[Molecular causes of thalassemia. III. Molecular genetic variants of beta-thalassemia in Azerbaijan].

Twelve patients with homozygous beta-thalassemia from Azerbaijan are described. From biosynthetic studies, we have established that seven children had beta +-thalassemia, while five had beta 0-thalassemia. In six patients with beta +-thalassemia a close correlation has been found between alpha/beta globin chain synthesis and alpha/beta mRNA content determined by molecular hybridization. In one case of beta +-thalassemia no such correlation has been observed. It was possible to study nuclear and cytoplasmic RNA from spleen erythroid cells in one of the patients. alpha/beta globin RNA ratio was 5 in both cases, suggesting the possibility of a defect in beta-globin gene transcription. In cases of beta 0-thalassemia, heterogeneity of the relative content of beta-globin mRNA was revealed: either it is found in considerable amounts, or it is completely absent. Mapping of DNA from two beta-thalassemic patients by restriction enzymes yielded a normal pattern for the beta-globin gene region.