SOD1 and amyotrophic lateral sclerosis: As shown in Fig. 7a–e, sulfenic acid modification of wild-type SOD1 was remarkably observed in CSF samples from 13 patients with sporadic ALS (S1–S5 and S8–S15), but was not remarkably observed in those of 6 non-ALS control patients (C1-C6) and 2 sporadic ALS patients (S6 and S7).