SOD1 and amyotrophic lateral sclerosis: ALS-causing mutations such as fused in sarcoma (FUS) and superoxide dismutase 1 (SOD1) conspicuously lack TDP-43 proteinopathy in most cases.145 Mutations are found in the FUS C-terminal nuclear localization sequence, causing the mislocalization of the normally nuclear protein to the cytoplasm, leading to the accumulation of cytoplasmic FUS and FUS aggregation.146 FUS is a 53 kDa protein, present in cellular inclusions, and has not been reported in body fluids including urine.