Two international teams of scientists have identified a rare mutation in a gene linked with inflammation that significantly increases the risk for the most common form of Alzheimer's disease, the first such discovery in at least a decade.
The findings, published on Wednesday in the New England Journal of Medicine, offer new insights into the underpinnings of Alzheimer's, a deadly, brain-wasting disease that robs people of their memories, their independence and their lives.
In separate studies, teams led by privately held deCode Genetics and John Hardy of University College London found that people with a mutation in a gene called TREM2 were four times as likely to have Alzheimer's as people who did not have the gene.
"It quadruples the risk of Alzheimer's," said Dr. Kari Stefansson of Reykjavik-based deCode in a telephone interview.
The level of risk compares with ApoE4, the best-known genetic cause of late-onset Alzheimer's, the form of the disease that occurs in older adults.
But this new gene variant is 10 times more rare than ApoE4, which is present in about 40 per cent of people with late-onset Alzheimer's.
Rare or not, scientists say the discovery represents a big breakthrough for Alzheimer's research.
"This is one of the most common, most devastating illnesses in humans and we still don't have a very good understanding of what causes the disease," said Dr. Allan Levey, director of the Emory Alzheimer's Disease Center of Excellence in Atlanta, which helped confirm the deCode findings.
Drug companies have been stymied in their efforts to develop drugs that can alter the steady course of Alzheimer's.
