Muscular dystrophies and their genetic aspects

1. Big picture

Muscular dystrophies are inherited progressive muscle diseases caused by mutations in genes encoding structural or functional muscle proteins.

The key exam sentence:

Muscular dystrophies are genetic myopathies; the clinical pattern depends on the affected protein, inheritance pattern, age of onset, and muscle distribution.

The most important genetic principle:

The same “muscular dystrophy” clinical picture may be caused by different genes, and the same gene may cause different severity depending on the mutation.

The classic example is:

• Duchenne muscular dystrophy: absent dystrophin → severe disease.
• Becker muscular dystrophy: abnormal or reduced dystrophin → milder disease.

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