What is thalassemia?
Thalassemia is a medical condition characterized by production of defective oxygen carrying particle of the blood the hemoglobin. Hemoglobin (Hb) is an essential part of the red blood corpuscles (RBCs), thus deformed Hb leads to increased destruction of RBCs and subsequently symptoms of anemia. Thalassemia is an inherited disorder, where the defective genes responsible for production of deformed Hb pass down from parents to children.
There are different varieties of thalassemia namely alpha-thalassemia, beta-thalassemia, Cooley’s anemia and Mediterranean anemia, among otherd. Mild thalassemia may not require any treatment however for moderate to severe thalassemia repeated blood transfusion is necessary. These days, a bone marrow transplant is an option in selected patients with severe thalassemia.
Signs and Symptoms
Symptoms of thalassemia occur mainly due to anemia. These are increased tiredness, severe degree of weakness, pale appearance, respiratory distress, increased irritability, yellowish discoloration of skin and mucous membrane, including the white of the eyes (jaundice), characteristic deformed facial growth (hemolytic facies), growth retardation, swelling in the abdomen due to enlargement of the spleen and the passing of dark colored urine. The severity of the symptoms usually depends upon the severity of the disease. In many children the symptoms become apparent as early as at birth whereas others may develop symptoms during first few years of the life.
There are number of complications associated with thalassemia namely :
- Widening of the bones of the skull and face due to expansion of bone marrow in thalassemia patients. As a result the bones become thin and brittle with increased risk of fracture. The bones of the face and skull are more commonly affected.
- Enlargement of spleen: spleen is the organ of the body which is responsible for destruction of old RBCs. In Thalassemia patients the defective RBCs are destroyed by the spleen leading to increased workload on the spleen. As a result the spleen becomes enlarged (splenomagaly). Splenomagaly can destroy even the normally circulating RBCs obtained from blood transfusion. Hence sometimes enlarged spleen is removed surgically.
- Severe degree of thalassemia may lead to increased work load on the heart leading to heart failure and rhythm abnormality (arrhythmia).
- Increased tendency to contract infection especially in patients in whom the spleen has been removed.
- Repeated blood transfusion may lead to iron overload damaging the heart, liver or other vital organs.
Causes and Risk Factors
Hemoglobin is made up of haem and globin consisting of two proteins namely alpha globin and beta globin. In thalassemia patients the genes responsible for production of these two genes are defective. There are mainly two types of thalassemia – alpha-thalassemia and beta-thalassemia.
In alpha thallassemia there is either complete absence or defect in the genes producing alpha globin and in beta thalassemia similar problem is present with beta globin gene.
Thalassemia is an autosomal recessive disorder so inheritance of defective genes from the both parents is essential for disease manifestation (thalassemia major). In patients who have inherited only single defective gene usually there is no disease manifestation (thalassemia minor) only carrier state. The most important risk factor for thalassemia is a family history. Alpha-thalassemia is more common in people with Asian origin whereas beta-thalassemia is more common in people with Mediterranean origin.
Treatment is required only in moderate and severe degree of thalassemia. Blood transfusion at regular interval and bone marrow transplant in some selected patients are the treatment options.