Genetic Testing for ALS

Genetic testing looks for changes, also called mutations, in your DNA. When these mutations occur in specific genes, they can cause ALS or increase your risk of developing the disease.

With the approval of the first genetically targeted therapy for ALS and the advancement of prevention research, knowing whether you have an ALS-linked gene mutation has become more important. However, deciding whether to get a genetic test is very personal. Below, we answer some common questions about genetic testing for ALS so you can start to think about whether it might be right for you. 

Who Can Get Tested?

While previously reserved for those with a strong family history of ALS, genetic testing is now an option for anyone who has received a diagnosis. This is because both people with familial ALS and those with sporadic ALS can have a mutation in one of the more than 40 genes known to be linked with the disease. 

If genetic testing identifies a disease-linked mutation in a person with ALS, their family members generally have the option to pursue testing themselves. This type of genetic testing is called predictive or presymptomatic genetic testing because it provides information about a person’s future risk of disease before they have any signs or symptoms. This type of testing should be discussed in more detail with a genetic counselor.

If I’ve Already Been Diagnosed with ALS, What Can a Genetic Test Tell Me?

Genetic testing results can help you better understand why you developed the disease, how it might progress, and your family members’ potential risk of developing ALS. The results also can help match you to a gene-targeted therapy, such as Qalsody (tofersen), which is approved by the FDA to treat ALS connected to mutations in the SOD1 gene, or provide an opportunity to participate in a clinical trial testing a treatment targeted at another specific gene.

For people with familial ALS, about 60-70% will receive a positive genetic test result (mutation identified). For the other 30-40%, that doesn't mean the disease hasn't been inherited. It could mean that your ALS was caused by a mutation in a gene or genes that haven't been discovered yet. Click here for a graphic outlining possible genetic testing results and what they may mean for you and your family.

What Do I Need to Consider Before Testing?

Although genetic testing comes with many potential benefits, there are also potential psychological, social, and legal risks. For example, the results can strain relationships as they can reveal information about family members’ chances of getting ALS and may affect family planning. A genetic counselor can help you work through the pros and cons of genetic testing, taking your concerns and values into account, as you decide whether or not to get tested.

If One of My Family Members Has an ALS-Linked Genetic Mutation, Should I Get Tested Too?

This is a very personal choice, especially if you currently do not have any symptoms. Testing may cause feelings of fear, anxiety, depression, and/or guilt and can open you up to discrimination in disability, long-term care, or life insurance. Also, since not everyone who tests positive for an ALS-linked gene mutation will develop the disease, your results cannot tell you if or when you might start developing symptoms.

Genetic counseling is generally recommended before people without ALS symptoms get tested to make sure they understand the potential risks and benefits and are psychologically and emotionally prepared to receive their results. Learn more about the potential risks and benefits of genetic testing for family members of people with ALS here.

How Can I Start a Conversation with My Doctor about Genetic Testing?

If you are interested in genetic testing, it’s important to talk with your doctor. You might want to begin this conversation by explaining the reasons why you would like to know if you have an ALS-linked gene mutation. It is also important to talk about any hesitations or anxieties you may have about testing.

Here are some questions to consider asking:

Would genetic testing be helpful for me? Why or why not?
What test is recommended and why?
What will I learn from this test?
How will the results potentially impact me and my family?
What won’t I learn from this test?
Should I meet with a genetic counselor before making a decision about testing?

What Does Genetic Testing Involve?

Because genetic testing needs to be ordered by a health care professional, you usually need to go to a doctor’s office or hospital to give a blood or saliva sample. Your sample then gets sent to a lab, where technicians isolate your DNA and test for changes in genes known to be linked to ALS.

In some cases, your doctor or genetic counselor can order the test for you to take at home. For an at-home test, you'll receive a testing kit in the mail and will follow the directions to take a cheek swab. Then, you'll mail back the swab to the testing company in a prepaid envelope.

According to guidelines developed by a nationwide group of 40 experts, people with ALS should be tested for changes in the following genes:

C9orf72
SOD1
FUS
TARDBP
Any other gene considered to be “strongly” or “definitely” associated with ALS by ClinGen (examples: ALS2, CHMP2B, KIF5A, NEK1, UBQLN2)
Any gene targeted by an FDA-approved therapy

For presymptomatic testing, individuals who don't have ALS symptoms are often required to undergo a neurological exam, psychological assessment, and genetic counseling before getting tested.

When Will I Get My Results?

It can take anywhere from a few weeks to a few months to get your results, depending on the type of testing ordered. Your doctor and/or your genetic counselor will talk you through the results, either in person or over the phone. Click here for a graphic outlining possible genetic testing results and what they may mean for you and your family.

What Does Genetic Testing Cost?

Health insurance plans will often cover the cost of genetic testing when it's recommended by a doctor. However, different health insurance providers have different policies about which tests they will cover, so it's important to reach out to your insurance company before getting tested if you have questions.

Some people may choose to pay for a genetic test out of pocket when their insurance does not cover the cost of the test. Patient “self-pay” costs are often cheaper than what laboratories charge insurance companies.

Another option is ALS Identified, a program sponsored by Biogen and offered through the diagnostic company Invitae, which offers free genetic testing to people with ALS and their families. Only a health care professional can order this test, so talk with your doctor for more information.

Download Genetic Testing Information Sheet

You can also learn more about genetic testing and counseling in this video, which was produced through our collaboration with the International Alliance of ALS/MND Associations.