Interaction of alpha-thalassemia genes with each other and with HbC in an American black family.

The relative rates of in vitro synthesis of hemoglobin chains have been studied in an American black family in which the mother is doubly heterozygous for alpha-thalassemia and HbC and the father is heterozygous for alpha-thalassemia. The alpha/non-alpha synthetic ratio was equally unbalanced in both the bone marrow and the peripheral blood of the mother. Although HbC comprised 35% of her hemoglobin (compared to 42.2 +/- 2.2 in individuals with HbC trait and balanced globin synthesis), synthetic data showed that the newly synthesized beta C chain was 44% of the total newly synthesized beta chains. Isolated membranes contained more newly synthesized beta C than beta A chains. Three of the offspring were within the normal range, and the remaining three had alpha-thalassemia. There were two spontaneous abortions during the second trimester of pregnancy. Hydrops fetalis did not occur, and none of the children had HbH disease or HbC trait.