Find out the mismatched pair

Options

A. Haemophilia - Sex linked recessive
B. Cystic fibrosis - Autosomal recessive
C. Down's syndrome - Trisomy 21
D. Turner's syndrome - Y-linked

Answer

To find the mismatched pair among the given options, we will analyze each option one by one.

### Step-by-Step Solution:

1. **Identify the Disorders:**
- We have four pairs of genetic disorders to evaluate: Hemophilia, Cystic Fibrosis, Down Syndrome, and Turner's Syndrome.

2. **Evaluate Each Disorder:**
- **Hemophilia:** This is a sex-linked recessive disorder. It is indeed X-linked inheritance. This statement is correct.
- **Cystic Fibrosis:** This is classified as an autosomal recessive disorder. This statement is also correct.
- **Down Syndrome:** This condition is characterized by an extra copy of chromosome 21, also known as trisomy 21. This statement is correct as well.
- **Turner's Syndrome:** This condition is often misrepresented as Y-linked. However, Turner's syndrome is actually a condition that arises from the absence of one X chromosome (45,X or 45,XO). It is not Y-linked, making this statement incorrect.

3. **Conclusion:**
- The mismatched pair is **Turner's Syndrome**, which is incorrectly labeled as Y-linked. The correct classification is that it is a condition related to the X chromosome.

### Final Answer:
The mismatched pair is **Turner's Syndrome (Y-linked)**.

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