Cytogenetic Nomenclature
Abbreviation
Meaning
Example
Condition
46, XX Normal Female Karyotype
46, XY Normal Male Karyotype
cen centromere
del deletion 46,XX,del(5p) Female with cri du chat syndrome due to deletion of part of short arm of one chromosome 5
der derivative chromosome der(1) Translocation chromosome derived from chromosome 1 and containing the centromere of chromosome 1
dic dicentric chromosome dic(X;Y) Translocation chromosome containing centromeres from both the X and the Y chromosomes
dup duplication
fra fragile site 46, Y fag(X)(q27.3) Male with fragile X chromosome
i isochromosome 46,X,i(Xq) Female with isochromosome fro the long arm of the X chromosome.
ins insertion
inv inversion inv(3)(p25:q21) Pericentric inversion of chromosome 3
mar marker chromosome 47,XX,+mar Female with an extra unidentified chromosome.
mat maternal origin 47,XY,der(1)mat male with additional der(1) translocation chromosome inherited from his mother.
p short arm of chromosome
pat paternal origin
q long arm of chromosome
r ring chromosome 46,X,r(X) Female with ring X chromosome
rcp reciprocal  translocation
rob Robertsonian translocation
t translocation 46,XX,t(2;8)(q21;p13) Female with balanced translocation between chromosome 2 and chromosome 8, with breaks in 2q21 and 8p13
ter terminus 46, X,Xq-(pter-->q21:) Female with partial deletion of the long arm from Xq21 to Xqter (nomenclature shows the portion of the chromosome that is present)
+ gain of 47,XX,+21 Female with trisomy 21
- loss of 45,XX,-14,-21,+t(14q21q) Normal female carrier of a robertsonian translocation between the long arms of chromosomes 14 and 21; karyotype is missing a normal 14 and a normal 21
4p- Chromosome 4 with a on of the short arm  deleted.
: break 5qter -->5p15: deleted chromosome 5 in a patient with cri du chat syndrome, with a deletion breakpoint in band p15
:: break and join 2pter-->2q21::8p13-->8pter Description of der(2) portion of t(2,8)
/ mosaicism 46,XX/47,XX,+8 Female with two populations of cells, a normal karyotype and one with trisomy 8