Further Studies on the Antenatal Detection of Sickle Cell Anemia and other Hemoglobinopathies

Abstract

The synthesis of hemoglobin A was measured in small samples of peripheral blood cells from 9- to 20-week human fetuses. In 15 fetuses, synthesis of hemoglobin A accounted for 4 to 13% of total hemoglobin synthesis and the percent of hemoglobin A synthesis varied directly with fetal size. In one aborted fetus of a mother heterozygous for hemoglobins A and S, the synthesis of hemoglobin S was 3.4% and that of hemoglobin A was less than 3% of total hemoglobin synthesis. Peripheral blood cells of normal mothers (AA) synthesize 15–20% as much hemoglobin A as do comparable aliquots of peripheral blood of their fetuses. Therefore, the prenatal diagnosis of sickle cell anemia and other β-chain hemoglobinopathies appears biologically feasible, even with samples of fetal blood in which up to one-third of the cells are of maternal origin. Since amniotic fluid samples do not consistently contain the necessary numbers of fetal blood cells, we believe antenatal diagnosis of hemoglobinopathies awaits development of a safe, reliable, amnioscope to aid in the sampling of small quantities of fetal blood under direct visualization.