CHROMOSOMAL-ABERRATIONS-CHROMOSSAL ABNORMALITIES.pptx

Chromosomal aberrations, also known as chromosomal abnormalities, refer to changes or mutations in the structure or number of chromosomes within a cell. These abnormalities can occur during cell division, resulting in genetic variations that may impact an organism's development, health, or function.

There are two primary types of chromosomal aberrations:

Numerical Aberrations: These occur when there is an abnormal number of chromosomes. This can involve either an extra chromosome (a condition called trisomy) or the loss of a chromosome (called monosomy). A well-known example of numerical chromosomal aberration is Down syndrome, where individuals have an extra copy of chromosome 21 (trisomy 21). Another example is Turner syndrome, where females have only one X chromosome (monosomy X).
For example:

Trisomy: An extra chromosome (e.g., Down syndrome, where there are three copies of chromosome 21).
Monosomy: A missing chromosome (e.g., Turner syndrome, where there's only one X chromosome instead of two).

Structural Aberrations: These involve physical changes in the structure of a chromosome. These changes can include:

Deletions: A portion of the chromosome is lost.
Duplications: A segment of the chromosome is repeated.
Inversions: A segment of the chromosome is reversed.
Translocations: A piece of one chromosome breaks off and attaches to another chromosome.
Ring Chromosomes: A chromosome forms a ring due to deletions at both ends.
Chromosomal aberrations can lead to a range of health issues, from developmental delays and congenital malformations to an increased risk of cancer. The severity of the effects largely depends on the type of aberration and which chromosome is involved. Some chromosomal abnormalities can be inherited, while others occur spontaneously during the formation of eggs or sperm or during early cell divisions in embryonic development. Detection of chromosomal aberrations is often performed through techniques such as karyotyping, fluorescence in situ hybridization (FISH), and chromosomal microarray analysis. These methods allow scientists and healthcare providers to identify genetic disorders and make informed decisions about treatment, prenatal care, and genetic counseling.
Chromosomal aberrations are abnormalities in the structure or number of chromosomes in a cell. These can occur during cell division and lead to significant genetic changes, potentially affecting the organism's development or health.
Chromosomal aberrations can lead to various health conditions, developmental issues, or disorders, such as intellectual disabilities, birth defects, or cancer. Diagnostic tests like karyotyping or FISH (fluorescence in situ hybridization) are used to detect these abnormalities.

1. CHROMOSOMAL ABERRATIONS Prepared by: Ms. Patrice Duane Vergara, LPT

2. Chromosomal abnormalities Chromosomal abnormalities occur when there is a defect in a chromosome, or in the arrangement of the genetic material on the chromosome. Abnormalities can be in the form of additional material which may be attached to a chromosome, or where part or a whole chromosome is missing, or even in defective formation of a chromosome. Any increases or decreases in chromosomal material interfere with normal development and function.

3. Types of chromosomal abnormalities NUMERICAL ABERRATIONS STRUCTURAL ABERRATIONS These are usually caused by a failure of chromosome division, which results in cells with an extra chromosome or a deficiency in chromosomes . These occur due to a loss or genetic material, or a rearrangement in the location of the genetic material .

4. NUMERICAL ABBERRATIONS Triploidy Trisomy Monosomy - is the presence of an additional set of chromosomes in the cell for a total of 69 chromosomes rather than the normal 46 chromosomes per cell . A trisomy is  a chromosomal condition characterized by an additional chromosome Monosomy is the state of having a single copy of a chromosome pair instead of the usual two copies found in diploid cells.

5. Trisomy 18 Monosomy

6. STRUCTURAL ABERRATIONS Deletions - A portion of the chromosome is missing or deleted. Known disorders include Wolf-Hirschhorn syndrome, which is caused by partial deletion of the short arm of chromosome.

7. Duplications - A portion of the chromosome is duplicated, resulting in extra genetic material. Example: Charcot-Marie-Tooth

8. Translocations - When a portion of one chromosome is transferred to another chromosome. STRUCTURAL ABERRATIONS

9. Inversions - A portion of the chromosome has broken off, turned upside down and reattached, therefore the genetic material is inverted.

10. Rings - A portion of a chromosome has broken off and formed a circle or ring. This can happen with or without loss of genetic material.

11. Isochromosome - Formed by the mirror image copy of a chromosome segment including the centromere.