Molecular mechanisms of inherited disease

Question 1

X-linked muscular dystrophies

Answer 1

• replacement of musle fibres by fibrofatty tissue
• Dystrophin gene: mutations during translocation process
• 2 types:
  
  • Duchenne Muscular Dystrophy (DMD)
  • Becker Muscular Dystrophy: mild
• Dystrophin protein found in muscle cells and some neurons
• Dx in boys usually occurs b/w 16 mo & 8 years
  high CK-MM initially
  levels fall during later stages
  immunostain for Dystrophin absent in DMD & low in Beckers
• Death from DMD usually occurs by age 30
• X-linked Receissve
• Sx:
  
  • delays in standing, walking, sitting
  • learning difficulties
  • Gowers’ maneuver
• Rx: no specific rx exists
  
  • Tracheostomy & ventilatory support for breathing
  • Orthopedic devices for support & occassionally surgery to correct problems
  • gene therapy