Congenital myasthenic syndrome with sleep hypoventilation

We report the case of a 13-year-old boy with acetylcholinesterase deficienc y, a congenital myasthenic syndrome, who developed sleep hypoventilation sy ndrome during a period of rapid growth. His symptoms were insidious and lif e-threatening despite changes in strength or lung volume measurements that were not marked. He responded well to noninvasive nocturnal ventilation, wi th reversal of symptoms and normalization of blood gases. His lung volumes, but not motor function, improved after treatment. (C) 2000 John Wiley & So ns, Inc.