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Thalassemia

Oxygen is carried in the red blood cells by a form of protein called haemoglobin, which also gives blood its red colouring. Thalassaemia is a disorder that affects the production of haemoglobin and results in severe anaemia.

The disorder is passed from parent to child via genes, and is the most common inherited blood disorder in the world. Thalassaemia can affect anyone of any nationality, but it is particularly prevalent in people from Mediterranean countries and a broad region extending across the Middle East and South East Asia. Thalassaemia is usually diagnosed within the first six months of life and can be fatal in early childhood without ongoing treatment. There are two different types of thalassaemia, alpha (thalassaemia major) and beta (thalassaemia minor), with the most common being beta thalassaemia.

Thalassaemia minor

Beta thalassaemia is common. People who have beta thalassaemia minor have one copy of the beta thalassaemia gene. It is estimated that 100,000 people in Victoria have beta thalassaemia minor and carry this gene. These individuals are healthy carriers. The only way to detect the presence of the gene is by a specific blood test for thalassaemia.

Thalassaemia major

The concern arises when two carriers of beta thalassaemia wish to start a family. If two carriers conceive a child, then the child has a:

• 25 per cent risk of developing alpha thalassaemia (thalassaemia major) because they inherited the thalassaemia gene from both parents.
• 25 per cent chance of not inheriting the thalassaemia gene at all.
• 50 per cent chance of inheriting the gene from one parent, and becoming a carrier.

Thalassaemia major requires lifelong treatment. The red blood cells of a person with thalassaemia major can only survive for a few weeks, compared to normal red blood cells that survive for around four months. Lack of haemoglobin results in reduced oxygen to every cell in the body. The following signs appear in early childhood:

• Severe anaemia, because red blood cells are produced without sufficient oxygen-carrying haemoglobin.
• Paleness.
• Sleep difficulties.
• Poor appetite.
• Failure to grow and thrive.
• Enlargement of organs, such as the spleen and liver.

Treatment

There is no cure for thalassaemia major, and treatment must continue for life. Ongoing treatment includes regular transfusions to boost haemoglobin levels in the blood. However, the resulting iron build-up can cause serious side effects, including diabetes, heart failure and liver disease. A medication called desferrioxamine, or Desferal, is used to remove excess iron from the blood. It works by binding with the iron and allowing it to be excreted by the kidneys. Desferal is infused into the body with a special slow infusion pump that has to run for eight to 12 hours every night.

Bone marrow transplants A bone marrow transplant is the only chance of a cure, but the risks are considerable. The odds of finding a compatible donor are around 30 per cent, and most donors are siblings. This operation is more successful in young children who don't suffer from iron overload, but graft rejection or even death can still result. The risks involved mean that bone marrow transplantation is not a viable option for some families. It should be remembered that a person with thalassaemia major can live a normal life with regular transfusions and medication. Genetic research is ongoing in the hope of finding a cure.

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