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The following table summarizes symbols and abbreviations used in cytogenetics:[1][2]

Symbol Description
, Separates modal number (total number of chromosomes), sex chromosomes, and chromosome abnormalities
- Loss of a chromosome
( ) Grouping for breakpoints and structurally altered chromosomes
+ Gain of a chromosome
; Separates rearranged chromosomes and breakpoints involving more than one chromosome
/ Separates cell lines or clones
// Separates recipient and donor cell lines in bone marrow transplants
del Deletion
der Derivative chromosome
dic Dicentric chromosome
dim diminished signal intensity
dn de novo (not inherited) chromosomal abnormality
dup Duplication of a portion of a chromosome
enh enhanced signal intensity
fra Fragile site (usually used with Fragile X syndrome)
h Heterochromatic region of chromosome
i Isochromosome
idic Isodicentric chromosome (duplication & inversion of centromere-containing segment)
ins Insertion
inv Inversion
.ish Precedes karyotype results from FISH analysis
mar Marker chromosome
mat Maternally-derived chromosome rearrangement
p Short arm of a chromosome
pat Paternally-derived chromosome rearrangement
psu dic pseudo dicentric - only one centromere in a Dicentric chromosome is active
q Long arm of a chromosome
r Ring chromosome
t Translocation
ter Terminal end of arm (e.g. 2qter refers to the end of the long arm of chromosome 2)
tri Trisomy
trp Triplication of a portion of a chromosome

See also


  1. ^ "Cytogenetics Basics | Wisconsin State Laboratory of Hygiene".
  2. ^ "ISCN rules for listing chromosomal rearrangements". Current Protocols in Human Genetics. Appendix 4: Appendix 4C. May 2001. doi:10.1002/0471142905.hga04cs17. ISBN 978-0471142904. ISSN 1934-8258. PMID 18428230. S2CID 46677230.