Definition: Progressive supranuclear palsy (PSNP) is a sporadic neurodegenerative Parkinson-like movement disorder. Progressive supranuclear palsy (PSNP) is characterized by vertical eye movement disturbances, rigidity (resistance to imposed movement), severe gait and balance problems and FTD-like dementia later in the disease course.
Progressive Supranuclear Palsy (PSP) is an illness characterized clinically by:
truncal rigidity with dysequilibrium
nuchal dystonia
pseudobulbar palsy
abnormal speech
ocular disturbances, including vertical gaze palsy progressing to difficulty with all eye movements
mild progressive dementia in most patients.
The onset of the disease is usually between the fifth and seventh decades, and males are affected approximately twice as frequently as are females. The disease is often fatal within 5 to 7 years of onset.
Neuropathology
There is widespread neuronal loss in the globus pallidus, subthalamic nucleus, substantia nigra, colliculi, periaqueductal gray matter, and dentate nucleus of the cerebellum.
Globose neurofibrillary tangles are found in these affected regions, in neurons as well as in glia. Ultrastructural analysis reveals 15-nm straight filaments that are composed of 4 repeat tau.
Abundant tau pathology in the form of tau tangles characterizes PSP neuropathologically (tauopathie). PSNP is part of the FTD spectrum of disorders (tauopathie).
Etiology
Mutations in tau have not been found in PSP. Analysis of the tau gene has shown that there is an extended haplotype (a series of polymorphic markers spread out along the gene that are in complete linkage disequilibrium; that is, recombination events do not appear to occur between the sites).
Of the two haplotypes, one of them is strongly overrepresented in PSP patients. How this haplotype influences the risk of PSP is unknown.
See also
neurodegenerative diseases
- frontotemporal dementia (FTD)
- FTD spectrum of disorders (FTDs)
