- The symposium marked the 30th anniversary of the SOD1 gene discovery, the first known monogenic cause of ALS.
- Approximately 15% of ALS cases are now linked to known pathogenic genetic variants.
- The ClinGen ALS Expert Panel has reviewed over 50 genes to standardize ALS gene variant classification.
- Genetic testing is essential for identifying treatment options and assessing risk for family members.
- Sano Genetics launched "Light The Way" to provide free DNA testing and counseling for the ALS community.
The exploration of ALS's genetic landscape was a central theme of the symposium. Researchers have now linked more than 40 genes to ALS risk and development, with about 15% of ALS cases understood to be associated with pathogenic variants in known ALS genes. This expanding map of the disease's genetic architecture has opened pathways into non-coding genomic regions and structural variants, areas that were previously difficult to characterize. Critically, this progress is not only advancing scientific understanding. It is laying the foundation for genetically targeted therapies, a class of treatment that has already reached clinical practice for SOD1-associated ALS.
Advances in ALS gene variant classification
The work presented by the ClinGen ALS Gene Curation Expert Panel stood out for its direct clinical relevance. In the closing session, Dr. Matthew Harms presented findings from a three-year effort by the ClinGen ALS Variant Curation Expert Panel, which developed systematic criteria for classifying ALS gene variants. Their review of over 50 genes associated with ALS moves the field closer to a shared framework for determining which variants are clinically actionable. This matters now more than ever: with the first genetically targeted ALS therapy already approved by the FDA, accurate variant classification is a prerequisite for identifying patients who may be eligible for current and future treatments.
For sponsors designing ALS studies that depend on genetic stratification, the refinement of variant classification criteria has direct consequences for eligibility design. Clearer pathogenic variant definitions reduce ambiguity at the screening stage and help teams set more accurate expectations for patient prevalence, screen failure rates, and protocol feasibility in genetically defined populations.
The implications extend beyond research. Variant classification has a direct impact on patients and families, shaping how genetic testing results are interpreted and what actions follow. As Dr. Harms noted:
"I also want to remind everyone that genetic testing will prepare entire families for changes in actionability as these genetic therapies move forward in the clinic. Additionally, from a patient's perspective, it can be equally important that they receive an explanation for why the disease has occurred, and then importantly, inform the ALS risk assessment for close relatives."
This points to the layered role genetic testing plays in ALS. It informs eligibility for genetically targeted therapies. It provides families with an explanation for why the disease occurred. And it enables risk assessment for close relatives. Yet the majority of people living with ALS have not been tested or do not carry a currently identifiable gene change, which means the gap between what genetic testing can offer and how widely it is applied remains significant. As genetically targeted therapies advance, closing that gap becomes both a clinical priority and an operational one.
The Light the Way initiative
Against this backdrop, Sano introduced the "Light The Way" initiative at the symposium. The program provides free DNA testing, genetic counseling, and educational resources to individuals diagnosed with ALS, those showing symptoms, and those at risk due to family history. The rationale is straightforward: if genetically targeted therapies are advancing, the infrastructure for identifying who may benefit needs to keep pace. "Light The Way" addresses this by lowering the barriers to genetic testing and counseling, expanding the genetically characterized ALS population, and contributing data that supports ongoing research. It reflects a practical response to the gap between therapeutic progress and the current reach of genetic testing in the ALS community.
The 34th International Symposium on ALS/MND made one thing clear: the genetic understanding of ALS has reached a level where it directly shapes clinical decision-making. Variant classification frameworks are maturing. Genetically targeted therapies are entering practice. And the need for accessible, well-coordinated genetic testing pathways is growing in parallel. These developments are converging to create a new era of precision medicine for ALS. Programs like "Light the Way" represent one part of that shift, working to ensure that the patients who stand to benefit from these advances can be identified and supported.
For a deeper look at the genetic landscape of ALS and its implications for research and patient identification, download our insights report below.