THALESSEMIA- a blood disorder

Tuesday 13 September 2011

      The term Thalassemia represents a group of hereditary haemolytic anemias resulting from a defect in the synthesis of haemoglobin which produces extremely thin and fragile R.B.C's.It occurs primarily in populations from countries near mediterranean sea hence the name in the synthesis in alpha-globin and beta-globin chain.It is hereditary because the defect in the production of globin chain occur due to defect in these genes responsible for synthesis of the globin chains(Note that: in synthesis of haemoglobin there is synthesis of globin which is the protein part of haemoglobin .The synthesis of globin involves Globin genes i.e.,the synthesis of alpha-globin chain of Haemoglobin is due to two genes genes present on each one on chromosome number:16 whereas synthesis of beta-globin occursdue to gene located on each one of chromosome number:11 )Thalassemias occurs due to deletion or substitution or they also occur due to defection in synthesis of globin chains.Those Thalassemias which  are of defect due to beta-globin are of two types mainly beta-Thalassemia minor and beta-Thalassemia major.
            Thalassemia minor means it is a heterozygous stste with defect in only one of two beta-globin gene pairs on chromosome number:11. Thalassemia major mean it is a Homozygous state with defect in both genes responsiblefor beta-globin synthesis present on chromosome no:11. The infants born with thalassemia major die within 1 to 2 days as they are severly anemic.However, those with thalassemia minor have longer life span.The treatment of thalassemia generally consist of blood transfusion.

   Thalassemia: Not just one disease but rather a complex series of genetic (inherited) disorders all of which involve underproduction of hemoglobin, the indispensable molecule in red blood cells that carries oxygen. The globin part of hemoglobin is made up of 4 polypeptide chains (usually 2 chains of one type and 2 chains of another type of chain). In thalassemia, there is a mutation (change) in one of the types of globin chains. Depending upon which globin chain is affected, the mutation typically leads to underproduction (or absence) of that globin chain, a deficiency of hemoglobin, and anemia.