APOE Gene Test

What is an APOE gene test?

An APOE gene test is a type of genetic test that identifies which variant of the apolipoprotein E (APOE) genotype you have. Having certain APOE genotypes may mean you have an increased risk of Alzheimer’s disease.

Having an increased risk of a condition doesn’t mean you’ll definitely develop it. A health risk tells you whether or not you’re more likely than others to develop a condition. Many factors go into your health risk, and genetics is only one of those factors.

A healthcare provider can help you understand your risk and what the results of this test mean.

What is the APOE gene?

The APOE gene gives your cells instructions to make apolipoprotein E. This protein merges with fats (lipids) to form lipoprotein molecules. Lipoproteins carry cholesterol and other fats through your bloodstream.

There are three types (alleles) of the APOE gene:

• APOE-ε2 (APOE2).
• APOE-ε3 (APOE3).
• APOE-ε4 (APOE4).

All humans inherit one copy of the APOE gene from each of their biological parents.

The combination of alleles may increase your risk of certain health conditions by affecting how your body is able to move cholesterol and other fats through your bloodstream.

Which APOE gene causes Alzheimer’s disease?

No gene has been found to directly cause Alzheimer’s disease. Having at least one copy of the APOE-ε4 gene increases your risk of developing Alzheimer’s disease. Late-onset Alzheimer’s disease usually affects people older than 65 and early-onset Alzheimer’s disease affects people before age 65. Alzheimer’s disease progressively causes memory loss (dementia).

The APOE-ε2 gene may protect you from Alzheimer’s disease. If the disease occurs in a person with this allele, it’s usually later in life than a person with the APOE-ε4 gene.

How do I get tested for the APOE4 gene?

The APOE gene test is a voluntary test. Many people learn about the APOE gene after taking an at-home genetic test or you can ask your healthcare provider about it if you’re interested in learning your risk of developing Alzheimer’s disease. You may choose to have this test if you have a biological family history of Alzheimer’s disease.

If you have Alzheimer’s disease, a healthcare provider may recommend this test to determine the best treatment options for you.

The APOE gene test is a helpful tool for researchers to learn more about the risk of developing Alzheimer’s disease among certain populations. Researchers may compare the test results with brain imaging studies to find new and effective treatments.

What can I expect during an APOE gene test?

You can expect the following during an APOE gene test:

• A healthcare provider will collect a sample of your DNA, either by blood test or by swabbing the inside of your cheek.
• They’ll send the DNA sample to a laboratory.
• The lab will examine the DNA sample and send the results back to your healthcare provider.
• Your provider or a genetic counselor will discuss the results with you and what they mean.

If you’re taking an at-home risk assessment test that includes data on the APOE gene, follow the instructions that come with the kit. They vary based on the brand. When you get your results back, you may want to discuss them with your healthcare provider.

What are the APOE test results?

The results of an APOE gene test tell you which type (allele) of the APOE gene you have.

At-home test kit results may look different from the results that your provider gives you. If you have questions, reach out to the company that performed the test.

A provider or genetic counselor will go over what the results of this test mean. If you have a higher risk of developing Alzheimer’s disease, your provider may suggest ways to improve your general health, like:

• Participating in physical activities or exercising regularly.
• Getting enough sleep for your body’s needs.
• Spending time with friends and loved ones to stay active socially.
• Challenging your brain by completing puzzles, reading or learning a new skill.

Your provider may have other recommendations specific to you and your health.

What is APOE4 positive?

APOE4 positive means that you have at least one copy of the APOE4 (APOE-ε4) gene in your DNA.

What are the odds of getting Alzheimer’s with APOE4?

An estimated 15% to 25% of people have one copy of the APOE4 (APOE-ε4) gene and 2% to 5% have two copies. Having at least one copy of the APOE4 gene may increase your risk of developing Alzheimer’s disease.

Just because you have at least one copy of this gene doesn’t mean you’ll develop Alzheimer’s disease. Remember, a genetic test isn’t a diagnostic test. It assesses your risk and doesn’t confirm or deny a disease’s presence in your body. A genetic counselor can help you understand what these results mean and what your next steps should be.

When should I know the results of an APOE gene test?

It usually takes a few days to receive the results of an APOE gene test. Your healthcare provider can give you more information on the timeline specific to your healthcare institution.

At-home tests usually take several weeks to months before you get your results. This varies based on the company.