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Basic Nomenclature For Cytogenetics

Abnormalities | Nomenclature

Symbols and Abbreviations:

 , Separates chromosome modal number, sex chromosomes, and chromosome abnormalities
 - Loss of a chromosome
 ( ) Surround structurally altered chromosomes and breakpoints
 + 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 (used when only one chromosome from a translocation is present, or when one chromosome has two or more structural abnormalities)
 dic Dicentric chromosome
dn Chromosomal abnormality not inherited from parents (de novo)
 dup Duplication of a portion of a chromosome
 fra Fragile site (usually used with Fragile-X syndrome)
 h Heterochromatic region of chromosome
 i Isochromosome (both arms of the chromosome are the same)
 ins Insertion of a portion of a chromosome
 inv Inversion
 .ish Precedes karyotype results from fluorescence in situ hybridization (FISH) analysis
 mar Marker chromosome (unidentifiable piece of chromosome)
 mat Maternally derived chromosome rearrangement
 p Short arm of a chromosome
 pat Paternally derived chromosome rearrangement
 psu dic Only one centromere is active (pseudo dicentric)
 q Long arm of a chromosome
r Ring chromosome
 t Translocation
 ter Terminal end of arm (i.e. 2qter - end of the long arm of chromosome 2)

 tri
 Trisomy
trp Triplication of a portion of a chromosome

General Guidelines:

modal number, sex chrom, abn abbrev (first chrom; second chrom) (arm band number; arm band number)

Ex:

46,XX,t(1;2)(p32;q22)

Definitions:

Modal number: total count of number of chromosomes in each cell of a given cell line

Sex chromosomes: complement of X and Y chromosomes

Band number: numerical description of the location on a chromosome arm, in order from the centromere out to the end of the chromosome. These numbers are a standard determined by the International System for human Cytogenetic Nomenclature (ISCN), revised in 2005.

UW Cytogenetic Services
University of Wisconsin - Madison

 
Feedback, questions or accessibility issues: cytogenetics@mail.slh.wisc.edu

The University of Wisconsin Cytogenetic Services Laboratory is affiliated with the Waisman Center, the University of Wisconsin Comprehensive Cancer Center, and the Wisconsin State Laboratory of Hygiene		  


UW Cytogenetic Services
465 Henry Mall, Room 419
Madison WI 53706
Phone: 1-608-262-0402
Fax: 1-608-265-7818

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