Aneuploidy is the condition used to describe a chromosomal abberation or alteration that is caused by an addition or deletion of one or a few chromosomes; It results in genetic disorders.
It differs from polyploidy which is the addition of one or more complete sets of chromosome in the genome. (2) Individuals having following chromosomal abnormalities are defined as:
(i) Trisomy of 21st chromosome It is also known as Down’s syndrome. In this, a person is born with three chromosomes at 21st position rather than normal pair.
(ii) XXX It is also known as triple X-syndrome or Klinefelter’s syndrome. This condition can occur only in females where they have three X-chromosomes instead of two.
(iii) XO It is also known as Turner’s syndrome. It always
affects the females in which one of the two chromosomes are defective or completely absent. The individuals with this syndrome are born with 45 chromosomes in each cell rather than 46.