Which one is correctly matched

Options

A. Sickle cell anaemia -X chromosomee
B. Haemophilia -Y chromosome
C. Down's syndrome -21st chromosomes
D. Parkinson 's disease -Y chromosome

Answer

To determine which option is correctly matched, we will analyze each option provided in the question regarding the diseases and their associated chromosomal causes.

### Step-by-Step Solution:

1. **Evaluate the first option: Sickle Cell Anemia**
- Sickle cell anemia is mentioned to be related to the X chromosome.
- **Fact Check:** Sickle cell anemia is actually an autosomal recessive disorder caused by a mutation in the hemoglobin gene located on chromosome 11.
- **Conclusion:** This option is incorrect.

2. **Evaluate the second option: Hemophilia**
- Hemophilia is said to be related to the Y chromosome.
- **Fact Check:** Hemophilia is an X-linked recessive disorder, meaning it is associated with mutations on the X chromosome, not the Y chromosome.
- **Conclusion:** This option is also incorrect.

3. **Evaluate the third option: Down Syndrome**
- Down syndrome is associated with the 21st chromosome.
- **Fact Check:** Down syndrome is indeed caused by the trisomy of chromosome 21, which means there is an extra copy of this chromosome.
- **Conclusion:** This option is correct.

4. **Evaluate the fourth option: Parkinson's Disease**
- Parkinson's disease is claimed to be related to the Y chromosome.
- **Fact Check:** Parkinson's disease is a neurodegenerative disorder that is not specifically linked to the Y chromosome. It is primarily associated with the degeneration of nerve cells in the brain.
- **Conclusion:** This option is incorrect.

### Final Conclusion:
The only correctly matched option is the third one: **Down syndrome is associated with the 21st chromosome.**