Tuesday, 20 November 2007

Thalassemia is a genetic disorders that are characterized with chronic anemia. The disease is cause from the gene that control hemoglobin production. Hemoglobins are proteins that are the major components of red blood cell. Human carries mutation of thalassemia genes may be asymptomatic or have mild anmia, or severe until they died before birth.
In Thailand, a south east Asian country, there are more than 30 percent having one mutated hemoglobin genes. We call this group as carrier. They will be healthy and asymptomatic, but they can inherited their mutated gene to their offsprings. If their couples are also the same type carriers, their off springs have chance to have mutated genes both from thier parents that will produce diseases. The number of thalassemia patients in Thailad is about 600000.
And each year, couples at risk (both are carriers) give thalassemic baby for more than 10000 annually.
Ther are two common type of thalassemia in Thailand: alpha-thalassemia and beta-thalassemia.
In general, everyone are inherited the genetic materials half from their father and the rest from their mother. Thalassemia is a disease transfered in recessive fashion, which means that you must have mutated genes from both parents to have disease. Besides, the mutation must be on the same gene. For example, alpha-thalassemia gene mutation should pair with alpha-thalassemia gene mutation to produce alpha-thalassemia patients. Who have one mutated gene of beta-type and onother mutated gene of alpha-type are healthy.
Thalassemia is the result of decreasing production of hemoglobin leading to unbalanced between each type of hemoglobin. In normal, two chain of alpha hemoglobin will be paired with two chains of beta hemoglobin. In the non-balancing situation, the excess hemoglobin will be aggregated and cause changing of red cell shape and vulnerability. red cell will be survived less, be easily destroy. These all lead to chronic anemia. Organ that produce red blood cell i.e. bone marrow, liver, and spleen have to be expanded for increasing production rate, so we will see these patients have a big and tall skull, fragile bone, big liver, big spleen. In severe cases, this occured early in thier life, and inevitable cause of death in their toddler. Milder case will be survived to their teen with regular blood transfusion. The drawbcak of blood transfusion is the iron stored in the blood cell will be accumulated in patient's heart, liver, skin, pancreas, and so on lead to malfunction of that organs that are fatal if lefted untreated. Nowadays, in the most severe type that will be dead before birth, we have technology to test the fetus and termination before birth or have complication will be done if test positive. In severe birth infants, we can treated with bone marrow transplantation, but this is a very expensive methods and there is a high death rate from this procedure and not everyone can performed these due to unmatched tissues. Milder case will receive regular blood transfusion to prevent abnormal growth and bone change, and iron-chelator will be given to prevent long term complication for iron-excess. Prevention is more appropriate practice, and prenatal screening method is the one of most success genetic project in our country. In the future , next four or five generation, we will have less thalassemia patients.

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