Hematological phenotype of the double heterozygous state for alpha and beta thalassemia

In this study, we have correlated the hematological phenotype of 56 Sardinian βdeg; -thalassemia heterozygotes with their αglobin genotype as defined by restriction endonuclease mapping. We found that the coinheritance of the deletion of one αglobin and, more obviously, two αglobin genes tend to normalize the thalassemia-like hematological phenotype commonly associated with the βdeg;thalassemia carrier state. On the other hand, the association of the deletion of three αglobin genes caused a more severe phenotype. By globin chain synthesis analysis, those βdeg;thalassemia heterozygotes with the (-αalpha;alpha; αglobin genotype had less deficiency of βchain synthesis than did those with the normal αglobin genotype (αalpha;alpha;alpha; In heterozygotes with the (-αalpha; and in those with the (-/-α αglobin genotype the imbalance was actually reversed with a mild or marked αchain synthesis excess respectively.