two sisters with congenital myasthenic syndrome: case report

purpose: to report two sisters with congenital myasthenic syndrome (cms) masquerading as myasthenia gravis. patients and findings: two six and seven years old sisters presented with variable strabismus, ptosis, and fatigue. all symptoms were aggravated with exercise and improved with rest. intramuscular prostigmin injection decreased their symptoms. a diagnosis of cms was made according to early onset (infancy), familial pattern, and lack of serum antibodies. oral neostigmin was begun for treatment. conclusion: although cms is a rare disorders, they should be considered in all cases with variable strabismus and ptosis.