TUESDAY, June 12 (HealthDay News) -- A common genetic risk
factor for Alzheimer's disease disrupts brain function in healthy
older women but has little effect in men, a new study has
People with two copies (one from each parent) of the ApoE4 gene
variant are at extremely high risk for Alzheimer's. Only 2 percent
of people have two copies of the variant, while about 15 percent of
people carry a single copy.
In this study of 91 healthy older people, researchers looked at
those with a single copy of the ApoE4 variant and found that women,
but not men, exhibited two characteristics that have been linked to
The women had a signature change in their brain activity and
elevated levels of a protein called tau in their cerebrospinal
The study, published June 13 in the
Journal of Neuroscience, is the first to identify this gender difference in healthy older adults with one copy of the ApoE4 variants, according to a Stanford University news release.
The findings suggest that men who carry a single copy of the
gene variant shouldn't be assumed to be at increased risk for
Alzheimer's disease. The findings also may help explain why women
are more likely than men to develop Alzheimer's disease, said Dr.
Michael Greicius, assistant professor of neurology and neurological
sciences and medical director at the Stanford Center for Memory
Disorders, and colleagues.
Alzheimer's disease affects nearly 5 million people in the
United States and nearly 30 million people worldwide, the news
release noted. For every three women with Alzheimer's, about two
men have the disease.
The U.S. National Institute of Neurological Disorders and Stroke
has more about