Thalassaemia

Thalassaemia is an autosomal recessive disorder characterised by defects of Hb’s alpha or beta chains.

N.B. Severity of disease depends on how many of the genes for the globin chains are defective.

The 2 types of it are:

• a-thalassaemia - Defects in a-chains

• b-thalassaemia - Defects in b-chains

  • These defects make the RBCs more fragile and easily destroyed

Definitively diagnosed with Hb electrophoresis.

a-thalassaemia

• 2 defective copies (trait) - mildly asymptomatic

• 3 defective copies - symptomatic

• 4 defective copies - incompatible with life

It presents with jaundice, fatigue, and facial bone deformities.

Diagnosis:

• FBC - shows microcytic anaemia

• Genetic testing

Management:

• Transfusions and stem cell transplants

• Splenectomy if persistant/recurrent

b-thalassaemia

This is caused by non-functioning copies of the two beta globin genes:

• b-thalassaemia minor (trait) - 1 functional and 1 dysfunctional copy

• b-thalassaemia major (trait) - 2 dysfunctional copies

Presentation:

• b-thalassaemia minor - asymptomatic

• b-thalassaemia major:

  • Severely symptomatic anaemia at 3-9 months where the normal replacement of HbF with HbA fails

  • Frontal bossing

  • Maxillary overgrowth

  • Hepatosplenomegaly

Management - Regular blood transfusions. The most important long-term consideration in these patients is to reduce the risk of iron overload toxicity; a condition which primarily affects the heart, joints, liver and endocrine glands. This can be prevented with iron chelating agents.

When managing these patients, they should be monitored for Iron overload toxicity, which is prevented with iron-chelating agents.