PHENOTYPIC EFFECT OF HETEROZYGOUS ALPHA-THALASSEMIA AND BETA-0-THALASSEMIA INTERACTION

  • 1 January 1983
    • journal article
    • research article
    • Vol. 62  (1) , 226-229
Abstract
Restriction endonuclease mapping was used to characterize the .alpha.-globin genotype of 10 Sardinian [Italy] .beta.0 -thalassemia heterozygotes, all of whom presented with normal red blood cell indices and increased HbA2 levels. Of these subjects, 8 had a deletion of 2 .alpha.-globin genes (-.alpha./-.alpha.) and the remaining 2 had a deletion of a single .alpha.-globin gene (-.alpha./.alpha..alpha.). In 3 of these carriers with the (-.alpha./-.alpha.) .alpha.-globin genotype and in 1 with the (-.alpha./.alpha..alpha.) genotype, the glucose-6-phosphate dehydrogenase (G6PD) defect of the Mediterranean type was found. The interaction of heterozygous .beta.0-thalassemia with .alpha.-thalassemia, due to the deletion of either 1 or 2 .alpha.-globin genes, may lead to the production of red blood cells with normal indices. The association of the G6PD defect with this thalassemia gene complex may eventually contribute to this effect. Screening programs for heterozygous .beta.-thalassemia in populations where .alpha.-thalassemia is also prevalent, should incorporate the determination of HbA2 in the 1st set of tests.