Neuronal Intermediate Filament Inclusion Disease

Neuronal intermediate filament inclusion disease (NIFID) is a rare distinct variant of frontotemporal dementia. The inclusion bodies that are present in NIFID are cytoplasmic and made up of intermediate filaments. Symptoms can include behavioural, and personality changes, memory and cognitive impairments, language difficulties, motor weakness, and extrapyramidal symptoms. NIFID is one of the FTLD-FUS proteopathies. Another rare FTD variant, also a FTLD-FUS proteopathy is basophilic inclusion body disease (BIBD) .

Imaging commonly shows atrophy in the frontotemporal region, and in part of the striatum in the basal ganglia. Post-mortem studies show clear atrophy of brain regions, and in NIFID a marked reduction in the caudate nucleus of the striatum.