α-Thalassemia in the American Negro

In Italian and Chinese patients with the α-thalassemia syndromes the production of α-chain of normal hemoglobin is decreased relative to that of β-chain in reticulocytes. In this study the relative rates of α- and β-chain synthesis were determined in members of three Negro families with α-thalassemia. Two of the families had members with hemoglobin H disease and α-thalassemia trait, while the mother of several children with α-thalassemia trait in the third family was doubly heterozygous for α-thalassemia and an α-chain mutant. The α/β ratios of globin synthesis in the patients with hemoglobin H disease and α-thalassemia trait indicated less severe biochemical defects in the peripheral blood than those previously determined in Italian and Chinese patients. In the third family, there was a heterogeneity of expression of the gene for α-thalassemia, including patients with normal red cell indices and synthesis ratios. These findings differ from those previously described in patients with α-thalassemia from other racial groups. Hydrops fetalis due to homozygous α-thalassemia may not occur in the Negro because of the relatively mild thalassemic defect.

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