GBA1 and Parkinson disease: GBA1 variants were also significantly more common (9.5%) in patients with a diagnosis of idiopathic RBD (iRBD) made by video-polysomnography (PSG), compared with controls (4.1%), and GBA1-positive iRBD patients showed significantly increased rate of conversion to neurodegenerative conditions (mainly PD) compared with GBA1-negative iRBD [18].