What is thalassaemia?
Thalassaemia, sometimes known as 'thal', is an inherited blood disorder caused by a defect in a gene. The condition causes the body to produce abnormal haemoglobin red blood cells, which in turn causes anaemia.
Red blood cells are important for carrying oxygen around the body.
Symptoms include weakness, fatigue, feeling faint and shortness of breath.
Thalassaemia is sometimes mistaken for iron deficiency anaemia until special blood tests are carried out.
Thalassaemia is a lifelong condition which can be managed.
Types of thalassaemia
The type of thalassaemia a person may have is down to how many faulty genes they have inherited.
The two types of thalassaemia are alpha thalassaemia and beta thalassaemia.
In alpha thalassaemia, having one faulty gene will cause little or no effect to a person. Two faulty genes are associated with mild anaemia. Three mutated genes result in haemoglobin H disease that needs regular blood transfusions to treat chronic anaemia. Unborn babies with four faulty genes are unlikely to survive pregnancy.
Beta thalassaemia also has different forms: beta thalassaemia major, also called BTM, requires lifelong regular blood transfusions. BTM is the most common form of the condition in the UK and the most serious. Beta thalassaemia intermedia is also known as BTI or non-transfusion dependent thalassaemia or NTDT. This is a milder form of the condition and the severity will differ between individuals, from mild anaemia to the need for regular blood transfusions.
Carrying alpha or beta thalassaemia genes does not cause any illness and the carriers may not know they are carriers. Only special blood tests can confirm carrier status. Carrier status is important for people planning to have children, as genes are passed down the generations.
People with family backgrounds from the Mediterranean, Middle East, Africa or Asia may be more likely to be carriers. Thalassaemia is common in these regions because it helps to protect the carriers against malaria.
Causes of thalassaemia
Thalassaemia cannot be caught from another person, only inherited from genes - and may be passed from either parent to children.
The NHS estimates there are around 1,000 people in the UK living with beta thalassaemia major (BTM). Most of these cases affect people with backgrounds in the Mediterranean, Middle East and South Asia - including India, Pakistan and Bangladesh.
Pregnant woman are tested for inherited disorders such as thalassaemia during routine antenatal screening using blood tests under the NHS Sickle Cell and Thalassaemia Screening Programme.
The UK Thalassaemia Society advises that before a person who is a carrier of beta thalassaemia decides to have children, they should find out if their partner is also a carrier. If positive, there's a 25% chance a child would inherit beta thalassaemia from both parents, causing beta thalassaemia major that would have serious medical implications.
GPs can arrange testing. Special counselling may be offered depending on the test results.