SOD1 and amyotrophic lateral sclerosis: In contrast, when spinal cord homogenates were treated with 0.5% Nonidet P-40, significantly more amounts of SOD1 were detected in the insoluble fraction of a SOD1-ALS case (A4V mutation) than those of two familial ALS cases with unknown genetic causes, 12 sporadic ALS cases, and three controls [60].