There are 23 pair of chromosomes in human body. When there is change in the number of the chromosomes or alteration in the structure of the chromosomes, It leads to chromosomal disorder. These orders are called syndromes. There are two types of chromosomal disorders one is due to change in numbers. These are of two types:
- Aneuploidy: It is a condition in which there is loss or gain of chromosome during cell division. It is found in humans.
- Euploidy: It is a type of disorder in which entire set of chromosomes is deleted or gets added.
On the basis of structural change:
- Deletion: loss of part of chromosomes
- Addition: Addition on the chromosomes
- Translocation: one parts get detached and gets attached to non homologous pair or homologous pair.
- Inversion: Parts get detached and attached to the same chromosome in reverse order
These type of aberration are lethal in humans.
Types of syndrome:
- Down syndrome: It is due to addition of one chromosome to 21st Hence it is also called 21 trisomy. It is named after the person who discovered it Mr. Langdon Down. The person is short with round head. Physical and mental development is retarted. Broad Palm.
Klinefelter syndrome: This disorder takes place due to addition of X chromosomes in male. 44+ XXY is the total number of chromosomes. Such Individuals are sterile i.e. they cannot produce or reproduce. Such a person has masculine physique.