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BETA-THALASSAEMIA

What is Beta-Thalassaemia ?

Thalassaemia is a group of inherited disorders of the haemoglobin inside the red blood cells. Haemoglobin is the red pigment in the red blood cells which carries oxygen from the lungs to the body tissues. Thalassaemia patients fail to make haemoglobin properly. Thalassaemia includes a number of different conditions of varying severity. The commonest type which causes problems is call beta-thalassaemia. The most severe form of this is called thalassaemia major. This results in severe anaemia (lack of red blood cells). The liver and spleen are enlarged because they are trying to help the bone marrow to make red cells. Children born with thalassaemia usually become unwell at about 6 months. They are very pale, due to the anaemia, and may be jaundiced. Very often they develop slowly and may not reach a normal height.

How does Beta-Thalassaemia occur ?

Our haemoglobin type is inherited from our parents through a pair of genes, one from each parent. A person with thalassaemia major has inherited an abnormal gene from each parent so that instead of making normal amounts of haemoglobin the red cells can make only small amounts of haemoglobin, thus producing severe anaemia. If a person inherits one normal gene and one gene for beta-thalassaemia, then their red cells make haemoglobin at a reduced rate and they are mildly anaemic. This is called beta-thalassaemia trait. If both parents have beta-thalassaemia trait there is a one in four chance that any child will be born with thalassaemia major.

Why does Beta-Thalassaemia occur ?

Thalassaemia affects mainly people of Mediterranean origin. It also occurs in people from African, Asian and Arab countries. This is because in the past, before effective treatment for malaria, the presence of thalassaemia protected children against malaria. Malaria parasites do not like growing in the blood cells of thalassaemic patients. They are therefore more likely to survive and have children than people with normal haemoglobin in such areas.

Treatment Involved for Beta-Thalassaemia

The defect in haemoglobin manufacture cannot be changed. In thalassaemia major, the mainstay of treatment is blood transfusion. Transfusions have to be given every 4 to 6 weeks throughout life. This allows the haemoglobin level to be kept near the normal level, and helps normal growth and development to occur as the child grows up. In thalassaemia trait there is mild anaemia but this is not severe enough to cause any symptoms. Transfusion is not needed. The level of haemoglobin can be thought of as normal for that person. It is important to realize that giving iron treatment will not improve the anaemia because lack of iron is not the reason for the anaemia.

During Treatment for Beta-Thalassaemia

The child will improve as soon as the first transfusion is given. As well as the inconvenience and discomfort of regular transfusions some problems can occur. One is that the child may become allergic to the white blood cells in the transfusions and develop fevers during the transfusion. This can be prevented by giving the blood through a special filter which removes the white cells. Another problem is that too much iron accumulates in the body. This comes from the eventual destruction of the transfused red cells. The body is not able to get rid of the excess iron. However, the doctor can get rid of the iron with drugs called iron chelators. The treatment is called chelation. It is very effective in getting rid of the excess iron but unfortunately has to be given by injection. It needs to be given every day or nearly every day. The most effective method is by a continuous drip infusion into the tissue just beneath the skin. This can be done overnight at home with a small battery-operated syringe. Research is in progress to find an effective chelating drug which can be taken by mouth. Before effective iron chelation, children with thalassaemia often died before the age of 20 due to heart damage, but the outlook has changed dramatically and thalassaemic children can now be expected to develop normally to adult life. It is therefore very important to adhere to the iron chelation therapy.

If Beta-Thalassaemia is Left Untreated

The child would become progressively more and more anaemic and ultimately heart failure would develop.

Effects on Family of Beta-Thalassaemia

Thalassaemia is an inherited condition, so other members of the family may have thalassaemia or thalassaemia trait. Of course one usually knows if anyone else has thalassaemia major: but the trait is only detected as a result of a blood test. The doctor may suggest that other members of the family are tested so that they know whether they have thalassaemia trait or not. This is important for people of child-bearing age. Many large cities in Great Britain have thalassaemia centres. Here anyone who wishes can find out more about thalassaemia and have a blood test. Counselling is available for couples who both have thalassaemia trait.