Introduction to Prions (2)

Question 1

What are prion diseases called?

Answer 1

Transmissible Spongiform Encephalopathies (TSEs)

Question 2

What diseases do TSEs cause?

Answer 2

Unique group of progressive fatal neurodegenerative disorders.

Question 3

Are prions transmissible?

Answer 3

yes

Question 4

What causes TSEs?

Answer 4

Caused by accumulation of an abnormal form of a naturally occurring protein (‘prion’ protein, PrPc) in the brain.

Neuronal loss, astrocyte proliferation, and vacuolation of the brain leading to a spongiform appearance.

Question 5

What is the incubation period for an individual with TSEs?

Answer 5

Variable incubation periods (60 days - years).

Question 6

Are TSEs treatable?

Answer 6

no

Question 7

What is aetiology?

Answer 7

the cause, set of causes, or manner of causation of a disease or condition.

Question 8

What are the 3 main forms of human prion diseases (distinguished by aetiology?)

Answer 8

genetic

sporadic

acquired

Question 9

How is a prion genetically made into a disease causing form?

Answer 9

mutations is the prion encoding gene (PRNP)

Question 10

What is the aetiology of the sporadic prion form?

Answer 10

unknown

possibly spontaneous protein change

Question 11

What is the aetiology of the acquired prion form?

Answer 11

Transmission of disease from an animal or person-to-person.

Question 12

What is the most common group of prion diseases?

Answer 12

sporadic prion diseases

spontaneous confo change

Question 13

How are sporadic prion disease transmitted?

Answer 13

May be transmitted iatrogenically.

Question 14

What are the 3 main forms of acquired prion disease?

Answer 14

Kuru: confined to Papua New Guinea (historical importance) transmission by ritualistic cannibalism

Variant CJD (vCJD): resulting originally from Bovine Spongiform Encephalopathy (BSE) contamination of food.

Iatrogenic CJD: CJD transmitted accidentally during the course of medical or surgical procedures.

Question 15

What is the bovine spongiform encephalopathy?

Answer 15

cow form of the scrappie infected cows

mad cow disease

Question 16

What is vCJD?

Answer 16

Evidence vCJD transmitted from BSE in cattle to humans via food (primary transmission).

acquired

Question 17

What is iatrogenic CJD?

Answer 17

CJD transmitted accidentally during the course of medical or surgical procedures.

Question 18

How do most cases of iatrogenic CJD arise?

Answer 18

• Most cases arisen from contaminated human growth hormone treatment in children or human dura mater grafts.
• Few cases from corneal transplantation, neurosurgery and specialised brain electrode techniques.
• At least four cases from blood transfusion.

Question 19

Where is vCJD in humans demonstrated (iatrogenic and variant)?

Answer 19

PrPsc demonstrated in tonsils, spleen and lymph nodes in vCJD.

Question 20

Can iatrogenic CJD as risk of human to human transmission?

Answer 20

Risk of human to human transmission through medical procedures including the use of blood and blood products.

Question 21

What is the effect on the human brain of Prpsc?

Answer 21

shrinkage