International System for Human Cytogenomic Nomenclature

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The International System for Human Cytogenomic Nomenclature (previously International System for Human Cytogenetic Nomenclature), ISCN in short, is an international standard for human chromosome nomenclature, which includes band names, symbols and abbreviated terms used in the description of human chromosome and chromosome abnormalities.

The ISCN has been used as the central reference among cytogeneticists since 1960.[1][2]

Three chromosomal abnormalities with ISCN nomenclature, with increasing complexity: (A) A tumour karyotype in a male with loss of the Y chromosome, (B) Prader–Willi Syndrome i.e. deletion in the 15q11-q12 region and (C) an arbitrary karyotype that involves a variety of autosomal and allosomal abnormalities.[3]
Human karyotype with annotated bands and sub-bands as used for the nomenclature of chromosome abnormalities. It shows dark and white regions as seen on G banding. Each row is vertically aligned at centromere level. It shows 22 homologous autosomal chromosome pairs, both the female (XX) and male (XY) versions of the two sex chromosomes, as well as the mitochondrial genome (at bottom left).

Abbreviations of this system include a minus sign (-) for chromosome deletions, and del for deletions of parts of a chromosome.[4]

Revision history[edit]

See also[edit]


  1. ^ Slovak M.L., Theisen A., Shaffer L.G. (2013) "Human Chromosome Nomenclature: An Overview and Definition of Terms." In: Gersen S., Keagle M. (eds) The Principles of Clinical Cytogenetics. Springer, New York, NY doi:10.1007/978-1-4419-1688-4_3
  2. ^ Brothman AR, Persons DL, Shaffer LG (2009). "Nomenclature evolution: Changes in the ISCN from the 2005 to the 2009 edition". Cytogenet Genome Res. 127 (1): 1–4. doi:10.1159/000279442. PMID 20110655.
  3. ^ Warrender JD, Moorman AV, Lord P (2019). "A fully computational and reasonable representation for karyotypes". Bioinformatics. 35 (24): 5264–5270. doi:10.1093/bioinformatics/btz440. PMC 6954653. PMID 31228194.{{cite journal}}: CS1 maint: multiple names: authors list (link)
    - "This is an Open Access article distributed under the terms of the Creative Commons Attribution License ("
  4. ^ "ISCN Symbols and Abbreviated Terms". Coriell Institute for Medical Research. Retrieved 2022-10-27.

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