Article Sections

Introduction

Sickle cell disease (SCD) is a group of inherited hemoglobinopathies characterized by the predominance of hemoglobin S (Hb S), a structural variant of hemoglobin, within red blood cells (RBCs).  Unlike normal hemoglobin, Hb S polymerizes under hypoxic conditions, forming rigid sickle-shaped RBCs.  Patients have lifelong chronic hemolysis and vaso-occlusion ( Figure 1) that can cause both acute (eg, ischemic pain) and chronic (eg, chronic kidney disease) complications.

Pathogenesis

Normal hemoglobin production

Hemoglobin is composed of 4 globin chains and carries oxygen in RBCs.  Normally, 2 different pairs of globin chains (eg, a pair of alpha globin chains and a pair of beta globin chains) join to form a tetramer ( Figure 2).  Globin chain synthesis is a highly regulated process that results in a predominant tetramer (

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Figures

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Tables

Table 1