DNA Tests for Dementia

Updated January 16, 2019

This article was scientifically reviewed by YourDNA

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Understanding the risk factors associated with the many forms of dementia helps you stay prepared. Here at YourDNA, we are staying on top of the newest developments in genetic testing to keep you fully informed so you can make educated decisions about yours and your family's future.

What's in this Guide?

Disclaimer: Before You Read

It is important to know that your genes are not your destiny. There are various environmental and genetic factors working together to shape you. No matter your genetic makeup, maintain ideal blood pressure and glucose levels, avoid harmful alcohol intake, exercise regularly, get regular sleep. And for goodness sake, don't smoke.

Genetics is a quickly changing topic.

Quick Overview

Dementia affects an estimated 50 million people globally, with over 5 million of these cases in the United States alone.

This number is expected to increase exponentially in the next several decades. Currently, there is no cure, but with the proper research and knowledge, you can learn how to handle the prognosis and progression of the disease.

Early detection is the key to making life more comfortable, and while not all cases are genetic or hereditary, DNA testing can help pinpoint markers for specific types of dementia.

What Is Dementia?

While it's commonly thought to be a single disease, dementia is a broad term and actually encompasses a range of diseases.

Each presents with common symptoms that result in deteriorating mental, emotional and sometimes, physical capacity. It's a progressive disease that worsens over time and without a cure, can prove to be fatal.

Early warning signs are usually detectable if you know what to look for. Some of these symptoms to be aware of include, but are not limited to:

  • Memory loss
  • Change in vocabulary, using simpler or vague terms to describe an object
  • Exercising increasingly poor judgement
  • Withdrawing from society
  • Mood or personality changes
  • Difficulty completing everyday tasks

Early detection is the key to implementing treatment, though there is no way to stop or cure most forms. While many who are diagnosed are past the age of 65, it's not considered a normal part of aging.

However, early-onset dementia often affects those with the hereditary and genetic forms of the disease.

Some groups of people, such as those with Down syndrome, are more susceptible to developing dementia, with some studies suggesting approximately 75 percent of the population having Alzheimer's.

This is likely due to their already impaired cognitive function and gene markers that come from the extra chromosome 21, particularly the one that involves the amyloid precursor protein, also known as APP.

What Are the Most Common Types of Dementia?

To begin to understand dementia, you have to distinguish between the two forms: cortical and subcortical.

The difference between these two is the part of the brain that each affects. Cortical dementia affects the cerebral cortex, while subcortical affects the areas of the brain beneath the cortex.

Cortical dementia affects mainly memory and language while subcortical is related to the way a person thinks and functions.

There are several diseases that fall under the umbrella of dementia, and they fall into one of several categories and causations.

  1. Degenerative: The form most people are familiar with is Alzheimer's, which is estimated to be responsible for up to 80 percent of dementia diagnoses. Other degenerative causes include Parkinson's and Huntington's. These tend to progress over time.
  2. Vascular: Vascular dementia is brought on by circulation issues in the brain. This type is second only to Alzheimer's. It can be brought on by complications from diabetes and high blood pressure.
  3. Traumatic: Brain injuries can damage areas of the brain related to cognitive function and cause dementia. Concussions and blunt force trauma are two examples of traumatic brain injuries that can lead to dementia.

In addition to these three causes, there are other factors that come into play as well. Long-term drug and alcohol abuse, for example, can lead to brain chemistry changes and significantly different ways of thinking as well as permanent personality changes.

Infections and fluid buildup are two more factors that if left untreated can do permanent damage that results in dementia, though if caught early enough they can be treated effectively.

What Are the Stages of Dementia?

There are three stages of dementia: early, middle and late. Each stage has markers that physicians use to diagnose patients.

Unfortunately, in many cases, most forms of dementia aren't diagnosed until they are in the middle or late stage, because people erroneously associate forgetfulness with aging.

In the early stages, you're able to function normally but experience forgetfulness and potentially get easily confused. As the disease progresses into the middle stage, you might need help with personal care and experience difficulty communicating.

Forgetfulness is also amplified in the middle stage, but not as much as in the late stage where it's common to repeat stories or ask questions over and over. Additionally, late-stage patients tend to need more hands-on care and often end up in facilities where they can get around the clock attention.

Is Dementia Hereditary or Genetic?

While it's not unusual to see some people in the same family suffer from dementia, this does not mean that it's genetic or hereditary.

As a matter of fact, only two forms of dementia tend to be passed down in one form or another: vascular and Familial Alzheimer's disease (FAD).

Vascular dementia, caused by circulation issues, is not necessarily hereditary, but the risk factors that lead to its development may be. These are the same factors that are related to issues such as high blood pressure, increased risk of stroke, and heart disease.

The presence of these genes, however, does not necessarily mean that the carrier will develop vascular dementia. It does, however, stress the importance of living a healthy lifestyle in order to take preventative steps.

FAD, on the other hand, is the passing down of mutated genes. Those who inherit the genes will go on to develop Alzheimer's, typically the early-onset variety, meaning it occurs in the patient's 40s and 50s, up to 15 years younger than late-onset dementia.

What Part Do Genes Play in Dementia?

Genes can play a significant role in dementia. While it's not a disease that's definitely passed on through a bloodline, there are certain genes associated with the risk, more specifically the APOE and APOE-e4 genes.

APOE stands for Apolipoprotein E, and every one of us has a variation of it which determines your risk level for developing Alzheimer's. There are three different variations: APOE2, APOE3, and APOE4, with the majority of the population carrying the e3 gene which is neutral.

The e4 gene is the second highest and people who have it tend to be at a higher risk of developing Alzheimer's in their later years, though it's not definite. The e2 gene is the rarest and is associated with a lower risk of developing the disease.

If a familial tie is suspected as with Familial Alzheimer's disease, or FAD, three genes are involved on chromosomes 1, 14 and 21. These genes, identified as presenilin 1 and 2, and APP, or amyloid precursor protein, will show mutations if the person is a carrier. This is a form of hereditary dementia, as discussed above.

Can You Be DNA Tested for Dementia?

The simple answer is yes, you can be DNA tested for dementia. The complex answer is that while you ascertain if you're carrying any of the related genes associated with Alzheimer's or FAD, it cannot provide much more information than that.

For example, if your DNA test results show that you have the e4 gene, it's not certain that you'll actually develop the disease. Many people who carry it go on to lead perfectly healthy lives well into their senior years. It also cannot tell you what age you might begin displaying the symptoms.

The genes relating to FAD, on the other hand, if present, do indicate that the carrier will develop the disease. FAD is commonly diagnosed in a person's 40s or 50s and is one of the more common early-onset forms of dementia.

What Are the Pros and Cons of Getting Your DNA Tested for Dementia?

There are several pros and cons to getting your DNA tested, but ultimately the choice to undergo the test is 100 percent your decision.

If you do decide to get tested, you will at least have an answer to whether you have inherited the genes responsible for the disease. The main downside of getting your DNA tested is that if the results come back positive, you have to live with the fact that your future holds uncertainty.

The pros exist for both negative and positive markers. If the test identifies that you carry the genes associated with dementia, you can begin to make preparations and important decisions such as creating a living will that outlines your desired care plan.

You can also appoint which, if any, family members you want in charge of carrying out your living will. In the long run, you'll be better prepared than someone who is unaware they're carrying the genes.

The other positive is that your tests may come back and indicate you're carrying no markers, which of course, would be welcome news.

Is It Recommended to Get a DNA Test for Dementia?

There are many reasons why you might want to get a DNA test, detecting dementia is just one.

However, learning your APOE status might be beneficial, because it can give you at least some of the answers you're looking for. It can also help you determine which, if any, precautionary measures are good to take and what correlated risks are associated with your APOE status.

What Could Be the Emotional Effects of Knowing Your Status?

There are many emotions involved with DNA testing, especially for something as serious as dementia.

Receiving the news that you carry the gene mutation for FAD or the e4 gene that puts you at higher risk of developing Alzheimer's can come with a myriad of them. It's not uncommon to feel fear, particularly when you're dealing with the unknown.

A DNA result that shows you as an e4 carrier can be frightening, even more so if you've seen someone go through the trials of the disease. However, while it's been stated before, it's important to know that just because you're at a greater risk doesn't mean that you will definitely develop Alzheimer's.

Rather, take it as a precautionary approach and better prepare for the future.

Similarly, those with a reduced or neutral risk may be elated to receive this news, but it's noteworthy to mention that they may still develop the disease, so there's no definitive answer with these types of tests. Take the information and process it as it's intended, as a soft guide to your genetics.

However, the effects tend to be more psychological and can lead to feeling clinically anxious or depressed. Some may feel regret after taking the test, feeling as though they're better off not knowing the results, especially since most forms are incurable.

If you do decide to get your DNA tested, consulting with a genetic counselor might help you deal with the ramifications of your results.

Who Should Get a Genetic Test for Dementia?

Anyone suspects they are a carrier for FAD should definitely consider getting a genetic test for dementia.

If you feel that your family history puts you at a higher risk, by all means, get yourself tested.

Even if there are no family ties to the disease, it can't hurt to know which APOE gene you carry. Many companies such as 23andMe offer the service so you can at least arm yourself with knowledge.

More detailed testing, known as predictive genetic testing, is required to determine if you carry the mutated genes that are passed down among family members.

They work by comparing your inherited traits to determine if you have the same mutations that lead to the development of dementia in loved ones.

How Accurate Are DNA Tests for Dementia?

In 2017, 23andMe developed an FDA-approved genetic test that evaluates 500,000 genes and variants to ascertain the risk of developing dementia.

Most saliva exams on the market that test for dementia are touted to be 99 percent accurate, giving you the most comprehensive information available at this time. The APOE tests cannot tell you if or when you will develop the disease, it just outlines your risk factors, where more detailed testing can identify the mutated genes that are genetically inherited. Detailed testing comes with a more certain outlook.

Where Can You Get Genetic Testing for Dementia?

There are many places you can get genetic testing done.

You can opt to have it done as part of a yearly physical, though the costs will be higher for clinical tests. If you prefer to do the test in the privacy of your own home, you can order online from reputable companies such as 23andMe and ADx Healthcare.

How Much Is a DNA Test for Dementia?

The cost for DNA testing varies depending on where you get the tests done.

If you opt for the at-home saliva collection, you can expect to pay between $100 and $200 for the supplies, processing and access to your results. Clinical tests may cost a bit more, ranging from several hundred to several thousands of dollars depending on whether you have insurance and if that insurance covers the testing.

Are There At-Home DNA Tests for Dementia?

Yes, currently you can buy the tests online at various retailers and have them shipped to your door.

This allows you to do the test in the privacy of your own home. Some stores, such as Best Buy, CVS and Walgreens also carry a limited number of these at-home solutions, as does Amazon.

Do You Need Genetic Counseling If You Get DNA Tested for Dementia?

Depending on the results you get from your DNA tests, you may want to opt for genetic counseling.

It is designed to help you understand how your genes can impact your health and in the long run, your family's health. For example, if you're an FAD carrier, there's a 50 percent chance that you could pass that onto your children.

Genetic counseling will help you pinpoint the risk factors and make educated decisions. Counselors can explain your results in detail, covering the points that you may not understand when it comes to your DNA panel.

If you test positive, it's worth looking into genetic counseling to get the peace of mind you deserve. They can also refer you to a specialist or support group if you feel that you need additional care and moral support in dealing with your results.

How Long Does It Take to Get DNA Test Results Back?

The amount of time it takes to get your DNA test results back largely depends on the company you use.

Some labs can expedite results and have them to you in as little as 3 weeks, but most will take up to 6 to 8 weeks.

Use this time to research the various factors that the test evaluates so you can have a clear understanding of what to expect when you receive your results.

Could a Positive DNA Test Result Be Used Against You by Insurance Companies?

It's only natural to be concerned with your DNA results being used against you.

For example, perhaps you're worried that your insurance company will deny coverage because of a pre-existing condition, which is a valid concern. However, the Genetic Information Nondiscrimination Act, or GINA, safeguards Americans from being discriminated against by health insurance companies.

This means they cannot use your DNA results against you to deny coverage for treatment.

Unfortunately, the same cannot be said for life and disability insurers. While GINA originally fought to include these types of insurance, the bill makers eventually relented when these companies fought back and they were removed.

So if you're planning to get life insurance, be aware that your DNA could potentially be used against you.

Is a DNA Test for Dementia Right for You?

Only you can determine if a DNA test for dementia is right for you.

If you have a long family history of the disease, it might be worth it to find out if you potentially carry the mutations or APOE genes associated with the various forms. If there is no history in your family, then your results may go either way. Some people like to know what they're at risk for, while others believe that ignorance is bliss when it comes to factors they can't change.

What Are the Best DNA Tests for Dementia?

There are different types of genetic testing available to determine if you're at risk including those carried out in clinical labs.

The technology is still new, but there are also a few DNA tests for dementia on the market that are available for over-the-counter purchase.

  • Predictive genetic testing - this type of testing does a comparison between a person who has been diagnosed with dementia and another person related by birth. The panels will compare the genes to see if the same mutations exist. However, it's only useful in detecting the inherited forms of dementia. Predictive testing is carried out in a medical facility by a doctor and processed in a lab onsite.
  • 23andMe DNA Health and Ancestry Reports - 23andMe has released an over-the-counter DNA test that evaluates your Alzheimer's risk. The company had to undergo examination by the Food and Drug Administration to prove that their test could accurately identify the risk factors with a high degree of accuracy, no lower than 99 percent.

Testing your DNA for dementia links is a highly personal choice that depends on whether or not you have a long family history of the disease. If you suspect that there is the potential for the disease to be inherited, knowing may give you a better idea of what to expect in the future.

It can help you plan ahead, but it's always a good idea to talk your results over with a qualified doctor as well before making any life-altering decisions.

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