In a second study, the same group of researchers found that amyloid plaques begin to accumulate in the brains of people with the PSEN1 mutation when they are in their late 20s.
The findings will "help set the stage for the evaluation of treatments to prevent familial Alzheimer's disease, and hopefully aid our understanding of the early stages of late-onset Alzheimer's disease, which is more widespread," the researchers wrote in the report.
Nick Fox, a professor at the Institute of Neurology at University College London, wrote a journal commentary that accompanied the first study.
"These findings question our models of Alzheimer's disease on several fronts. They suggest that neurodegenerative changes occur over 20 years before symptom onset and somewhat earlier than was suggested by previous brain imaging studies of individuals at risk of inherited Alzheimer's disease," Fox wrote.
"Further research is needed, but one interpretation of these results might be that they add to the accumulating evidence that Alzheimer's disease is characterized by a long presymptomatic period of slowly progressive changes that can potentially be tracked, thereby opening up a therapeutic window for early intervention," he added.
The U.S. National Institute of Neurological Disorders and Stroke has more about Alzheimer's disease.
-- Robert Preidt
SOURCE: The Lancet Neurology, news release, Nov. 5, 2012
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