So tell me about prion diseases

General Questions
#1

The only prion diseases I know of are BSE (a.k.a. Mad Cow Disease), scrapie (in sheep), vCJD (which I think is Mad Cow except in humans) and kuru, prevalent in cannabal societies in New Guinea.

Are any other prion diseases known? The ones that exist seem to be quite particular: they are primarily transmitted through cannabalism of neural tissues (hence BSE in cows fed on ground up cow scraps) and they cause degenerative brain diseases. Is there any particular reason that they couldn’t affect other tissues? Or is only one particular protein susceptible, one that happens to be in the brain? Do kuru and vCJD affect the same protein?

Naturally these diseases are hard to trace - testing for them is quite complicated. Is there any possibility that other degenerative neural diseases that appear to be genetic could actually be prions? Are there any convincing modes of transmission for prion diseases that don’t involve eating the tissue (e.g. could a mother pass it to her spawn in utero?)

Oh, and, uh, I’ve probably forgotten some questions, so feel free to chime in with whatever else you care to add. :cool:

#2

There are other prion diseases. Fatal Familial Insomnia, chronic wasting disease of elk, and Gerstman-Strausler-Scheinker Syndrome come to mind, but there may be others.

I believe it is just one protein, termed Prion Protein (PrP), but I haven’t read about this field extensively, so I could be wrong. There are other ways to spread prion diseases other than cannibalism – corneal and dural transplants can also spread the diseases.

It is of course possible that other tissues and other diseases are due to prions. But other tissues are less susceptible than the brain. Relatively small changes can cause large phenotypes in the brain, it is highly metabolically active and therefore producing and turning over lots of protein, it is very cell dense, and the cells are not turned over throughout life.

Interestingly, genetic mutations in PrP can mimic prion diseases and cause things like familial CJD.

#3

White tail deer also get Chronic Wasting Disease. Some deer with CWD were found in Wisconsin recently. (1st time east of teh Mississippi) The response was massive testing effort, extra hunts in the affected areas, etc. Last I heard, it looks like it is contained.

Brian

#4

This page also identifies TME (transmissible mink encephalopathy) in mink and Alpers Syndrome in humans as additional prion diseases. Prion Protein-Scrapie (PrPsc) appears to be responsible for all the prion diseases, even though each prion disease seems to have a number of variants. PrPsc doesn’t appear to be identical conformationally or chemically from species to species or from variant to variant.

#5

Scrapie in sheep came to mind immediatly, but when I looked it up to give a reference, they mention feline spongiform encephalopathy which I never knew existed.

Ahh the power of the Dope!