Congenital Myasthenic Syndromes

Diagnosis

Mayo Clinic doctors trained in nervous system conditions (neurologists) and other specialties diagnose congenital myasthenic syndromes.

Congenital myasthenic syndromes may be difficult to diagnose. Symptoms vary and may be similar to those of myasthenia gravis and other conditions. Doctors at Mayo Clinic have experience diagnosing congenital myasthenic syndromes.

To diagnose congenital myasthenic syndromes, your doctor will review your medical history and your family medical history. Your doctor will perform a thorough physical and neurological examination and review your symptoms, including signs of muscle weakness with repeated activity. Your doctor and other specialists also may conduct several tests to diagnose congenital myasthenic syndromes and rule out other conditions.

Tests may include:

• Blood tests. A blood test checks to see if abnormal antibodies may be blocking your muscle receptors from nerve signals and causing your symptoms.
• Electromyography (EMG). Electromyography (EMG) measures electrical activity within muscles or individual muscle fibers (single-fiber EMG).
• Nerve conduction studies. Nerve conduction studies measure the strength of muscle contraction by stimulating nerves with a small electrical impulse applied to your skin. The application of repeat impulses can reveal specific muscle weakness.
• Genetic testing. Your doctor may recommend genetic testing for the mutation present in congenital myasthenic syndromes and for other neurological conditions with similar symptoms.

Read more about electromyography and genetic testing at MayoClinic.com.