Genetics & Genetic Counseling in FTD-ALS Spectrum Disorders
- Penn FTD Center
- Feb 21, 2024
- 3 min read
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that involves progressive paralysis due to muscle weakening over time. While ALS is a neuromuscular disease, frontotemporal dementia (FTD) is typically associated with changes to behavior and/or language. Despite these distinctions, FTD-ALS disorders are on a spectrum, with substantial overlap in the clinical presentation, the pathology, and genetics of FTD and ALS. Indeed, patients who are initially diagnosed with either FTD or ALS can develop symptoms of both conditions later in disease course.
While most forms of FTD/ALS are sporadic, and not associated with a disease-causing mutation, some individuals do have a genetic cause for their disease. This is more common when there is a family history of FTD, ALS, or related conditions. Genetics can provide important information about the underlying pathology of disease. When we talk about genes, we are talking about the instruction manual of the body. They tell your body how to grow and develop. Mutations in a gene can cause variations in the body, similar to how changing a letter in a sentence can change the meaning of that sentence. While some mutations are harmless, some can cause problems in the body.
Some genes can cause a wide variety of symptoms, even in the same family. This means that both conditions can be present in a single family or even a single person. Scientists have discovered several genes that are associated with FTD and ALS, including C9orf72, which is the most common genetic cause of both diseases. Understanding the genetic cause of disease can help patients and their families anticipate future medical needs.
With a variety of potential causes to ALS-FTD spectrum disorders, it can be difficult to pinpoint the cause of an individual’s symptoms. But without a current cure or prevention for FTD-ALS disorders, many families wonder: “Why ask why?" Why would we want to know the cause of our symptoms? Someone with a clinical diagnosis could benefit from getting tested because it can help alleviate guilt, or misconception about why the disease developed. It can also help confirm the diagnosis if it isn’t clear to the physician. A genetic diagnosis can provide information on what you might expect in the future, including needs you may have and symptoms that may arise. Importantly, a genetic diagnosis may also open doors to trial entry.
Learning the genetic cause of the disease in the family also allows family members to consider whether predictive testing (testing before symptoms appear) is something they want to pursue. Predictive testing is a highly personal choice. There are many things to consider when deciding to know your genetic status including reproductive choices, life planning, and how you will feel knowing your risk status. It’s also important to know if the results will become a part of your medical record, because this may affect your ability to obtain life, long term care, and disability insurance if you do not already have these policies and are otherwise healthy. We encourage people to think about what insurance policies are in place before deciding to get tested, but a counselor can also help you make an informed decision.
You can access more information about what privacy protections exist (and their loopholes) by visiting GINAhelp.org – Your GINA Resource. A genetic counselor can help you make an informed decision. Remember, counseling is a huge part of genetic counseling!
Genetic testing can be either for clinical or for research purposes. A clinical test will be done with your health care provider, will inform you of your status, and will go into your medical record. A research test is not performed to inform you of your status, but to advance science and researchers’ knowledge. If you decide to participate in a genetic test for research purposes, it’s important to discuss beforehand whether or not you will receive the results.
The science is always evolving, and new genes related to ALS and FTD may be discovered in the future. So, we encourages you to keep all your genetic records for the future, and to stay in touch with your genetics team and your neurologist. Anyone, even if they don’t want to get tested, can get genetic counseling. If you have any questions about genetic counseling, you are always welcome to contact Penn’s Neurology Genetic Counseling team at 215-829-6500, or find a genetic counselor near you using the link below.
