C9orf72 and neurodegenerative disease: Moreover, it is expected that the antibody will be a powerful tool to further dissect the biochemical basis of occasional FTLD–TDP cases with difficult to classify and/or mixed patterns of pathology that seem to be particularly common in C9orf72 mutation carriers [13, 14, 21, 26, 27] and to identify potential molecular overlaps of TDP-43 aggregates in FTLD–TDP with those in secondary TDP-43 proteinopathies, e.g., cases with anatomically restricted TDP-43 pathology in association with other common neurodegenerative diseases and aging [7].