Although the genes giving rise to early-onset Alzheimer’s are extremely rare, these inherited mutations do run in families worldwide and the study of these mutations has provided critical knowledge to the molecular underpinnings of the disease. These familial forms of Alzheimer’s result from mutations in genes that are typically defined as being autosomal dominant, meaning that you only need to have one parent pass on the gene to their child. If this happens, there is no escape from an eventual Alzheimer’s diagnosis.

What scientists have learned from these rare mutations that cause early-onset Alzheimer’s is that in every case the gene mutation leads to the overproduction of a rogue, toxic, protein called beta-amyloid. The build up of beta-amyloid in the brain produces plaques that are one of the hallmarks of the disease. Just as plaques in arteries can harm the heart, plaques on the “brain” can have dire consequences for brain function.

By studying families with early-onset Alzheimer’s, scientists now realize that the build up of beta-amyloid can happen decades before the first symptoms of the disease manifest. This gives scientists tremendous hope in terms of a large therapeutic window to intervene and stop the beta-amyloid cascade.

Hope is high for large trial underway of 5,000.

Indeed, one of the most anticipated clinical trials under way at this moment involves a large Colombian family of over 5,000 members who may carry an early-onset Alzheimer’s gene. Three hundred family members will participate in this trial in which half of those people who are young and years away from symptoms but who have the Alzheimer’s gene will receive a drug that has been shown to decrease the production of beta-amyloid. The other half will take a placebo and will comprise the control group.

Neither patient nor doctor will know whether they will be receiving the active drug, which helps eliminate any potential biases. The trial will last 5 years and although it will involve a small percentage of people with early-onset Alzheimer’s, the information from the trial could be applied to millions of people worldwide who will develop the more conventional, late-onset form of Alzheimer’s disease.

Currently there are no effective treatments or cure for Alzheimer’s and the only medications available are palliative in nature. What is critically needed are disease-modifying drugs: those drugs that actually stop the beta-amyloid in its tracks. Devastating as early-onset Alzheimer’s is, there is hope that prevention trials as described above could ultimately lead to effective treatments in the near future for this insidious disease.

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