Two Sisters with Congenital Myasthenic Syndrome: Case Report

To report two sisters with congenital myasthenic syndrome (CMS) masquerading as myasthenia gravis. Patients and 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. Although CMS is a rare disorders, they should be considered in all cases with variable strabismus and ptosis.