Question

Number of sex chromosomes is normal in _________.

• A. Super female
• B. Turner's syndrome
• C. Klinefelter's syndrome
• D. Down's syndrome

Answer 1

The correct option is D Down's syndrome

• Super females or Triple X syndrome, also called trisomy X or 47, XXX - a female with three X chromosomes.
• Turner's syndrome - This syndrome occurs due to a missing X chromosome and is written as XO.
  
• Klinefelter’s syndrome - The syndrome is represented as XXY where males have an extra X chromosome, i.e.- 44 + XXY = 47.
• Down's syndrome is also known as trisomy 21. It is a genetic disorder caused by the presence of all or part of the third copy of chromosome 21. It does not result in any change in the number of sex chromosomes.

So, the correct answer is 'Down's syndrome'.