Question

In alpha thalassemia, the gene HBA1 is located on this chromosome.
A. 8
B. 22
C. 9
D. 16

Answer 1

Hint: Thalassemia in an inherited disorder. It is caused by the faulty synthesis of haemoglobin. Thalassemia is a mendelian disorder. It is a blood related disorder which lowers the amount of oxygen carrying protein i.e. haemoglobin. It can be life threatening in severe conditions.

Complete Answer:
- The word ‘Thalassemia’ is derived from the greek word ‘thalassa’ which means ‘the sea’. Thalassemia is called so because it was first described in the population that lives near the Mediterranean sea.
- But now the disease is prevalent in Africa, the Middle east and Asia. Adult haemoglobin consist of two haemoglobin alpha polypeptide chains and two haemoglobin beta polypeptide chains.
- haemoglobin alpha polypeptide chains – There are two copies of haemoglobin alpha gene i.e. HBA1 and HBA2. Bothe the copies of genes encode alpha chains. These both genes are located on chromosome 16.
- haemoglobin beta polypeptide chains – There is one haemoglobin beta gene i.e. HBB that code for beta chains. This gene is located on chromosome 11.
- Alpha thalassemia: In alpha thalassemia there is deficient synthesis of alpha chains. So, the number of beta chains increases. The excess of beta chains bind with oxygen leading to the lower concentration of oxygen in tissues.

Symptoms of alpha thalassemia:
Anemia, Enlarged spleen, Gallstones, Delayed growth, etc.

Hence, option D is the correct option for this question.

Note: Treatment for alpha thalassemia:
- Blood transfusion.
- Splenectomy.
- Gallstones can be removed by surgical methods.
- Stem cell transplantation.
- Gene therapy.