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Apolipoprotein E-4 Genetic (DNA) Test - Topic Overview

Most people who develop Alzheimer's disease do not have a history of the disease in their families. But if you do have a family history of Alzheimer's disease (one or more members of a family have had the disease), then your risk of getting it is higher. When a disease is found in families, the cause could be genetic (heredity), something in the environment, lifestyle choices, or a combination of these things.

A blood test can look for a substance that seems to increase a person's risk for Alzheimer's disease. The gene is called apolipoprotein E-4 (ApoE-4). The presence of ApoE-4 cannot predict for sure whether a person will develop Alzheimer's disease. Many people who have the ApoE-4 gene do not get Alzheimer's disease, and many people who do not have the gene still develop the disease. Most experts do not consider ApoE-4 testing a necessary or useful part of evaluating a person with suspected Alzheimer's disease.

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The U.S. population is getting older, and as it ages, Alzheimer's disease is becoming an increasingly bigger concern. Within the next 50 years, the incidence of Alzheimer's is expected to quadruple, affecting one in 45 Americans. Today, there is still no cure for Alzheimer's. People with the disease progressively lose memory and the ability to function. Researchers are still trying to fully understand how its brain plaques and tangles lead to memory loss and other cognitive, behavioral and psychiatric...

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Early-onset Alzheimer's

Sometimes people develop Alzheimer's disease at a young age, between the ages of 30 and 60. This is referred to as early-onset Alzheimer's disease or autosomal dominant Alzheimer's disease. It is not common (less than 5 out of 100 cases), and this form of the disease has been linked to defects in specific genes. There is a 50% risk that these genes will be passed on. A person who inherits the genetic defect will most likely develop Alzheimer's disease.

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WebMD Medical Reference from Healthwise

Last Updated: October 29, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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