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Progressive supranuclear palsy-parkinsonism syndrome
PSP-parkinsonism (PSP-P) is an atypical variant of progressive supranuclear palsy (PSP; see this term), a rare late-onset neurodegenerative disease.
ORPHA:240085Classification level: Subtype of disorder
- Prevalence: Unknown
- Inheritance: Not applicable
- Age of onset: Adult
- ICD-10: G23.1
- OMIM: 260540
- UMLS: -
- MeSH: -
- GARD: -
- MedDRA: -
Prevalence is unknown.
The disease manifests during the sixth decade of life with parkinsonism, including bradykinesia, axial and limb rigidity, and occasional tremor. In the early stage of the disease, eye movements are normal and postural instability is not seen. Over the years (generally after more than two years), patients develop some clinical features characteristic of classical PSP (see this term) such as abnormalities of eye movements, cognitive dysfunction and falls. The disease is characterized neuropathologically by gliosis with astrocytic plaques, accumulation of tau-immunoreactive neurofibrillary tangles and neuronal loss in specific brain areas, especially in the subthalamic nucleus and substantia nigra. PSP-P tau pathology is less severe than in classical PSP.
PSP is a 4R tauopathy composed of a preponderance of four-repeat tau isoforms and a characteristic biochemical profile (doublet tau 64 and tau 69). The MAPT H1-clade specific sub-haplotype, H1c, is a risk factor for this disease. The factors that initiate tau-neurodegeneration are unknown.
Diagnosis is based on the clinical picture and neuropsychological evaluation. The clinical syndrome may be indistinguishable from idiopathic Parkinson disease (PD) in the early stages, although cardiac MIBG scanning may be helpful (normal in PSP-P and abnormal in PD). The first sign that the diagnosis is PSP-P rather than PD may be an attenuated or reduced response to dopaminergic medications, progressive postural instability and falls within the first 7 years of disease.
Other differential diagnoses include other atypical parkinsonian disorders (APD) such as multiple system atrophy parkinsonian (MSA-P) form and corticobasal degeneration (see these terms).
Management and treatment
There is no treatment curing the disease. Some patients present a moderate response to levodopa that improves bradykinesia and rigidity.
Difficulties in breathing and swallowing, and infections are the main causes of death, generally 6-12 years after onset of the disease.
- Clinical genetics review
- English (2010)