Thalassemia is the name of a group of genetic inherited disorders of the blood. More specifically, it is a disorder of the hemoglobin molecule inside the red blood cells. It is an inherited genetic disease, i.e. a disease that is passed from parents to children through the genes. It is not infectious and cannot be passed on from one individual to another by personal or any other contact, through blood transfusion, food or air.
The two main types of Thalassemia are β (beta) and α (alpha). Both affect the production of normal hemoglobin – a key constituent of human red blood cells.
Other abnormal types of adult hemoglobin, also known as structural hemoglobin variants, have been identified. These include hemoglobin S (HbS), hemoglobin E (HbE), hemoglobin C, hemoglobin D and Lepore. Structural hemoglobin variants can combine with β-Thalassemia to produce other related clinically significant blood disorders.
The name β- Thalassemia derives from a combination of two Greek words: “thalassa” meaning sea, i.e. the Mediterranean Sea, and anemia (“weak blood”). β-Thalassemia is also known as Mediterranean anemia. Both of these names reflect the fact that the disorder was first described in patients originating from countries around the Mediterranean, and for many years it was believed that Thalassemia occurred exclusively in these countries. Another term, nowadays less frequently used in literature, for β-Thalassemia is Cooley’s anemia, in recognition of the contribution of Professor Thomas Cooley, a pediatrician in the United States who first described the clinical characteristics of this disorder in patients of Italian origin in 1925.
Individuals who are carriers of the β-Thalassemia/Mediterranean anemia/ Cooley’s anemia trait, or with β-Thalassemia minor, or the heterozygous form of β-Thalassemia are not patients, but individuals who have inherited a normal hemoglobin (β-globin) gene from one parent and the defective gene from the other parent. Individuals with β-Thalassemia major or Mediterranean anemia or Cooley’s anemia, or homozygous β-Thalassemia are those who have inherited both the defective hemoglobin (B-globin) genes, one from each parent. These individuals are going to develop the full-blown disease.
About carriers of the Thalassemia Trait
Carriers of the Thalassemia trait do not have a disease. They have no physical or mental symptoms and do not require a special diet or medical treatment. The condition cannot become a serious disease over time – indeed, most carriers will be unaware that they carry the trait unless specifically tested. Some carriers may experience mild anemia, which may be inaccurately diagnosed as iron deficiency anemia. However, laboratory tests can differentiate between the two. Pregnant women carriers may experience moderate anemia, which is addressed by prescribing iron supplements during pregnancy.
Last updated: December 2010.
By Dr Androulla Eleftheriou BSc Biochemistry, MSc Biochemistry, PhD Microbiology, PhD Virology, Dip Mgt