Gene therapy shows promise for Parkinson's
Severe tremors, rigidity of the limbs and loss of muscle control characterize Parkinson's disease, strikes as many as 100,000 Americans each year. The cause is unknown and the disorder results from death of brain cells that produce a neurotransmitter called dopamine. The dopamine plays a key role in transmitting commands from the brain's muscle control centers.
Researchers had two teams that used the same technology for performing gene therapy. They inserted a desired gene into a common virus called adeno-associated virus. The genes each team used where very different. Both teams' leaders had no financial ties to the company.
One team study, led by Dr. Matthew J During, used a gene that is the blueprint for an enzyme called glutamic acid decarboxylase. This enzyme converts chemicals in the cell into a neurotransmitter called GABA, which is important for controlling muscle movements. Injecting GABA directly into the brain ease symptoms of the disease but the hormone is quickly cleared out of the system.
Twelve patients were injected with one to three different concentrations of the gene therapy. All patients had improvement of Parkinson's system of at least twenty-five percent. Five of the twelve had an improvement between forty to sixty percent. These patients' benefits have been monitored for a year.
Dr. William J. Marks Jr led the second study. This study used the growth factor called neurturin. Twelve patients were injected with one of two different doses of the gene therapy. The patient receiving the lower dose had a forty percent decrease in Parkinson's symptoms while those receiving the higher dose had a fifty percent reduction. These patients have been monitored for nine months.
The first studies of human gene therapy for Parkinson's disease have shown that the technique is safe and can reduce...