Thalassemia major, also known as beta thalassemia major or Cooley's anemia, is a genetic blood disorder that causes the body to manufacture an abnormal form of hemoglobin. Hemoglobin is the protein molecule in red blood cells that carries oxygen. Thalassemia major occurs when production of the beta globin protein is affected by gene defects, resulting in red blood cell destruction and anemia.
In order 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 do not exhibit symptoms and are simply carriers of the defective gene.
Thalassemia major is most 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 screenings and genetic counseling are available to those who are 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 fussiness, poor appetite, and increased infections. As the child matures, other symptoms may include delayed growth, bone deformities in the face, and an extended abdomen caused by liver and spleen swelling. Without treatment, the blood disorder can result in heart failure and liver problems.
Thalassemia major is diagnosed using 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 viewed under a microscope. An additional test called a 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 damaging effects of the transfusions, since they can cause an abnormal accumulation of iron in the body. Most patients are also advised to 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 matched bone marrow donors. Though these treatment options have improved the prognosis for many patients, long term survival remains a challenge for those who are affected by severe cases of the disease.