In a similar fashion, homozygous mutations in the gene coding for the glucocerebrosidase (GBA) enzyme cause Gaucher's disease, a lysosomal storage disease characterized by the accumulation of GBAs (51), while heterozygous variants in GBA have been associated with an increased risk of PD (52), DLB (66) and PD with dementia (67). This evidence concerns the gene GBA1 and Parkinson disease.