RT Journal A1 Ackerman BD T1 INfantile pyknocytosis in mexican-american infants JF American Journal of Diseases of Children JO American Journal of Diseases of Children YR 1969 FD April 1 VO 117 IS 4 SP 417 OP 423 DO 10.1001/archpedi.1969.02100030419005 UL http://dx.doi.org/10.1001/archpedi.1969.02100030419005 AB IN 1959 Tuffy et al1 described 11 infants with a syndrome which they called infantile pyknocytosis. Seven of these infants had a clinical picture consistent with erythroblastosis fetalis; two of these seven infants required exchange transfusions, because of a bilirubin level over 20 mg/100 ml. Four other infants had no significant neonatal hyperbilirubinemia, but presented at 3 weeks of age with anemia or jaundice. Evidence of a hemolytic process persisted until 4 months, after which all abnormalities disappeared.The common denominator in these infants was the presence of abnormal erythrocytes in the peripheral blood called pyknocytes, or burr cells. All known forms of maternal isoimmunization were excluded. In one infant, the burr cells persisted following two exchange transfusions. One patient had diminished red blood cell glucose-6-phosphate dehydrogenase (RBC G-6-PD) activity, but this was felt to be an incidental finding. It was concluded that these patients had an extracorpuscular