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Gene That Fights Alzheimer's May Inspire New Treatments
Posted: Tuesday, July 17, 2012 1:39 AM
Joined: 12/6/2011
Posts: 3326

From Alzheimer's Daily News:

(Source: Reuters) - A gene that causes the rare, early-onset form of Alzheimer's disease can also stave off the devastating illness, scientists announced on Wednesday.

"Less than 1 percent of the population has these alleles," or DNA variants, said Dr. William Thies of the Alzheimer's Association. "So there's no impetus to go out and get tested. But many companies are working on compounds that target the mechanism they found and so might be encouraged by these results."


Alzheimer's disease is defined by the presence of sticky plaques, composed of a peptide called amyloid beta. Amyloid beta comes from a larger protein called amyloid precursor protein, or APP. Over the last two decades, scientists have identified some two dozen mutations in the APP gene that cause early-onset Alzheimer's, which strikes before age 65.


A novel mutation in the APP gene does the opposite, scientists at deCODE Genetics in Reykjavik found. Persons 85 or older who have the beneficial mutation were 81 percent less likely to develop the neurodegenerative disease. The variant also makes developing Alzheimer's four times less likely across all age groups.


"It confers extraordinarily strong protection," said Stefansson. "We found only five Alzheimer's cases (out of thousands of people) with it."


Because the beneficial mutation is so rare, however, its value is likely to be in pointing the way to drugs that prevent or treat Alzheimer's, rather than encouraging testing to see which patients have the variant.


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