SOD1 and amyotrophic lateral sclerosis: In sporadic ALS the C:N‐terminal peptide ratio (Figure 4F) and the N‐terminal cleaved peptide (Truncation 2, Figure 4G) were increased in the insoluble fraction in line with the presence of C‐terminal fragments, compared to ALS caused by p.I114‐T, p.D102N or p.I113T mutations within SOD1.