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Disorders of Iron
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Search by Disorder
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| Iron Related Issues
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| Thalassemia
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Thalassemia is an inherited disorder. It is sometimes called Mediterranean anemia, von Jaksch anemia or Cooley's anemia, named after the physicians who first diagnosed it.
Genes involved are those that control the production of proteins known as globins, contained in hemoglobin. Hemoglobin production involves two sets of genes on different chromosomes which produce two different pairs of proteins. One set is alpha, the other is beta. Each hemoglobin molecule contains these sets of proteins: two alpha and two beta. Hemoglobin properly binds and releases oxygen when two alpha proteins connected with two beta proteins. Chromosome #16 controls the alpha, protein set and chromosome #11 controls the beta set. Depending on the genetic outcome from the parents, thalassemia occurs when one or more of the genes fails to produce protein. In alpha thalassemia one or more of the genes is actually missing. In beta thalassemia: both globin genes are present but fail to produce hemglobin.
When a beta globin gene fails, beta thalassemia results; when the alpha globin fails, alpha thalassemia results.
If one of the beta globin genes fails, the amount of beta globin in the cell is reduced by half; this condition is called thalassemia minor also called alpha-thalassemia and thalassemia minima. If both genes fail, no beta globin protein is produce; this condition is thalassemia major also called beta-thalassemia.
Other forms of thalassemia are minima, intermedia and E-thalassemia
E Thalassemia-is not truly thalassemia; it is considered a hemoglobinopathy (disorders characterized by structural alteration of globin chains) and otherwise known as Hemoglobin E which is a mild form of hemolytic anemia. In this disorder, abnormal globins are formed. Thalassemia on the other hand, is characterized by the inability to produce sufficient number of globin chains.
Thalassemia major, minor or intermedia: most common in Mediterranean (Greek, Italian,) near-by & Middle Eastern, African, and Southeastern Asia. Hemoglobin E is most common in southeast Asia, especially in Cambodia, Laos, and Thailand.
Thalassemia Major:
When homozygous (i.e. both alleles are affected), one can be symptomatic as early as three months of age. In the first year or two of life and in the absence of transfusion, a child can demonstrate severe anemia and expansion of the facial and other bones. These children may be pale or jaundiced, have a poor appetite, fail to grow normally, have an enlarged spleen, liver or heart. Because treatment involves frequent blood transfusion (approximately once every month) iron overload occurs. Excess iron accumulates leading to liver, heart and pituitary damage and failure of these organs. Other complications of iron overload include diabetes mellitus, hypothyroidism and hypoparathyroidism. Those with thalassemia intermedia fluctuate between being asymptomatic and having symptoms as severe as those associated with thalassemia major. Diagnosis of thalassemia intermedia is usually made after a period of observation; the decision to transfuse is often a complex one.
Thalassemia Minor:
those heterozygous are mostly asymptomatic, have no anemia (except during pregnancy).
Diagnosis of thalassemia major is confirmed by Hemoglobin electrophoresis with an increase in total hemoglobin, and analysis of lymphocyte DNA.
Diagnosis of thalassemia minor is confirmed by MVC ( mean corpuscular volume) is slightly decreased; MCH (mean corpuscular hemoglobin) is decreased.
Hemoglobin (electrophoresis) studies:
Hgb A decreased; Hgb A2 increased; Hgb F slightly increased or normal.
Thalassemia major:
(Beta Thalassemia)
Treatment may include: frequent (every 3-4 weeks) transfusion; when iron build up occurs, Desferal treatment is added. This treatment is one that is used for patients who have simultaneous anemia and iron loading conditions. Desferal is administered subcutaneously (under the skin) from a small battery operated pump about the size of a portable cassette tape player.
Bone marrow transplantation may be considered but it is expensive and a suitable donor must be identified. Cord blood transplant is presently being done experimentally in China.
Thalassemia Minor:
(Alpha Thalassemia or Thalassemia Minima)
There is no treatment when asymptomatic. If splenomegaly (inflamed spleen) is present-depending upon severity-splenectomy may be required.
Thalassemia Intermedia:
No treatment
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