What is the most common chromosomal disorder in humans?

Chromosomal Disorders:

1. Every species also has a characteristic structure & number of chromosomes present.
2. Due to certain irregularities at the time of cell division, alteration in structure or number of chromosomes may happen.
3. Even the slightest alteration can also lead to various abnormalities.
4. Examples of chromosomal disorders: Down syndrome, Turner syndrome, Trisomy 81, Trisomy 13.
5. There are two types of chromosomal abnormality: Aneuploidy and Polyploidy.
6. Aneuploidy is the loss or gain of a chromosome.
7. Polyploidy is an increase in the number of chromosomes due to the failure of cytokinesis during cell division.

The most common chromosomal disorders are:

Klinefelter's Syndrome:

1. In Klinefelter's Syndrome males have an extra copy of the X chromosome(XXY).
2. The total number of chromosomes becomes 47, it is referred to as trisomic.

Turner's syndrome:

1. In Turner's syndrome, a female is born with the absence of an X chromosome (XO).
2. The total number of chromosomes gets reduced to 45. It is referred to as monosomic.

Down's syndrome:

1. Down's syndrome is a chromosomal condition where the 21st chromosome has an extra copy.
2. It is called trisomy 21, the individuals with Down syndrome have 47 chromosomes.