Prions:
Prions are misfolded proteins, where the normal alpha helixes are abnormally folded into beta pleated sheets. They cause a group of diseases known as transmissible spongiform encephalopathies (TSE). In humans, they are the causative agent of the human disease Creutzfeldt-Jakob Disease, which causes permanent and fatal changes in the brain. This degenerative neurological disorder is uncurable and ultimately fatal in just weeks-to-months, 6 months at most. The degenerative changes in the brain occur quite rapidly, destroying the brain and turning the matter into "spongy" material, causing it to develop holes. The brain's nerve cells, neurons, are destroyed and die due to the buildup of plaques called amyloids. The misfolded proteins also affect the brain's normal signaling pathways. Prions are replicated by the abnormal refolding of proteins into diseased proteins, which increase exponentially and buildup. Additionally, these misfolded proteins are insoluble and are unable to break down or undergo digestion by the body's immune system. Therefore, the normal function of neuronal cells is destroyed and the cells die.
Variant CJD is believed to be caused by consumption of food that is contaminated with prions, which also causes bovine spongiform encephalopathy, or "mad cow disease".
Sporadic CJD is responsible for approximately 85% of cases of CJD.
Familial CJD is responsible for approximately 15% of cases of CJD.
Iatrogenic CJD is CJD of an unknown cause, usually from coming into contact with contaminated tissue or blood products.
Symptoms of CJD include the following:
-dementia that is rapid and progressive
-memory loss
-changes to the personality
-hallucinations
-anxiety and depression
-paranoia
-obsessive-compulsive behavior
-psychosis
-difficulty walking
-speech difficulty
-balance problems
-seizures
-weird postures, gait, muscular movements
-impaired coughing reflexes
Prions are also responsible for transmissible bovine spongiform encephalopathy (BSE) (mad cow disease), scrapie in sheep, chronic wasting disease in mule deer, white-tailed deer, red deer, elk, and moose, feline spongiform encephalopathy in cats, and kuru in cannibals.
Variant CJD is believed to be caused by consumption of food that is contaminated with prions, which also causes bovine spongiform encephalopathy, or "mad cow disease".
Sporadic CJD is responsible for approximately 85% of cases of CJD.
Familial CJD is responsible for approximately 15% of cases of CJD.
Iatrogenic CJD is CJD of an unknown cause, usually from coming into contact with contaminated tissue or blood products.
Symptoms of CJD include the following:
-dementia that is rapid and progressive
-memory loss
-changes to the personality
-hallucinations
-anxiety and depression
-paranoia
-obsessive-compulsive behavior
-psychosis
-difficulty walking
-speech difficulty
-balance problems
-seizures
-weird postures, gait, muscular movements
-impaired coughing reflexes
Prions are also responsible for transmissible bovine spongiform encephalopathy (BSE) (mad cow disease), scrapie in sheep, chronic wasting disease in mule deer, white-tailed deer, red deer, elk, and moose, feline spongiform encephalopathy in cats, and kuru in cannibals.