Genetic testing and genetic counseling for amyotrophic lateral sclerosis: an update for clinicians

Patients with amyotrophic lateral sclerosis (ALS) often have questions about why they developed the disease and the likelihood that family members will also be affected. In recent years, providing answers to these questions has become more complex with the identification of multiple novel genes, the newly recognized etiologic link between ALS and frontotemporal dementia (FTD), and the increased availability of commercial genetic testing. A genetic diagnosis is particularly important to establish in the era of emerging gene-based therapies, such as SOD1 antisense oligonucleotide trials. In the span of a few years, ALS genetic testing options have progressed from testing of a single gene to multigene next-generation sequencing panels and whole-exome sequencing. This article provides suggestions for genetic counseling and genetic testing for ALS in this new environment.