P2‐189: Longitudinal atrophy rate as a biomarker of disease progression in frontotemporal lobar degeneration

characterized by severe progressive psychobehavioural abnormalities in the absence of significant aphasia, cognitive-intellectual dysfunction or motor features. The neuropathological features were highly consistent, with small, round, neuronal cytoplasmic inclusions that were immunoreactive for ubiquitin (ub-ir), but negative for tau, -synuclein, intermediate filaments and TDP-43. Cytoplasmic inclusions were most numerous in the neocortex, dentate granule cells and hippocampal pyramidal neurons. Ub-ir neuronal intranuclear inclusions were also present in neocortical and hippocampal neurons and had the unusual appearance of straight, curved, or twisted filaments. Conclusions: We believe that these cases represent a new entity that is clinically and pathologically distinct from all currently recognized subtypes of FTLD. Moreover, the existence of such cases indicates that the designations of “FTLD-U” and “TDP-43 proteinopathy” should not be considered to be synonymous.