October 29, 2003
Scientists at Duke University and other medical centers have uncovered a gene that may play a role in determining the age at which symptoms of Alzheimer's and Parkinson's disease first appear. The finding may open up new avenues of research to target therapies that may delay the onset of these devastating ailments.
"Although physicians generally consider Alzheimer and Parkinson diseases to be distinct disorders, the two exhibit a lot of overlap both clinically and pathophysiologically," said Jeffrey Vance, M.D., a study author. "This study emphasizes the similarity between the two diseases by highlighting a single gene that influences their age of onset."
Scientists have uncovered a number of inherited factors that increase one's risk for Alzheimer's, the leading cause of dementia in seniors that affects some 4.5 million Americans. Various genes, for example, are known to increase susceptibility to early-onset disease, a rare form of Alzheimer's that runs in families and causes mental deterioration as early as age 30. Genes also play a role in the far more common late-onset form of Alzheimer's, as well as the stiffness, trembling and loss of balance that characterize Parkinson's disease.
"By combining evidence based on gene expression and genetic association, we found a gene that modifies when the diseases start," said Yi-Ju Li, Ph.D., the study's lead author. "Understanding the role this gene plays in Alzheimer and Parkinson disease may, in the future, lead to a means to delay the disorders' onset." Even a short delay would benefit many at-risk patients and their caregivers, experts say.
The researchers, from Duke University's Center for Human Genetics and other medical centers, looked at gene activity in the hippocampus, a seahorse-shaped part of the brain that serves as a control center for memory. They examined 1,773 people with Alzheimer's and another 635 with Parkinson's disease, and compared them with several hundred healthy people who did not have either illness.
One gene, called GST01, for glutathione S-transferase omega-1, showed variations that were associated with the age of symptom onset. The researchers speculate that the gene may play a role in inflammation, which may underlie the development of a number of serious maladies, including Alzheimer's.
'This is an interesting and unexpected report that awaits independent confirmation," comments Samuel E. Gandy, M.D., Ph.D., Chairman of the Scientific Advisory Board of the Fisher Center for Alzheimer's Research Foundation. Much more research is needed to determine the precise role of this and other genes in the development of Alzheimer's. This study, however, presents an additional step in the search for a cure. The findings will be published in the December 15, 2003 issue of the scientific journal Human Molecular Genetics and appeared in the on-line version last week.
By Toby Bilanow, Medical Writer, for www.ALZinfo.org, The Alzheimer's Information Site.
Reviewed by Samuel E. Gandy, M.D., Ph.D., Chairman of the Scientific Advisory Board, Fisher Center for Alzheimer's Research Foundation.