Thalassaemia

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Thalassaemia is an inherited blood disorder.

The incidence of thalassaemia carriers varies greatly from country to country throughout the world. It's very common in the Middle East, the Indian sub-continent and through out South East Asia, in a region including Southern China, Thailand, Malaysia and parts of the southern Mediterranean. These regions coincide with areas where malaria occurs. Thalassaemia trait is believed to offer some resistance to malaria. Thalassaemia is common in those parts of the world where malaria is endemic.

Blood is made up of plasma (fluid), red blood cells, white blood cells and platelets. The white cells protect your body against and fight infection and the platelets are responsible for normal blood clotting. The red blood cells carry red blood protein called haemoglobin. Haemoglobin contains iron and transports oxygen from your lungs around the body. Anaemia is caused by reduced haemoglobin. If the anaemia is mild it does no harm and may not be noticeable.

A normal haemoglobin molecule contains four protein (globin) chains (two alpha globin chains and two beta globin chains) Different genes are responsible for producing each chain. In thalassaemia there is an inherited defect in one of these genes. If the alpha chain is affected this causes alpha thalassaemia. If the beta chain is affected this causes beta thalassaemia.

There are a number of different types of thalassaemia within these groups, alpha thalassemia being less diverse than beta thalassaemia.

Alpha plus thalassaemia is the mildest type of thalassaemia. It will not affect your health but you may pass it on to your children, who will also be perfectly healthy. This form of thalassaemia is very common in people who come from, or have ancestors from Africa, including many Afro-Caribbeans, India, Pakistan or Bangladesh.

Alpha zero thalassaemia is a rare type of alpha thaassaemia. This form of thalassaemia may occur if you or your ancestors originally came from South East Asia, China, the Mediterranean area, and the Middle East. You will be healthy but if you have children and your partner also has Alpha Zero Thalassaemia, your baby has a 1 in 4 chance of having a very serious anaemic disorder called alpha zero thalassaemia major, which is life threatening. Babies who have alpha thalassaemia major are unlikely to survive pregnancy.

Beta thalassaemia is seen most commonly in people who originate from Mediterranean Islands, Asia, Middle and the Far East. Because of migration and intermarriage it is also seen in other parts of the world including the UK.

Beta Thalassaemia Trait (Carrier) If you have beta Thalassaemia trait you will be healthy but if you have children and your partner also has beta Thalassaemia trait then there is a 1 in 4 chance of each child having the much more serious disorder Beta Thalassaemia major or Beta Thalassaemia Intermedia.

Also if you have children and you partner has another blood disorder (Hb E, Hb O Arab or Hb Lepore) your child may have symptoms of beta thalassaemia intermedia or beta thalassaemia major. If your partner has the gene for sickle cell your child may have a serious anaemia, sickle cell/beta thalassaemia. Therefore although carriers are healthy, if there is any family history of the condition it is extremely important to have a special blood test to detect this poorly functioning beta gene.

Beta Thalassaemia Intermedia and Beta Thalassaemia major If you have beta thalassaemia intermedia or Thalassaemia major, you have inherited a poorly functioning beta gene from both your parents. This usually causes Thalassaemia major, which is a serious condition requiring regular blood transfusions and many associated problems. Sometimes this causes thalassaemia intermedia, which is a less serious condition and you can often keep well without the need of regular blood transfusions. This is because the inherited genes may be mildly affected.