: Why do prion diseases have 100% fatality rate ?

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I recently found out about the so-called prion diseases, which are incurable and fatal diseases that affect (a euphemism, the real word is destroy) the CNS and cause a rapid deterioration of mental and physical abilities.

There are many prion diseases, the two most famous are probably the mad cow disease (non-human mammals), and the Creutzfeldt–Jakob disease (CJD) (for human mammals). Both are 100% fatal, and *no one* is known to have survived longer than 2.5 years after a CJD diagnosis. That’s the kind of stuff you wouldn’t wish on your worst enemy.

Why are these diseases so deadly? I read that it has to do with abnormal proteins but that was way over my head.

EDIT : I have another question, can prion diseases be rightly called the most dangerous diseases known to man ?

Thanks;

In: Biology

18 Answers

Anonymous 0 Comments

Imagine you have a folding chair. When you have that chair set up in a form that you can sit on it, then you can’t easily stack another chair on top of it. If you did, that stack of chairs would be unstable. 

Now imagine you folded that chair. You can easily stack layers upon layers of chairs against the wall. Or you can put the stacked chairs on a rack that you otherwise couldn’t put an unfolded chair on. All in all, this stack of chairs would become much easier to put in storage than unfolded chairs would.

This is how prion diseases work. Normal prion proteins (known as PrP) aren’t able to stack together because that would result in a chemically unstable formation, just like the unfolded chair. However, if a prion protein is misfolded just right, then they can convert those healthy prions into that misfolded form that would actually result in more stable formations when stacked together, just like the folded chairs. 

This accumulation of misfolded proteins prevents your brain from doing its normal function. In the end, your brain becomes nothing more than a jumbled mess.

Just to add: misfolded proteins actually happen more frequently than you think. It’s just that enzymes in your body, known as proteases, are able to take care of these. 

Prions are protease-resistant, meaning that either proteases cannot catalyze the prions quick enough to keep up with the cascade, or the proteases can’t do anything altogether.

As to your edit: they are very dangerous because there is no vaccine or treatment. Rabies is dangerous as well, but you can at least get treated with a strict vaccine regiment if you’re exposed. 

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