Arimoclomol showed some efficacy in mouse models of fALS due to mutation in the superoxide dismutase I (SOD1) gene (ALS1)6 or valosin-containing protein,7 and promise in ALS patients with SOD1 mutation,8 but it failed to meet primary endpoints in a clinical trial in sALS patients. This evidence concerns the gene SOD1 and amyotrophic lateral sclerosis.