In alpha thalassemia, a decreased amount of alpha globin chains is produced. There are at least four forms of alpha thalassemia. The type which an individual has depends upon his genetic inheritance for alpha globin chain production. Usually an individual inherits four genes (two from each parent) which control production. The most frequent occuring types of alpha thalassemia are: Silent Carrier, Alpha Thalassemia Minor, Hemoglobin H Disease, and Alpha Thalassemia Major.
This is a condition in which an individual inherits only one of the four genes which regulate production of alpha globin chains (two genes from one parent and one gene from the other parent). This is not a disease and does not affect one's mental or physical health in any manner. It is called a "silent carrier" condition because it can be detected only by performing very specialized laboratory tests. Persons with this condition may pass on genes for decreased alpha globin chain production to their children.
This is a condition in which only two genes are inherited for the production of alpha globin chains. This condition may cause confusion with iron deficiency anemia, because both lead to the production of small red blood cells. However, iron treatment is of no value in alpha thalassemia trait. The decrease in alpha globin chain production does not lead to health problems. As with the "silent carrier" state, this may be passed on to an individual's offspring.
This is a condition in which only one gene for alpha globin chain production is inherited. Persons with hemoglobin H disease have one parent who has alpha thalassemia trait and one who has the "silent carrier" state. This results in a decreased production of alpha globin chains and an excess of beta globin chains. This excess of beta globin chains leads to the formation of tiny precipitates (impurities) in the red blood cell. The presence of impurities leads to the more rapid destruction of the red blood cells as they circulate in the bloodstream. The results is a lifelong anemia of mild to moderate degree. The condition may be worsened by certain drugs. It can lead to medical complications, such as inlarged spleen and gallstones. Therefore, persons with hemoglobin H disease should receive regular medical care. However, they generally live normal lives with only slight, if any, limitations from their disease. NOTE: All ATR-X patients have Hemoglobin H Disease.