Which of the following abnormalities is due to X-linked recessive mutation ?

Options

A. Cystic fibrosis
B. Thalassaemia
C. Klinefelter's syndrome
D. Lesch-Nyhan syndrome

Answer

To determine which of the listed abnormalities is due to an X-linked recessive mutation, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding X-Linked Recessive Mutations**:
- X-linked recessive mutations are genetic disorders that are associated with genes located on the X chromosome. Males (XY) are more likely to express these disorders because they have only one X chromosome, while females (XX) have two and can be carriers without showing symptoms.

2. **Analyzing the Options**:
- **Cystic Fibrosis**: This condition is caused by mutations in the CFTR gene, which is located on chromosome 7. It is classified as an autosomal recessive disorder.
- **Thalassemia**: This is a blood disorder caused by mutations in the genes that produce hemoglobin, located on chromosome 11 and 16. It is also an autosomal recessive disorder.
- **Klinefelter Syndrome**: This condition occurs in males who have an extra X chromosome (XXY). It is not classified as X-linked recessive but rather as a chromosomal aneuploidy.
- **Lesch-Nyhan Syndrome**: This is caused by a mutation in the HPRT1 gene located on the X chromosome. It is an X-linked recessive disorder.

3. **Identifying the Correct Answer**:
- From the analysis above, the only condition that is caused by an X-linked recessive mutation is **Lesch-Nyhan Syndrome**.

### Conclusion:
The correct answer to the question is **Lesch-Nyhan Syndrome**, which is due to an X-linked recessive mutation.

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