Progress on the cause of Alzheimer’s

A recently discovered gene mutation could triple the risk for Alzheimer’s disease. Whilst this is a cause for concern, it is not one that should cause widespread panic. The gene is called TREM2, and the mutation is rare, occurring in about 1 in 150 people. By comparison one in five people carry a form of a different gene called APO-E that can triple the risk.
One in 50 people carry a form of APO-E that raises the risk 13 times.

However the research from two teams, one headed by Dr. Kari Stefansson at DeCode Genetics in Iceland and the other by Dr. John Hardy of University College London and both published in the New England Journal of Medicine, is critically important science that may yield clues about the causes of Alzheimer’s disease and the search for better treatments.

TREM2 in its normal form plays a role in inflammation, the body’s response that sends white blood cells to destroy invading germs and diseased tissue. The mutation cuts the ability to mount an inflammatory response, so it is possible the ability to fight other diseases is tied up with the risk for Alzheimer’s. For more than a century pathologists
have noted a build up of white blood cells in the brains of people who died from Alzheimer’s.

No one is sure what causes Alzheimer’s. The numbers of people affected are projected to worsen as people get older. There is no treatment and there is no cure.

The leading contender as the main cause of Alzheimer’s is the accumulation of plaques of protein called amyloid-beta. It is likely that the inflammatory response is attempting to keep that build up at bay. Last July, Dr. Stefansson’s team discovered a different gene mutation, even more rare, that actually protects against Alzheimer’s. That was important
science because that gene is responsible for production of amyloid-beta.  So it both supports the hypothesis about the cause and leads to ideas about how to make drugs to stop it.

The source of this article is NBC News.