prions
Table of Contents
prions
see also:
introduction
- prions are protein rods that are the cause of a class of diseases called subacute spongiform encephalopathies.
- prions induce existing endogenous prion protein (PrPC) in the host organism to take on extremely stable, rogue mis-folded forms (PrPSc) that is responsible for the formation of amyloid plaques and neurodegeneration.
- PrPC may have a role in myelin repair, long term memory, the sense of smell, and in the ability of stem cells to regenerate bone marrow.
- all known prion diseases affect the structure of the brain or other neural tissue, and all are currently untreatable and are always fatal.
- prion diseases tend to have long incubation periods measured in years or decades and tend to be twice as long when the disease crosses to another species.
- most are spread primarily by eating affected neural tissue, but variant CJD also affects lymph tissues and blood, and thus can be transmitted by blood transfusions or organ transplants.
- fungal prions appear to allow another mechanism of inheritance and provide fungi with evolutionary advantage.
- originally discovered in the 1960's when a tribe of cannibals in New Guinea were found to be dying of kuru in 1957, a rare form of spongiform encephalopathy, which was eventually traced back to a single native in 1910 who presumably acquired it spontaneously.
diseases caused by prions include:
- scrapie, a disease in sheep
- bovine spongiform encephalopathy (mad cow disease) - when crosses to humans it is called variant CJD
- mink and feline encephalopathy
- wasting disease, a disease of deer and elk
- kuru
- sporadic Creutzfeldt-Jakob disease (sCJD)
- arises spontaneously in 1 per million population per year
- can be acquired genetically (the cause of 5-10% of cases)
- Gerstmann-Straussler-Scheinker syndrome
- fatal familial insomnia
prions.txt · Last modified: 2010/12/19 11:03 by 127.0.0.1