GBA1 and Parkinson disease: Here, we report on technical aspects of a phase I clinical trial of microbubble-assisted MRgFUS in patients with PD and mutations in GBA1 [24], in which a 55 kDa recombinant form of the human beta-glucocerebrosidase enzyme (encoded by GBA1) was delivered biweekly across BBB to the putamen, a key brain structure related to movement.