TARDBP and amyotrophic lateral sclerosis: However, and most excitingly, the results of pTDP-43S375 immunohistochemistry (IHC) distinguished FTLD–TDP with type A pathology from other types of FTLD–TDP and ALS–TDP, most likely due to conformational differences of TDP-43 aggregates; thereby providing further evidence for the existence of distinct subtype-specific TDP-43 strains.