SOD1 and amyotrophic lateral sclerosis: We identified 19 SOD1-ALS cases (9 male patients and 10 female patients) from 15 independent families (3.3%), including 15 fALS (21.7% of all familial forms and 78.9% of SOD1-ALS) and four sALS cases (0.8% of all sporadic forms and 21.1% of SOD1-ALS).