Hemoglobinopathy

Hemoglobinopathy is a group of inherited disorders affecting hemoglobin, the oxygen-carrying protein in red blood cells. They are divided into qualitative disorders, caused by structural variants of the globin chains, and quantitative disorders, usually called thalassemias, caused by reduced production of one globin chain.

Structural variants include HbS, HbC, HbD, and HbE. Sickle cell disease, typically due to homozygous HbS or compound heterozygosity, causes red cell deformation, hemolysis, and vaso-occlusive episodes, particularly under low oxygen tension.

Thalassemias involve decreased synthesis of alpha- (alpha-thalassemia) or beta-globin (beta-thalassemia) chains, from gene deletions or mutations. This leads to an imbalance of globin chains, ineffective erythropoiesis, and anemia of varying severity.

Diagnosis relies on routine blood tests and is confirmed by hemoglobin electrophoresis or high-performance liquid chromatography and genetic testing. Newborn screening and morphological clues on the blood smear help differentiate conditions.

Management is tailored to the disorder. Carriers require little or no treatment; affected individuals may need transfusions, iron management, infection prevention, and supportive care. Sickle cell disease may be treated with disease-modifying therapies such as hydroxyurea and newer agents; curative options include stem cell transplantation in selected cases.

Hemoglobinopathies are common in regions with historic malaria selection and among certain ethnic groups, with prevalence varying by population. Advances in molecular genetics improve diagnosis and enable ongoing development of targeted therapies.