Folks with variant have almost double the risk of developing dementia, study finds
WEDNESDAY, April 14 (HealthDay News) -- Researchers have pinpointed a gene variant that nearly doubles the risk of developing late-onset Alzheimer's disease, a new study says.
A U.S. research team examined gene variations across the human genome, or full DNA sequence, of 2,269 people with late-onset Alzheimer's and 3,107 people without the disease. This research -- known as a genome-wide association study -- looks throughout the entire genome for small differences, or variants, in long stretches of DNA that are more prevalent in those with a particular disease or condition.
About 9 percent of those with late-onset Alzheimer's had a specific variation in the gene MTHFD1L on chromosome 6, according to the study. Only about 5 percent of those who did not have Alzheimer's had the variant.
Late-onset Alzheimer's, which affects those 60 and up, is the most common form of the brain disorder.
With the number of people with Alzheimer's expected to nearly double from 18 million worldwide to 34 million by 2025, according to the World Health Organization, researchers have been hunting for genes that play a role in Alzheimer's disease. The hope is that understanding the function of the genes could help in developing better treatments, which are sorely lacking.
So far, the primary known genetic contributor to late-onset Alzheimer's is a variant of the gene APOE on chromosome 19. The Alzheimer's-linked APOE variant occurs in about 40 percent of people who develop late-onset Alzheimer's, while about 25 to 30 percent of the general population has it, according to the National Institute on Aging.
The influence of the MTHFD1L variation is not as strong as APOE, and the variation itself is not as common in the population, said principal investigator Margaret Pericak-Vance, director of the University of Miami Miller Scho
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