Pick disease

Definition: Pick disease (lobar atrophy) is a rare, distinct, progressive dementia characterized clinically by early onset of behavioral changes together with alterations in personality (frontal lobe signs) and language disturbances (temporal lobe signs).

While most cases of Pick disease are sporadic, there have been some familial forms identified and linked to mutations in tau.

Pick disease belongs to a class of neurodegenerative diseases known as frontotemporal dementia (FTD) (MIM.600274)

The term ’Pick complex’ represents the overlapping syndromes of:

• frontotemporal dementia (FTD) (MIM.600274)
• primary progressive aphasia (PPA)
• corticobasal degeneration (CBD)
• progressive supranuclear palsy (601104)
• FTD with motor neuron disease

Pathology

The brain invariably shows a pronounced, frequently asymmetric, atrophy of the frontal and temporal lobes with conspicuous sparing of the posterior two thirds of the superior temporal gyrus and only rare involvement of either the parietal or occipital lobe.

The atrophy can be severe, reducing the gyri to a thin wafer ("knife-edge" appearance). This pattern of lobar atrophy is often prominent enough to distinguish Pick disease from Alzheimer disease on macroscopic examination. In addition to the localized cortical atrophy, there may also be bilateral atrophy of the caudate nucleus and putamen.

On microscopic examination, neuronal loss is most severe in the outer three layers of the cortex. Some of the surviving neurons show a characteristic swelling (Pick cells) or contain Pick bodies, which are cytoplasmic, round to oval, filamentous inclusions that are only weakly basophilic but stain strongly with silver methods.

Ultrastructurally, these are composed of straight filaments, vesiculated endoplasmic reticulum, and paired helical filaments that are immunocytochemically similar to those found in Alzheimer disease and contain 3 repeat tau.

Unlike the neurofibrillary tangles of Alzheimer disease, Pick bodies do not survive the death of their host neuron and do not remain as markers of the disease.

Synopsis

 Pick bodies

Etiology

 mutations in the gene MAPT encoding microtubule-associated protein tau (TAU) (MIM.157140) on 17q21.11.
 mutation in the presenilin-1 gene (PSEN1) (MIM.104311)

See also

 tauopathies