Gene Variant Could Lower Alzheimer's Risk
Jan. 13 -- TUESDAY, Jan. 12 (HealthDay News) -- A gene variant that is good for the heart also appears to be good for the brain, slowing age-related decline in mental function and cutting the odds for Alzheimer's disease, a study indicates.
"If you carry two copies of the favorable form of the gene, it reduces the risk of Alzheimer's disease by 70 percent," explained study lead author Dr. Richard B. Lipton, professor and vice chair of neurology at Albert Einstein College of Medicine in New York City.
Drugs that mimic the activity of the gene variant already are being developed, said Lipton, whose group reported the finding in the Jan. 13 issue of the Journal of the American Medical Association.
A 2003 study by Lipton and his associates identified a variant of the gene for cholesterol ester transfer protein (CETP) -- involved in carrying cholesterol in the bloodstream -- as being associated with a longer life span. "The longer you live, the more common is the favorable variant," Lipton noted. "The incidence is 5 percent at age 50 and 35 percent at age 95."
The new study followed 523 people, all age 70 or older, for four years, testing their mental function and relating it to the variant of the CETP gene they carried.
Participants who carried two copies of the variant gene experienced an age-related decline in mental function that was about half as rapid as people with two normal versions of the gene, the study found.
Individuals with two copies of the favorable CETP variant also had a reduced risk of developing Alzheimer's disease compared to those with two normal versions of the gene, the study found.
Besides its effects on the brain, the favorable CETP gene variant also appears to boost blood levels of HDL ("good") cholesterol, which helps prevent artery-blocking clots from forming.
How does the gene variant work its magic? Lipton put forth two theories.
"We know that it protects against disease in blood vessels," he said. "It lowers the risk of heart attack and stroke, and stroke is a risk factor for cognitive decline. So it protects the brain against atherosclerotic disease.
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