Thalassemia
Introduction
Thalassemia — also called Mediterranean anemia — is an inherited blood disorder characterized by less hemoglobin and fewer red blood cells in your body than normal. Defects in the genes that make hemoglobin cause thalassemia. Hemoglobin is the substance in red blood cells that allows the cells to carry oxygen from your lungs to the other parts of your body. Because of low hemoglobin and a low amount of red blood cells, thalassemia results in anemia.
If you have a mild form of thalassemia, you may not require any treatment. But, if you have a more severe form, you may need blood transfusions on a regular basis. Although in some cases severe thalassemia can be life-threatening, milder forms of thalassemia usually can be effectively treated.
Although thalassemia causes anemia, don't confuse thalassemia with iron deficiency anemia. People with thalassemia often have more iron in their bodies than they need. For this reason, if you have thalassemia, don't take iron supplements unless your doctor recommends it.
Signs and symptoms
Signs and symptoms of thalassemia include:
- Fatigue
- Weakness
- Shortness of breath
- Yellow discoloration of the skin (jaundice)
- Bone deformities in the face
- Slow growth
- Protruding abdomen
- Dark urine
Causes
Blood consists of liquid, called plasma, and three types of cells that float within the plasma:
- White blood cells. These blood cells fight infection.
- Platelets. These blood cells help your blood clot after a cut.
- Red blood cells (erythrocytes). These blood cells carry oxygen from your lungs, through your bloodstream, to your brain and your body's other organs and tissues. Your body needs a supply of oxygenated blood to function. Oxygenated blood helps give your body its energy and your skin a healthy glow.
Thalassemia disrupts the normal production of hemoglobin and leads to a low level of hemoglobin and a high rate of red blood cell destruction, causing anemia. When you're anemic, your blood doesn't have enough red blood cells to carry oxygen to your tissues — leaving you fatigued.
Thalassemia is caused by defects in the genes that make hemoglobin. The only way to get thalassemia is to inherit one or more defective hemoglobin genes from your parents.
There are two types of thalassemia: alpha and beta, named for the two protein chains that make up normal hemoglobin. The type of thalassemia you have depends on the type of defective gene you inherit.
Alpha-thalassemia
Four genes are involved in making the alpha hemoglobin chain. You get two from each of your parents. If one or more of the alpha hemoglobin genes are defective, you develop alpha-thalassemia.
The more defective genes you have, the more severe your alpha-thalassemia:
- One gene. If only one of your alpha hemoglobin genes is defective, you'll have no signs or symptoms of thalassemia. But, you're a carrier of the disease and can pass it on to your children.
- Two genes. If you have two defective alpha hemoglobin genes, thalassemia signs and symptoms are mild. This condition is called alpha-thalassemia minor.
- Three genes. If three of your alpha hemoglobin genes are defective, your signs and symptoms will be moderate to severe. This condition is also called hemoglobin H disease.
- Four genes. When all four alpha hemoglobin genes are defective, the condition is called alpha-thalassemia major or hydrops fetalis. It usually causes a fetus to die before delivery or shortly after birth.
Two genes are involved in making the beta hemoglobin chain. You get one from each of your parents. If one or both of the beta hemoglobin genes are defective, you develop beta-thalassemia.
- One gene. If one of your beta hemoglobin genes is defective, you have mild signs and symptoms. This condition is called beta-thalassemia minor.
- Two genes. If both of your beta hemoglobin genes are defective, your signs and symptoms will be moderate to severe. This condition is called beta-thalassemia major or Cooley's anemia. Babies born with two defective beta hemoglobin genes usually are healthy at birth, but develop signs and symptoms within the first year of life.
Treatment for thalassemia depends on which type you have and how severe it is.
Thalassemia minor (alpha or beta)
Signs and symptoms are usually mild with thalassemia minor and little, if any, treatment is needed. Occasionally, you may need a blood transfusion, particularly after surgery, after having a baby or if you develop an infection.
Beta-thalassemia major (Cooley's anemia) or hemoglobin H disease
These more severe forms of thalassemia often require frequent blood transfusions. Over time, blood transfusions cause a buildup of iron in your blood, which can damage your heart, liver and other organs. To help your body get rid of the extra iron, you may need to take medications known as "iron chelators." These medications may be given as a pill or as an infusion under your skin. In some cases, a bone marrow transplant or a stem cell transplant may be used to treat severe thalassemia.
Prevention
In most cases, thalassemia cannot be prevented. If you have thalassemia, or if you carry a thalassemia gene, consider talking with a genetic counselor for guidance before you have a child.
Credit: National Institute of Health.