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 advances in technology and the development of gene-targeted therapies, knowing whether your ALS has an underlying genetic cause – and if so, identifying the disease-causing mutation – has become more important. However, the decision whether to get a genetic test is a very personal one. Below, we answer some common questions about genetic testing for ALS so you can start to think about whether it might be the right choice 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. Research has shown that about two-thirds of people with familial ALS and about 10% of people with sporadic ALS have a mutation in at least one of the more than 40 genes that have been linked to the disease. 

If genetic testing identifies a disease-causing genetic 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 genetic testing and 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 people living with ALS better understand why they got the disease, how it might progress and their family members’ risk of developing ALS. Knowing whether your ALS is connected to a gene mutation could make you eligible for ongoing clinical trials testing treatments targeted at specific genes. In the future, the results could also point you or your family members to a gene-targeted therapy (if and when they are approved by the FDA). 

For people with familial ALS (have a family history of the disease), 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

Doctor and patient

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 inherited 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 see 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 harmful 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. This is offered through many testing laboratories, including the ALS Identified program from Invitae (see below for more information). 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
  • Any other gene considered to be “strongly” or “definitely” associated with ALS by ClinGen (examples: ALS2CHMP2BKIF5ANEK1UBQLN2)
  • Any gene targeted by an FDA-approved therapy

For predictive 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 speak 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. 

Download Genetic Testing Information Sheet

Free Genetic Testing with ALS Identified

The ALS Association believes that people living with ALS and their families must have the right to access genetic counseling and testing, education about clinical genetics in ALS, and safeguards against genetic discrimination. 

ALS Identified, a program sponsored by Biogen and offered through the diagnostic company Invitae, offers free genetic testing to people with ALS and their families. 

Invitae’s ALS panel looks for mutations in more than 20 genes associated with ALS, including the C9ORF72 gene. It's available to people in the U.S. and Puerto Rico who have been diagnosed with ALS or have a family history of the disease. Only a doctor can order this test for you. 

You may take this test at home or in a doctor’s office. If you take it at home, you'll receive a testing kit in the mail, and you'll mail back a cheek swab in a prepaid envelope. If you take the test at a doctor’s office, you'll supply either a blood, saliva, or cheek swab sample. 

About 2-3 weeks later, your doctor will receive your results. Your doctor and/or genetic counselor will share the results with you, taking time to explain them and their potential impact on you and your family.  

For more information about ALS Identified and how to participate, click here.

Click here to learn more about genetic counseling. 

Click here to download a printable summary of this page. 

Learn more about genetic testing and counseling in a video from experts through our collaboration with the International Alliance of ALS/MND Associations. 

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