The muscular dystrophies are a group of genetic and hereditary myopathies that are characterized by progressive muscle weakness and loss of muscle tissue and caused by defects in structural muscle proteins. Major types are Duchenne and Becker muscular dystrophies, myotonic dystrophy, limb-girdle dystrophy, fascioscapulohumeral muscle dystrophy and severe childhood autosomal recessive muscular dystrophy. The most frequent symptoms are muscle weakness (frequent falls, walking problems, eyelid drooping), skeletal and muscle deformities. Neurologic examination often reveals loss of muscle tissue (wasting), muscle contracture, pseudohypertrophy and weakness. Diagnosis is usually established by muscle biopsy, elevated serum CK levels and electromyography examination, which is consistent with myogenic involvement. Some types of muscular dystrophy may present with additional cardiac disease, intellectual deterioration and infertility. There is no known cure for muscular dystrophy. Inactivity (such as bedrest and even sitting for long periods) can worsen the disease. Physical therapy and orthopedic instruments (e.g. wheelchairs) may be helpful.