Possible Link Between Immune System and Alzheimer’s Disease
Finding supports pathogenic role of brain inflammation (Nov. 14)
An international research team, including scientists at the University of Toronto (UT), has found a link between a mutation in an immune-system gene and Alzheimer’s disease (AD).
“This discovery provides an increasingly firm link between brain inflammation and increased risk for Alzheimer’s,” said Dr. Peter St. George-Hyslop, director of UT’s Tanz Center for Research in Neurodegenerative Diseases.
Using data from 25,000 people, the researchers discovered that a rare genetic mutation in the TREM2 gene — which helps trigger immune-system responses — is also associated with an increased risk of AD. The discovery supports an emerging theory about the role of the immune system in the disease.
The team began by sequencing the genes of 1,092 people with AD and a control group of 1,107 healthy people. The results showed that several mutations in the TREM2 gene occurred more often in people with the disease than in those without. One mutation — known as R47H — had a particularly strong association with the disease.
The mutation makes a patient three times more likely to develop AD, although it affects only 0.3% of the population.
“While the genetic mutation we found is extremely rare, its effect on the immune system is a strong indicator that this system may be a key player in the disease,” said lead author Dr. Rita Geurreiro.
The new study was published in the New England Journal of Medicine.
Source: University of Toronto; November 14, 2012.