Abstract
There are few reports describing young‐onset amyotrophic lateral sclerosis (ALS). Age at onset is a prognostic factor in ALS, and thus it is relevant to investigate the clinical features of very young ALS patients. We describe three young‐onset ALS cases and review the literature. SOD1 mutations were not identified. Our cases and 24 others from the literature indicate that young‐onset ALS is characterized by slowly progressive symmetrical weakness; nevertheless, progression is variable. Young‐onset ALS seems to be a distinct clinical syndrome but its aetiological background is largely unknown.