Fighting Parkinson’s With Genes
The first successful double-blind study on gene therapy in a neurological disorder has given scientists cause for optimism.
Last March, Emad Eskandar, director of stereotactic and functional neurosurgery at MGH, and his colleagues published the first evidence that gene therapy—transferring genes into patients to relieve the symptoms of a disorder—may be effective in treating Parkinson’s disease. The researchers modified a common cold virus to carry a gene that makes the enzyme glutamic acid decarboxylase, or GAD, into an area of the brain called the subthalamic nucleus. GAD is necessary for the production of GABA, a neurotransmitter in the subthalamic nucleus that is depleted in Parkinson’s.
The results of the therapy were small but significant: Compared with patients who underwent sham surgery, those who received the actual treatment experienced greater improvement (even the sham surgery had some effect). Though there are still questions—from how long such improvements will last and what the long-term effects of introducing viruses into the brain may be to how gene therapy compares with deep brain stimulation, which produces similar results—the study was the first successful randomized, double-blind gene therapy trial for a neurological disorder. It gives researchers fresh enthusiasm for further study of gene therapy for Parkinson’s disease and other neurological problems, such as Alzheimer’s disease, Huntington’s disease and severe depression.