Pick out the correct statements: (i) Haemophilia is a sex-linked recissive disease.
(ii) Down's syndrome is due to aneuploidy.
(iii) Phenylketonuria is an autosomal recessive gene disorder.
(iv) Sickle cell anaemia is an X-linked recessive gene disorder.

Options

A. (i) and (iv) are correct
B. (ii) and (iv) are correct
C. (i),(iii) and (iv) are correct
D. (i),(ii) and (iii) are correct

Answer

To solve the question, we need to evaluate each statement regarding genetic disorders and determine which ones are correct.

### Step-by-Step Solution:

1. **Evaluate Statement (i)**: "Haemophilia is a sex-linked recessive disease."
- Haemophilia is indeed a genetic disorder that is caused by a mutation in genes responsible for blood clotting. It is located on the X chromosome, making it a sex-linked disorder. Since it is recessive, it primarily affects males who inherit the affected X chromosome from their mothers.
- **Conclusion**: This statement is **correct**.

2. **Evaluate Statement (ii)**: "Down's syndrome is due to aneuploidy."
- Down's syndrome is caused by the presence of an extra copy of chromosome 21, which results in a total of 47 chromosomes instead of the normal 46. This condition is known as trisomy 21 and is classified as an aneuploidy.
- **Conclusion**: This statement is **correct**.

3. **Evaluate Statement (iii)**: "Phenylketonuria is an autosomal recessive gene disorder."
- Phenylketonuria (PKU) is indeed an autosomal recessive disorder caused by a mutation in the gene responsible for the metabolism of phenylalanine. Individuals with PKU cannot properly metabolize phenylalanine, leading to its accumulation and potential intellectual disability if untreated.
- **Conclusion**: This statement is **correct**.

4. **Evaluate Statement (iv)**: "Sickle cell anaemia is an X-linked recessive gene disorder."
- Sickle cell anaemia is a genetic disorder caused by a mutation in the HBB gene on chromosome 11, which is an autosome. It is not linked to the X chromosome and is classified as an autosomal recessive disorder.
- **Conclusion**: This statement is **incorrect**.

### Final Summary:
The correct statements are:
- (i) Haemophilia is a sex-linked recessive disease. **(Correct)**
- (ii) Down's syndrome is due to aneuploidy. **(Correct)**
- (iii) Phenylketonuria is an autosomal recessive gene disorder. **(Correct)**
- (iv) Sickle cell anaemia is an X-linked recessive gene disorder. **(Incorrect)**

Thus, the correct answers are statements (i), (ii), and (iii).