What is Nemaline Myopathy?

Congenital myopathy is a group of diseases caused by genetic mutations that result in problems with the tone and contraction of skeletal muscles.


Signs and symptoms vary by the type of congenital myopathies. The severity also varies, though the conditions are often stable or slowly progressing. Common signs and symptoms include:
  • Lack of muscle tone
  • Muscle weakness
  • Delayed motor skills
  • Facial weakness
  • Drooping eyelids
  • Muscle cramps or contractions
Due to chronic muscle weakness, there are other complications in some congenital myopathies, including feeding and breathing difficulties, and skeletal conditions, such as scoliosis, osteopenia or hip problems.

Causes and Inheritance

Different types of congenital myopathies are caused by mutations in different genes, and can be inherited in various patterns, including autosomal recessive, autosomal dominant, and X-linked recessive. Some types of congenital myopathies are caused by a variety of genetic mutations, each affecting one of the filament proteins which are required for muscle tone and contraction; can be inherited in an autosomal recessive or autosomal dominant pattern.


Usually, diagnosis begins with evaluation of the patient’s personal and family history, and proceeds with physical and neurological examinations that test reflexes and strength. Specialized tests can be used to examine the muscles, such as a muscle biopsy (examined for physical signs), and electromyography (EMG) to measure a muscle’s activity. Genetics tests are available for many of the genetic mutations underlying various myopathies.

Management and Treatment

There are no known cures for congenital myopathies. Supportive treatments, such as physical, occupational and speech therapies, nutritional support, and assisted breathing, may help to alleviate the symptoms and support functioning, mobility and strength.