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← Repeat Errors

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Showing Revision 1 created 09/30/2013 by Cogi-Admin.

  1. You're right. Its really hard to keep track of where you are.
  2. >> Exactly. And the replication machinery inside
  3. your cell has an equally difficult time.
  4. It literally slips on these repeat regions,
  5. which can cause deletions or additions of sequence.
  6. >> You know, I think, you're right, I've heard about this
  7. before. In psychology, there's a disorder where there's repeats in the CAG?
  8. >> Yeah, so that's called Huntington's Disease.
  9. >> Yeah, yeah.
  10. >> Huntington's Disease is a neurodegenerative disorder
  11. affecting the brain, and eventually causing death. Due
  12. to an abnormal number of repeat regions in
  13. a gene within your genome specifically the CAG
  14. repeats. Now a normal person unaffected by Hungtington's,
  15. would have around 25 or possibly fewer CAG
  16. repeats. But as repeat errors occur, if you
  17. get up to 40 or more CAG repeats,
  18. then you're going to be someone who's affected by Huntington's.
  19. >> So having repeats causes
  20. slippage in the first place, then having more repeats, will it just
  21. cause more slippage and more likely to pass it down to your children?
  22. >> Unfortunately, that's true. And that's
  23. exactly what happened to an individual
  24. named Katherine Moser whose story was written about in the New York Times.
  25. At age 23 Miss Moser found out well before the onset of Huntington's
  26. that she had 45 CAG repeats. More than her grandfather had who
  27. actually died of Huntington's.
  28. >> It's just a really sad story.
  29. >> It's really unfortunate also because there's currently no cure
  30. for Huntington's. All we can do is treat the symptoms.
  31. >> I want to ask, would you want to know how many
  32. CAG repeats you had and if you're going to develop Huntington's.