SOD1 and amyotrophic lateral sclerosis: The presence of 43 kDa Tar-DNA binding protein (TDP-43), whose pathological misfolding and accumulation is observed in the brains and spinal cord of patients with ALS, except for cases of superoxide dismutase 1 (SOD1) mutation, suggests a common underlying process.4 TDP-43 is a predominantly nuclear protein involved in transcriptional regulation.