SOD1 and amyotrophic lateral sclerosis: Although cytotoxic mutations in SOD1 represent only a fifth of familial ALS cases, we and others reported on the presence of misfolded SOD1 in sporadic ALS and non-SOD1 familial ALS3, 4, 5, 19, potentially implicating misfolded SOD1 as a pathogenic molecule in all types of ALS.