Thalassemia signs and symptoms may include:

• Fatigue

• Weakness

• Pale or yellowish skin

• Facial bone deformities

• Slow growth

• Abdominal swelling

• Dark urine

Several types of thalassemia exist, including alpha-thalassemia, thalassemia intermedia and Cooley anemia. The signs and symptoms you experience depend on the type and severity of your condition. Some babies show signs and symptoms of thalassemia at birth, while others may develop them during the first two years of life. Some people who have only one affected hemoglobin gene don't experience any thalassemia symptoms.

Thalassemia is caused by mutations in the DNA of cells that make hemoglobin — the substance in your red blood cells that carries oxygen throughout your body. The mutations associated with thalassemia are passed from parents to children.

Thalassemia disrupts the normal production of hemoglobin and healthy red blood cells. This causes anemia. With anemia, your blood doesn't have enough red blood cells to carry oxygen to your tissues — leaving you fatigued.

Types of thalassemia

The type of thalassemia you have depends on the number of gene mutations you inherit from your parents and which part of the hemoglobin molecule is affected by the mutations. The more mutated genes, the more severe your thalassemia. Hemoglobin molecules are made of alpha and beta parts that can be affected by mutations.

Alpha-thalassemia

Four genes are involved in making the alpha hemoglobin chain. You get two from each of your parents. If you inherit:

• 1 mutated gene, you'll have no signs or symptoms of thalassemia. But you are a carrier of the disease and can pass it on to your children.

• 2 mutated genes, your thalassemia signs and symptoms will be mild. This condition may be called alpha-thalassemia trait.

• 3 mutated genes, your signs and symptoms will be moderate to severe.

• 4 mutated genes. This type is rare. Affected fetuses have severe anemia and usually are stillborn. Babies born with this condition often die shortly after birth or require lifelong transfusion therapy. In rare cases, a child born with this condition may be treated with transfusions and a stem cell transplant, which is also called a bone marrow transplant.

Thalassemia minor

Two genes are involved in making the beta hemoglobin chain. You get one from each of your parents. If you inherit:

• 1 mutated gene, you'll have mild signs and symptoms. This condition is called thalassemia minor or beta-thalassemia.

• 2 mutated genes, your signs and symptoms will be moderate to severe. This condition is called thalassemia major, or Cooley anemia. Babies born with two defective beta hemoglobin genes usually are healthy at birth but develop signs and symptoms within the first two years of life. A milder form, called thalassemia intermedia, also may occur with two mutated genes.

Factors that increase your risk of thalassemia include:

• Family history of thalassemia. Thalassemia is passed from parents to children through mutated hemoglobin genes. If you have a family history of thalassemia, you may have an increased risk of the condition.

• Certain ancestry. Thalassemia occurs most often in African-Americans and in people of Mediterranean and Southeast Asian ancestry.

Possible complications of thalassemia include:

• Iron overload. People with thalassemia can get too much iron in their bodies, either from the disease or from frequent blood transfusions. Too much iron can result in damage to your heart, liver and endocrine system. This system includes hormone-producing glands that regulate processes throughout your body.

• Infection. People with thalassemia have an increased risk of infection. This is especially true if you've had your spleen removed.

In cases of severe thalassemia, the following complications can occur:

• Bone deformities. Thalassemia can make your bone marrow expand, which causes your bones to widen. This can result in abnormal bone structure, especially in your face and skull. Bone marrow expansion also makes bones thin and brittle, increasing the chance of broken bones.

• Enlarged spleen (splenomegaly). The spleen helps your body fight infection and filter unwanted material, such as old or damaged blood cells. Thalassemia is often accompanied by the destruction of a large number of red blood cells. This causes your spleen to enlarge and work harder than normal. Splenomegaly can make anemia worse, and it can reduce the life of transfused red blood cells. If your spleen grows too big, your doctor may suggest surgery to remove it (splenectomy).

• Slowed growth rates. Anemia can cause a child's growth to slow. And thalassemia may cause a delay in puberty.

• Heart problems. Heart problems — such as congestive heart failure and abnormal heart rhythms (arrhythmias) — may be associated with severe thalassemia.