Question

Down's syndrome is caused due to ________ of chromosomes.

• A. autosomal addition
• B. autosomal deletion
• C. allosomal addition
• D. allosomal deletion

Answer 1

Answer: (A)

Chromosomal disorder occurs when there is addition or deletion of chromosome in the individual. In case of trisomy of the $21^{st}$ chromosome causes Down's syndrome. This results in mental retardation and physical development is retarded as well. The palm of the individual is broad with characteristic palm crease.