Thalassemias are blood disorders that result in mild to severe anemia, a condition in which too few red blood cells prevent oxygen from being properly circulated in the body. Thalassemias are caused by an inherited disorder that affects how red blood cells are formed and their oxygen-carrying capacity. Specifically, thalassemia affects the development of hemoglobin, which is the protein in blood that carries oxygen. Patients with severe forms of the disorder require regular transfusions of blood.

Hemoglobin is made up of two proteins, known as alpha and beta. Thalassemias can affect either of these proteins, thus the two categories of thalassemia are:

• Alpha thalassemia. Occurs when at least one of the four genes that produce the alpha globin (a type of protein) chain of hemoglobin is either missing or abnormal. If more than two genes are missing, mild to severe anemia will result.
  
  
• Beta thalassemia. Occurs when one or both of the two genes that produce the beta globin chain of hemoglobin are abnormal. The type of abnormality and whether or not one or both genes are affected determine the severity of the disease. When both genes are affected, moderate to severe anemia may result.

The severity of thalassemias depends on how the genes are inherited by a child. If both parents pass on abnormal genes, the child may have a moderate or severe form of thalassemia. Children who inherit an abnormal gene from one parent and a normal gene from another may be carriers of the disease, a condition known as thalassemia trait. This means they will not have the disease themselves, but can pass it on to their children.

People with mild to severe forms of thalassemia may experience anemia that causes symptoms such as fatigue, shortness of breath or heart palpitations. Anemia also causes bone marrow to work harder to create more red blood cells, which can lead to enlargement of bones such as the cheekbones and those of the forehead.

Prenatal testing can help determine if a fetus has thalassemia and how severe the condition is likely to be. A blood test called hemoglobin electrophoresis is performed on newborn infants to check for thalassemia or thalassemia trait. A complete blood count (CBC) also can provide valuable insights into whether or not a patient has thalassemia.

Thalassemia that causes mild anemia may not require specific treatments, though patients with moderate to severe thalassemia may require ongoing therapy. Blood transfusions are the most common form of treatment for severe cases of thalassemia. These transfusions provide the body with healthy red blood cells that carry adequate levels of oxygen. Repeated transfusions can cause excessive levels of iron to build up in the body, a potentially fatal condition known as iron overload (hemochromatosis). A treatment known as chelation therapy can be used to remove excess iron deposits from the body.

Scientists continue to work on new ways to treat thalassemias. For example, one day gene therapy may make it possible to cure thalassemia in fetuses by inserting normal cells into a child’s stem cells.

Couples who are considering having children may want to undergo genetic testing to find out if they are carriers of thalassemias or other disorders that can be passed on to children.

Patients with severe thalassemia are vulnerable to infections that can worsen anemia. As a result, they are urged to receive vaccinations for pneumonia as well as annual flu shots.