Most cases of Parkinson's disease are not caused by a defective gene, but rather by exposure to as yet unknown chemicals in the environment, California scientists reported today.
The discovery should provide some comfort to family members of Parkinson's victims who fear for their own future health, said the research team from the Parkinson's Institute in Sunnyvale. The study also suggests that research should focus on potential environmental causes, such as pesticides and herbicides, they added.
Dr. Caroline M. Tanner and her colleagues at the Parkinson's Institute report in today's Journal of the American Medical Assn. that the disorder most commonly affected only one member of a twin pair, whether the pair consisted of identical or fraternal twins.