SOD1 and amyotrophic lateral sclerosis: Induced astrocytes recapitulate one of the key hallmarks of ALS, i.e. TDP-43 proteinopathy, detected as the presence of TDP-43 fragments (observed at 35 kDa) in sporadic and C9orf72 ALS patient iAstrocytes (Fig. 6E), but not in SOD1 cases (Suppl.