Gene May Accelerate Memory Loss

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Alzheimer's-Related Gene May Accelerate Memory Loss in Healthy Adults

ST. PAUL, MN -- Accelerated memory loss may occur in healthy adults with the gene variant known as apolipoprotein E-4 (apoE-4), according to a study in the July 13 issue of Neurology, the scientific journal of the American Academy of Neurology.

The apoE-4 gene is associated with an increased risk for Alzheimer's disease. Those with two copies of the apoE-4 gene have the highest risk for developing the disease.

"According to our results, normal memory loss that occurs in all people as they age starts earlier for people with two copies of the apoE-4 gene compared to those of the same age with one or no copies of the gene," said neurologist and study author Richard Caselli, MD, of the Mayo Clinic Scottsdale in Scottsdale, AZ. "Although the memory loss was within the normal range of performance, accelerated memory loss can be an early sign of Alzheimer's disease."

Researchers studied a group of 100 healthy adults an average age of 56 who had at least one immediate family member with Alzheimer's disease. Participants were divided into three groups based on those with zero, one or two copies of the apoE-4 gene variant. Participants were tested on behavioral and mental abilities, delayed memory (the recall of events that occurred at an earlier time period) and immediate memory (recalling a list or event that occurred within seconds). Brain imaging tests were used to measure activity within specific brain regions of 20 people without the apoE-4 gene, 10 people with one gene and 10 of those with two copies of the gene.

All participants had normal behavioral and mental abilities, but those with two copies of the apoE-4 gene showed age-related decline in both immediate and delayed memory. Typically, a decline in delayed memory is an early sign of Alzheimer's disease.

Brain imaging tests of those with two copies of the apoE-4 gene showed mildly lower brain metabolism in parietal, temporal and frontal lobe regions compared to those with one or no copies of the gene. Reduced metabolism in the brain's parietal and temporal lobes may signal early Alzheimer's disease even before memory loss becomes noticeable.

"These results provide clues for identifying the age in which Alzheimer's disease may actually begin," said Caselli. "If we can identify Alzheimer's before it starts, in the future we may be able to develop preventative measures to fight the disease."

Caselli advises patients against undergoing genetic testing to determine the presence or number of the apoE-4 gene. "Currently there is no cure or preventative therapy for Alzheimer's that necessitates testing for the apoE-4 gene," said Caselli. "And even if a person has two copies of the apoE-4 gene doesn't mean he or she is destined to get the disease."

Alzheimer's disease affects nearly four million people in the United States. Alzheimer's is a debilitating, life-altering disease that attacks the brain, causing progressive loss of memory and reasoning skills. Patients also suffer difficulties with vision, language skills, judgment, personal care skills and emotional control.

The American Academy of Neurology, an association of more than 15,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research.

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