ISCN 2013
An International System for Human Cytogenetic Nomenclature (2013)

This publication extends the now classic system of human cytogenetic nomenclature prepared by an expert committee and published in collaboration with .Cytogenetic and Genome Research' since 1963.

Revised and finalized by the ISCN Committee and its advisors at a meeting in Seattle, Wash., in April 2012, the ISCN 2013 updates, revises and incorporates all previous human cytogenetic nomenclature recommendations into one systematically organized publication that supersedes all previous ISCN recommendations. ...

The ISCN 2013 is an indispensable reference volume for human cytogeneticists, technicians and students for the interpretation and communication of human cytogenetic nomenclature.

Table of Contents

1

1.1
1.2
1.3
1.4
1.5
2

2.1
2.2
2.2.1
2.2.2
2.2.3
2.3
2.3.1
2.3.2
2.4
2.5
3

4

4.1
4.2
4.3
4.3.1
4.3.1.1
4.3.1.2
4.3.1.3
4.3.2
4.3.2.1
4.3.2.2
4.4
4.5
Historicallntroduction . 1
1956-1984 .. 1
1985-1995 . 3
1996-2004 . 4
2005-2009 . 5
2010-2013 . 5

Normal Chromosomes . 6
Introduction . 6
Chromosome Number and Morphology . 6
Non-Banding Techniques . 6
Banding Techniques . 7
x-and Y-Chromatin . 8
Chromosome Band Nomenclature . 9
Identification and Definition of Chromosome Landmarks, Regions, and Bands .. 9
Designation of Regions, Bands, and Sub-Bands .. 10
High-Resolution Banding . 12
Molecular Basis of Banding .. 15

Symbols and Abbreviated Terms . 36

Karyotype Designation .. 39

General Principles . 39
Specification of Breakpoints . 41
Designating Structural Chromosome Aberrations by Breakpoints and
Band Composition . 42
Short System for Designating Structural Chromosome Aberrations . 42
Two-Break Rearrangements . 42
Three-Break Rearrangements . 43
Four-Break and More Complex Rearrangements .. 44
Detailed System for Designating Structural Chromosome Aberrations .. 44
Additional Symbols . 44
Designating the Band Composition of a Chromosome .. 45
Derivative Chromosomes . 45
Recombinant Chromosomes . 46

5
5.1
5.2
5.3
5.4
6

7

7.1
7.1.1
7.1.2
7.2
8

8.1
8.2
8.3
8.4
9

9.1
9.2
9.2.1
9.2.2
9.2.3
9.2.4
9.2.5
9.2.6
9.2.7
9.2.8
9.2.9
9.2.10
9.2.11
9.2.12
9.2.13
9.2.14
9.2.15
9.2.16
9.2.17
9.2.17.1
9.2.17.2
9.2.17.3
9.2.17.4
9.2.18
9.2.19
9.3
Uncertainty in Chromosome or Band Designation .. 49

Ouestionable Identification . 49

Uncertain Breakpoint Localization or Chromosome Number. .. 50

Alternative 1nterpretation . 50

Incomplete Karyotype . 51

Order of Chromosome Abnormalities in the Karyotype .. 52

Normal Variable Chromosome Features .. 53

Variation in Heterochromatic Segments, Satellite Stalks, and Satellites .. 53

Variation in Length . 53

Variation in Number and Position . 53

Fragile Sites . 54

Numerical Chromosome Abnormalities . 55

General Principles . 55

Sex Chromosome Abnormalities . 56

Autosomal Abnormalities . 57

Uniparental Disomy . 58

Structural Chromosome Rearrangements . 59

General Principles . 59

Specification of Structural Rearrangements . 60

Additional Material of Unknown Origin . 60

Deletions . 61

Derivative Chromosomes . 62

Dicentric Chromosomes . 67

Duplications . 69

Fission . 69

Fragile Sites . 69

Homogeneously Staining Regions . 70

Insertions .. 71

Inversions . 72

Isochromosomes . 72

Marker Chromosomes . 73

Neocentromeres . 75

Ouadruplications . 75

Ring Chromosomes . 75

Telomeric Associations . 77

Translocations . 78

Reciprocal Translocations . 78

Whole-Arm Translocations . 80

Robertsonian Translocations . 81

Jumping Translocations . 82

Tricentric Chromosomes . 83

Triplications . 83

Multiple Copies of Rearranged Chromosomes . 83

10
10.1
10.1.1
10.1.2
10.2
10.2.1
10.2.2
10.3
11

11.1
11.1.1
11.1.2
11.1.3
11.1.4
11.1.5
11.1.6
11.2
11.3
12

12.1
12.1.1
12.1.2
13

13.1
13.2
13.2.1
13.2.2
13.3
13.3.1
13.3.2
13.3.2.1
13.3.2.2
13.3.2.3
13.3.2.4
13.4
13.5
13.5.1
13.6
13.7
13.8
Chromosome Breakage . 85

Chromatid Aberrations . 85

Non-Banded Preparations . 85

Banded Preparations . 86

Chromosome Aberrations . 86

Non-Banded Preparations . 86

Banded Preparations . 87

Scoring of Aberrations . 87

Neoplasia . 88

Clones and Clonai Evolution . 88

Definition of a Clone . 88

Clone Size . 89

Mainline . 89

Stemline, Sideline and Clonai Evolution .. 90

Composite Karyotype . 92

Unrelated Clones . 94

Modal Number . 94

Constitutional Karyotype . 95

Meiotic Chromosomes . 97

Terminology . 97

Examples of Meiotic Nomenclature .. 98

Correlation between Meiotic Chromosomes and Mitotic Banding Patterns .. 100

ln situ Hybridization .. 105

Introduction . 105

Prophase/Metaphase in situ Hybridization (ish) . 105

Use of dim and enh . 111

Subtelomeric Metaphase in situ Hybridization . 111

Interphase/Nuclear in situ Hybridization (nuc ish) . 111

Number of Signais . 112

Relative Position of Signais . 115

Single Fusion Probes .. 117

Single Fusion with Extra Signal Probes .. 117

Dual Fusion Probes . 117

Break-Apart Probes . 118

ln situ Hybridization on Extended Chromatin/DNA Fibers (fib ish) .. 119

Reverse in situ Hybridization (rev ish) . 119

Chromosome Analyses Using Probes Derived from Sorted or Microdissected
Chromosomes . 119

Chromosome Comparative Genomic Hybridization (cgh) .. 120

Multi-Color Chromosome Painting . 120

Partial Chromosome Paints . 120


14 Mieroarrays....................................................................................... 121

14.1 Introduction.......................................................................................... 121

14.2 Examples of Microarray Nomenclature....................................................... 122

14.2.1 Nomenclature Specifie to SNP Arrays......................................................... 127

14.2.2 Complex Array Results 128

15 Region-Specifie Assays..................................................................... 129

15.1 Introduction............................................ 129

15.2 Examples of RSA Nomenclature for Copy Number Detection......................... 129

15.3 Examples of RSA Nomenclature for Balanced Translocations or Fusion Genes... 130

16 References 131

17 Members of the ISCN Standing Committee and Consultants........ 133

18 Appendix 135

19 Index 137