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September 30, 2010

Coffee Could Help Shed More Light On Battling Parkinson’s

Researchers have discovered a gene that may help explain why coffee helps to lower the risk of Parkinson's disease for some people.

Haydeh Payami of the New York State Department of Health told the World Parkinson Congress in Glasgow on Wednesday that about a quarter of the population carries this version of the gene, and drug developers may be more successful if they test people for it.

Payami told the meeting that only people with this particular version of the gene are likely to be helped by an experimental class of drugs designed to mimic some of the coffee's benefits.

"We are trying to explain why some people benefit from the effects of coffee in terms of reducing the risk of getting Parkinson's disease and others don't," Payami said in a telephone interview with Reuters.

"But by extension I am proposing that this translates into explaining why drugs that are like caffeine that are in clinical trials are not succeeding," she added.

"The immediate application right now would be for people who already have Parkinson's."

Parkinson's patients with and without the specific gene are currently being included in the study.

His team studied 4,000 people, half of which had Parkinson's, by using an Illumina "gene chip" to show an entire genetic map of each volunteer.

They identified a gene called GRIN2A that appeared to protect people who drank coffee from the disease.

"About 25 percent of the population has the variant that boosts the protective effect of coffee," Payami told Reuters.

GRIN2A is linked to glutamate, a compound that is thought to kill the brain cells that die off in Parkinson's patients.  Glutamate can affect another compound known as adenosine, and coffee interferes with this process.

Adenosine A2A receptor antagonists have been tested against Parkinson's and other neurological diseases.  The team's genetic findings may help explain the disappointing results of these drugs.

"If this gene really is interacting with coffee to boost neuroprotection, it should work in these clinical trials," she told Reuters.

Caffeine can protect nerves, but could also cause unappealing side effects, including jitters.  Payami said the drugs are designed to reduce these side effects.

"I think it is about time we brought genetics into the design of clinical trials for Parkinson's disease," she told Reuters.

"This work shows the potential of using genetic and epidemiological approaches to identify new risk factors for Parkinson's disease," Margaret Sutherland of the NINDS, one of the U.S. National Institutes of Health, told Reuters.

Parkinson's is a fatal and incurable brain disease that affects 1 to 2 percent of people over the age of 65.  The disease starts with tremors, sluggish movement, muscle stiffness, and difficulty with balance.

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