Select correct statement w.r.t. thalassemia. (a) It is a recessive autosomal genetic defect. (b) Alpha thalassemia is connected to the deletion of 16p(short arm) chromosome. (c) Beta thalassemia is caused due to mutations in the HBB gene on chromosome 11. (d) About 30% of adult haemoglobin is made up of alpha and delta chains. (e) In beta thalassemia, excess B-chains form unstable tetramers which have abnormal oxygen dissociation curve.

Options

A. (b), (c) & (d)
B. (a), (b) & (e)
C. All except (b) & (e)
D. All except (d) & (e)

Answer

To solve the question regarding thalassemia, let's analyze each statement step by step:

1. **Statement (a): It is a recessive autosomal genetic defect.**
- Thalassemia is indeed an autosomal recessive disorder. This means that the disorder is inherited when an individual receives two copies of the defective gene, one from each parent. Therefore, this statement is **correct**.

2. **Statement (b): Alpha thalassemia is connected to the deletion of 16p (short arm) chromosome.**
- Alpha thalassemia is caused by deletions or mutations in the genes located on chromosome 16. This chromosome has two genes responsible for the production of alpha globin chains. Thus, this statement is also **correct**.

3. **Statement (c): Beta thalassemia is caused due to mutations in the HBB gene on chromosome 11.**
- Beta thalassemia results from mutations in the HBB gene, which is located on chromosome 11. This gene is responsible for producing the beta globin chains of hemoglobin. Therefore, this statement is **correct**.

4. **Statement (d): About 30% of adult hemoglobin is made up of alpha and delta chains.**
- This statement is incorrect. In adults, hemoglobin is primarily composed of two alpha and two beta chains, with only a small percentage (around 3%) being made up of alpha and delta chains. Thus, this statement is **incorrect**.

5. **Statement (e): In beta thalassemia, excess B-chains form unstable tetramers which have abnormal oxygen dissociation curve.**
- This statement is also incorrect. In beta thalassemia, there is a deficiency of beta chains, leading to an accumulation of alpha chains, which can form unstable tetramers (alpha4). Therefore, this statement is **incorrect**.

Based on the analysis, the correct statements regarding thalassemia are (a), (b), and (c). Statements (d) and (e) are incorrect.

### Final Answer:
The correct statements with respect to thalassemia are:
- (a) It is a recessive autosomal genetic defect.
- (b) Alpha thalassemia is connected to the deletion of 16p (short arm) chromosome.
- (c) Beta thalassemia is caused due to mutations in the HBB gene on chromosome 11.