(Posted:25-Jul-2015)

Thalassemia are inherited disorders caused by genetic lesion leading to decreased synthesis of either alpha or beta globin chain of heamoglobin A. In beta thalassemia there is inadequate production of beta globin chain and in alpha thalassemia there is inadequate production of alpha chain. Thalassemia are genetic disorder s and exist in both homozygous and heterogygous states.When the abnormality is heterozygous,synthesis of heamoglobin is only mildly affected and little disability occurs.In homogygous,synthesis is grossly impaired and there is an imbalance in polypeptide chain production. Microcytic hypochromic anaemia occurs in thalassemia. Beta thalassemia major: It isheterozygous states.There is a total suppresion of beta chain synthesis.It is usually severe disease and death may accurs during childhood unless frequent blood transfusion are given. Beta thalassemia minor: Suppression of beta chain is much less severe.It is a heterogygous state and is a minor and asymptomatic condition. Little or no anaemia. Alpha thalassemia: There are four alpha genes,2 alpha genes from each parent.which are loci on chromosome 16.If one gene is deleted there is no clinical effect.If two genes are deleted there may be mild hypochromic anaemia.If three genes are deleted the patient has heamoglobin H disease.If all genes are deleted baby is still born. There are 3 types of alpha thalassemia; 1)Hydrops fetalis. 2)Heamoglobin H disease. 3)Alpha thalassemia trait. Clinical features: The initial menifestation being pallor,growth and development in early childhood are retarded.The child fails to thrive,anorexia,diarrohea,loss of body fat and fever occur. Spleenomegaly and hepatomegaly occurs. Changes in skeletal system are constant;they result in characteristic mongoloid facies due expansion of the marrow in the malar bones and in X ray changes in the skull,long bones,hands and feet.