Gene therapy for Parkinson's disease: where are we now and where are we going?

Thousands of patients worldwide have received some kind of gene therapy. A subset of those patients have received intracranial injections of adeno-associated viruses encoding various therapeutic genes directed at ameliorating the symptoms of Parkinson’s disease. In this article, the authors briefly review the current status of Phase I and Phase II trials of gene therapy for Parkinson’s disease and preview some of the ongoing work aimed at improving delivery of genes that promise to make adeno-associated virus-based therapy safer and more accessible for patients and neurologists around the world.