Conversely, patients with Parkinson’s disease that carry mutations in the gene encoding the lysosomal enzyme glucocerebrosidase (GBA) show deficits in visuospatial tasks (Alcalay et al., 2012), have impaired visual memory (Zokaei et al., 2014) and show a higher frequency of visual hallucinations (Neumann et al., 2009; Wang et al., 2014) than patients with idiopathic Parkinson’s disease. This evidence concerns the gene GBA1 and Parkinson disease.