SOD1 and amyotrophic lateral sclerosis: In this mathematical modeling study, Chiò et al. analyzed four major genes with mutations in ALS: hexanucleotide expansion repeat in Chromosome nine Open Reading Frame 72 (C9orf 72), transactive response DNA Binding protein 43kDa (TARDBP), fused in sarcoma (FUS), and superoxide dismutase 1 (SOD1).