Sporadic CJD – Prions

by Vincent Racaniello, PhD

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    00:01 encephalopathy and by eating their brains they spread the disease to others.

    00:01 We also recognize sporadic spongiform encephalopathies. These are TSEs that arise with no warning whatsoever, they don't seem to be transmitted. And one of them is called sporadic Creutzfeldt-Jacob disease, this affects about 1 to 2 people per million worldwide. They're typically 50 to 70 years old of age, and this accounts for most of the TSE that we find globally, about 65% of the cases. In sporadic CJ, the disease appears with no warning, there is no epidemiological indication that the individual has not consumed anything or received any transplant that would cause the disease, they have normal prnp genes, so there's no mutation associated with it, it just is sporadic as the name would suggest. So we think what happens here is that the normal prion protein of these individuals simply starts misfolding spontaneously.

    01:02 And as soon as you have a little bit of misfolded prion protein in you, it then catalyzes the conversion of your other protein and you develop the disease. So if you develop a sporadic CJD, you can transmit it to other people and that will cause an infectious form to arise.

    01:22 So you can imagine that a person who is incubating a sporadic CJD, there are many years of incubation involved, during which you have no symptoms. If you made some kind of a tissue or blood donation during that period, you could transmit the disease to others and in fact this disease has been known to be transmitted as I've said from corneal transplants, hormonal transplants and so forth. We think that kuru may have originally arisen in New Guinea from the first case many years ago, from a sporadic case of CJD, that person died, their brain was consumed and then that initiated the infectious mode of transmission.

    02:06 And finally, we have a familial or genetic TSE, and this as the name would indicate is associated with a mutation in the gene encoding prion protein, and this is an autosomal dominant mutation and by sequencing the genome of people who have developed TSEs, we know exactly what kind of amino acid changes are associated with development of the disease. So you can now go and have this gene sequence, then know if you're at risk for developing a TSE. And when these individuals develop this genetic TSE, they began to develop symptoms of the disease but before that, again, there is a long incubation period, during that time if they donate corneas or organs or blood products, they can spread the disease to someone else.

    About the Lecture

    The lecture Sporadic CJD – Prions by Vincent Racaniello, PhD is from the course Microbiology: Introduction.

    Included Quiz Questions

    1. 50-70 years
    2. 10-15 years
    3. 1-6 months
    4. 8-12 months
    5. 1-5 years
    1. Many years
    2. 2 weeks
    3. 4 weeks
    4. Few months
    5. A year

    Author of lecture Sporadic CJD – Prions

     Vincent Racaniello, PhD

    Vincent Racaniello, PhD

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    By ??? О. on 20. February 2021 for Sporadic CJD – Prions

    Thank you, dear professor for amazingly informative and interesting lectures