Pick out the correct statements
a. Haemophilia is a sex linked recesive disease
b. Down's syndrome is due to aneuploidy
c.Phenylketonuria is an autosomal recessive gene disorder
d.Sickle cell anaemia is a X-linked recessive gene disorder

Options

A. a,b and c are correct
B. b and d are correct
C. b and d are correct
D. a,c and d are correct

Answer

To determine which statements are correct regarding genetic disorders, let's analyze each statement one by one:

### Step-by-Step Solution:

1. **Statement a: Haemophilia is a sex-linked recessive disease.**
- **Analysis:** Haemophilia is indeed a sex-linked recessive disorder, primarily affecting males. It is caused by mutations in genes located on the X chromosome that are responsible for blood clotting. Therefore, this statement is **correct**.

2. **Statement b: Down's syndrome is due to aneuploidy.**
- **Analysis:** 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 (abnormal number of chromosomes). Hence, this statement is **correct**.

3. **Statement c: Phenylketonuria is an autosomal recessive gene disorder.**
- **Analysis:** Phenylketonuria (PKU) is indeed an autosomal recessive disorder caused by a deficiency in the enzyme phenylalanine hydroxylase. Individuals must inherit two copies of the mutated gene to express the disorder. Thus, this statement is **correct**.

4. **Statement d: Sickle cell anaemia is a X-linked recessive gene disorder.**
- **Analysis:** Sickle cell anaemia is not an X-linked disorder; it is an autosomal recessive disorder caused by a mutation in the HBB gene on chromosome 11. Therefore, this statement is **incorrect**.

### Conclusion:
The correct statements are:
- a. Haemophilia is a sex-linked recessive disease. (Correct)
- b. Down's syndrome is due to aneuploidy. (Correct)
- c. Phenylketonuria is an autosomal recessive gene disorder. (Correct)
- d. Sickle cell anaemia is a X-linked recessive gene disorder. (Incorrect)

Thus, the correct options are **a, b, and c**.