Thalassemia



The word 'Thalassemia' is derived from the Greek words, 'thalassa' meaning 'sea' and 'emia' meaning 'blood'. This is to infer that the disease is more prevalent in people living in the Mediterranean region.

Thalassemia is an autosomal genetic disorder (caused by mutation of recessive genes). This disorder is primarily characterized by prevalent anemia, attributed to the underproduction of globin proteins which are the integral components of the pigment of blood, hemoglobin.

Thalassemia is different from sickle cell anemia, another genetic disorder of blood. Sickle cell anemia is a defect in the quality of hemoglobin cells which have restricted capacity to transport nutrients and oxygen. On the contrary, thalassemia causes a reduction in the number of hemoglobin cells in the body, again hindering the functionality of the blood in transporting nutrients and oxygen. 

Thalassemia can be categorized into the following types, based on the globin chains affected. The hemoglobin molecule is composed of two alpha chains and two beta chains.

  • Alpha thalassemia is seen in the people who live in Western Africa and South. The disease is now seen among Indians as well as Americans. The affliction is caused by mutation of HBA1 and HBA2 genes on chromosome 16.
  • Beta thalassemia is seen in people of Mediterranean region and other parts of Europe. It involves mutation of HBB gene on chromosome 11.
  • Delta thalassemia is caused by mutation of the delta globin chains. Apparently, 3% of the globin proteins in the body are constituted of 2 chains each of delta and alpha proteins. As such, a mutation in delta chains lead to the respective variant of the affliction.

Alternative Names:

Cooley's anemia; Mediterranean anemia; Beta thalassemia; Alpha thalassemia