Chromosomal abnormalities are the type of genetic disorders caused due to the change in many chromosomes or the abnormal arrangement of the chromosomes. There are different types of chromosomal abnormalities as follows:
- Aneuploidy – It is a condition in which there is a loss or gain of chromosomes due to abnormal segregation of genes during cell division.
- Polyploidy – It is a condition in which the count of the entire set of chromosomes increases due to the failure of cytokinesis in cell division. It is mostly observed in plants.
In humans, when there is an additional copy of a chromosome apart from the 46 chromosomes, the situation is called trisomy. Similarly, when the person lacks a pair of chromosomes from the 23 pairs, it is called monosomy.
Examples of Chromosomal Abnormalities
The most common examples of these chromosomal abnormalities are down syndrome, Klinefelter syndrome, and Turner syndrome.
A kid suffering from Down Syndrome
Let us look at these three examples in detail:
- Down syndrome: This syndrome is a type of trisomy as there is an extra copy of chromosome 21. It is named so after the person who discovered this chromosomal disorder – Langdon Down. The symptoms in a person include the following:
- The person is short and has a small and round head
- Physical and mental development is retarded
- Furrowed tongue and partially open mouth
- Klinefelter syndrome: This genetic disorder arises due to the presence of an additional X chromosome in males. Thus, resulting in a chromosome count of 47 (44 + XXY) instead of 46.
- Such a person has a masculine physique but has feminine development like the development of breasts
- Such individuals are sterile, i.e.; they cannot reproduce
- Turner syndrome: Unlike Klinefelter syndrome, in this chromosomal disorder there is the absence of one X chromosome in females. Hence, decreasing the chromosomes count to 45 (44 + X0). The symptoms include the following:
- Such females are sterile
- Have rudimentary ovaries and there is the absence of secondary sexual characters.
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