SOD1 and amyotrophic lateral sclerosis: Taken together, these studies suggest that in SOD1, C9orf72 and TARDBP MNs, the expression of NF-L subunits could be directly or indirectly altered by mutant proteins, and this could explain the abnormal NF-L accumulations in soma and decreased NF-L expression in neurites, we observed in ALS MNs.