Article Sections

Introduction

Thalassemias are a group of hereditary anemias characterized by reduced or absent synthesis of one or more globin chains (eg, reduced beta globin chains in beta thalassemia).  As a result, hemoglobin production is impaired, and patients can develop microcytic anemia.  The clinical presentation varies in severity; in beta thalassemia, this depends on the degree of preserved beta globin chain synthesis.

Pathogenesis

Hemoglobin is a protein that carries oxygen in red blood cells (RBCs).  It is composed of 4 subunits, each being a globin chain attached to a heme group containing iron.  Normally, 2 different pairs of subunits (eg, a pair of alpha globin chains and a pair of beta globin chains) join to produce hemoglobin ( Figure 1).  Globin chain synthesis is a highly regulated process that results in a predominant tetramer (ie, hemoglobin type) for each stage of development (eg, embryo, fetus, infant) (

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