TARDBP and amyotrophic lateral sclerosis: Furthermore, pathological TDP-43 aggregates that accumulate within the brain of ALS and FTD patients contain proteolytically cleaved C-terminal fragments, TDP-35 (35 kDa) and TDP-23 (25 kDa), which must be cleared from cells to prevent further aggregation and sequestration of neuronal components that result in toxicity [32].