After an ALS/MND diagnosis, people living with ALS/MND and their family members often have questions about genetics. Did a genetic change play a role? Could other family members be at risk? This section introduces genetic counselling and testing, brings together resources to help people and families think through whether to pursue them, and points to broader information about access to these services.
About 90% of ALS/MND cases are sporadic, meaning only one person in a family is affected, and about 10% are hereditary or familial, where more than one person in the same family is affected. A genetic change may still be present in sporadic ALS/MND, even when no family history is known. For more on sporadic and hereditary ALS/MND, see the Genetics section.
Genetic counselling and genetic testing can help people and families explore these questions. They are two related services, and a person can choose to use one without the other.
Genetic counselling is a conversation with a trained professional, often called a genetic counsellor. The counsellor reviews personal and family medical history, explains what genetics may or may not show in a particular situation, and helps a person decide whether genetic testing is right for them.
Counselling does not automatically lead to testing. Many people meet with a counsellor simply to understand their options, and some choose not to pursue testing.
Genetic testing looks at a person’s DNA to check for changes in genes linked to ALS/MND. There are two main types. Diagnostic testing is for a person who already has an ALS/MND diagnosis and helps identify whether a known genetic change is involved. Predictive testing is for a family member who does not have ALS/MND but who may be at risk because of a known genetic change in the family.
All people living with ALS/MND should have access to information on genetic counselling and testing, regardless of whether their ALS/MND is sporadic or familial.
Test results are not always clear-cut. A follow-up conversation with a genetic counsellor or healthcare provider is usually recommended to help explain what a result does and does not mean.
Deciding whether to pursue genetic testing is personal. Results may bring useful information, but they may also raise new questions for the person tested and for their family. The resources below introduce genetic counselling and testing in more detail.
What are genetic counselling and testing?
To better understand what these services involve, it can help to start with broad introductions. The resources below give an overview of genetic counselling and testing in ALS/MND.
Access to genetic counselling and testing is recognized by the Alliance as a fundamental right for people living with ALS/MND, alongside related rights to genetic education and safeguards against genetic discrimination. The webinar below introduces what counselling and testing involve, and why access to them matters as therapies for genetic forms of ALS/MND continue to develop. For more on the Alliance’s Fundamental Rights, see the Fundamental Rights for People with ALS/MND and Caregivers page.
Genetics – Counselling and Testing
This Alliance webinar offers a broad introduction to genetic counselling and testing in ALS/MND. It may be especially useful for people and families who prefer to hear specialists explain these topics in their own words, rather than only reading about them, and who want a fuller overview before turning to more specific materials.
Genetic Testing for ALS – The ALS Association
This page from The ALS Association explains how genetic testing for ALS/MND works, including how a sample is taken, which genes are typically tested, and how long results take. It covers who may be offered testing, what results may or may not show, and the potential benefits and risks, including possible insurance and discrimination concerns. The page also links to further information on genetic counselling and on the benefits and risks of testing for both people living with ALS/MND and their family members.
Why or why not get genetic testing?
Choosing whether to have genetic testing is a personal decision that depends on a person’s circumstances, what they hope to learn, and how a result might affect them and their family. The resources below fall into two groups: those that help a person think through the considerations of testing, and those that show why a genetic result may matter in practice.
Ethical considerations
Ethical considerations help a person weigh what testing might mean for them and their family. They cover possible risks, emotional impact, and decisions about whether and how to share results with relatives.
Ethical Considerations in ALS/MND Genetics
This infographic compares ethical considerations for two situations: people already diagnosed with ALS/MND, and asymptomatic relatives of someone with a known genetic variant. It is useful for seeing at a glance how the considerations differ depending on a person’s situation.
Ethical Considerations for Genetics
This Alliance webinar discusses ethical considerations for genetic testing across different situations, including symptomatic people with or without a family history and asymptomatic relatives. It may be especially useful for people who prefer to hear specialists talk through these considerations rather than only reading about them, and who want a fuller treatment than the infographic provides.
Therapeutic considerations
Knowing about therapy approaches helps explain why a genetic result may matter beyond personal information. Some treatments and clinical trials are designed for specific genetic mutations, so a genetic result can affect which options are available.
ALS/MND Genetics: What can we do about genetic ALS/MND?
This infographic introduces the main therapy approaches that target ALS/MND-associated genetic mutations. It is useful for showing one practical reason a genetic result may matter, since some therapies are designed for specific mutations. A Spanish-language version is also available.
ALS/MND Genetically-Targeted Therapy Acceleration Timeline
This timeline shows the years between gene discoveries in ALS/MND and the start of clinical trials targeting those genes. It is useful for understanding why a genetic result may connect a person to specific trial or treatment opportunities.
Note: This timeline currently reflects gene discoveries and trial launches through 2021. An updated version is not yet available.
Diagnostic testing
Diagnostic testing is offered to a person who already has an ALS/MND diagnosis. It looks for a known genetic change that may be linked to their ALS/MND, and the result can have implications for both the person tested and their family.
A diagnostic test does not always identify a genetic cause. In familial ALS/MND, where more than one person in the family has been diagnosed, a known genetic change is found in roughly 60 to 70% of people who are tested. The remaining cases may involve a genetic change that has not yet been linked to ALS/MND or that current tests do not detect.
In sporadic ALS/MND, where there is no known family history, a genetic change can still sometimes be found. As genetic testing becomes more widely available, understanding of how often this happens continues to grow.
Whatever the result, a genetic counsellor or healthcare provider can talk through what it means for the person and their family, and what next steps may be available.
The Alliance recognizes diagnostic testing as part of the fundamental right of people living with ALS/MND to access genetic counselling, testing, and education, regardless of whether their ALS/MND is sporadic or familial.
Predictive testing
Predictive testing is for a family member who does not have ALS/MND but who may be at risk because a known genetic change has been identified in their family. It can help a person understand whether they carry that genetic change, but it cannot say if or when a person will develop ALS/MND. Because of the personal and family implications, predictive testing is usually offered alongside genetic counselling, both before and after the test.
The Alliance also recognizes that, subject to education and counselling, blood relatives of people living with ALS/MND should have access to genetic counselling and testing where relevant. This is part of the same fundamental right.
Accessibility
Knowing what genetic counsellors do, and how to find one, is part of being able to access these services. The resource below introduces the role of the genetic counsellor and notes that some counsellors offer telehealth, which may make access easier for people who cannot meet in person.
About Genetic Counsellors – National Society of Genetic Counselors
This page from the National Society of Genetic Counselors describes who genetic counsellors are and how they support people and families before, during, and after testing. Although based in the United States, the foundational information is broadly useful, and the page also notes that some counsellors offer telehealth.