Prions

Question 1

What are TSE’s ?

Answer 1

Transmissible Spongiform Encephalopothy-a family of rare progressive neurodegenerative disorders that affect both humans and animals.

Question 2

How are TSE’s distinguished?

Answer 2

• long incubation periods,
• characteristic spongiform changes
• neuronal loss,
• failure to induce inflammatory response

Question 3

What are the most common TSE diseases?

Answer 3

• Creutzfeldt-Jakob
• Variant Creutzfeldt Jakob
• Mad-Cow
• Gerstmann-Straussler Scheinker syndrome
• Fatal Familial insomnia
• Kuru

Question 4

What is the normal prion in the human body?

Answer 4

Cellular prion protein PrPC

Question 5

What codes for the normal prion protein?

Answer 5

the PRNP gene

Question 6

What is the abnormal prion protein?

Answer 6

PrPSc

Question 7

How is the abnormal prion protein created?

Answer 7

PrPC undergoes a conformational change to the abnormal PrPSc

Question 8

How does this abnormal prion protein cause disease?

Answer 8

PrPSc is insoluble and initiates an autocatalytic reaction leading to the accumulation of amyloid (protein) in the CNS which via unknown mechanisms leads to neurodegeneration

Question 9

What are the 3 forms of Creutzfeldt-Jakob Disease?

Answer 9

• Sporadic
• Hereditary
• Acquired

Question 10

What are the signs and symptoms of CJD?

Answer 10

• abnormal shaking/jerking movements,
• rapid mental deterioration * dementia with seizures,
• previous dural implants
• human growth hormone treatment.

Question 11

What is CJD resistant to?

Answer 11

• formalin fixation

* paraffin embedding.

Question 12

When does CJD usually manifest?

Answer 12

60s, death within 6 months

Question 13

How can CJD be transmitted?

Answer 13

• dural implants,
• contaminated pituitary growth hormone,
• cornea tranplants.

Question 14

What are ways to inactivate CJD?

Answer 14

• Incineration at 1000 degrees C
• Autoclaving at 134 degrees C for 20 minutes
• Bleach for one hour

Question 15

What commo methods of inactivation do not work on CJD?

Answer 15

• Ammonia
• Formaldehyde fixation
• Autoclaving at 121 degrees C

Question 16

What are the differences between CJD and vCJD?

Answer 16

• The median age of death for vCJD is 28 years old

* Prominent psychiatric and sensory symptoms (vCJD)

Question 17

What causes Kuru?

Answer 17

Cannibalism in the indigenous people of New Guinea and ingesting prion infected brains

Question 18

What are signs/symptoms of Fatal Familial Insomnia?

Answer 18

• Sleep disturbances,
• muscle spasms,
• stiffness,
• eventually mental deterioration.

Question 19

What causes Fatal Familial Insomnia?

Answer 19

• Genetic defect in PRNP gene coding for PrPc
• Almost all cases are inherited
• Autosomal dominant pattern.

Question 20

What scan can identify Fatal Familial Insomnia?

Answer 20

PET scan may detect abnormalities

Question 21

What are the signs/symptoms of Gertsmann-Straussler-Scheinker?

Answer 21

• Prion disease exhibits loss of coordination
• slowly delayed mental dysfunction.
• deterioration of the cerebellum responsible for muscle tone and coordination, balance

Question 22

Is Gertsmann-Straussler-Scheinker inherited or acquired?

Answer 22

• Autosomal Dominant disorder (mutations in PRNP gene)

* though some cases are sporadic (NIH).

Question 23

Can CWD be transmitted to humans?

Answer 23

No documented cases currently exist