 |
 |
Hints of a Parkinson's 'cluster' Thursday, May 16, 2002 - NEW YORK - 2 years ago, after giving up his television series "Spin City," Michael J. Fox created a medical research foundation that already is renowned for its fast-paced disbursements to scientists. Since April of last year, the Michael J. Fox Foundation for Parkinson's Research has given out nearly $17 million to help finance 57 studies. The foundation supports studies covering everything from gene therapy to the effects of caffeine on Parkinson's disease. It has recently dedicated $4.4 million to developing stem cell lines that could be implanted in the brains of Parkinson's patients to replace the dopamine-producing cells they have lost. It is about to underwrite strategies for reducing dyskinesia, the involuntary movements that are side effects of taking L-dopa, the drug used most often to quell the tremors and rigidity of Parkinson's disease. Fox's celebrity can do more than raise money. It may also help open an avenue of research that scientists have long wanted to explore. Fox, it turns out, was one of 4 people who worked on a production crew at a television studio in Vancouver in the late 1970s and developed Parkinson's disease. Given that only 125 people worked on the crew in those years - including actors, directors, writers, production people and technicians - the number of cases seems extraordinary. Typically, Parkinson's disease afflicts 1 in 300 people. In people as young as Fox, 30 when the disease was diagnosed in 1991, the illness is much rarer. Fewer than 5 percent of Parkinson's patients develop symptoms before age 50, said Caroline Tanner of the Parkinson's Institute. So the situation is even more unusual because the Vancouver cluster includes Fox and a woman who learned she had Parkinson's at age 38. The 4 people worked together from 1976 to 1980, when it is possible that the disease began in all of them. Parkinson's progresses gradually, taking 5 to 10 years from the time it starts to the appearance of the first symptoms - usually, rigidity in an arm or leg or tremor in a hand. Donald Calne, director of the neurodegenerative disorders center at the University of British Columbia, estimates that the odds of the four cases occurring at the same time in such a small group of people are less than 1 in 1,000. He and other scientists say the cluster warrants investigation. "I would say that would certainly show up on my radar screen," said William Langston, director of the Parkinson's Institute in Sunnyvale, California, and chief scientific adviser to the Fox Foundation. "I would definitely want to look further." Clusters of Parkinson's cases occur from time to time, when, for example, a number of people in a neighborhood or small town develop the disease. But they often go unnoticed or are ignored because scientists lack the time and money to look into them. In this case, the publicity surrounding Fox's admission that he had Parkinson's, nearly three and half years ago, drew the cases into the spotlight. Don Williams, who directed Fox in two Canadian situation comedies beginning when the actor was 16, also has Parkinson's. He learned of his illness 9 years ago, when he was 55. Sally Gardner, whose Parkinson's was diagnosed when she was 38, in 1984, had been a script supervisor in the late 1970s, and had worked with Fox and Williams. The fourth member of the cluster is a cameraman who has kept his identity secret; his diagnosis came at age 54. Could something at the television studio have caused the disease in all 4 people? Calne, Langston and other experts believe it could have. Perhaps something they breathed or ate or drank - a toxin, perhaps, or an infectious agent - set the disease process in motion. "If this is a genuine cluster and not a statistical fluke," said Oliver Sacks, a neurologist and writer, "it would certainly suggest an environmental agent at work." The mystery is especially compelling because scientists do not know what causes most cases of Parkinson's. Most believe that both genetic and environmental factors are at work. "We often say that maybe people have some gene that predisposes them to be susceptible to any number of things in the environment," said William Weiner, chairman of neurology department at the University of Maryland School of Medicine. "But that's probably just another way of saying we don't know the cause." The disease occurs when cells in the substantia nigra, a darkly pigmented part of the midbrain, about half the size of an adult index fingernail, start to die off. These cells produce dopamine, a chemical messenger that is essential for normal muscle movement. The cell death occurs gradually, and that is why Parkinson's can go unnoticed for so long. Once dopamine production declines by about 80 percent, the patient begins to experience the 4 classic symptoms: tremor, stiffness, slow movement and problems with walking, posture and balance. In some cases, the cell death is set off by genetic mutations. Scientists have identified two genes that are involved in Parkinson's and have pinpointed the locations of 4 others. But Parkinson's does not seem to be primarily a genetic disorder. It runs in the families of only about 10 percent to 15 percent of patients, Tanner of the Parkinson's Institute said. A large study she conducted indicated that the identical twins of Parkinson's patients are no more likely to have the disease than fraternal twins - a sign that the disease is not largely genetic. Environmental agents have also been known to create symptoms. In the era of World War I, for example, some people who had contracted the virus that causes sleeping sickness later developed what came to be known as post-encephalitic parkinsonism, a particularly severe disorder that left people in trancelike states. It is possible that a virus could also have been involved in the so-called Fox cluster. "It is important to look for infectious as well as toxic agents," Sacks said. Mary Duenwald The New York Times Copyright 2002 The International Herald Tribune http://www.iht.com/articles/57830.htm janet paterson: an akinetic rigid subtype, albeit perky, parky pd: 55/41/37 cd: 55/44/43 tel: 613 256 8340 email: [log in to unmask] smail: 375 Country Street, Almonte, Ontario, Canada, K0A 1A0 a new voice: http://www.geocities.com/janet313/ ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn