What Is Muscular Dystrophy (MD)?
Muscular Dystrophy (MD) is a group of neurological conditions with defects in structural proteins in the muscles, resulting in progressive muscle weakness. There are many different types of MD. The best known are:
- Duchenne muscular dystrophy and the milder Becker muscular dystrophy, both caused by defects in the muscle protein called dystrophin found on the X chromosome.
- Emery-Dreifuss muscular dystrophy causes wasting and weakness of the shoulders and upper arms and the calf muscles of the legs, as well as contractures in the elbows, neck, and heels, and a heart rhythm problem known as conduction block.
- Facioscapulohumeral (FSH) muscular dystrophy begins in the teenage years and causes progressive weakness in muscles of the face, shoulders, and chest, with lesser involvement of the arms and legs.
- Limb-girdle muscular dystrophy (LGMD) affects the large muscles of the shoulders and hips.
- Myotonic dystrophy presents in adulthood with muscle spasms, cataracts, cardiac abnormalities, and endocrine problems.
- Oculopharyngeal muscular dystrophy (OPMD) predominantly affects the eye movement muscles and those associated with speech and swallowing.
Diagnosis of MD Syndromes
Diagnosis of these MD syndromes is made by a neuromuscular specialist based on the pattern of weakness, changes in serum CK (a muscle enzyme that is increased in the blood due to muscle breakdown), muscle biopsy, EMG, and genetic testing. Since the heart is a muscle that is affected in several forms of MD, we often obtain an EKG, echocardiogram, and x-rays. While there is no specific treatment for most MD, physical therapy, supportive devices, and other measures are used to improve function and quality of life. A few medications are under investigation for specific MD types.