Thalassaemia

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[sửa] Bệnh thiếu máu thalassaemia là gì?

Thalassaemia là một bệnh hoại máu di truyền. Trong hồng huyết cầu của bệnh nhân, chất hồng tố haemoglobin A không được cấu tạo hoàn toàn. Do đó hồng huyết cầu bị bất thường và bị dễ tiêu hủy khi đi qua lá lách.



Haemoglobin is an iron-containing protein which is vital because it carries oxygen around the body.

[sửa] Who gets thalassaemia?

It can be found in any population of people but is most common in people from the Mediterranean, the Middle East, south-east Asia and the Indian sub-continent.

In some of these regions the frequency of the gene is as high as one in five people. It is uncommon in people of northern European ancestry.

[sửa] What is the nature of its inheritance?

Thalassaemia is a genetic disorder passed down from parent to child through the genes. It is one of the world’s most common inherited genetic disorders.

Its most severe form is seen only in those people who inherit the gene from both parents.

When it is inherited from only one parent the person has the thalassaemia “trait” and is also described as a carrier of the gene. This is by far the most common form of inheritance.

There are therefore two types of thalassaemia:

1. Thalassaemia minor — the carrier or trait state.

2. Thalassaemia major — the disorder.

[sửa] Is thalassaemia minor serious?

People with this common form are healthy and most go through life unaware they have a problem. The disorder can only be detected by a special blood test.

[sửa] Is thalassaemia major serious?

Yes, it is invariably a severe lifelong condition due to the resultant anaemia (called haemolytic anaemia). The main symptoms of anaemia are tiredness, weakness, breathlessness and pallor.

A child who has the disorder tends to be lethargic and inactive and cannot keep up with the activities of other children.

[sửa] What are the risks?

People with thalassaemia major are at risk from severe anaemia and the consequences of multiple blood transfusions required for treatment.

This will cause a build-up of iron in the body which can result in damage to the pancreas, heart and liver.

However, with good treatment most children will be able to lead a reasonably normal life, although constant care and monitoring will be necessary.

[sửa] Is there a cure for thalassaemia?

There is no available cure but it is hoped that new information on the structure and transmission of genes may lead to effective gene therapy in the future.

[sửa] What should be done?

Individuals from a high-risk background should be tested for the thalassaemia trait.

The main tests are a full blood examination and haemoglobin electrophoresis. DNA analysis may be needed to detect the carrier state.

[sửa] How should family planning be carried out?

If a couple are both carriers (thalassaemia minor) it is important that they obtain genetic counselling for information about possible outcomes and options.

Possible Outcomes:

  • If a carrier marries a non-carrier there is a one-in-two chance of a child being a carrier but no chance of thalassaemia major.
  • If a carrier marries a carrier there is a three-infour chance of a child being healthy (one in four — no abnormal genes; two in four — being carriers) and a one-in-four chance of having thalassaemia major.

Options

There are various options for family planning including choosing not to have children naturally or electing to take the one in four risk of having a child with thalassaemia major.

Discuss these and other possible options with your doctor.

[sửa] What is the treatment for thalassaemia major?

Treatment is based on regular blood transfusions for anaemia. These are started in childhood as the anaemia develops and then given every 3-4 weeks. Later on, excess iron in the body can be removed by injecting a special drug.