1. Genetic Defect

• mutations in dystrophin gene -> truncated or altered dystrophin protein -> clinical features (mild form of Duchenne Muscular Dystrophy with onset later and slower progression)

1. Muscle Biopsy

• degeneration and regeneration
  • atrophy, increased fibre size variability, necrosis, phago-cytosis, variable loss of fibres
  • proliferation of adipose and endomysial connective tissue
• decreased dystrophin level on immunohistochemistry (>20% of N)
• type 2b fibres unaffected

1. Muscle Weakness

• proximal > distal muscle groups
• shoulder girdle and hips affected
• waddling gait with tendency to fall, easy fatiguability, cramps, and positive Gower's sign
• pseudohypertrophy
• slowly progressive course with loss of ambulation usually after the age of 20 yrs
• delayed gross motor development
• ? normal intelligence and learning disabilities

2. Others

• lordosis, pes cavus
• mild cardiomyopathy
• rarely malignant hyperthermia, myalgia, myoglobinuria, and
• Achilles tendon contractures

1. Serum

• significantly elevated CPK
• dystrophin level about 20% of normal

2. EMG

• myopathic

3. Nerve Conduction Studies

• normal

1. Supportive

• multidisciplinary approach
  • Paediatrics - promote ambulation and physiotherapy, moniter deformities, bracing
  • Surgery - moniter and correct deformities
  • Genetics - genetic counselling, prenatal diagnosis

2. Prognosis

• death in mid to late 20's with 50% survival to age 40
• survivors are severely disabled