Which of the following is correctly matched with their chromosomal condition ?

Options

A. Sickle cell anaemia -Heterozygous condition of `Hb^s` gene
B. Down's syndrome -Trisomy of chromosome 22
C. Turner's syndrome -XO condition.
D. Klinefelter's syndrome -Failure of cytokinesis after teleophase.

Answer

To determine which of the listed genetic conditions is correctly matched with its chromosomal condition, we will analyze each option one by one.

### Step-by-Step Solution:

1. **Sickle Cell Anemia**:
- Sickle cell anemia is caused by a mutation in the hemoglobin gene.
- The condition is characterized by the presence of two copies of the mutated gene (HBS), leading to the homozygous condition (HBS/HBS).
- The statement mentions a heterozygous condition (HBS/HBA), which would only make the individual a carrier, not affected by the disease.
- **Conclusion**: This option is incorrect.

2. **Down Syndrome**:
- Down syndrome is caused by the presence of an extra chromosome 21, a condition known as trisomy 21.
- The statement incorrectly states that it involves trisomy of chromosome 22.
- **Conclusion**: This option is incorrect.

3. **Turner Syndrome**:
- Turner syndrome affects females and is characterized by the absence of one X chromosome, leading to the chromosomal condition XO.
- The statement correctly identifies the chromosomal condition associated with Turner syndrome.
- **Conclusion**: This option is correct.

4. **Klinefelter Syndrome**:
- Klinefelter syndrome occurs in males and is characterized by the presence of an extra X chromosome, resulting in the chromosomal condition XXY.
- The statement incorrectly mentions that it is due to failure of cytokinesis after telophase, which is not the cause of Klinefelter syndrome.
- **Conclusion**: This option is incorrect.

### Final Answer:
The only correctly matched condition is **Turner Syndrome (XO)**.