Thalassaemia

Thalassaemia (or thalassemia) is a genetic disorder of the blood which originated in the Mediterranean region.

In thalassaemia, the disease is caused by the weakening and destruction of red blood cells. This is caused by mutant genes which affect how the body makes haemoglobin. Haemoglobin is the protein in red blood cells which carries oxygen. People with thalassaemia make less haemoglobin and fewer circulating red blood cells than normal, which results in mild or severe anemia.

Thalassaemia can cause significant complications, including pneumonia, iron overload, bone deformities and cardiovascular illness. However, this inherited disease of red blood cells gives a degree of protection against malaria, which is or was common in the regions where the trait is common. This selective survival advantage for carriers (known as heterozygous advantage) is responsible for keeping the mutation in populations way above its mutation rate. Carriers are heterozygous for the thalassaemia allele, meaning only one of their two alleles is mutant (abnormal). There are a number of different versiona of thalassaemia. Each one is caused by a mutation in a different position in the genome.

Treatment for Thalassaemia


The goal of long-term hypertransfusional support is to maintain the patient's hemoglobin level at 9-10 g/dL, thus improving his or her sense of well being while simultaneously suppressing enhanced erythropoiesis. This strategy treats the anemia and suppresses endogenous erythropoiesis so that extramedullary hematopoiesis and skeletal changes are suppressed. Patients receiving long-term transfusion therapy also require iron chelation. (See Medication)

Blood banking considerations for these patients include completely typing their erythrocytes for Rh and ABO antigens prior to the first transfusion. This procedure helps future cross-matching processes and minimizes the chances of alloimmunization. Transfusion of washed, leukocyte-poor red blood cells (RBCs) at approximately 8-15 mL RBCs per kilogram (kg) of body weight over 1-2 hours is recommended.

Hapgood et al suggest that current recommendations lead to undertransfusion in males. As a result, males may be more likely to have extramedullary hematopoiesis and thus more likely to require splenectomy or to develop spinal cord compression, an uncommon but serious complication of paraspinal extramedullary hematopoiesis.