Thalassemia is an autosomal recessive disease of globin chain formation of haemoglobin molecule. Haemoglobin is a haeme containing protein present in RBCs and helps to carry oxygen towards tissues and carbon dioxide partly from the tissues to the atmosphere through alveoli.
General background –
As explained earlier this is a condition wherein globin chain formation is affected. Haemoglobin contains two alpha and two beta chains in normal individual which is called as HbA. Some other patterns of Haemoglobin are also present in the normal individuals and they are HbA2 and HbF (Foetal Haemoglobin). Two alpha and two delta chains are present in HbA2 and two Gama chain are present in HbF along with two alpha chains.
The basic approach -
Haemoglobin electrophoresis is a process by which we can determine the percentage of available Haemoglobin types. Usually HbA should be more than 97.5%, HbA2 should be less than 2% and HbF is present in very minute quantity in adults.
The chromosome 16 and 11 are involved in Alpha and Beta thalassemia respectively. There are 4 genes for Alpha chains and 2 genes for the Beta chains.
If the defect is in alpha chain formation then thalassemia is Alpha type and if Beta chain formation is affected then the thalassemia is of Beta type.
According to the involvement of genes in the pathogenesis the Alpha thalassemia is classified as Asymptomatic, Minor, Haemoglobin H disease and Bart’s disease. In the Asymptomatic Alpha thalassemia type only one out of 4 genes is missing , in Minor thalassemia two genes are missing ,in Haemoglobin - H three genes and in Bart’s disease all the four genes are missing hence the foetus cannot survive.
In Beta thalassemia the clinical conditions are classified as Major thalassemia and Minor thalassemia. In the major both genes are mutant and in minor only one gene is mutant.
General Features & Lab. Reports -
A patient of thalassemia is complaining of severe weakness, muscle fatigue, dyspnoea on exertion and all the clinical features of anaemia. The bone marrow remains hyperactive.
All the features of anaemia are observed in the report of CBC. MCV is less than 80 i.e. RBCs are microcytic, and hypo chromic, the iron levels are normal
Management of Thalassemaia -
The clinical management is based on symptoms of the individual. Repeated blood transfusion is recommended in the patients of thalassemia major. Hence the chances of iron overload are very high in these patients and they need iron chelation therapy. Though the morphological features shows the features of iron deficiency, use iron supplements should be avoided in thalassemia.
Specific treatment is not recommended in Thalassemia minor patients. However patients should be treated if there are symptoms for which he seeks the medical help. Vitamin C supplements, Folic Acid, Vitamin B-12 are commonly prescribed. Over the age of 6 years splenectomy is recommended. Endocrine correction is done by monitoring different hormones. Immunization against Hepatitis-B is done to avoid associated Liver complications. In few cases even the bone marrow transplantation is recommended however this procedure is very expensive and not convincing results are observed in thalassemia.