Question

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

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

Answer 1

The Correct Option is C

Answer: Option 3 - (a), (b) and (c) are correct.

Explanation:

Let’s analyze each statement:

(a) Haemophilia is a sex-linked recessive disease:

Correct. Haemophilia is indeed a sex-linked recessive disease. It is carried on the X chromosome, and because males have only one X chromosome, they are more likely to be affected by this disorder if they inherit the X chromosome with the mutation.

(b) Down's syndrome is due to aneuploidy:

Correct. Down's syndrome (also known as Trisomy 21) is caused by aneuploidy, specifically an extra chromosome 21, resulting in a total of 47 chromosomes instead of the typical 46.

(c) Phenylketonuria is an autosomal recessive gene disorder:

Correct. Phenylketonuria (PKU) is an autosomal recessive gene disorder. It is caused by a mutation in the gene for the enzyme phenylalanine hydroxylase, leading to a build-up of phenylalanine in the body.

(d) Sickle cell anaemia is an X-linked recessive gene disorder:

Incorrect. Sickle cell anaemia is not X-linked but an autosomal recessive disorder. It is caused by mutations in the hemoglobin gene on chromosome 11, not on the X chromosome.

Conclusion:

The correct statements are (a), (b), and (c), making Option 3 the correct choice.