A changed landscape: five-year retrospective on the paradigm shift in genetic testing practices for ALS in Canada

Offering genetic testing is increasingly recommended for all individuals with amyotrophic lateral sclerosis (ALS), particularly following the development of gene-targeted therapies, such as tofersen for SOD1-ALS. Historically, testing was routinely offered to those with familial ALS (fALS), but inconsistently to those with sporadic ALS (sALS). We evaluated changes in genetic testing and counseling practices among Canadian ALS physicians over a five-year period spanning pivotal clinical trial results and regulatory approval of tofersen. Members of the Canadian ALS Research Network were surveyed in 2020, 2022, and 2025 about genetic testing practices for symptomatic and asymptomatic individuals, gene panel composition, access to genetic counseling, and perceived drivers of change. Clinics offering genetic testing for sALS increased from 33% of clinics in 2020 and 57% in 2022 to 100% of respondents in 2025. Genetic testing for patients with a family history (fALS) was near-universal across all timepoints. Broader use of multi-gene panel testing increased over time, coinciding with sponsored testing availability. 61% of respondents reported that Health Canada approval of tofersen directly influenced their practice. Predictive testing offerings increased from 37% in 2020 to 61% in 2025. Genetic testing practices in Canada shifted substantially during late-stage clinical development and following regulatory approval of a gene-targeted therapy (tofersen). Proactive planning during the clinical trial phase facilitated rapid, nationwide adoption. This study captures a key turning point in ALS care, illustrating how therapeutic breakthroughs can redefine national clinical standards.