SOD1 and amyotrophic lateral sclerosis: Based on the results of analysis of these 20 SOD1 mutations in 27 sporadic ALS patients (13 men, 10 women, and 4 unknown), the average age at onset was 43.8 (range 18–77) years, which is about 10 years younger that the mean age at onset reported for the sporadic ALS population [22].