An Update on Research into Alzheimer's

In 1993, researchers discovered a gene known as ApoE4, carried by about a quarter of us that triples the risk for getting Alzheimer's.
In 2009, three more risky genes were discovered, and one of them, called clusterin, or CLU, was found to up the risk of getting Alzheimer's by another 16 percent.
But nobody could explain what the CLU gene actually did but now UCLA researchers know,. This risk gene begins to damage your brain a full 50 years before people normally get Alzheimer's.
In the current online edition of the Journal of Neuroscience, Paul Thompson, a UCLA professor of neurology, and his colleagues report that the C-allele of the CLU gene (an allele is one of two or more forms of a gene), which is possessed by 88 percent of Caucasians, impairs the development of myelin, the protective covering around the neuron's axons in the brain, making it weaker and more vulnerable to the onset of Alzheimer's much later in life.
The researchers scanned the brains of 398 healthy adults ranging in age from 20 to 30 using a high-magnetic-field diffusion scan. They compared those carrying a C-allele variant of the CLU gene with those who had a different variant, the CLU T-allele.
They found that the CLU-C carriers had what brain-imaging researchers call lower "fractional anisotropy", a widely accepted measure of white-matter integrity in multiple brain regions, including several known to degenerate in Alzheimer's. In other words, young, healthy carriers of the CLU-C gene risk variant showed a distinct profile of lower white matter integrity that may increase vulnerability to developing the disease later in life.
Thompson said four things are surprising with the discovery of this gene's function:

1. This risk gene damages your brain a full 50 years before people normally get Alzheimer's. The damage can be seen on an MRI scan, but there are no symptoms yet.
2. It's now known what this mysterious gene does, namely, make your brain wiring vulnerable to attack by impairing the wiring before any senile plaques or tangles develop.
3. Rather than being a gene that few people have, a whopping 88 percent of Caucasians have it. "So I guess you could say the other 12 percent have an 'Alzheimer's resistance gene' that protects their brain wiring," said Thompson.
4. Knowing  the role of this gene is useful in predicting a person's risk of the disease and in seeing if you can step in and protect the brain in the 50-year time window you have before the disease begins to develop.