Chromosome aberration

Genetic disorder involving abnormalities in chromosome structure or number

Chromosome aberration refers to any change in the normal structure or number of chromosomes, often resulting in genetic disorders. These aberrations can occur due to errors in cell division, such as during meiosis or mitosis.

Types of Chromosome Aberrations

Chromosome aberrations can be broadly classified into two categories: structural and numerical.

Structural Aberrations

Structural aberrations involve changes in the physical structure of chromosomes. These include:

• Deletion: A portion of the chromosome is missing or deleted.
• Duplication: A portion of the chromosome is duplicated, resulting in extra genetic material.
• Inversion: A segment of the chromosome is reversed end to end.
• Translocation: A segment of one chromosome is transferred to another chromosome. This can be balanced (no genetic material is lost) or unbalanced (genetic material is lost or gained).

Numerical Aberrations

Numerical aberrations involve changes in the number of chromosomes. These include:

• Aneuploidy: The presence of an abnormal number of chromosomes in a cell. Examples include trisomy, where there is an extra chromosome (e.g., Down syndrome), and monosomy, where a chromosome is missing.
• Polyploidy: The presence of more than two complete sets of chromosomes. This is more common in plants than in animals.

Causes of Chromosome Aberrations

Chromosome aberrations can be caused by various factors, including:

• Radiation exposure
• Chemical mutagens
• Viral infections
• Errors during DNA replication

Diagnosis and Detection

Chromosome aberrations can be detected using several techniques, such as:

• Karyotyping: A laboratory procedure that allows for the visualization of chromosomes under a microscope.
• Fluorescence in situ hybridization (FISH): A technique used to identify the presence or absence of specific DNA sequences on chromosomes.
• Comparative genomic hybridization (CGH): A method for analyzing copy number variations in the DNA content of a cell.

Implications and Treatment

The implications of chromosome aberrations vary depending on the specific type and severity of the aberration. Some may lead to developmental disorders, infertility, or cancer. Treatment options are often limited and focus on managing symptoms and improving quality of life.

See Also

• Genetic disorder
• Mutation
• Genetic counseling

External Links

• National Human Genome Research Institute: Chromosome Aberration