Familial infantile myasthenia.

Familial infantile myasthenia is a rare type of myasthenia that usually occurs in connection with respiratory depression. The condition is characterized by (1) absence of myasthenia in the mother, (2) occurrence of a similar disorder among siblings, (3) respiratory depression at birth, (4) episodic weakness and apnea during the first two years of life, and (5) improvement with age. Since the condition responds to anticholinesterase medication, early diagnosis is important. Familial infantile myasthenia is a potential cause of sudden infant death and should be considered in infants with unexplained respiratory distress.