Match the List-I with List-II:

List I	List II
(A) Tay-Sach disorder	(I) The 23rd pair is actually missing an X
(B) Down’s syndrome	(II) Fatal neurological disorder
(C) Klinefelter’s syndrome	(III) An extra chromosome in what normally be the 21st pair
(D) Turner’s syndrome	(IV) The 23rd set of sex chromosomes is XXY

Choose the correct answer from the options given below:

Correct option is B

The correct matching is:

• A. Tay-Sach disorder - II (Fatal neurological disorder): Tay-Sach disorder is a rare genetic condition that progressively destroys nerve cells in the brain and spinal cord, leading to severe neurological symptoms and early death.
• B. Down’s syndrome - III (An extra chromosome in what normally be the 21st pair): Down’s syndrome occurs due to trisomy 21, where there is an extra chromosome at the 21st pair, leading to developmental and intellectual disabilities.
• C. Klinefelter’s syndrome - IV (The 23rd set of sex chromosomes is XXY): This syndrome affects males who have an additional X chromosome (XXY), leading to symptoms such as infertility and lessened secondary sexual characteristics.
• D. Turner’s syndrome - I (The 23rd pair is actually missing an X): Turner’s syndrome affects females who are missing one X chromosome (X instead of XX), leading to short stature and infertility.

Information Booster:

1. Tay-Sach disorder: Caused by a mutation in the HEXA gene, it is more common in Ashkenazi Jews.
2. Down’s syndrome: Characterized by distinctive facial features, cognitive delays, and sometimes congenital heart defects.
3. Klinefelter’s syndrome: Symptoms may include gynecomastia, learning difficulties, and reduced testosterone levels.
4. Turner’s syndrome: Associated with short stature, delayed puberty, and heart or kidney issues