ALS/MND can affect families in different ways. In about 90% of cases, there is only one person in a family with ALS/MND. This is called sporadic ALS/MND. In about 10% of cases, more than one person in the same family is affected. This is known as hereditary or familial ALS/MND and may be linked to a change in a gene that runs in a family.
For some families, understanding hereditary ALS/MND may be an important next step. It can help explain why the condition affects more than one person in the same family and why symptoms may differ across family members. It may also help families understand what information they may want to explore next.
Even in cases of sporadic ALS/MND, meaning there is no known family history, genetics may still be relevant. This is because a genetic change may still be present even when ALS/MND appears to affect only one person in a family. This is one reason information about genetics may be useful to a wider group of people and families.
The materials below support different needs and different levels of interest. They include brief explanations, visual resources, and additional information for those who want to learn more about genetics in ALS/MND.
Starting with the basics
To better understand genetics, it can be helpful to start with the basics. The visual explainers below introduce the genome, DNA, genes, and chromosomes, and provide a simple foundation for the rest of this section.
- What is your genome? ( PDF): This infographic introduces the genome and shows how DNA, genes, chromosomes, RNA, and proteins are connected. It explains how genetic information is stored and used, helping build a foundation for genetics in ALS/MND.
- Introduction to Genetics (PDF): This infographic introduces genetics and how genetic changes can be passed through families in different ways. It helps explain why some are affected, others are unaffected carriers, and why hereditary conditions look different in each family.
Understanding genetics in ALS/MND
The visual explainers below build on these basic concepts and focus more directly on how genetics may relate to ALS/MND and why it may matter for individuals and families.
- Why is genetics relevant to ALS/MND? (PDF): This infographic shows how family history and genetic causes do not always fit simple categories. It explains the difference between hereditary and sporadic ALS/MND, varied inheritance patterns, and that a genetic cause can be found even without clear family history.
- Can genes affect the type of ALS/MND? (PDF): This infographic explains penetrance, which means that carrying a genetic change does not always mean a person will develop ALS/MND. It also shows that genes can lead to different types of ALS/MND across individuals.
Learn more about genetics in ALS/MND
These resources provide broader introductions to genetics and inherited ALS/MND. They may be helpful for readers who want to build on the visual explainers and explore these topics in more detail.
- Introduction to ALS/MND Genetics (video): This Alliance webinar gives an overview of genetics in ALS/MND and the current ALS/MND landscape. It is intended to help people living with ALS/MND and their families build a basic understanding of genetics, what it may mean for them, and what options may be available.
- Inherited MND: Introduction (webpage): This resource from the MND Association introduces inherited ALS/MND and is useful for readers wanting more after the visual explainers.
- ALS Genes and Mutations (webpage): This resource from the ALS Association explains the genes linked to ALS/MND, including the four most common, and provides an overview of genetic testing.