The quiet carrier of beta-thalassemia

Heterozygosity for beta-thalassemia is usually characterized by hypochromia, microcytosis, mild anemia, and increased percentage of Hb A2, and normal or mildly increased Hb F. We have studied an unusual type of beta-thalassemia with typical morphologic abnormalities but normal levels of Hb A2 and Hb F, with diagnosis confirmed by globin synthesis studies. The results indicate that globin synthesis studies may be necessary when the cause of hypochromia and microcytosis cannot be clearly determined by hemoglobin quantitation and electrophoresis and other standard clinical tests.