Declaring it the "dawn of a new day in Parkinson's disease," acollaborative team of researchers announced they discovered a 10million base pair region on chromosome 4 containing a gene thatwhen mutated results in Parkinson's disease in one large Italianfamily.
Even though it will take several years to identify the precise geneinvolved, the researchers maintain the finding is important because itvalidates speculation genes play a role in the progressive loss ofneurons that gives rise to Parkinson's disease.
"This is the most important finding in Parkinson's disease to date,"says Dr. Roger C. Douvisin professor of neurology at the RobertWood Johnson Medical Center in New Brunswick, N.J., and seniorinvestigator of the study which is being published in today's Science.Douvisin suspects this is only the beginning of discoveries inParkinson's genetics because he "believes that all cases ofParkinson's are genetic."
Parkinson's disease is caused by the mysterious death of dopamine-producing neurons in the part of the brain that controls movement.The tremors, shuffling gait and rigidity associated with the diseasewere first formally described in 1817 by a London physician namedJames Parkinson. However, the pattern of symptoms were mentionedin ancient Ayurvedic and Chinese medical texts.
About 50,000 new cases will be diagnosed in the U.S. this year andapproximately 500,000 Americans currently suffer from the incurabledisease. Patients are usually given levadopa to supplement theirdwindling supply of dopamine producing neurons. However,eventually this added neurotransmitter fails to relieve the symptoms.
For over a hundred years, physicians and scientists have recognizedParkinson's appears to run in families, but could not get a handle onwhat role genes played in the disease. The team of scientists from theRobert Wood Johnson Medical School, the National Institute ofNeurological Disease and Stroke, the National Center for HumanGenome Research and the Instituto de Scienze Neurologiche inNaples, Italy, studied a single, large family of Italian descent tolocate the gene.
Gene Traced To Chromosome 4
The family which traces its origins 11 generations ago to the smallvillage of Contursi in the Salerno province of Italy has had 60 familymembers afflicted with Parkinson's in the last 4 generations. Theresearchers studied 28 members of the family, 9 of whom had thedisease. They found the alteration in an area of 10 million base pairson the long arm of chromosome 4 in an area where genes that areexpressed in brain tissue, like alcohol dehydrogenase andformaldehyde dehydrogenase, can be found.
"Right now, any guess would be wild," said Mihael Polymeropolous,M.D. of the National Center for Human Genome Research inBethesda, MD. "But, we do know that people who inherit one copyof this gene have an 85% chance of developing Parkinson's disease."
The researchers, as yet, don't know if this gene, whatever it is, isresponsible for all cases of inherited Parkinson's or if it is unique tothis Italian family. NINDS Director Zack Hall, noted, "This studyshows there is a significant genetic component to Parkinson's diseaseand the time is right for the genetic approach."
While the discovery offers nothing to patients at the moment,eventually finding the gene can help researchers and pharmaceuticalcompanies come up with new and better treatments aimed at thedirect cause of Parkinson's disease. National Institutes of Healthdirector Harold Varmus, maintained the finding "offers hope andinspiration and paves the way for more productive scientific researchin this very important disease." n
-- Lisa Seachrist Washington Editor
(c) 1997 American Health Consultants. All rights reserved.