Question

Pick out the correct statements:
(i) Colour blindness is a sex-linked recessive gene disorder.
(ii) Klinefelter's syndrome is 18^th chromosomal trisomy.
(iii) Phenylketonuria is an autosomal dominant genetic disorder.
(iv) Down’s syndrome is due to aneuploidy.

• A. i, ii and iv are correct
• B. i and ii are correct
• C. ii, iii and iv are correct
• D. i and iv are correct

Answer 1

Answer: (D)

Colour blindness is usually a genetic condition. The gene which is responsible for the condition is carried on the X chromosome.
Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example, a human cell having 45 or 47 chromosomes instead of the usual 46. Down’s syndrome is due to aneuploidy with 47 chromosomes.
Edward syndrome is a genetic disorder caused by the presence of all or part of an extra 18^th chromosome.
Phenylketonuria is an autosomal recessive gene disorder.