Diagnosis

To diagnose the condition, your doctor will review your medical and family history. He or she will conduct a physical and a neurological examination to find the cause of the muscle weakness and rule out other conditions. Your doctor may conduct several tests to diagnose congenital myopathy.

• Blood tests. These may be ordered to detect an enzyme called creatine kinase.
• Electromyography (EMG). Electromyography measures electrical activity within muscles.
• Genetic testing. This may be recommended to verify a particular mutation in a given gene.
• Muscle biopsy. A specialist may remove and examine a small sample of tissue (biopsy) from your muscle.

Prenatal diagnosis

If you have a known family history of congenital myopathies, you can opt for minimally invasive prenatal testing. Chorionic villus sampling can be done after 11 weeks of pregnancy. Amniocentesis can be done after 15 weeks, and cordocentesis can be done shortly after that.

The risk of pregnancy loss associated with these tests is less than 1%.