Identify the incorrect statement about alpha thalassemia

Options

A. Excessive beta chains form unstable letramers
B. It is an autosome linked recessive gene disorder
C. Production of alpha chain of haemoglobin is conrolled by two closely linked genes on chromosome 16
D. Alpha thalassemia is a qualitative problem in the synthesis of globin molecules.

Answer

To identify the incorrect statement about alpha thalassemia, we will analyze each of the provided statements one by one.

### Step-by-Step Solution:

1. **Understanding Alpha Thalassemia**:
- Alpha thalassemia is a genetic blood disorder characterized by the impaired production of hemoglobin due to defects in the alpha globin chains.

2. **Analyzing the Statements**:
- **Statement A**: "Excessive beta chains form unstable tetramers."
- This statement is **correct**. In alpha thalassemia, the lack of alpha chains leads to an excess of beta chains, which can aggregate to form unstable tetramers (Hb Bart's or Hb H).

- **Statement B**: "It is an autosome linked recessive gene disorder."
- This statement is **correct**. Alpha thalassemia is indeed an autosomal recessive disorder, meaning that it is linked to genes on the autosomes (non-sex chromosomes) and requires two copies of the mutated gene for the disorder to manifest.

- **Statement C**: "Production of alpha chain of hemoglobin is controlled by two closely linked genes on chromosome 16."
- This statement is **correct**. The genes responsible for the production of alpha chains are located on chromosome 16, and there are two closely linked genes (HBA1 and HBA2) involved in this process.

- **Statement D**: "Alpha thalassemia is a qualitative problem in the synthesis of globin molecule."
- This statement is **incorrect**. Alpha thalassemia is primarily a **quantitative** problem, as it involves a reduced amount of alpha chains being produced, not a change in the quality of the chains.

3. **Conclusion**:
- The incorrect statement about alpha thalassemia is **Statement D**: "Alpha thalassemia is a qualitative problem in the synthesis of globin molecule."