Transmissible spongiform encephalopathy
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Differentiating Transmissible spongiform encephalopathy from other Diseases |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kiran Singh, M.D. [2] Rinky Agnes Botleroo, M.B.B.S.
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Synonyms and keywords: TSE; prion diseases
Overview
Historical Perspective
- Natural Scrapie is a infection that affects sheep and is caused by an unusual infectious agent.It was first described in 1732.
- Kuru is the first prion disease in humans which was described in 1957.It is a fatal exotic neurodegenerative disease that affects only people of a single language group in the remote mountainous interior of New Guinea.
- In 1959, veterinary pathologist W.J. Hadlow first recognized several similarities between Scrapie and Kuru[1].
- In 1959, I. Klatzo also noted that Kuru's histopathology resembled that of Creutzfeldt-Jakob disease (CJD), another fatal neurodegenerative progressive disease of unknown etiology that A.M. Jakob had first described in 1921[1].
- Gajdusek, C.J. Gibbs, Jr., and M.P. Alpers used the existing knowledge of Scrapie and started efforts to transmit Kuru by inoculating Kuru brain tissue into non-human primates, that-although requiring several years-ultimately proved successful in 1965[2].Later Gajdusek and colleagues went on to demonstrate that not only the more common sporadic form of CJD but also familial CJD and a generally similar familial brain disease (Gerstmann-Sträussler-Scheinker syndrome) were also transmissible, first to non-human primates and later to other animals.
- In 1982, Stanley B. Prusiner formulated "prion hypothesis". Prusiner recognized that a misfolded form of a ubiquitous normal host protein was usually (if not always) detectable in tissues containing TSE agents, greatly facilitating the diagnosis and understanding their pathogenesis. Prusiner proposed that the TSE agent was likely to be composed partly (if not entirely )of the abnormal protein, for which he used the term "prion" protein and "prion" for the agent. Expression of the prion protein by animals-while not essential for life-was later found to be obligatory to infect them with TSEs
Pathophysiology
Causes
- About 10 -15 percent of all cases of prion disease are caused by mutations in the PRNP gene.These form prion diseases are classified as familial prion diseases as they can run in families.These are familial Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), and fatal familial insomnia (FFI).
The PRNP gene provides instructions for making a protein called prion protein (PrP).The precise function of this protein is unknown, researchers have proposed roles in several important processes. These include the transport of copper into cells, protection of brain cells (neurons) from injury (neuroprotection), and communication between neurons.
In familial forms of prion disease, PRNP gene mutations result in the production of an abnormally shaped protein, known as PrPSc, from one copy of the gene. PrPSc can attach (bind) to the normal protein (PrPC) and promote its transformation into PrPSc,this process is not fully understood. The abnormal protein builds up in the brain, forming clumps which damage or destroy neurons. The loss of these cells creates microscopic sponge-like holes (vacuoles) in the brain, which leads to the signs and symptoms of prion disease.
- Rest of the 85-90 percent of cases of prion disease are classified as either sporadic or acquired.
- People with sporadic prion disease have no family history of the disease and no identified mutation in the PRNP gene. Sporadic disease occurs when PrPC spontaneously, and for unknown reasons, is transformed into PrPSc. Sporadic forms of prion disease include sporadic Creutzfeldt-Jakob disease (sCJD), sporadic fatal insomnia (sFI), and variably protease-sensitive prionopathy (VPSPr).
- Acquired prion disease results from exposure to PrPSc from an outside source. For example, variant Creutzfeldt-Jakob disease (vCJD) is a type of acquired prion disease in humans that results from eating beef products containing PrPSc from cattle with prion disease. This form of the disease in cows is known as bovine spongiform encephalopathy (BSE) or, more commonly, "mad cow disease." Another example of an acquired human prion disease is kuru, which was identified in population in Papua New Guinea. The disorder was transmitted when individuals ate affected human tissue during cannibalistic funeral rituals.
- Prion diseases can rarely be transmitted by accidental exposure to PrPSc-contaminated tissues during a medical procedure. This type of prion disease, which accounts for 1-2 percent of all cases, is classified as iatrogenic.
Differentiating Transmissible spongiform encephalopathy from other Diseases
Epidemiology and Demographics
Risk Factors
- Positive family history
- Eating meat infected by “mad cow disease”
- Receiving contaminated corneas or infection may occur from contaminated medical equipment.
Natural History, Complications and Prognosis
Major or Mild Neurocognitive Disorder Due to Prion Disease
Diagnosis
History and Symptoms | Physical Examination | Laboratory Findings | Other Diagnostic Studies
Treatment
Medical Therapy | Primary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies
Case Studies
References
- This entry incorporates public domain text originally from the National Institute of Neurological Disorders and Stroke, National Institutes of Health [3] and the U.S. National Library of Medicine [4]
- Brown P, Preece M, Brandel JP, Sato T, McShane L, Zerr I, Fletcher A, Will RG, Pocchiari M, Cashman NR, d'Aignaux JH, Cervenakova L, Fradkin J, Schonberger LB, Collins SJ (2000). "Iatrogenic Creutzfeldt-Jakob disease at the millennium". Neurology. 55 (8): 1075–81. PMID 11071481.
- Montagna P, Gambetti P, Cortelli P, Lugaresi E (2003). "Familial and sporadic fatal insomnia". Lancet Neurol. 2 (3): 167–76. PMID 12849238.
- Prusiner SB (2001). "Shattuck lecture--neurodegenerative diseases and prions". N Engl J Med. 344 (20): 1516–26. PMID 11357156.
- Weissmann C (2004). "The state of the prion". Nat Rev Microbiol. 2 (11): 861–71. PMID 15494743.
External Links
- Transmissible Spongiform Encephalopathy
- Neurodegenerative Disease.
- Neurodegenerative disease: Encephalopathy.
- American Symposium
cs:Transmisivní spongiformní encefalopatie da:TSE de:Transmissible spongiforme Enzephalopathie ko:프리온 질병 simple:Prion disease
- ↑ 1.0 1.1 Asher DM, Gregori L (2018). "Human transmissible spongiform encephalopathies: historic view". Handb Clin Neurol. 153: 1–17. doi:10.1016/B978-0-444-63945-5.00001-5. PMID 29887130.
- ↑ Liberski PP (2012). "Historical overview of prion diseases: a view from afar". Folia Neuropathol. 50 (1): 1–12. PMID 22505359.