[Neonatal polycythaemia and haemoglobin types in infants with G-trisomy (author's transl)].

The concentrations of haemoglobin A1, A2, and F were determined quantitatively by column chromatography in 11 newborns with G-trisomy (Down's Syndrome)) and correlated to haematocrit values. In 3 infants the haemoglobin pattern was followed throughout the first six months of life. In connection to the well know polycythaemia, newborns with G-trisomy were found to have significantly higher haemoglobin A1 attaining 35.5 plus or minus 6.6% and A2 equal to 0.79 plus or minus 0.32% as compared to normal infants (HbA1 equal 17.74 plus or minus 4.56%, HbA2 equal to 0.25 plus or minus 0.2%). In G-trisomy the switch-over from synthesis of haemoglobin F to haemoglobin A appears to be initiated earlier than in normal individuals, and it seems even to proceed more rapidly during the first weeks after birth. The amount of adult haemoglobin being synthesized in G-trisomy during the perinatal period may possibly be a response to the increased erythropoiesis, while the influence of chromosomal abnormality seems not to be a specific phenomenon.