Prion diseases feature

Aberrant metabolism of the prion protein is the central feature of prion diseases 792... 

Prion diseases have attracted immense attention over the past decade, prompted, in part, by the outbreak of mad cow disease in the United Kingdom. The most common prion disease is sporadic Creutzfeldt-Jakob disease (CJD). Clinically, CJD is characterized by a rapidly progressive dementia accompanied variably by early-onset seizures, insomnia, disordered movements, and psychiatric disturbances the disease is uniformly fatal. Histochemically, the principal pathological feature of prion disease is the abnormal accumulation of an amyloid-like material composed of prion protein (PrP), which is encoded by a single gene on the short arm of chromosome 20. 

Epidemiology and Clinical Features of Human Prion Diseases... 

PrP " deposition in the central nervous system is also a hallmark feature of prion disease (Prusiner, 1991). The type of Prpsc cleposit and its location varies among the human prion diseases. PrP is also a component of amyloid plaques. A characteristic of vCJD and kuru is florid amyloid plaques, which is a large cluster of PrP aggregates interspersed with vacuolar pathology. PrP deposition is also present in peripheral tissues of patients with vCJD, primarily in secondary... 

Steroid-responsive encephalopathies can be considered vasculitic or non-vasculitic. Clinical features are suggestive of Creutzfeldt-Jakob disease (CJD), dementia with Lewy bodies (DLB), and parkinsonism, but pathological examination revealed only AD-related findings without evidence of Lewy bodies or prion disease in most cases. AD is not diagnosed in life due to the atypical clinical features, lack of hippocampal atrophy on brain imaging, and a dramatic symptomatic response to steroids [97], Some cases of new-variant CJD may also be misdiagnosed as AD. 

Certain brain diseases of humans and animals known as proteinopathies are associated with the accumulation of misfolded proteins both inside and around neurons [1], Alzheimer s disease in humans is by far the most common member of this group. The prion diseases, exemplified by Creutzfeldt-Jakob disease (CJD) in man, scrapie in small ruminants, and bovine spongiform encephalopathy (BSE) in cattle, constitute a peculiar sub-group within proteinopathies by being experimentally transmissible [2], Because of this feature, together with the sponge-like appearance of vacuoles in affected brain areas, prion diseases are also known as Transmissible Spongiform Encephalopathies (TSEs). 

Like other neurodegenerative disorders, such as Alzheimer s and Parkinson s disease, prion diseases are characterized by the formation and accumulation of an aberrantly folded protein in the brain. However, a unique feature of prion diseases is their transmissibility. Prions (acronym for proteinaceous infectious particles) are mainly composed of PrPSc, polysaccharides, and lipids, but lack nucleic acids longer than 25 nucleotides, arguing against an essential role for DNA/RNA in mediating infectivity [35, 36]. Indeed, recent experiments support the protein-only hypothesis recombinant PrP expressed in and purified from bacteria and subsequently misfolded in vitro can transmit the disease [37-40]. 

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