Dystrophinopathies Flashcards
What is the inheritance pattern of the dystrophinopathies?
X-linked recessive
What causes the dystrophinopathies?
Mutation of the gene encoding for dystrophin on Xp21
What type of mutation occurs in Duchenne muscular dystrophy?
Frameshift mutation resulting in one or both of the binding sites being lost - severe form
What type of mutation occurs in Becker muscular dystrophy?
Non-frameshift insertion in the dystrophin gene resulting in both binding sites being preserved - milder form
What are the signs of Duchenne muscular dystrophy?
Progressive proximal muscle weakness 5 yrs +
Calf pseudohypertrophy
Gower’s sign: walking up legs with arms
30% of patients have intellectual impairment
Poor prognosis
What are the signs of Becker muscular dystrophy?
Onset 10 yrs +
Intellectual impairment less common