Question

A disease caused by an autosomal primary non- disjunction is:

• A. Klinefelter's Syndrome
• B. Turner's Syndrome
• C. Sickel Cell Anemia
• D. Down's Syndrome

Answer 1

The Correct Option is D

Down's syndrome is caused by non-disjunction of $21^{\text {st }}$ chromosome.

Answer 2

Explanation:

Down’s Syndrome- is a genetic disorder caused by trisomy of 21 chromosomes also called non disjunction. In other words, down’s syndrome is a disorder where an individual may inherit an extra part of chromosome 21 or an entire copy of chromosome 21.

An embryo with nondisjunction has three copies of chromosome 21 rather than the normal two. A pair of 21st chromosomes in the sperm or the egg does not split apart before or at fertilization.

Klinfelter syndrome- It is a genetic disorder that causes males to be born with an extra copy of X chromosome. Males with this syndrome may not have any symptoms or may have symptoms like breast growth, less facial and body hair.

Turners Syndrome- It is a genetic disorder which affects only females. It is caused due to the aneuploidy of sex chromosome, when one X chromosome is missing or partially missing. It results in short height and failure of ovary development.

Sickle Cell Anaemia-  Sickle cell anemia is an autosomal recessive disorder. It is a disorder of red blood cells. The normal RBCs are disc shaped whereas a person with sickle cell disease has an abnormal shape like that of a sickle making it sticky and difficult to travel through the blood vessels resulting in tissue damage and pain.