TARDBP and amyotrophic lateral sclerosis: TDP-43 pathology is seen in approximately 98% of patients with ALS, but is absent in the 2% of ALS that can be attributed to SOD1 mutations.33,36 The presence of TDP-43 pathology and the identification of an SOD1 mutation suggest a connection to ALS, and although there is some limited evidence in support of an autoimmune mechanism, this is far from conclusive.