Thalassemia is genetic, inherited form of anemia. This disease mainly affects individuals of Southeast Asian, Chinese, and Filipino ancestry and some people of African and Mediterranean ancestry; in its most severe form it results in the death of the fetus or newborn. Individuals with less severe cases have varying degrees of anemia. Affected individuals can't create hemoglobin properly, and they produce small, pale, short-lived red blood cells.
Hemoglobin proteins are composed of four polypeptides -- two "alpha chains" and two "beta chains". One of the two types of polypeptides making up the hemoglobin protein in the blood cells of people with thalassemia is defective or missing.
In alpha thalassemia, the alpha chains are defective or missing. In beta thalassemia, the more serious version of this disease, the beta chains are defective or missing.
There are three classifications of beta thalassemia. In order of increasing severity, they are thalassemia minor, thalassemia intermedia, and thalassemia major.
Thalassemia major is more commonly known as Cooley's anemia. Symptoms include slow growth, jaundice, an enlarged heart, liver, and spleen, and thinned bones. An enlarged skull, facial deformities, and tooth misalignment may also occur. Bone fractures can be common. Bone and tooth deformities occur because the body spurs the overgrowth of bone marrow (hyperplasia) to produce more blood cells in a futile attempt to compensate for the disease.
Untreated children die young, usually of heart failure or infections.
Thalassemia intermedia produces milder symptoms for the first two decades of life in most cases. In initial diagnoses, physicians sometimes mistake it for iron deficiency. Thalassemia minor may not produce any symptoms, though changes in the blood occur.
People suffering from any form of this disease are most often treated with transfusions of red blood cells. These frequent transfusions cause their bodies to accumulate too much iron, which can damage internal organs like the heart and kidneys. Ultimately, the excess iron will cause organ failure and death.
To prevent organ damage, patients are treated with a chelation medication called Desferal to remove excess iron. Desferal, which binds to the iron so that it can be removed by the kidneys, must be injected over a long period of time, and the treatment can be extremely painful. Scientists are seeking new chelation drugs that can be delivered more quickly and less painfully.
Part of the information in this writeup was found at www.thalassemia.org, http://www.emedicine.com/radio/topic686.htm and http://members.aol.com/neskander/ANEMIA.html. The rest is based on work I did for the science dictionary at http://biotech.icmb.utexas.edu/