Two decades ago, researchers began discovering rare gene mutations that cause Alzheimer's disease in all who inherit them. Now, they have found the opposite: a mutation that prevents the devastating brain disorder. The protective mutation also is very rare - it is not the reason most people do not develop Alzheimer’s disease. But what intrigues researchers is how it protects the brain. It does the reverse of what the mutations that cause Alzheimer’s do. Those mutations lead to excessive amounts of a normal substance, beta amyloid, in the brain. The protective mutation slows beta amyloid production, so people make much less.
The discovery, published online on Wednesday in the journal Nature, provides strong evidence that beta amyloid buildup is a driving force in this destructive brain disease. It also bolsters the hopes of drug companies that have zealously developed drugs to reduce amyloid levels with the expectation they might alter the course of the disease or even prevent it. So far, the drugs have not succeeded, but companies and many researchers have argued that there are reasons for that and that it is too soon to give up on them.
If for no other reason, the discovery’s implication for drug development “is hugely important,” said Dr. David Altshuler, a genomics expert at Harvard Medical School and the Broad Institute of Harvard and M.I.T. who was not involved with the research.
It indicates, he said, that drug companies’ big bets on anti-amyloid treatments could pay off.
"This paper provides strong evidence that it would work in the general population if you did it right,” Dr. Altshuler said.
Dr. Samuel Gandy, an Alzheimer’s researcher who directs the Mount Sinai Center for Cognitive Health, had a similar response, calling the finding “extraordinarily important” - the most significant in the field since researchers first reported a mutation that leads to the disease, 22 years ago.