Thalassaemias: Treatment, symptoms, advice and help
Thalassaemia is an inherited autosomal recessive blood disorder in which a genetic defect results in the reduced rate of synthesis of one of the globin chains that make up haemoglobin. This causes the formation of abnormal haemoglobin molecules, thus causing anemia. Heterozygotes have Thalassaemia minor, a condition in which there is usually mild anemia and little or no clinical disability. Homozygotes (Thalassaemia major) either are unable to synthesise haemoglobin A or produce very little of it and after the first 4 months of life, develop a profound hypochromic anaemia.
Thalassaemias: Incidence, age and sex
Thalassemias are particularly associated with people of Mediterranean origin, Arabs, and Asians. The Maldives has the highest incidence of Thalassemia in the world with a carrier rate of 18% of the population. The estimated prevalence is 16% in people from Cyprus, 1% in Thailand, and 3-8% in populations from South East Asia. A very low prevalence has been reported from people in Northern Europe (0.1%) and Africa (0.9%).
Signs and symptoms of thalassaemias: Diagnosis
Clinical features of Beta-Thalassaemia major include profound hypochromic anaemia and enlargement of the liver and spleen. Evidence of severe red cell dysplasia, erythroblastosis, absence or gross reduction of the amount of haemoglobin A and raised levels of haemoglobin Fin Hb electrophoresis and evidence that both parents have thalassaemia minor confirmss the diagnosis.
Minor produces only mild anaemia and enlargement of liver and spleen, Microcytic hypochromic erythrocytes (not iron-deficient), target cells, punctate basophilia, raised resistance of erythrocytes to osmotic lysis, raised haemoglobin A2 fraction and evidence that one parent has thalassaemia minor confirms the diagnosis.
Causes and prevention of Thalassaemias
In beta-thalassaemia defective production usually results from disabling point genetic mutations causing no (ß.) beta chain production. It is possible to identify a foetus with homozygous beta thalassaemia by obtaining chorionic villous material for DNA analysis sufficiently early in pregnancy to allow termination. This examination is only appropriate if both parents are known to be carriers (beta-thalassaemia minor) and will accept a termination.
Complications include failure of red cell production, iron overload due to repeated transfusions, splenomegaly causing mechanical problems and hypersplenism.
Transfusion to maintain Hb > 100 g/1, folic acid 5 mg daily and desferrioxamine therapy to remove excess iron in the body are the mainstay of treatment.
Cure is now a possibility for selected children with allogeneic bone marrow transplantation from a compatible sibling.