Thalassemias refer to a group of hereditary blood disorders characterized by the defective production of one of the four global chains of amino acids that make up hemoglobin. Patients with the disorder experience severely low red blood cell production.
Thalassemias are categorized according to which amino acid chain is affected and by the number of genes that are defective. The two main types are alpha-thalassemia and beta-thalassemia (the alpha and beta amino acid chains are affected). Thalassemia major refers to two inherited defective genes (both parents) while thalassemia minor refers to one inherited defective gene.
Children diagnosed with the major form of beta-thalassemia develop anemia
during their first year of life. Liver
and growth disorders are not uncommon. Symptoms are rare in people diagnosed with the minor form of beta-thalassemia. The severe form of alpha- thalassemia can cause a stillborn fetus. Alpha-thalassemia is most common in African-Americans while beta-thalassemia is usually found in people of Mediterranean origin, and to a lesser extent, Chinese and other Asians.
Thalassemias are difficult to diagnose and are usually based on hereditary patterns and hemoglobin tests.
- Blood Disorders: Overview