Globin chain synthesis and clinical and hematologic findings in double heterozygotes for the silent and classical ß-thalassemia genes, and their parents

Abstract

Detailed hematologic and globin chain synthesis studies were performed in a special group of six patients with thalassemia syndrome who were offsprings of segregation of classical β-thalassemia trait (increased HbA2 and normal or slightly elevated HbF), to "silent" β-thalassemia trait (normal HbA2 and HbF, but impaired β-chain synthesis). Clinically these patients varied widely, from those severely affected which necessitated regular transfusions since the first year of life, to others with an intermediate clinical course without transfusion requirements. The levels of both HbA (28-80%), and HbF (18-70%), varied widely. Of interest were the results of globin chain synthesis in the patients with the "silent" β-thalassemia gene and their siblings; the ratio of a to non-a chains ranged from 1.43 to 3.02 indicating a considerable variation in the degree of impairement of β-chain synthesis. This favors the assumption that a heterogeneity in "silent" β-thalassemia gene may exists, and that the extreme variation in the clinical severity observed in double heterozygotes patients, could be associated with heterogeneity of the "silent" thalassemia gene.