Cytogenetic notation

The following table summarizes symbols and abbreviations used in cytogenetics:

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

• Chromosome abnormalities
• Directionality (molecular biology) for 3' and 5' notation
• locus (genetics) for basic notational system
• International System for Human Cytogenetic Nomenclature