Phenotypic Effect of Heterozygous a and $#{176}-Thalassemia Interaction

In this study. we carried out restriction endonuclease mapping in order to characterize the a-globin genotype of 10 Sardinian $#{176}-thalassemia heterozygotes, all of whom presented with normal red blood cell indices and increased HbA2 levels. In 8 of these subjects, we found the deletion of two a-globin genes ( -al -a), and in the remaining two the deletion of a single a-globin gene (-a/act). In three of these carriers with the ( a I a) a-globin genotype and in one with the ( a I aa) genotype. we also found the glucose-6-phosphate dehydrogenase (G6PD) defect of the Mediterranean type. On the basis of these findings. we may