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THURSDAY, April 15 (HealthDayNews) -- Identification of a gene that causes a rare, inherited form of Parkinson's disease could revolutionize research on the condition and other neurological disorders, researchers report.

"It is a completely novel and, to my mind, completely unexpected gene/protein to be involved in Parkinson's disease," said Dr. Nicholas W. Wood, a professor of clinical neurology and neurogenetics at the Institute of Neurology in London and lead author of a report on the discovery in the April 16 issue of Science. "It opens the door to a whole new area of Parkinson's disease, and perhaps other neurodegenerative disease research."

Parkinson's disease is a progressive disorder caused by degeneration of nerve cells in the part of the brain that controls movement. First described as "the shaking palsy" in 1817, it affects an estimated 500,000 Americans, with 50,000 new cases reported each year. The most famous Parkinson's patient is Pope John Paul II.

The first symptoms of the condition generally occur at about age 60. The gene described by Wood and collaborators in three European countries and the United States was identified in three families in which the disease appears much earlier in life.

Close study found that members of those families all had a mutation of a gene designated PINK1, which makes a protein active in mitochondria, cellular units that convert food into energy. A first guess is the normal version of the gene protects mitochondria in brain cells against damage, but that is just a starting point, Wood said.

"We need to know more about what the protein does normally, as well as when it is mutated," he said. "This will involve structural chemistry, biochemistry, cell and animal model systems."

Another question is the role the gene might play in the common form of the condition, Wood said.

"I do not think primary pathogenic mutations in this gene are likely to contribute to lots of common forms of Parkinson's disease, but we will need to sequence a lot of individuals to be certain what proportion of cases are due to mutations in this gene," he said.

The discovery has some potential applications to the detection and treatment of Parkinson's disease, Wood said.

"Initially, I think it will be most useful as a genetic test, to sequence at-risk individuals and counsel the families," he said. "However, this new area does of course open the way for potential novel therapeutic targets."

It's an important finding because it helps confirm a suspicion about the role of mitochondrial malfunction in Parkinson's and other neurological diseases, said Dr. Robert Nussbaum, chief of the genetic diseases research branch of the National Human Genome Research Institute, a part of the National Institutes of Health. His group helped identify one of the families in the study.

"For many years, it has been suggested that there is a connection between Parkinson's disease and mitochondrial dysfunction," Nussbaum said. "We've never really understood what defects inside the mitochondria might lead to dysfunction. Now this points to a protein, or set of proteins, that when altered can induce the disease. This is a process that we didn't know existed, and it could be involved in the more common forms of Parkinson's disease."

More information

The role of genetics in Parkinson's disease is explained by the National Human Genome Research Institute, while you can get background on the condition from the National Institute of Neurological Disorders and Stroke.

(SOURCES: Nicholas W. Wood, M.D., Ph.D, professor, clinical neurology and neurogenetics, Institute of Neurology, London; Robert Nussbaum, M.D., chief, genetic diseases research branch, National Human Genome Research Institute, Bethesda, Md.; April 16, 2004, Science)

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