A c.112G>A also resulting in a p.Gly38Arg exchange was one of the original SOD1 mutations found to cause ALS following linkage analysis of fALS pedigrees.2 This mutation has been reported in fALS patients in Germany, Spain, Taiwan, Turkey and the USA and overexpression in a transgenic mouse model results in a murine MND.14 The delay in central conduction time on MEP stimulation observed in Patient A has earlier been observed in ALS patients with SOD1 mutations.15 All evidence supports that a p.Gly38Arg substitution in SOD1 can cause ALS (online supplemental table 1). This evidence concerns the gene SOD1 and amyotrophic lateral sclerosis.