Which type of genetic disorder is related tochromosomal disorder :-

Options

A. Haemophilia
B. Cystic fibrosis
C. Phenylketonuria
D. Down's syndrome

Answer

**Step-by-Step Solution:**

1. **Understanding Genetic Disorders**: Genetic disorders can be broadly classified into two categories: single-gene disorders and chromosomal disorders. Single-gene disorders are caused by mutations in a single gene, while chromosomal disorders are caused by abnormalities in chromosome number or structure.

2. **Identifying the Options**: The question provides four options: Haemophilia, Cystic Fibrosis, Phenylketonuria, and Down Syndrome. We need to determine which of these is a chromosomal disorder.

3. **Analyzing Each Option**:
- **Haemophilia**: This is a genetic disorder caused by a deficiency in blood clotting factors, specifically factors VIII or IX. It is linked to mutations in specific genes, not chromosomal abnormalities.
- **Cystic Fibrosis**: This disorder is caused by mutations in the CFTR gene, which is responsible for the regulation of salt and water transport in cells. It is also not related to chromosomal abnormalities.
- **Phenylketonuria (PKU)**: This condition is caused by a mutation in the gene that encodes the enzyme responsible for breaking down phenylalanine. Like the previous two, it is a single-gene disorder.
- **Down Syndrome**: This is a chromosomal disorder, specifically known as Trisomy 21, where there is an extra copy of chromosome 21. This results in a total of three copies of this chromosome instead of the usual two.

4. **Conclusion**: Based on the analysis, Down Syndrome is the only option that qualifies as a chromosomal disorder due to the presence of an extra chromosome.

5. **Final Answer**: The correct answer is Down Syndrome.

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