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Common Gene Suspected In Alzheimer's, Parkinson's By JOHN FAUBER [log in to unmask] Posted: April 27, 2004 San Francisco - For years, doctors have known that Alzheimer's and Parkinson's disease share some common traits. Now, a new study suggests they may share a common gene. Scientists Tuesday said they have found evidence that a gene on chromosome 10 may play a role in both brain disorders. The finding could have important consequences for understanding the causes of both diseases and developing treatments. "This is the first time that there has been a corresponding linkage of evidence for both Alzheimer's and Parkinson's," said the study's lead author, Nathan Pankratz, a researcher in the department of medical and molecular Genetics at Indiana University. The research, which involved genetic analysis of about 400 families with siblings who had Parkinson's, was presented Tuesday at the American Academy of Neurology annual conference. Pankratz said the finding makes sense, given what doctors already know about the symptoms and possible causes of the disorders. Both are diseases of aging that involve clumps of protein forming in the brain. Oxidative stress also seems to play a role in both diseases, he said. And in both diseases, brain cells die, said Mark Hallett, chief of the human motor control section at the National Institutes of Health. "We don't know why the neurons degenerate," Hallett said. "There very well could be some common mechanism." In addition, dementia, a trademark in Alzheimer's, also occurs in a substantial number of Parkinson's patients. "The more we find about these (diseases), the more I think there will be overlap," said Nicholas Wood, a professor of clinical neurology and neurogenetics at the Institute of Neurology in London. In the coming years it's likely that several common genes will be found, said Wood, who presented his own research Tuesday involving genetic causes of Parkinson's. The Indiana University study is the second in the last two years suggesting a common gene or genes for both diseases. In 2002, researchers at Duke University found that a common gene may control the age at which the two diseases occur. Treatment implications Finding a common gene or genes could have important implications for new treatments. "If we find what the gene does, we might be able to develop a therapy that corrects the problem," Pankratz said. Indeed, other research presented Tuesday suggests that identifying people early on who are predisposed to neurodegenerative diseases may be a big step in limiting the damage. In one study, researchers with the Honolulu Department of Veterans Affairs found that the loss of brain cells in Parkinson's disease begins 13 years before the disease is diagnosed. That conclusion was reached by examining the brains of 12 deceased Parkinson's patients and counting brain cells in the area of the brain affected by the disease. That finding was compared with brain cell counts in 174 deceased men of similar ages who did not have Parkinson's. "If people destined to develop Parkinson's disease could be identified during this preclinical window, then, theoretically, it should be possible to intervene with some treatment to prevent the symptoms of Parkinson's from developing fully," co-author G. Webster Ross, a Honolulu VA neurologist, said in a statement. Drug shows promise In other Parkinson's research, scientists reported that after two years of having an experimental drug pumped continuously into their brains, five patients with advanced Parkinson's continued to show improvement in symptoms. The study, which was first reported about a year ago, involved researchers from Great Britain and the University of Wisconsin-Madison. Parkinson's is a disorder in which neurons that produce the chemical dopamine die or degenerate in a brain region that controls movement. That causes symptoms such as tremors, slow movement, a loss of facial expression and speech problems, as well as depression and dementia. The five patients received a continuous infusion of a substance known as glial-cell-derived neurotrophic factor, a protein that has been compared to plant food. Rather than just treat symptoms, the drug is believed to promote the health of dopamine-producing brain cells. After two years, patients had an average 44% improvement in symptoms. In addition, brain scans showed a significant increase in the amount of dopamine being taken up by brain cells where the drug was delivered. Before treatment, the patients were immobile 30% to 40% of the day, said study co-author Gary Hotton, a researcher at Imperial College and Hammersmith Hospital in London. Now, they are able to do everyday activities, such as brushing their teeth and eating, he said. Later this year, the researchers expect to report the results of the drug compared with a placebo in 37 new patients. If that study is successful, researchers say, the drug eventually might be delivered using genetically engineered stem cells. From the April 28, 2004 editions of the Milwaukee Journal Sentinel SOURCE: The Milwalkee Journal Sentinel http://www.jsonline.com/alive/news/apr04/225470.asp * * * ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn