Thalassemia major, also known as beta thalassemia major or Cooley's anemia, is a genetic blood disorder that causes the body to make an abnormal form of hemoglobin. Hemoglobin is the protein molecule in red blood cells that carries oxygen. Thalassemia major occurs when the production of the beta globin protein is affected by genetic defects, resulting in the destruction of red blood cells and anemia.
To develop the blood disorder, patients must inherit a defective gene from both parents. Thalassemia minor occurs when a patient inherits only one defective gene. Patients diagnosed with thalassemia minor have no symptoms and are simply carriers of the faulty gene.
Thalassemia major is more common in people of Mediterranean descent, including Greeks and Italians. African Americans and Asians, especially Chinese, are also genetically predisposed to the blood disorder. Prenatal testing and genetic counseling are available for those concerned about a family history of the disease.
When a baby is born with thalassemia major, the diagnosis is not always apparent until the child develops anemia, usually during the first year of life. Symptoms of thalassemia major that a parent may notice include irritability, poor appetite, and increased infections. As the child matures, other symptoms may include growth retardation, bony deformities in the face, and an enlarged abdomen caused by inflammation of the liver and spleen. Without treatment, the blood disorder can lead to heart failure and liver problems.
Thalassemia major is diagnosed by blood tests. A complete blood count (CBC) identifies anemia, while smaller-than-average red blood cells and other abnormalities that are characteristic of the blood disorder can be seen under a microscope. An additional test called hemoglobin electrophoresis helps to further identify the abnormal hemoglobin that is typical of this type of thalassemia.
The most common treatment for thalassemia major is a regimen of regular blood transfusions. Patients are often prescribed an additional medication, called chelation therapy, to reduce the harmful effects of transfusions, as they can cause an abnormal buildup of iron in the body. It is also recommended that most patients take daily doses of folic acid. Bone marrow transplantation may be a viable treatment option in some patients, especially children, and those who have full siblings who can serve as compatible bone marrow donors. Although these treatment options have improved the prognosis for many patients, long-term survival remains a challenge for those affected by severe cases of the disease.