Congenital Myasthenic Syndromes

Diagnosis

To diagnose congenital myasthenic syndromes, a doctor performs a physical and neurological examination, reviews symptoms, and takes a detailed medical and family history. Additional tests are often done to rule out other conditions with similar symptoms and to determine the severity of the disorder.

Common diagnostic tests include:

• Blood tests: Identify abnormal antibodies that affect communication between nerves and muscles and help rule out other conditions.

• Electromyography (EMG): Evaluates muscle and nerve cell health, revealing nerve or muscle dysfunction or problems with signal transmission.

• Repetitive nerve stimulation: Measures the nerve’s ability to send repeated signals to a muscle to detect worsening fatigue.

• Genetic testing: Identifies the specific gene responsible for the condition and helps guide treatment decisions.

• Cholinesterase challenge test: Uses medication such as pyridostigmine to assess whether muscle fatigue improves with repetitive movement.

• Other tests: May include lung function tests, sleep studies to detect breathing issues or apnea, and muscle biopsies to analyze muscle fibers.

Genetic Testing

Genetic testing examines DNA to detect mutations that cause congenital myasthenic syndromes. It may also be offered to family members to understand genetic risks. Talking with a medical geneticist or genetic counselor helps clarify the purpose of the test and its implications for you and your family.

Treatment

Treatment depends on the specific genetic type and severity of the syndrome. Some children with mild symptoms may not require medical therapy.

Medication

While medications cannot cure congenital myasthenic syndromes, they can improve muscle strength and contraction. The effectiveness of each medication depends on the affected gene, so genetic testing is crucial before beginning treatment.

Possible medications include:

• Acetazolamide

• 3,4-diaminopyridine (3,4-DAP) or amifampridine (Firdapse, Ruzurgi)

• Albuterol

• Ephedrine

• Fluoxetine (Prozac)

• Neostigmine (Bloxiverz)

• Pyridostigmine (Mestinon, Regonol)

Supportive Treatments

Supportive care is tailored to the individual’s condition and may include:

• Therapies: Physical, occupational, and speech therapy to maintain function and support mobility with devices like wheelchairs or braces.

• Breathing support: Use of apnea monitors, continuous positive airway pressure (CPAP), or in severe cases, mechanical ventilation.

• Feeding support: For those with swallowing difficulties, enteral nutrition via a gastrostomy or jejunostomy tube may be recommended.

• Surgery: Orthopedic surgery may correct severe deformities in the spine or feet.

Ongoing Care

Regular follow-up with a multidisciplinary medical team helps prevent complications and provides ongoing support at home, school, or work. Pregnant women with congenital myasthenic syndromes require close monitoring, as symptoms can worsen during and after pregnancy.

Coping and Support

Caring for a family member with congenital myasthenic syndrome can be challenging. Steps that may help include:

• Learning about the condition to make informed decisions.

• Working with a trusted team of specialists to coordinate care.

• Connecting with other families for shared experiences and emotional support.

• Seeking caregiver support and respite care when needed.

• Considering counseling to help with emotional adjustment and stress management.

Preparing for Your Appointment

If symptoms suggest congenital myasthenic syndromes, schedule a medical evaluation. Be ready to discuss:

• When symptoms began and how they have changed.

• What factors improve or worsen symptoms.

• Any family history of neuromuscular disorders.

Your doctor will review this information and may order additional tests to confirm the diagnosis and create a personalized treatment plan.