Becker muscular dystrophyObjectives
- Describe the clinical features of Becker muscular dystrophy,
including age at onset, and physical findings at the time the dystrophy
becomes clinically apparent
- Describe the genetic origin of Becker muscular dystrophy
- Describe the natural history of Becker muscular dystrophy
- Discuss orthopaedic aspects of the treatment of Becker muscular dystrophy
Becker muscular dystrophy is essentially a less severe and considerably less common form of Duchenne muscular dystrophy. The same genetic focus on the short arm of the "X" gene is responsible for both dystrophies. In contrast to Duchenne dystrophy, however, there is not a complete absence of dystrophin in muscle cells of patients with Becker muscular dystrophy. Transmission is in an X-linked recessive pattern. Clinical evidence of the disease appears later than with Duchenne dystrophy, as early as the second half of the first decade to as late as well into adulthood. Since the deficient protein is the same as with the Duchenne dystrophy, clinical signs and symptoms are similar. The natural history is more favorable, with a lower incidence of scoliosis (probably as the spine achieves skeletal maturity with muscular support). Restrictive lung disease is a late feature. Cardiomyopathy occurs much more frequently than in Duchenne dystrophy. There appears to be a tremendous hetergenicity in expression of Becker muscular dystrophy. Principles of treatment of contractures are the same as with Duchenne dystrophy.
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