Researchers Find Gene that Damages Brain 50 Years Before Onset of Alzheimer’s Disease

Sometimes, it comes down to a single gene.

In 1993, researchers discovered a gene known as ApoE4 — carried by about a quarter of the population — 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 increase the risk of getting Alzheimer’s by another 16 percent.

But until now, the exact function of the CLU gene was unknown.  However, UCLA researchers recently have discovered that this particular risk gene begins to damage the brain 50 years before people normally get Alzheimer’s.

Paul Thompson, a UCLA professor of Neurology, and his team, have found that CLU impairs the development of myelin, which is the protective covering around the neuron’s axons in the brain.  This makes the brain weaker and more vulnerable to the onset of Alzheimer’s later in life.

The researchers scanned the brains of nearly 400 healthy adults aged 20 to 30 by using a newer type of MRI that maps the brain’s connections.  They compared the brains of people who carried the risky variant of CLU against those who carried a different variant.

They found that those who carried the risky variant had lower white matter integrity, which may increase vulnerability to developing Alzheimer’s.

While Alzheimer’s has traditionally been considered as a disease marked by neuron loss and widespread gray matter atrophy, according to Thompson, this study shows that the destruction of myelin in white-matter brain pathways is also a key component of disease development.

According to researchers, 88 percent of Caucasians carry the CLU gene.  The other 12 percent are considered to have an ‘Alzheimer’s resistance gene’ that protects their brain wiring.

The researchers hope that knowing the role of the gene will prove useful in predicting people’s risk of developing Alzheimer’s and taking preventative steps in protecting the brain 50 years before the disease’s onset, long before symptoms ever develop.

“We know that many lifestyle factors, such as regular exercise and a healthful diet, may reduce the risk of cognitive decline, particularly in those genetically at risk for Alzheimer’s, so this reminds us how important that is,” Thompson said in a press release.