Thalassemia

Question 1

Explain the biochemical basis of beta thalassemia

Answer 1

1. ↓HbA; ↑ HbA2; ↑ HbF
2. @ chromosome 11, it consists of 2 genes for Beta globin chain synthesis + separate genes for Gamma globin chains & Delta globin chains
3. Beta thalassemia occurs due to hereditary persistence of HbF for prolonged time even after birth, due to genetic mutation in gamma-globin synthesizing genes
4. After birth, these genes are inactivated, and only beta chain is synthesized, BUT due to incomplete inactivation of gamma genes, synthesis of adequate beta chains is impaired
5. HbA consists of a2b2 composition; there is no defect in synthesis of alpha chain
6. Due to↓ beta, Delta chains are produced more in order to compensate
7. } Beta thalassemia has occurred due to genetic mutations & ↓ HbA levels