CLINICAL HISTORY.—This female infant, weighing 3,799 gm (8 lb 6 ounces), was the product of a 25-year-old mother whose pregnancy and delivery were uncomplicated. Breathing time and crying time were immediate, and the infant was well until 2 days of age, when she became jaundiced. Total serum bilirubin was 17.2 mg/100 ml. Blood types of mother and infant were A positive, and the patient was Coombs' negative. The infant was admitted to this medical center at age 6 days because of lethargy and poor feeding.
On physical examination, the child was mildly jaundiced and markedly hypotonic. Laboratory studies revealed the following results: temperature, 99.5 F (37.5 C); pulse rate, 110 beats per minute; respiratory rate, 30 breaths per minute; weight, 3.94 kg (9 lb) (50th percentile); and length, 50 cm (7 inches). Deep tendon reflexes and Moro responses were absent. Rooting and sucking responses were poor. Laboratory data also