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Alzheimer's Risk Gene Disrupts Brain Function in Healthy Older Women, but Not Men
Myriam
Posted: Wednesday, June 13, 2012 3:50 PM
Joined: 12/6/2011
Posts: 3326


From Alzheimer's Daily News: 

 

(Source: ScienceDaily ) - Investigators at the Stanford University School of Medicine found that the most common genetic risk factor for Alzheimer's disease disrupts brain function in healthy, older women, but has little impact on brain function in healthy, older men.  


 

Women harboring the gene variant, known to be a potent risk factor for Alzheimer's disease, show brain changes characteristic of the neurodegenerative disorder that can be observed before any outward symptoms manifest.

 

Both men and women who inherit two copies (one from each parent) of this gene variant, known as ApoE4, are at extremely high risk for Alzheimer's. The double-barreled ApoE4 combination is uncommon, affecting only about 2 percent of the population, whereas about 15 percent of people carry a single copy of this version of the gene.

 

The researchers demonstrated for the first time the existence of a gender distinction among outwardly healthy, older people who carry the ApoE4 variant. In this group, women but not men exhibit two telltale characteristics that have been linked to Alzheimer's disease: a signature change in their brain activity, and elevated levels of a protein called tau in their cerebrospinal fluid (CSF).

 

Study findings included:

 

  • The implication that men revealed by genetic tests to carry a single copy of ApoE4 shouldn't be assumed to be at elevated risk for Alzheimer's.
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  • For every three women with Alzheimer's disease, only about two men have the neurodegenerative disorder explained Dr. Michael Greicius.
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  • Besides age, another major risk factor is genetic: possession of a particular version of the gene known as ApoE. But the heightened risk ApoE4 imposes may be largely restricted to women.
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  • The CSF of women, but not men, who carried at least one E4 allele was substantially enriched in tau. Elevated tau levels in cerebrospinal fluid are a key biomarker of Alzheimer's disease.
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Go to full story: http://www.sciencedaily.com