Mild Homozygous Beta-Thalassemia

Abstract

Two families with [beta]-thalassemia are described. In the first family studies of 16 members comprising 3 generations suggest that in this family a "mild" thalassemia gene is present which produces asymptomatic simple heterozygotes with mild elevation of Hb F [fetal hemoglobin] and a 2-fold increase of A2 and homozygotes with relatively mild disease consistent with asymptomatic survival to adulthood and Hb F levels of approximately 30%. In the double heterozygotes with hemoglobin S [sickle hemoglobin] or C the synthesis of Hb A [adult hemoglobin] was only partially suppressed. Another family is described in which thalassemia intermedia seemed to have occurred on a heterozygous basis since only one parent had the classical findings of the thalassemia trait. In the other parent, however, there was a heterogeneous distribution of Hb F among the erythrocytes as the only evidence of the thalassemia trait suggesting that the slide elution test for Hb F is sufficiently sensitive to permit the detection of carriers of [beta]-thalassemia trait is the absence of other stigmata of thalassemia. The findings support the hypothesis that the variability of the clinical severity of [beta]-thalassemia is related to genetic heterogeneity of thalassemia genes.