Question

Which of the following is not a chromosomal disorder?

• A. Down’s syndrome
• B. Klinefelter’s syndrome
• C. Turner’s syndrome
• D. Haemophilia

Hint:

Chromosomal disorders = abnormal chromosome number/structure; Mendelian disorders = single gene mutation (e.g., Haemophilia).

Answer 1

The Correct Option is D

Step 1: Chromosomal disorders.
Disorders caused due to numerical or structural abnormalities in chromosomes include Down’s syndrome (trisomy 21), Klinefelter’s syndrome (XXY), and Turner’s syndrome (XO).
Step 2: Haemophilia.
Haemophilia is a genetic disorder caused by a mutation in a single gene located on the X-chromosome, not due to chromosomal number abnormalities.
Step 3: Conclusion.
Thus, the disorder that is not chromosomal is Haemophilia.