Learn how genetic testing, inheritance patterns, and multidisciplinary care empower families affected by hereditary ALS to make informed decisions. Understanding your genetic status and building a coordinated care team early gives you the knowledge and support to navigate this journey with hope and agency.
Understanding Hereditary ALS: Genetic Inheritance Patterns and Risk
Four genes account for most familial ALS cases, each with distinct inheritance patterns your care team should understand before genetic testing.
How likely is ALS genetically inherited and what does familial ALS mean
Familial ALS means the disease is caused by an inherited gene mutation passed down through a family, and it accounts for roughly 5-10% of all ALS cases. [1] The remaining 90-95% of cases are classified as sporadic -- occurring in people with no known family history -- though research shows that some sporadic cases also carry identifiable genetic variants. [2] One key difference between these two forms is age of onset: people with familial ALS typically develop symptoms in their late 40s to early 50s, compared to late 50s to early 60s for sporadic cases. [2] Understanding the [familial ALS inheritance pattern](https://alsunited.org/blog/familial-als-inheritance-pattern) can help families prepare for genetic counseling and make more informed decisions about testing.
Key genes linked to hereditary ALS and their inheritance patterns
Four genes -- C9ORF72, SOD1, FUS, and TARDBP -- account for the majority of familial ALS cases, with each carrying a distinct inheritance pattern your care team will want to understand. [3] C9ORF72 is the most frequently mutated, present in 30-50% of familial cases; SOD1 accounts for 10-20%, FUS for roughly 5%, and TARDBP for 1-4%, with all four typically following autosomal dominant inheritance, meaning one mutated copy is enough to cause disease. [3] Some SOD1 mutations and rarer genes such as ALS2 and SPG11 follow an autosomal recessive pattern, requiring both gene copies to carry the mutation before disease develops. [3] In rare cases like UBQLN2, inheritance is X-linked and primarily affects men, since they carry only one X chromosome. [3]
Why genetic counseling matters before and after diagnosis
Genetic counseling should happen before testing because understanding potential outcomes in advance helps you weigh the benefits, risks, and limitations of testing for yourself and your family. [4] A counselor documents your family history going back at least three generations, explains inheritance patterns and incomplete penetrance, and prepares you for a positive, negative, or uncertain result. [4] After testing, counseling helps you interpret what results actually mean -- a positive finding rarely predicts individual disease course, and a negative result does not rule out a genetic form of ALS. [4] Posttest sessions also cover presymptomatic testing for adult relatives, clinical trial eligibility, and how results may affect insurance coverage or family communication -- all decisions that are easier to navigate with trained support. [5]
Key Treatment Approaches Hereditary ALS Patients Actively Seek
Tofersen is the first FDA-approved genetic treatment for SOD1-linked ALS, delivered by spinal injection to reduce toxic protein accumulation in motor neurons.
What is the genetic treatment for ALS and current FDA-approved options
The only FDA-approved genetic treatment for ALS is tofersen (Qalsody), approved in April 2023 specifically for SOD1-linked ALS -- a form caused by mutations in the superoxide dismutase 1 gene that accounts for roughly 2% of all ALS cases. [6] Tofersen is an antisense oligonucleotide that binds to SOD1 messenger RNA to reduce production of the toxic mutated protein that accumulates in and damages motor neurons. [7] It is delivered by spinal injection on a defined schedule: three loading doses given two weeks apart, followed by a maintenance dose every 28 days. [6] The FDA granted approval under its accelerated approval pathway, based on tofersen's ability to reduce plasma neurofilament light levels -- a blood biomarker of nerve damage -- rather than a direct functional measure of disease progression, with confirmatory trials still ongoing. [6]
Gene-directed therapies and antisense oligonucleotide treatments explained
Antisense oligonucleotides work by binding to a target messenger RNA and triggering its degradation through an enzyme called RNase H, which prevents the harmful protein from accumulating in motor neurons. [8] Beyond SOD1, researchers have targeted C9ORF72 -- the most common familial ALS gene -- with two ASO candidates, BIIB078 and WVE-004, both discontinued after failing to meet efficacy endpoints despite favorable safety profiles. [9] A separate program called Jacifusen (ION363) targets FUS-linked ALS and is now in Phase III trials after compassionate-use data in a single patient showed measurable reductions in mutant FUS protein. [9] These programs confirm the biological logic of gene-directed therapy while underscoring that safety alone does not translate into clinical benefit for patients. [8]
Symptom management and multidisciplinary care as essential treatment pillars
Beyond disease-modifying drugs, symptom management through multidisciplinary care is a core pillar of ALS treatment, with research showing it reduces 1-year mortality by as much as 30% and lowers both hospitalization rates and overall cost of care. [10] A multidisciplinary ALS clinic coordinates care across [physical therapy, occupational therapy, speech therapy, respiratory therapy, nutrition, and mental health services](https://alsunited.org/blog/what-type-of-doctor-treats-als-understanding-als-medical-care) -- addressing the full range of symptoms as the disease progresses rather than reacting to each one in isolation. [11] This team-based approach also encompasses neuropalliative care planning and access to durable medical equipment, helping patients and caregivers prepare for disease-related changes before they become urgent. [10] For hereditary ALS patients who often begin this process earlier in life, establishing this team promptly after diagnosis gives families more time to plan, adapt, and access the right support on their own terms. [10]
Genetic Testing for ALS: What You Need to Know Before Testing
Free genetic testing through the ALS Identified program includes counseling and results at no cost to you and your family members.
Where can I get genetic testing for ALS and what the process involves
Genetic testing for ALS is available at no charge through the ALS Identified program, a 26-gene panel offered by Invitae and sponsored by Biogen, open to anyone diagnosed with ALS and their family members -- including those with no known family history of the disease. [12] The process begins with a genetic counselor who reviews your medical records, takes a detailed family history going back several generations, and discusses the benefits and limitations of testing before you sign a consent form. [5] Once ordered through Invitae's online portal, a specimen collection kit is sent to you, and results are delivered online with post-test genetic counseling included at no additional cost. [12] To find an independent genetic counselor outside this program, the National Society of Genetic Counselors maintains a searchable directory at nsgc.org. [5]
ALS genetic testing cost, insurance coverage, and financial assistance options
The ALS Identified program eliminates direct testing costs, but coverage for genetic testing ordered outside this program varies -- and in most U.S. states, genetic results can still be used by life, disability, and long-term care insurers to deny coverage, so discussing this risk with a counselor before testing matters. [13][14] Broader ALS care expenses can reach $80,000-$250,000 per year out of pocket, and [financial navigators through the ALS Association and Patient Advocate Foundation](https://alsunited.org/blog/medicare-medicaid-and-private-employer-insurance) help with insurance appeals, benefit enrollment, and Medigap supplemental coverage -- which can cover the 20% Medicare does not pay. [13] Charitable organizations also offer grants for equipment, home modifications, and respite care not covered by insurance, and at least eight states now operate drug affordability boards to help keep ALS medications accessible. [13][15]
Interpreting results and next steps after a positive genetic diagnosis
A positive genetic diagnosis confirms a specific mutation is causing your ALS, but it does not change most treatment options -- the main exception is SOD1 mutations, where tofersen (Qalsody) offers a targeted FDA-approved therapy. [16] Results are classified as pathogenic (disease-causing), a variant of uncertain significance (VUS), or negative, and each carries different implications for you and your family. [17] When a VUS is returned, DNA banking is recommended so that additional testing or segregation analysis with family members can be completed as scientific understanding advances. [17] Your genetic counselor can then walk you through sharing results with adult relatives, presymptomatic testing options, and the insurance and employment concerns that may follow a positive finding. [16]
Building Your ALS Care Team: Medical Resources and Support Networks
Multidisciplinary ALS clinics coordinate neurologists, therapists, and social workers to build a unified care plan during a single comprehensive visit.
Finding specialists through ALS United clinic finder and coordinating multidisciplinary care
Finding a specialist clinic quickly after diagnosis matters -- the average time from ALS symptom onset to first multidisciplinary clinic attendance has been documented at 19 months, a gap that delays timely care planning and coordinated support. [18] Our clinic finder connects you with ALS United partner clinics staffed by coordinated teams that include neurologists, respiratory therapists, speech-language pathologists, occupational therapists, nutritionists, and social workers -- all meeting with you during a single comprehensive visit to review findings and build a unified care plan. [19] For people in rural or geographically isolated areas, virtual clinic visits through partner clinics provide consistent, expert-level access without requiring long-distance travel. [19] We are here for you -- our [care services page](https://alsunited.org/blog/our-care-services) can help you locate the nearest clinic and understand exactly what your first visit will involve. [19]
Emotional counseling and family support services for hereditary ALS diagnosis
A hereditary ALS diagnosis carries emotional weight that extends beyond the clinical -- for both the person diagnosed and family members who may share the same genetic risk. [21] Genetic counselors address this directly, helping patients and relatives process the psychological effects of testing, navigate difficult family conversations, and make informed decisions about when and how to share results with others. [20] Peer support organizations focused on the genetic ALS and FTD community connect families with genetic education, counseling access, and guidance on next steps including clinical trials and family planning. [20] [ALS support groups](https://alsunited.org/blog/als-support-groups-connecting-with-others-facing-the-disease/) can complement this specialized support with ongoing community connection as families continue to navigate what a hereditary diagnosis means over time.
Community connection and advocacy programs that empower hereditary ALS patients
Patient advocacy teams built specifically for the hereditary ALS/FTD community work to raise awareness, engage affected families, and advocate directly with researchers and funders on their behalf. [23] The NIH-funded AMP ALS program's Lived Experience and Advocacy Working Group also includes people at genetic risk for ALS alongside those diagnosed, caregivers, and family members -- giving the hereditary community a formal seat in shaping research priorities. [24] Enrolling in the National ALS Registry connects at-risk individuals to clinical trial notifications and allows biological sample donation through the National ALS Biorepository. [24] [ALS advocacy](https://alsunited.org/blog/als-advocacy-get-involved-make-a-difference/) through these programs -- joining a community team, contributing to a biorepository, or attending policy briefings -- channels lived experience into decisions that shape how ALS is studied and funded. [22]
References
- Also known as inherited ALS, familial ALS accounts for approximately 5-10% of all ALS cases. In these instances, the disease results from the inheritance of a causative variant in a specific single gene.
- Familial ALS is clearly genetic: There's a family history of ALS. In contrast, sporadic ALS, which accounts for roughly 90% to 95% of ALS cases, appears to occur randomly. People with familial ALS will usually begin showing symptoms in their late 40s to early 50s. People with sporadic ALS typically become symptomatic in their late 50s to early 60s.
- The most common ALS-associated genetic mutations affect the genes C9ORF72, SOD1, FUS, and TARDBP... The gene most commonly linked to ALS is C9ORF72, which is mutated in 30% to 50% of people with familial disease... Mutations in the SOD1 gene account for 10% to 20% of familial ALS cases... The FUS gene is mutated in about 5% of people with familial ALS... The TARDBP gene is mutated in 1% to 4% of people with familial ALS cases... The vast majority of ALS-linked mutations are inherited in an autosomal dominant manner... A SOD1 mutation called p.Asp90Ala is inherited in an autosomal recessive pattern, as are some rarer ALS-linked genes like ALS2 and SPG11... One rare mutation that causes familial ALS in the gene UBQLN2 is inherited in an X-linked manner... women usually have a second healthy copy of the gene on the other X chromosome, which can compensate if one copy is mutated, X-linked inheritance predominantly affects men.
- Genetic counseling should be provided before testing, to empower persons with ALS to weigh the potential benefits, risks and limitations of testing, and anticipate the possible impact of testing on themselves and their family members. A pedigree going back three generations at minimum should be documented. Posttest counseling should inform persons with ALS with a pathogenic or likely pathogenic test outcome that result may or may not allow prediction of disease course. Posttest counseling should inform persons with ALS with a negative outcome that the result does not exclude a genetic form of ALS.
- After the test, they will review and interpret your results. Finally, your counselor will help you plan next steps, such as additional screening or entry into a clinical trial.
- FDA approved Qalsody (tofersen) to treat patients with amyotrophic lateral sclerosis (ALS) associated with a mutation in the superoxide dismutase 1 (SOD1) gene. Approximately 2% of ALS cases are associated with mutations in the SOD1 gene. The recommended dosage is 100 mg per administration. Patients receive three initial doses administered at 14-day intervals, followed by a maintenance dose every 28 days. Qalsody is approved under the accelerated approval pathway based on a reduction in plasma neurofilament light (NfL), a blood-based biomarker of axonal injury and neurodegeneration.
- Tofersen is an antisense oligonucleotide (ASO), a type of precision therapy designed to modify the expression of a specific gene. Tofersen binds to normal and mutated SOD1 messenger RNA (mRNA) and prevents translation into protein, thereby reducing the overall level of SOD1 protein, including the toxic mutated form.
- ASOs are short, single-stranded sequences of synthetic nucleotides designed to bind to specific mRNA transcripts. Once bound, they induce degradation of the target mRNA via the RNase H enzyme, thereby reducing the production of the corresponding protein.
- BIIB078 and WVE-004 targeting C9ORF72 failed to meet efficacy endpoints and were discontinued. ION363 (Jacifusen) targets FUS and is now in Phase III trials after compassionate-use data showed reductions in mutant FUS protein levels and aggregation.
- Numerous studies have demonstrated that multidisciplinary care decreases 1-year mortality by as much as 30 percent, reduces hospitalizations and cost of care, improves quality-of-life outcomes, and increases patient satisfaction. A multidisciplinary clinic also provides neuropalliative care services for individualized advanced care planning based on ALS disease progression.
- In addition to medication, people with ALS can benefit from supportive forms of therapy, including physical therapy, occupational therapy, speech therapy, respiratory therapy, psychotherapy, and counseling.
- 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... This program offers testing with the ALS Identified Panel, a 26 gene panel... Individuals in the US tested through the ALS Identified(TM) program are eligible for post-test genetic counseling to help them understand their test results. This service is made available by Invitae at no charge as part of the program.
- People with ALS can pay between $80,000 and $250,000 a year out of pocket for care and ALS treatment. In the area of genetic testing, which many people with ALS undergo, folks who do that before getting a life insurance policy may not be able to get one in states without genetic testing protections. The ALS Association and the Patient Advocate Foundation have an ALS insurance and benefits resource line. By 2024, at least eight U.S. states will have created drug affordability boards.
- While the physical risks associated with genetic testing may be minimal, there can be emotional, social, or financial consequences of obtaining a genetic test. The possibility of genetic discrimination in employment, as well as for disability or life insurance, can also be a concern for patients.
- We're committed to supporting people and families living with ALS through our grant programs & equipment loans. These programs offer financial assistance, helping cover the costs of vital equipment, home modifications, respite care, and more, which are often not covered by insurance.
- A positive test means that the genetic cause of FALS has been identified. A positive test does not change medical treatment at this time. In 2023, Qalsody was FDA approved as a treatment for those with ALS who have a specific SOD-1 gene mutation. A genetic counselor can further discuss the issues involved in presymptomatic testing including insurance and employment discrimination concerns.
- Despite these approaches, however, uncertainty regarding the significance of a VUS often remains. DNA banking is an option in these cases to enable testing of additional genes and/or segregation analysis in the future. If affected family members are available for testing, segregation analysis can be a powerful tool in variant interpretation.
- The average time from symptom onset to attendance at the MDC was 19 months.
- Multidisciplinary clinics bring together a team of specialists who meet with the person living with ALS during a several-hour visit. Providers offer focused assessments, education, and individualized conversations. After the visit, the care team meets to review findings and coordinate a unified plan of care. Virtual clinic visits also play a critical role in expanding access, particularly for individuals living in rural or geographically isolated areas.
- Emotions associated with genetic counseling and predictive genetic testing; Tips for communicating with your family; End the Legacy -- a patient-led organization dedicated to the needs and interests of the Genetic ALS & FTD community; Light the Way -- provides individuals and families with access to genetic education, peer support, genetic counseling, and guidance on next steps including peer support, trials, therapies, family planning.
- A genetic counsellor or other healthcare providers can discuss options with the individual and their family if there is a positive test result. All people living with ALS/MND should have access to, and be provided information on, genetic counselling and testing, regardless of whether they have sporadic or familial ALS/MND.
- I AM ALS launched the first-of-its kind Navigation program designed as a single entry point for patients and their loved ones to learn about and access ALS resources. I AM ALS is a patient-centric movement revolutionizing how to fight disease.
- Mission Statement: To raise awareness of familial ALS/FTD and engage, empower, and support the familial ALS community and advocate for them with ALS/FTD researchers and funders.
- The Accelerating Medicines Partnership(R) for Amyotrophic Lateral Sclerosis (AMP(R) ALS) is seeking individuals with lived experience of ALS. Whether you're diagnosed, at genetic risk, a caregiver, or a family member, your insights are invaluable. The National ALS Registry is a nationwide program designed to better understand amyotrophic lateral sclerosis (ALS)... Participants can also join the National ALS Biorepository and donate their blood and saliva to expand research on genetics and biomarkers.