Controversial Alzheimer's Gene Discovered:

It is rarely we see a gene mutation which leads to beneficial effects in living organisms. Even rarer still is a beneficial gene mutation occurring in animals, let alone humans.

Yet, such a mutation has been discovered, in the form of the APP gene – the gene which causes Alzheimer’s disease. Fabrizio Tagliavini, a neurologist, and his team from the Carlo Besta National Neurological Institute (in Milan); have observed a 44-year-old man who had two copies of the mutated APP gene. Symptoms of early Alzheimer’s disease appeared in the man during his mid thirties. However, six of his family members only have one of the mutated APP gene, and none of them are afflicted with Alzheimer’s disease. The man also had a younger sister with two copies of the faulty APP gene. She has exhibits some mild symptoms of Alzheimer’s but is not completely afflicted with the disease.

The APP gene, in case you are wondering, causes clumping in the brain through the production of the sticky A-beta protein, which, as it accumulates, sticks together and prevents the communication between neurons in the brain. This leads to the telltale symptoms of Alzheimer’s disease: memory loss and the deterioration of physical functions.

Tagliavini’s team tested the mutant gene by mixing the mutant A-beta clumps with normal A-beta clumps. When the genes were left unmixed, they clumped together more than when they were mixed with each other. This could explain why people with only one of the mutated APP gene apparently show no signs of the disease.

With the discovery of the faulty A-beta protein, scientists may find a way to produce a cure for Alzheimer’s disease, or at least slow down the creation of A-beta clumping in Alzheimer’s sufferers.

Original Article: http://www.newscientist.com/article/dn16750-paradoxical-gene-causes-and-protects-against-alzheimers.html