result in Gaucher
disease (GD), a lysosomal storage disorder. Heterozygous mutations have not until recently
been thought to be associated with any pathological process. However, it is clear that the
presence of a GBA mutation in homozygous or heterozygous form is associated with an
approximately 20-fold increase in the risk for PD, with little if any difference in risk burden …