Question

Give a detail account of thalassemia.

Answer 1

1. Thalassemia is an autosomal, inherited recessive disease.
2. A haemoglobin molecule is made of four polypeptide chains- 2 alpha (α) and 2 betas (β) chains.
3. The synthesis of alpha chains is controlled by two closely linked genes (HBA1 and HBA2) on chromosome 16 while the synthesis of the beta chain is controlled by a single gene (HBB) on chromosome 11.
4. Depending upon which chain of haemoglobin is affected, thalassemia is classified as alpha-thalassemia and beta-thalassemia.
5. It is caused due to deletion or mutation of a gene that codes for alpha (α) and beta (β) globin chains that result in the abnormal synthesis of haemoglobin.
6. Symptoms: In Thalassemia, the person shows symptoms like anemia, pale yellow skin, change in size and shape of RBCs, slow growth and development, dark urine, etc.
7. Massive blood transfusion is needed for these patients.
8. Thalassemia differs from sickle-cell anemia. Thalassemia is a quantitative problem of synthesizing few globin molecules, while sickle cell anemia is a qualitative problem of synthesizing an incorrectly functional globin.