The several forms of myasthenia gravis that occur in infancy include transient neonatal myasthenia, congenital myasthenia, and familial infantile myasthenia gravis. The latter is inherited in an autosomal recessive pattern. Severe episodes of respiratory distress are frequent in infancy, and are often provoked by mild respiratory infections. 2 sisters with congenital myasthenia gravis are described. Probably 2 other sisters died of the same disease, but no definite diagnosis was made in their cases.