Genetic tests for Alzheimer’s can detect specific genes linked to the disease. In most cases, they can’t definitively confirm or predict a diagnosis, but they can provide insight into your relative risk.

Alzheimer’s disease is a progressive brain disorder that causes memory loss and cognitive decline, affecting daily functioning and quality of life.

Alzheimer’s results from a complex mix of genetic, environmental, and lifestyle factors. While genetic tests cannot confirm or predict an Alzheimer’s diagnosis, they may help you assess your risk of developing the condition. These tests examine specific genes linked to an increased likelihood of Alzheimer’s.

This article explains the genetics of Alzheimer’s disease, the process of genetic testing, and its pros and cons.

Research has linked around 80 genes to the development of Alzheimer’s disease.

According to the Alzheimer’s Association, in 1% or less of cases, a genetic marker means you will develop the condition. In these cases, people carry one of three genes known as deterministic genes.

But in most cases, having an associated gene may affect your risk in combination with several other factors. These genes are known as risk genes.

Genetic testing can identify deterministic and risk genes for Alzheimer’s. In addition to informing you about your risk, genetic testing might allow for earlier detection and intervention. It may also allow you to contribute to ongoing research aimed at understanding and treating Alzheimer’s disease.

Still, it’s important to note that, in most cases, a genetic test will not definitively predict whether or not you’ll develop Alzheimer’s.

You can have genes that increase your risk of Alzheimer’s and not develop the condition. You can also develop the condition without one of the associated genes.

What genes are involved in Alzheimer’s?

Research links several genes to Alzheimer’s disease, including genes involved in processing amyloid-beta peptide and the tau protein and genes related to:

Deterministic genes, such as APP, PSEN1, and PSEN2, are associated with early onset Alzheimer’s disease.

The apolipoprotein E-4 allele (APOE4) is the most common risk gene variant linked to Alzheimer’s disease.

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Genetic testing alone cannot diagnose Alzheimer’s disease. However, it can assess your genetic risk by identifying certain genetic variations associated with the condition.

A diagnosis of Alzheimer’s typically requires a comprehensive evaluation from a qualified healthcare professional. An evaluation typically includes:

The genetic testing procedure for Alzheimer’s is straightforward. A healthcare professional starts by collecting a blood or saliva sample.

After collecting the sample, they send it to a laboratory for analysis. Lab technicians examine your genetic material for any genetic variations or mutations associated with an increased risk of developing Alzheimer’s.

The lab analysis itself can vary in duration, typically taking a few weeks to complete. However, this time frame may differ depending on the specific lab and other factors.

Once the results are ready, a healthcare professional meets with you to interpret the findings.

While it’s possible to take a genetic home test for Alzheimer’s to assess the risk of developing it, these tests may provide inconclusive or inaccurate results if not used correctly.

Therefore, experts recommend a healthcare professional supervise Alzheimer’s genetic testing.

The most common form of genetic testing for Alzheimer’s risk looks for variants in the APOE gene. However, having these risk variants does not guarantee you’ll develop Alzheimer’s.

Consider talking with a healthcare professional to discuss genetic testing options.

Pros of genetic testing for Alzheimer’s

  • learn more about your risk
  • allow for early detection and treatment
  • contribute to ongoing research

Cons of genetic testing for Alzheimer’s

  • may provide false reassurance
  • potential emotional effect on you and your family
  • ethical and privacy considerations regarding the sharing of sensitive personal data
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While genetics may determine your risk for developing Alzheimer’s, other factors that increase your risk include:

These factors, in combination with genetic factors, may increase the risk of developing Alzheimer’s disease.

Although there is no known cure for Alzheimer’s, you can reduce your risk by adopting certain lifestyle strategies. These may include:

  • getting regular physical activity, such as aerobic exercise and strength training
  • eating a nutritious diet that includes plenty of fruits, vegetables, whole grains, lean proteins, and healthy fats
  • maintaining a moderate weight and managing any chronic conditions you may have, like diabetes and high blood pressure
  • staying mentally and socially active by challenging your brain with puzzles, learning new skills, and staying connected with others
  • limiting or avoiding alcohol consumption
  • not smoking

Here are some frequently asked questions about Alzheimer’s genetic testing.

How much of Alzheimer’s disease is genetic?

Estimates for the genetic influence on Alzheimer’s disease range from 60–84%, according to a 2021 research review, though this percentage is higher for cases of early onset Alzheimer’s. Lifestyle and environmental factors account for the remaining percentage.

Which parent passes the Alzheimer’s gene?

Both parents can pass on genes linked to Alzheimer’s. According to a 2019 study, people who have a parent with Alzheimer’s have a higher risk of developing the disease. However, multiple genes influence Alzheimer’s disease, and it’s not only inherited from one parent.

That’s unless one of your parents carries a deterministic gene, like APP, PSEN1, or PSEN2. Deterministic genes pass on to the next generation in an autosomal dominant pattern. That means they are not linked to sex, and you can inherit them from either parent.

What are the odds of getting Alzheimer’s if a parent has it?

If one of your parents has a gene that causes Alzheimer’s, like APP, PSEN1, or PSEN2, you have a 50-50 chance of inheriting the gene. But for most cases of Alzheimer’s, the genetics and risk factors can be more complicated.

In a 2019 study, having a first-degree relative (like a parent or sibling) with Alzheimer’s increased personal risk by 73%. Having more relatives with the condition further increased the risk. For example, people with four or more first-degree relatives with Alzheimer’s were almost 15 times as likely to develop the condition.

How much does the Alzheimer’s gene test cost?

Genetic testing through the Alzheimer’s Organization costs $125. This test checks for the APOE gene variant.

However, the cost of an Alzheimer’s gene test can vary depending on the specific test and the provider. Consider talking with a qualified healthcare professional or genetic testing laboratories for specific pricing information.

Although Alzheimer’s genetic testing can help you identify your risk of developing the condition, it cannot diagnose Alzheimer’s.

Some genes linked to Alzheimer’s do lead to the development of the disease, but this only accounts for about 1 in 100 cases. In most cases, a complex set of factors contribute to your risk.

If you’re considering genetic testing, talk with a qualified healthcare professional or genetic counselor to understand the implications. They can help you make informed decisions about your health.