GBA1 and Parkinson disease: Mutations and polymorphisms in GBA are estimated to be found in up to 12% of patients with PD of European descent, and mutations in 15%–20% of Ashkenazi Jewish cases, making GBA the most significant genetic risk factor for PD.1, –, 5GBA-associated PD has been shown to manifest at a younger age and with a lower median survival time from diagnosis compared to idiopathic PD.6, –, 8 Further, GBA mutation status is an independent risk factor for cognitive impairment.3,5,9, –, 11