What is the pathology of frontotemporal dementia (FTD)?

Updated: Dec 23, 2019
  • Author: Thomas J Montine, MD, PhD; Chief Editor: Adekunle M Adesina, MD, PhD  more...
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Answer

Answer

Frontotemporal dementia (FTD) refers to a group of neurodegenerative disorders that are characterized clinically by early onset (usually sixth and seventh decade of life), loss of executive function, disrupted language and motor function, and relative sparing of memory and visuospatial functions. [9] Pathologically, they have variable atrophy of the frontal and temporal lobes that is often asymmetric. FTDs are heterogenous with multiple etiologies, and many have characteristic histopathologic changes. [23]

Pick disease is probably the most well-known of the FTDs and is characterized by widespread presence of spherical intraneuronal Pick bodies that are positive for microtubule-associated protein tau (MAPT), as well as other proteins (see the image below). Pick bodies may also be identified using silver staining techniques such as Bielschowsky or Gallyas.

Dementia pathology. A: Hematoxylin and eosin stain Dementia pathology. A: Hematoxylin and eosin staining at 400× magnification of the dentate fascia of the hippocampus reveals round eosinophilic Pick bodies (arrows) in the soma of granular neurons. B: Immunohistochemical staining (brown) against tau at 400× magnification reveals round intraneuronal Pick bodies in cortical neurons.

One FTD characterized by the presence of ubiquitin-positive inclusions (FTD-U) occurs as part of a disease spectrum with motor neuron disease. A familial form of FTD, FTD with parkinsonism linked to chromosome 17, was later found to map to the MAPT locus and has characteristic tau pathology. Multiple other FTDs exist; some have characteristic neuronal inclusions (eg, neurofilament, TAR DNA binding protein-43), whereas others lack distinctive histopathologic changes. Single gene defects have been identified for many FTDs, including PGRN, FUS, CHMP2B, and VCP. The prevalence of FTD is low, and the population prevalence of sporadic and genetic disease is not known.


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