Thalassemia

What is thalassemia?

Thalassemia is a blood disorder that affects the way your body produces red blood cells. It is an inherited condition, meaning your parents pass on one or more faulty genes to you which prevent you from making normal hemoglobin.

Hemoglobin is the protein in red blood cells that carries oxygen. If you have thalassemia, your body produces less hemoglobin than normal because it does not produce enough alpha- or beta-globin chains – the protein chains that make up hemoglobin. This can cause anemia, a condition in which your blood has a reduced ability to carry oxygen. Your red blood cells may also have a shorter lifespan.

Are there different types of thalassemia?

There are two main types of thalassemia, which are named after the globin chains within the hemoglobin:

Alpha-thalassemia:

This happens when the genes responsible for making the alpha-globin chain are faulty or missing. There are four genes responsible for making the alpha-globin chain. You inherit two of the four alpha genes from each parent.

• If one alpha gene is faulty or missing, then there will usually be no symptoms.
• If two alpha genes are faulty or missing, you may have mild or no symptoms.
• If three alpha genes are faulty or missing, symptoms will be moderate to severe.
• If all four alpha genes are faulty or missing, then the condition is often fatal before or shortly after birth. If someone born with this condition survives, then lifelong blood transfusions are likely. Beta-thalassemia:This happens when the genes that form the beta-globin chain are faulty or altered. There are two genes responsible for making beta-chain globin. You inherit one of the two beta genes from each parent.
• If one beta gene is faulty or altered, symptoms will be mild or there will be none at all.
• If two beta genes are faulty or altered, symptoms will be moderate to severe.

If blood transfusions are needed regularly, then the condition is referred to as transfusion-dependent thalassemia.

What are the symptoms of thalassemia?

The symptoms of thalassemia depend on the type and severity of the condition that you have. If you have one alpha gene missing, then you will most likely be asymptomatic (no symptoms). If you have two alpha genes missing or one altered beta gene, then you may be asymptomatic or experience mild symptoms of anemia, such as fatigue.

Moderate symptoms of thalassemia that do not require regular blood transfusions may cause symptoms of anemia, as well as complications such as an enlarged spleen, growth problems, delayed puberty or weak bones.

More severe forms of thalassemia can cause severe anemia, which may develop during infancy. Additional symptoms can include poor appetite, pale or yellowish skin, or changes to the bones of the face or skull.

What causes thalassemia?

Thalassemia is an inherited condition. If you have thalassemia, then you inherited abnormal genes that instruct your body to make alpha or beta globin chains from your parents. These chains make hemoglobin, a protein needed for red blood cells to work properly.

What are the risk factors for thalassemia?

You are more at risk of carrying a gene for or having thalassemia if you have a family history of thalassemia. Certain ancestry can also increase the risk, with thalassemia being most common in people of Mediterranean, Middle Eastern, African, South Asian, and Southeast Asian descent.

What are the complications of thalassemia?

Moderate to severe thalassemia can cause health problems such as:

• Iron overload: This can be caused by frequent blood transfusions or from the disease itself. Too much iron can lead to heart and liver damage and damage to the glands that produce hormones.
• Infection: The risk of infection is increased, particularly if the spleen has been removed.

Severe thalassemia can cause the following complications:

• Enlarged spleen: The spleen helps to fight infection and remove damaged blood cells. As thalassemia can cause the destruction of many red blood cells, the spleen needs to work harder and may become enlarged. If the spleen is enlarged, it can make anemia worse and reduce the lifespan of transfused red blood cells. If it becomes too large, it may need to be removed.
• Bone changes: Thalassemia may cause bone marrow to expand, causing bones to widen and form an irregular structure, particularly in the face and skull. This can also make bones thinner, brittle and more likely to break.

How is thalassemia diagnosed?

Symptoms of moderate and severe thalassemia usually appear in early childhood, so the condition is often diagnosed before a child is 2 years old. Blood tests used to help diagnose thalassemia include:

• A complete blood count (CBC): This shows if there are too few or too many blood cells.
• Genetic testing: This can detect the abnormal genes that cause thalassemia.
• Hemoglobin analysis: This can identify abnormal hemoglobin chains and determine the type of thalassemia.
• Hemolysis tests: These can find substances in blood that indicate that red blood cells are dying too early.
• Iron blood tests: These help to rule out iron deficiency as the cause of anemia.

Prenatal testing of unborn babies can show if the disease is present, and the type and severity of the condition. Prenatal tests include chorionic villus sampling, which involves removing a sample of the placenta to testing, and amniocentesis, which involves checking a sample of amniotic fluid.

How is thalassemia treated?

If thalassemia is mild, then it may not need treatment.

Moderate to severe thalassemia may require:

• Blood transfusions: These may be needed as often as every few weeks. They can lead to a buildup of iron in the body which can damage the liver, heart and other organs.
• Chelation therapy: A treatment which removes excess iron from the body which is vital for preventing organ damage.
• Folic acid supplements: These may be recommended to help your body to make new, healthy red blood cells.
• Medications: Certain medications can help your body remove iron. Others can reduce the need for blood transfusions.
• Stem cell transplant: Also referred to as a bone marrow transplant, this may be offered to some people with severe thalassemia. It can potentially cure the condition and prevent the need for lifelong blood transfusions, but it carries risks.

Can thalassemia be prevented?

Thalassemia is an inherited condition that you are born with. If you carry a gene that causes thalassemia, genetic counseling can help you to understand the likelihood of passing it on to your children. This is done via carrier screening and advice on family planning choices.