Thalassemia

Overview

Thalassemia is a blood disorder in which the body makes an abnormal form of hemoglobin, the molecule in red blood cells that carries oxygen. This can happen when there is an imbalance in the different protein components that make up a hemoglobin molecule. The disorder results in fewer red blood cells, which leads to anemia and fatigue. Thalassemia is an inherited disorder and more common in people of Mediterranean, Middle Eastern, Chinese and Southeast Asian ancestry.

There are several types of thalassemia. Some forms are mild and do not require treatment, while others are more severe, and may require blood transfusions or bone marrow transplants.

A single hemoglobin molecule is made of two types of proteins: two alpha globins and two beta globins. People with thalassemia have a defect in the ability to balance production of these two types of globins.

Thalassemia is therefore categorized as alpha thalassemia, when there is too little alpha globin; or beta thalassemia, when there is too little beta globin.

Both alpha and beta thalassemia include the subtypes "major" and "minor." Individuals whose anemia is severe enough to require transfusion on a regular basis have thalassemia major (typically, all of the globin genes of a particular subtype are defective in these patients). Individuals who have some defective globin genes, but do not, or rarely, require transfusions have thalassemia minor. Individuals with thalassemia minor are carriers of the disorder, but often don't develop any symptoms themselves. Some individuals have a subtype whose severity is in between no symptoms and needing transfusions on a regular basis, such patients have thalassemia intermedia.

Beta thalassemia major is also called Cooley's anemia.

Signs & symptoms

Children born with beta thalassemia major, or Cooley's anemia, do not have any signs or symptoms at birth, but develop severe anemia during their first few years.

The most severe form of alpha thalassemia major causes stillbirth.

Other symptoms of thalassemia include fatigue, shortness of breath, jaundice, facial bone deformities and growth failure.

Individuals with alpha and beta thalassemia minor have smaller than normal red blood cells, but do not have any associated symptoms. However, they can pass there defective globin genes on to their offspring, and if their partner also has defective globin genes of the same type, their children may have more severe forms of thalassemia.

Diagnosis

In order to make a diagnosis, a blood sample will be taken and sent to our laboratory. A complete blood count (CBC) will determine anemia, or reduced red blood cell count. Another test — called hemoglobin electrophoresis, where blood is drawn and collected in an airtight vial — shows the presence of an abnormal form of hemoglobin. A test called mutational analysis can help identify the specific alpha and beta globin gene defects and can help detect alpha thalassemia mutations that cannot be seen in the hemoglobin electrophoresis test.

Treatment

There is generally no treatment necessary for minor forms of thalassemia.

A common treatment for all major forms of thalassemia is red blood cell transfusions. These frequent transfusions will temporarily give the individual a healthy supply of red blood cells with normal hemoglobin. A side effect of frequent blood transfusions is the accumulation of iron in the body, which can damage vital organs. Medication is then required to get rid of the excess iron. For some thalassemia intermedia patients, certain medications may be able to enhance their ability to make red blood cells. This lessens their degree of anemia and allows them to rely even less on transfusions.

In some cases, a bone marrow transplant may be used to treat thalassemia.