Making sense of thalassaemia
Making sense of thalassaemia
Thalassaemia is a group of inherited conditions that prevent the bone marrow from producing enough healthy red blood cells. This leads to low levels of haemoglobin, a protein in the blood which carries oxygen from the lungs to all cells in the body. Low levels of haemoglobin can cause anaemia. Left untreated, anaemia can lead to severe health problems.
Some people with thalassaemia develop high levels of iron in the blood. This may be caused by the condition itself or by repeated blood transfusions, which are a common treatment for thalassaemia. This is known as iron overload. If it is not treated, iron overload can cause damage to organs such as the heart and liver.
There are a number of different types of thalassaemia. These vary from a mild form that needs no treatment to a serious condition that needs lifelong management. Without close monitoring and regular treatment, severe types of thalassaemia can be life-threatening.
It is also possible to be a ‘carrier’ of thalassaemia with no obvious symptoms.
Thalassaemia is present from birth and is a lifelong condition. Current treatments can usually help to keep the symptoms of thalassaemia under control, but they do not treat the underlying condition or prevent complications such as iron overload, from getting worse. A range of potential new treatments is currently being studied. One area under investigation is called gene silencing therapy. This aims to target the underlying cause of iron-overload in thalassaemia and improve the outlook for thalassaemia patients.
+Why is haemoglobin important?
Healthy red blood cells contain haemoglobin, a protein produced inside the bone marrow. It is haemoglobin that gives blood its red colour.
Haemoglobin is needed to carry oxygen from the lungs to all of the cells in the body. Low levels of haemoglobin can lead to anaemia. If untreated, anaemia can cause a range of symptoms and in severe cases, can be life-threatening.
Haemoglobin contains iron. In some cases, the body tries to absorb more iron than usual or may have low levels of a hormone called hepcidin, which controls iron levels in the body.
This can lead to a build-up of iron in the body, a condition known as iron overload. This can be made worse by repeated blood transfusions which contain iron along with other vital substances.
+Is there more than one type of thalassaemia?
Haemoglobin contains two different proteins, called alpha and beta proteins. If the body cannot produce enough of either of these, it cannot make enough haemoglobin and the red blood cells cannot carry oxygen in the usual way. Thalassaemia is classified as alpha or beta, depending upon which protein is lacking.
Thalassaemia is also sometimes classified depending upon how severe it is. It may be called thalassaemia ‘minor’, ‘intermedia’ or ‘major’. In some countries, thalassaemia major is known as Cooley’s anaemia.
It is possible to be a carrier with no obvious symptoms. This is known as thalassaemia trait or thalassaemia minor. Many people are unaware they carry the thalassaemia gene.
+How many people are affected by thalassaemia?
Thalassaemia is more common in people from certain parts of the world. These include: Mediterranean countries (such as Greece, Italy and Turkey), South Asia (India, Pakistan and Bangladesh), China and Southeast Asia, North Africa and the Middle East.
It is estimated that on average, 3 in 100 of the world’s population has a thalassaemia gene.
80-90 million people worldwide are believed to be carriers of beta thalassaemia, with around 60,000 people living with the disease in Europe and the US.
Including beta thalassaemia, about 100,000 babies worldwide are born with severe forms of thalassaemia each year.
Why do people get thalassaemia?
Thalassaemia is an inherited condition, which means that it is passed from parents to children through faulty genes. It is not possible to ‘catch’ thalassaemia from someone else.
Some people carry the thalassaemia gene but have no symptoms. This is known as being a carrier or having the thalassaemia trait. It is also sometimes called thalassaemia minor.
+The genetics of thalassaemia
Thalassaemia is an inherited condition, which means that it can run in families.
A child inherits haemoglobin genes from both parents.
A child who inherits a faulty gene from one parent will be a carrier but will not have the disease.
A child of two carriers has a 25% chance of developing thalassaemia and a 50% chance of being a carrier.
+How are carriers affected?
A carrier has at least one of the faulty genes that cause thalassaemia but does not have the condition themselves. In most cases, they are still able to produce enough normal haemoglobin.
Carriers do not usually have health problems but may experience mild anaemia because their red blood cells are smaller than usual. In most cases, no treatment is needed.
If both parents of a child are carriers, the child has a 1 in 4 chance of developing thalassaemia. If two carriers are planning to start a family together, they may be offered counselling to discuss the possibility of conceiving a child with severe thalassaemia.
Blood tests can be carried out at any stage of life to see if a person has thalassaemia or is a carrier. This is particularly useful if there is a family history of thalassaemia.
Your guide to the symptoms of thalassaemia
The signs of thalassaemia often develop a few months after birth but less severe cases may not be obvious until childhood or adulthood. Some people only discover they have thalassaemia after a routine blood test.
Almost all people with severe types of thalassaemia will develop anaemia, which will require regular, ongoing treatment. They are also at risk of developing health problems caused by iron overload (a build-up of iron in the body). This can be a side effect of repeated blood transfusions or because the disease itself causes the body to store too much iron.
Without close monitoring and regular treatment, severe types of thalassaemia can cause serious damage to the heart, bones or liver and can be life-threatening.
+What are the key features of thalassaemia?
- Slow growth in children
- Weak or brittle bones (osteoporosis) or changes to the usual growth of bones in the forehead and jaw
- Enlarged spleen
- Symptoms associated with anaemia: severe tiredness, weakness, shortness of breath, palpitations (pounding, fluttering or irregular heartbeats), pale skin or yellowing of the skin and eyes (jaundice)
- If untreated, anaemia can lead to serious health problems, such as heart disease
- Symptoms associated with too much iron in the body (iron overload): problems with the heart, liver and hormone levels if untreated
+Living with thalassaemia: the outlook
The outlook for people with thalassaemia has improved in recent years but depends on how well complications such as iron overload can be managed.
People with mild types of thalassaemia will need little if any treatment and will be able to live normal or near-normal lives.
Those with more serious types of thalassaemia (such as beta thalassaemia major) will need ongoing specialist care for life to keep their symptoms under control. Unfortunately, current treatments do not treat the underlying cause of the condition or prevent it from getting worse.
The more severe types of thalassaemia can cause life-threatening symptoms if untreated.