Alzheimer’s Risk Increased by Rare Mutation

A rare mutation that has been found in one of every 200 Icelanders who are 85 years of age or older increased the risk by three times of developing Alzheimer’s, the debilitating disease, said researchers.

The mutation, in TREM2, an immunoregulatory gene, was much more common in patients with Alzheimer’s disease than in the general population of those 85 and older in Iceland.

The function of the gene is inside the body’s central nervous system therefore the mutation could lead to a higher predisposition to developing Alzheimer’s through the impaired containment of some inflammatory processes, said researches who published the study in the New England Journal of Medicine online.

These processes have been tied to Alzheimer’s previously said the research group. In fact, the amyloid theory of Alzheimer’s says that inflammation in the brain is the later effect of the gradual accumulation of the plaques made up of beta-amyloid protein, wrote the researchers.

However, the mutation in the TREM2 is rare and the fact many carriers who were in the study remained free from Alzheimer’s until a very old age, suggesting that it is neither sufficient or necessary to trigger Alzheimer’s disease.

Researchers in their study first analyzed all genome sequences for the 2,260 Icelanders in the study so as to identify variants that are considered likely in loss or gain of function mutation in proteins.

In the analysis, the TREM2 gene mutation that caused an amino acid to be substituted at the 47 position was the only one substantially associated with the disease.