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Congenital Myopathies

by Michael Rubin, MDCM

Congenital myopathies is a term used to describe a wide variety of inherited disorders of the muscles, which are present at birth or during infancy.

There are several types of congenital myopathies. The four most common types of congenital myopathy are

  • Nemaline myopathy

  • Myotubular myopathy

  • Core myopathy

  • Congenital fiber type disproportion myopathy

These four types cause muscle weakness and facial weakness, and symptoms range from mild to severe. Depending on the type of myopathy, children may also have weakness of the muscles used for breathing, problems with swallowing, and respiratory failure (see Respiratory Failure). Life span varies with the form and severity of the myopathy. Some infants who are severely affected at birth die during the first year of life because of respiratory failure. Other infants may survive longer.

The diagnosis is based on characteristic symptoms of weakness and the symptoms that are caused by each specific type. Doctors confirm the diagnosis by taking a sample of the weak muscle tissue for biopsy (a piece of tissue is removed for examination under a microscope). Specific treatments are not available, but physical therapy may help preserve function.