Different types of muscular dystrophy begin to show symptoms at different ages and, depending on the type of muscular dystrophy, different muscle groups throughout the body will be affected.
Symptoms may include:
- Progressive muscle weakness and wasting (atrophy)
- Waddling way of walking
- Difficulty climbing stairs
- Difficulty rising from lying or sitting
- Repeated falling
- Curvature of the spine
- Wasting of thigh muscles
- Abnormal enlargement of the calves
- Trouble breathing or swallowing
- Limbs drawing inward and becoming fixed in position
- Enlargement of the heart
In addition to Duchenne and Becker muscular dystrophies, there are other less common types:
- Facioscapulohumeral muscular dystrophy (FSHD or Landouzy-Dejerine syndrome), which affects mainly facial, shoulder and arm muscles
- Limb-girdle muscular dystrophy, first affecting hips and shoulders
- Myotonic muscular dystrophy (MMD or Steinert's disease), which causes the inability to relax muscles and generally affects facial muscles first
- Oculopharyngeal muscular dystrophy, typically occurring in middle age with weakness of eye, face and throat muscles causing drooping eyelids and issues with swallowing
Causes and Risk Factors
Defective genes are the cause of muscular dystrophy. The specific gene disorder has been discovered for the most common muscular dystrophies. For example, a defective gene for dystrophin, a protein that helps keep muscle cells intact, is what causes Duchenne's muscular dystrophy.
For the less common forms of muscular dystrophy, researchers are still trying to find the specific gene defect that causes the disease. While most forms of muscular dystrophy are inherited, a few types originate in a spontaneous gene mutation without any family history of the disease.