Chromosome aberrations ( Latin aberrare "deviate"), also called chromosomal anomalies, are structural or numerical changes in the chromosomes of an organism or a cell that are visible with a light microscope .
These are major changes in the genetic make-up that can lead to serious clinical pictures. Chromosome aberrations in humans are described in clinical cytogenetics using the ISCN nomenclature (International System for Human Cytogenetic Nomenclature). Smaller changes that are not visible under a light microscope in cytogenetic preparations, such as mutations in individual genes ( gene mutations ), on the other hand, are not counted as chromosome aberrations.
Chromosomal aberrations are divided into two groups:
- Numerical chromosome aberrations, i.e. a change in the number (also: genome mutation ): aneuploidy (e.g. monosomy , trisomy ), polyploidy (e.g. triploidy )
- Structural chromosome aberrations, i.e. changes in the structure of a chromosome (also: chromosome mutation ): inversion , deletion , translocation
Structural chromosomal aberrations can be caused by mutagens with clastogenic potential. Numerical chromosome aberrations can be triggered by substances with aneugenic potential. Both groups are described in more detail in their own articles.
- Werner Buselmaier, Gholamali Tariverdian: Humangenetik. Text accompanying the item catalog . Springer, Berlin 1991, ISBN 3-540-54095-4 .
- ISCN 2009: An International System for Human Cytogenetic Nomenclature (2009). Recommendations of the International Standing Committee on Human Cytogenetic Nomenclature
- William Hovanitz: Textbook of Genetics. Elsevier Press, Inc., Houston, New York, 1953 (p. 190). "(...) if a change in structure (of chromosomes) is large enough to be visible in cytological preparations it is considered a chromosomal mutation. If it is too small to be readily observed, is known only from the genetic results of segregation and can be localized on a chromosome, it is known as a gene mutation. There is no sharp dividing line between gene mutations and chromosomal mutations. Eventually all gene mutations in their ultra-fine structure will be found to be structural, if only in the molecular arrangement of which the gene is composed. "