Pick out the correct statement
(I) Haemophilia is a sex-linked recessive disease
(II) Down's syndrome is due to aneuploidy
(III) Phenylketonuria is an autosomal recessive gene disorder lt brgt (IV) Sickle-cell anaemia is an X-linked recessive gene disorder

Options

A. (ii) & (iv) are correct
B. (i), (iii) and (iv) are correct
C. (i), (ii) and (iii) are correct
D. (i) and (iv) 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 sex-linked recessive disorder, primarily affecting males. It is caused by mutations in genes located on the X chromosome. Therefore, this statement is **correct**.

2. **Evaluate Statement II: Down's syndrome is due to aneuploidy.**
- Down's syndrome, also known as Trisomy 21, occurs due to the presence of an extra copy of chromosome 21, which is a form of aneuploidy (an abnormal number of chromosomes). Hence, this statement is also **correct**.

3. **Evaluate Statement III: Phenylketonuria is an autosomal recessive gene disorder.**
- Phenylketonuria (PKU) is caused by a mutation in the PAH gene located on chromosome 12 and is inherited in an autosomal recessive manner. Thus, this statement is **correct**.

4. **Evaluate Statement IV: Sickle-cell anaemia is an X-linked recessive gene disorder.**
- Sickle-cell anaemia is caused by a mutation in the HBB gene on chromosome 11 and is inherited in an autosomal recessive manner, not X-linked. Therefore, this statement is **incorrect**.

### Conclusion:
The correct statements are I, II, and III. Thus, the answer to the question is that statements I, II, and III are correct.

### Final Answer:
The correct statements are:
- (I) Haemophilia is a sex-linked recessive disease.
- (II) Down's syndrome is due to aneuploidy.
- (III) Phenylketonuria is an autosomal recessive gene disorder.