Muscular dystrophy causes gradually worsening muscle weakness. In the most common type of muscular dystrophy, Duchenne's muscular dystrophy, symptoms usually begin before 5 years of age.

Symptoms of muscular dystrophy include:

• Muscle weakness:
• Arm weakness (unilateral)
• Arm weakness (bilateral)
• Leg weakness (unilateral)
• Leg weakness (bilateral)
• Hand weakness (unilateral)
• Hand weakness (bilateral)
• Facial weakness
• Difficulty running and jumping
• Difficulty walking
• Frequent falls
• Enlarged muscles
• Muscle atrophy:
• Progressive loss of muscle tissue
• Scoliosis
• Difficulty breathing