In the countries within the Mediterranean region, which includes Turkey, the major disease of β-thalassemia, in which the β-globin chain is produced in reduced quantities or not at all, is often observed. β-thalassemia is one of the most common single gene diseases and is an important public health problem. Mutations in the β-globin (HBB) gene are responsible for this disease and the disease is inherited as autosomal recessive. The major strain of β-thalassemia occurs in those who carry the mutations as a homozygote or combined heterozygote.
β-thalassemia is a form of hemolytic anemia characterized by major growth retardation, deterioration in almost all organ functions, increased iron absorption, and iron loading due to recurrent blood transfusions. The minor strain of β-thalassemia (β-thalassemia carrier) refers to the carrier state resulting from the presence of one mutation in the gene. Carriers often do not exhibit clinical symptoms and it may not be picked up during routine blood counts. The β-thalassemia carrier rate is as high as 10% in some regions in our country.
The disease is caused by mutations in the HBB gene. More than 800 mutations have been identified in the HBB gene.