Gene therapy trial for Parkinson's disease

For the first time, gene therapy has shown promise for people with severe Parkinson's disease. Results from a proof-of-concept clinical trial in the US were published in the journal Lancet Neurology. Experts have welcomed the study, but stress more research is needed to assess long-term safety.

Parkinson's disease affects around 120,000 people in the UK and symptoms include slowness of movement, shaking and stiffness of muscles. The trial was designed to increase levels of a brain chemical called GABA (gamma-Aminobutyric acid), which is lacking in people with the condition.

The small study included 45 people with severe Parkinson's disease. Participants had a small tube implanted in their brains. The tube leads to areas that control movement. Half were then injected with a virus containing a gene to increase GABA production in brain cells. Half were injected with a harmless saline solution.

After six months, people who had been given the gene therapy showed a 23 percent improvement in movement, compared to a 12 percent improvement in those who had been given saline. There were no serious side effects during the six-month study.

Dr Michelle Gardner, from the charity Parkinson's UK, said: 'This research shows the promise of gene therapy for neurological conditions like Parkinson's. But further research is still needed... We still don't know for how long the benefits of this treatment may last or whether there may be long-term problems due to introducing viruses into the brain'. She added: 'Any new treatment must be shown to be more effective than those currently available for Parkinson's, which this treatment has not yet been shown to be'.