In the UK, hundreds of people live with the inherited blood condition, thalassaemia.
Thanks to better treatments, sufferers can enjoy a full and active life

Thalassaemia is a blood disorder that affects the haemoglobin in the red cells, the chemical that carries oxygen around the body. It is most common in people who originate from Mediterranean countries, the Middle East, Africa and Asia.

As the distribution of thalassaemia coincides with that of malaria, it’s thought that carriers of the thalassaemia gene have some protection from malaria.

Haemoglobin is made up of chains of proteins and to work properly, adult haemoglobin needs both alpha and beta chains (there are two of each). A mutation that affects the alpha chain causes alpha thalassaemia, and a mutation of the beta chain causes beta thalassaemia.

Thalassaemia is not something you catch or develop. It’s an inherited disorder. In order to have the condition, a child needs to have inherited an affected gene from both parents. If they inherit only one gene then they will simply be a carrier of thalassaemia (sometimes called thalassaemia trait), and will usually suffer no ill health and need no treatment.

Alpha Thalassaemia

There are two genetic types of alpha thalassaemia, alpha plus and alpha zero. Alpha plus is the mildest form and does not affect the individual’s health. About one in three people originating from Africa or the Indian subcontinent are carriers.

Alpha zero is uncommon and carriers of the gene are not affected. If both parents are carriers some of their babies could inherit two copies of the affected gene and develop severe anaemia.

Beta Thalassaemia

This takes three forms. Beta thalassaemia carrier or trait is the mildest, and arises in someone who has inherited only one affected gene. The affected person is usually healthy and without symptoms. However their red cells may be slightly smaller and paler than those of people without the trait.

 People with beta thalassaemia intermedia inherit a thalassaemic (or poorly functioning) beta gene from both parents, but are only mild affected and often keep well without extensive medical intervention. People with this form can suffer from a mild form of anaemia and it can affect a child’s physical development.

How the trait is passed on?

(Please refer to the diagram above)

When one parent has one affected gene, s/he has the thalassaemia trait, and is called a carrier.
If the other parent has no affected genes, then, on average half of their children would have normal haemoglobin and half would be carriers for the thalassaemia trait.

If both parents have thalassaemia trait i.e. each has one affected gene, then, on average, one in four of their children would suffer from beta thalassaemia major, two in four would be carriers, and a one in four would have normal haemoglobin