TTBK2 and amyotrophic lateral sclerosis: Of the two ALS cases with pathologic changes in brain, a subset of neurons in the hippocampus and frontal cortex containing phospho-TDP-43 aggregates also co-expressed TTBK1 and TTBK2, while other neurons appeared to be immunoreactive for phospho-TDP-43 alone (Fig. 5 C–H).