No abstract

Some 2 years ago we investigated a child with profound psychomotor retardation who had had an occipital meningoencephalocele removed at birth. Contrast studies were carried out which showed a large midline defect in the posterior fossa and absence of the vermis. At the time we disregarded the nurses' comments about the child's abnormal breathing. A year later, Dr P P Demers referred this patient's baby brother to us because he was concerned about his abnormal breathing and retarded development. It was then found that a third and older child in this family was retarded, ataxic, and breathing abnormally. Finally we were able to trace yet another sibling who had died in infancy and who, at autopsy, proved to have agenesis of the vermis. This diagnosis was then confirmed in the two affected living children by contrast studies.From this investigation there emerged a familial syndrome of episodic hyperpnea, abnormal eye movements, ataxia, and mental retardation associated with a common malformation in the four affected siblings, agenesis of the vermis. This syndrome has not previously been described in the literature.The affected children will be presented in the order in which the abnormality was identified, which happens to be in reverse to the birth order (Figure 1). CASE REPORTS Case 1. M.D., a 6-month-old French Canadian boy, was admitted to the Montreal Children's Hospital on Oct. 9, 1967, for evaluation of abnormal breathing and develop-mental retardation. He was the last of six children in his sibship, bom after a normal pregnancy. Forceps were used during delivery. There was no history of trauma or anoxia at birth; however, his breathing, even at birth, was abnormally rapid. He smiled early. At the age of 4 months, he was unable to hold up his head. At 5 months, he showed almost continuous protruding movements of the tongue.Examination on admission revealed a well-developed boy in no distress. His nutritional status was good. His head circumference was 44 cm. A few telangiectasiae were seen on the cheeks, ears, and eyelids, more on the right side. A few dilated blood vessels were seen on the conjunctivae. His pupils were equal and reacted well to light, and the fundi were normal. Abnormal, conjugate, irregular, jerky eye movements were frequently seen, and rotatory nystagmus was present. When fixing with his left eye, the right eye deviated upward and laterally. His mouth was usually held open and his tongue protruded rhythmically His breathing was abnormal, particularly when he was stimulated. Periods of 12 to 16 seconds of hyperpnea, usually around 120 per minute but increasing up to 168 per minute, alternated with periods of apnea lasting 5 to 12 seconds. Occasional respiratory excursions were noted during the periods of apnea (Figure 2). During sleep, this respiratory abnormality was absent.The child moved all extremities well. Tone was diminished in the upper extremities. Deep tendon reflexes were brisk and plantar responses were extensor. His head control was poor. A weak grasping reflex was present. He ...