Thalassaemia is an inherited condition affecting the blood. There are different types, which vary from a mild condition with no symptoms, to a serious or life-threatening condition. For the more severe forms of thalassaemia, modern treatment gives a good outlook, but lifelong monitoring and treatment are needed. Good treatment is important to prevent complications developing. Thalassemia can be diagnosed from a blood test. Pregnant women and couples planning a family are advised to have a test for thalassaemia, because early diagnosis can be helpful.
Thalassemia is caused by genetic change, involving the genes which tell the body how to make an important chemical called ‘haemoglobin’. Haemoglobin is the chemical which carries oxygen in the blood – it is the one which gives blood its red colour. Haemoglobin is located in cells called ‘red blood cells’ which are part of the blood. Haemoglobin is made out of different parts. The main parts are called ‘alpha chains’ and ‘beta chains’ which are put together to make the haemoglobin molecule. In thalassaemia, part of the haemoglobin is faulty – usually either the alpha chains or the beta chains. This means that some of the haemoglobin does not work properly. As a result, there is not enough normal haemoglobin and the red blood cells break down easily. This makes the person ‘anaemic’ (lacking in haemoglobin), with various symptoms. Meanwhile, the body tries to make more haemoglobin and more red blood cells. So, the blood system goes into ‘overproduction’ mode which can cause more symptoms and complications.
Depending on the type of thalassaemia, the amount of abnormal haemoglobin varies. It can be most of the body’s haemoglobin, or only a small proportion. This is mainly what determines how severe the thalassaemia is. There are also other individual factors involved. So, two people with the same type of thalassaemia may have a different severity of illness from the same condition.
Anyone may carry a thalassaemia gene. On an average, 5 in 100 of the world’s population have a thalassaemia gene (and therefore have a thalassaemia trait). The chance of having a thalassaemia gene varies, depending on your family origin. In India mahar, sindhi, navahati community
Types of thalassaemia
The main types of thalassaemia are called alpha thalassaemia and beta thalassaemia. (The alpha and beta refer to which haemoglobin gene is affected, and which of the haemoglobin chains is faulty.) There are some rarer types too. Each type of thalassaemia (alpha and beta) is then classified into more types, according to how severe the condition is. This mainly depends on how many thalassaemia genes are involved. The mildest types are called thalassaemia trait (or thalassaemia minor). The more severe beta types are beta thalassaemia major (BTM) and beta thalassaemia intermedia (BTI). The more severe alpha forms are Hb Barts (very severe) and Hb H disease (moderate). There are also some rarer types of thalassaemia such as delta beta thalassaemia, or combinations of a beta thalassaemia gene with another abnormal haemoglobin gene such as HbE.
Diagnosis of Thalassemia
The diagnosis is made by a blood test. The blood sample is analysed to see what type of haemoglobin is present in the blood.In some cases, extra tests such as DNA (genetic) tests are needed to diagnose the exact type of thalassaemia. It may help to test other family members where possible. Thalassaemia trait may be suspected from the results of an ordinary blood test called a ‘full blood count’. If the result shows red blood cells that are smaller and paler than usual, this may be due to iron deficiency or to thalassaemia trait.
Treatment of Thalassemia
The mainstay of the treatment is regular blood transfusions that must be given every 3-4 weeks to maintain pre-transfusion haemoglobin level of at least 9 g/dl. The ideal blood to transfuse should have extended red cell phenotype matching and leukodepleted. Complications that may arise from regular blood transfusions include an overload of iron in vital organs causing diabetes, liver disease and heart failure. Iron overload can be controlled with regular medications reducing iron level. It is called iron chelation. It is done with injections or oral medicines ( Desferoxamine , Deferiprone or Deferasirox ). Deferasirox is available as oral drug and is very convenient and effective for controlling this important complication. It needs to be started early in life and taking it regularly with monitoring of liver, kidney function along dose adjustment with periodic assessment with blood test( ferritin) or sometimes with MRI of liver/ heart when organ dysfunction is suspected.
Bone Marrow Transplant from HLA matched sibling is the only curative therapy for thalassemia.. This means either a bone marrow transplant, or a cord blood transplant. These treatments take normal blood-making cells from a donor, and give them to the person with thalassaemia. Best results of 80-85% are achievable if done early in the course of disease before complications set in. If the transplant is successful, these cells last for life and make normal haemoglobin – a lifelong cure. However, a stem cell transplant is not suitable for everyone. You need a suitable donor, and there are some serious risks involved.
Prevention of Thalassemia
As mentioned earlier, Thalassaemia is an inherited condition. This means that if two carriers have a child, each carrier (trait) parent may donate an effected gene to their child. The probability of producing a child with thalassaemia is one in four if both parents are carriers. If one person has the disease and the other is a carrier the risk is greater —one in two. A thalassaemia gene combined with a sickle gene may result in sickle cell disease. The genetics of thalassaemia are complicated and you may speak with us or with geneticist. If you are pregnant, the best time to have a thalassaemia blood test for yourself is before you are 10 weeks pregnant. This allows more time to test your husband or your baby, if needed. You can ask your doctor for a test early in pregnancy. However, tests can still be done at a later stage. A prenatal test (on the unborn baby) can be done from 10 weeks of pregnancy onwards, depending on the type of test used. The usual tests offered are chorionic villus sampling (CVS) or amniocentesis. Women or couples may want to have tests for thalassaemia before starting a family, especially if their family origins make thalassaemia more likely. The Indian Thalassaemia Society and many health professionals encourage awareness of thalassaemia and early testing. The test can be arranged by your doctor.The advantage of having tests before you become pregnant, is that you will know whether or not there is a possibility that your baby could inherit a severe form of thalassaemia. This may be helpful when making decisions about pregnancy.
If you already have a child with thalassaemia, you are a thalassaemia carrier. This means
that at least one of your parents is a carrier, so your brothers, sisters and cousins may also be carriers. Please encourage your relatives to get tested before they have children, if they have not already done so.
List of website links you may find useful:
Dr Harsha Prasada L
MD, DCH, DNB, MRCPCH (London),
Consultant Paediatric Haematologist and Oncologist
Fellowship in Hemato-Oncology