Normally presents in the first year of life

Pathophysiology

• The gene coding for this protein is on chromosome 11
• Defects in the beta-globin chains, this leaves an excess of alpha chains, which precipitate in ertyhroblasts and RBCs causing ineffective erythropoeisis and haemolysis
• Normally HbF production ceases at around 6 months, in beta thalassaemia HbF continues to be produced to compensate for the abnormal erythropoeisis

The genes defect can either consist of abnormal copies that retain some function or deletion genes where there is no function in the beta-globin protein at all. Based on this, beta-thalassaemia can be split into three types:

• Thalassaemia trait (thalassaemia minor)
• Non transfusion-dependant thalassaemia (Thalassaemia intermedia)
• Transfusion dependant thalassaemia (Thalassaemia major)

Thalassaemia trait

Patients carry an abnormally functioning beta globin gene (one normal and one abnormal gene)

• The common carrier state is asymptomatic
• Causes a mild microcytic anaemia
• Differentiated from IDA as in thalassaemia trait the serum ferritin and iron stores are normal
• RDW is usally normal
• Haemoglobin electrophoresis usually shows a raised HbA2 and often a slightly raised HbF
• Usually patients only require monitoring and no active Tx