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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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Alzheimer’s Disease Symptoms

In Alzheimer’s disease, nerve cells in the brain die gradually. This makes it increasingly difficult for your brain’s signals to be sent properly. Alzheimer’s disease symptoms may be hard to recognize at first. You may assume that symptoms such as mild forgetfulness or an occasional loss of focus are normal signs of aging. But as the disease progresses, Alzheimer’s disease symptoms become more than “normal” changes. They become frightening, incapacitating, and dangerous. In the latter stages of...

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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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