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← Why is it so hard to cure ALS? - Fernando Vieira

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Showing Revision 3 created 05/31/2018 by Michelle Mehrtens.

  1. In 1963, a 21-year-old physicist
    named Stephen Hawking
  2. was diagnosed with a rare
    neuromuscular disorder
  3. called amyotrophic lateral sclerosis,
    or ALS.
  4. Gradually, he lost the ability to walk,
  5. use his hands,
  6. move his face,
  7. and even swallow.
  8. But throughout it all,
    he retained his incredible intellect,
  9. and in the more
    than 50 years that followed,
  10. Hawking became one of history’s most
    accomplished and famous physicists.
  11. However, his condition went uncured
  12. and he passed away in 2018
    at the age of 76.
  13. Decades after his diagnosis,
  14. ALS still ranks as one
    of the most complex,
  15. mysterious,
  16. and devastating
    diseases to affect humankind.
  17. Also called motor neuron disease
    and Lou Gehrig’s Disease,

  18. ALS affects about two out of every
    100,000 people worldwide.
  19. When a person has ALS,
  20. their motor neurons,
  21. the cells responsible for all voluntary
    muscle control in the body,
  22. lose function and die.
  23. No one knows exactly why
    or how these cells die
  24. and that’s part of what
    makes ALS so hard to treat.
  25. In about 90% of cases,

  26. the disease arises suddenly,
    with no apparent cause.
  27. The remaining 10% of cases are hereditary,
  28. where a mother or father with ALS passes
    on a mutated gene to their child.
  29. The symptoms typically first appear
    after age 40.
  30. But in some rare cases, like Hawking’s,
    ALS starts earlier in life.
  31. Hawking’s case was also a medical marvel
    because of how long he lived with ALS.
  32. After diagnosis, most people with
    the disease live between 2 to 5 years
  33. before ALS leads to respiratory problems
    that usually cause death.
  34. What wasn’t unusual in Hawking’s case
    was that his ability to learn,
  35. think,
  36. and perceive with his senses
    remained intact.
  37. Most people with ALS do not experience
    impaired cognition.
  38. With so much at stake
    for the 120,000 people

  39. who are diagnosed with ALS annually,
  40. curing the disease has become one of
    our most important scientific
  41. and medical challenges.
  42. Despite the many unknowns,

  43. we do have some insight into how ALS
    impacts the neuromuscular system.
  44. ALS affects two types of nerve cells
    called the upper and lower motor neurons.
  45. In a healthy body,
    the upper motor neurons,
  46. which sit in the brain’s cortex,
  47. transmit messages
    from the brain to the lower motor neurons,
  48. situated in the spinal cord.
  49. Those neurons then transmit
    the message into muscle fibers,
  50. which contract or relax in response,
  51. resulting in motion.
  52. Every voluntary move we make occurs
  53. because of messages transmitted
    along this pathway.
  54. But when motor neurons degenerate in ALS,

  55. their ability to transfer
    messages is disrupted,
  56. and that vital signaling system
    is thrown into chaos.
  57. Without their regular cues,
    the muscles waste away.
  58. Precisely what makes
    the motor neurons degenerate

  59. is the prevailing
    mystery of ALS.
  60. In hereditary cases, parents pass genetic
    mutations on to their children.
  61. Even then, ALS involves multiple genes
  62. with multiple possible impacts
    on motor neurons,
  63. making the precise triggers
    hard to pinpoint.
  64. When ALS arises sporadically,
    the list of possible causes grows:
  65. toxins,
  66. viruses,
  67. lifestyle,
  68. or other environmental factors
    may all play roles.
  69. And because there are
    so many elements involved,
  70. there’s currently no single test that
    can determine whether someone has ALS.
  71. Nevertheless, our hypotheses
    on the causes are developing.

  72. One prevailing idea is that certain
    proteins inside the motor neurons
  73. aren’t folding correctly,
  74. and are instead forming clumps.
  75. The misfolded proteins and clumps
    may spread from cell to cell.
  76. This could be clogging up normal
    cellular processes,
  77. like energy and protein production,
    which keep cells alive.
  78. We’ve also learned that along with
    motor neurons and muscle fibers,

  79. ALS could involve other
    cell types.
  80. ALS patients typically have inflammation
    in their brains and spinal cords.
  81. Defective immune cells may also play
    a role in killing motor neurons.
  82. And ALS seems to change the
    behavior of specific cells
  83. that provide support for neurons.
  84. These factors highlight
    the disease’s complexity,

  85. but they may also give us a fuller
    understanding of how it works,
  86. opening up new avenues for treatment.
  87. And while that may be gradual,
    we’re making progress all the time.
  88. We’re currently developing new drugs,
  89. new stem cell therapies
    to repair damaged cells,
  90. and new gene therapies
    to slow the advancement of the disease.
  91. With our growing arsenal of knowledge,

  92. we look forward to discoveries
    that can change the future
  93. for people living with ALS.