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Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob Disease. Presentation by: Stephie Abraham. What is CJD??. It is a rare, degenerative, and fatal brain disorder. Alternative name: Transmissible Spongiform Encephalopathy Commonly affects people above 60. 90% of patients die within a year. 3 Types . Sporadic CJD

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Creutzfeldt-Jakob Disease

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  1. Creutzfeldt-Jakob Disease Presentation by: Stephie Abraham

  2. What is CJD?? • It is a rare, degenerative, and fatal brain disorder. • Alternative name: • Transmissible Spongiform Encephalopathy • Commonly affects people above 60. • 90% of patients die within a year.

  3. 3 Types • Sporadic CJD • Most common • Appears in a person with no known risk factors. • 1 case per million in the US • Mean age is 62

  4. Hereditary CJD • Appears in people who has had a family history of CJD. • About 5-10% in the US • Acquired CJD • Exposure to infectious brain tissue • Least common • Less than 1%

  5. Symptoms • Early Stages: • Problems with muscular coordination • Personality changes • Impaired memory • Impaired vision • Myoclonus • blindness

  6. Later Stages: • Loss of ability to speak and move • Enter a coma • Death

  7. Causes • First theory: • CJD was caused by a slow-acting virus • Problems: • The disease causing agent did not have any characteristics similar to virus or bacteria. • No nucleic acid • Long incubation period- up to 40 years • Indestructible

  8. Second theory • Proposed by Stanley Prusiner • Disease was caused by Prions • Conformational change from cellular PrP to scrapie PrP

  9. Prions • “Proteinaceous infectious particle that lacks a nucleic acid” • Naturally occurring proteins in mammals • Made of 253 amino acids • High concentrations in the brain tissue • Initially encoded in chromosome 20 as amino acid residues • Soluble in detergents • Susceptible to enzyme digestion

  10. Rich in alpha-helical structure N-terminal contains an octapeptide region Disulfide linkage

  11. PrP forms in the nucleus • Translation of the ORF

  12. Nucleus Endoplasmic Reticulum Golgi Apparatus Plasma Membrane Vesicles

  13. Post-translational modifications • Removal of the N-terminal 23 residue signal peptide • Glycosylation at Asparagines 181 &197 • Formation of the disulfide bond between cysteine residues 179 & 214 • Proteolytic cleavage of the C-terminal 24 amino acids • Addition of Glycosyl Phosphatidylinositol (GPI) anchor

  14. Functions: • Cell adhesion • Signaling processes • Copper transport or metabolism

  15. Scrapie PrP

  16. Characteristics • 43% beta sheet • 30% alpha-helix • Resistant to proteolytic digestion • Insoluble in detergents

  17. Scrapie PrP forces normal cellular PrP to change its form. • Aggregates are formed • Cell death occurs

  18. Treatment • No known cure • Current Research • Focused on the mechanism of transformation of normal PrP to scrapie PrP.

  19. Questions???

  20. The End !!!

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