Three phase 1/2 clinical trials using an AAV9.CAG vector to deliver GBA1 to type 1 (clinicaltrials.gov: NCT05487599), type 2 (clinicaltrials.gov: NCT04411654), and PD patients with GBA1 mutations (clinicaltrials.gov: NCT04127578) are currently ongoing. The gene discussed is GBA1; the disease is Parkinson disease.