SOD1 and amyotrophic lateral sclerosis: In that sense, the involvement of wild-type SOD1 was examined in a SOD1-ALS patient with the G127insTGGG (G127X) mutation; such a truncated G127X-mutant SOD1 can be discriminated from the wild-type protein because of the difference in size and also of a non-native procession of the five amino acids following Gly127 in the variant [44, 45].