SOD1 and amyotrophic lateral sclerosis: These ratios are also lower than those in both the present cohort (689/393 = 1.75) and in the ALS population in China (1.47–1.7) [35, 38]; however, they are comparable to that of SOD1-mutant patients found in the United States (1.3, 175 fALS included) [29].