Ann Lab Med.  2012 Jul;32(4):307-311. 10.3343/alm.2012.32.4.307.

Ring Chromosome 5 in Acute Myeloid Leukemia Defined by Whole-genome Single Nucleotide Polymorphism Array

• Huh J
• Mun YC
• Chung WS
• Seong CM

• KMID: 1380093
• DOI: http://doi.org/10.3343/alm.2012.32.4.307

Abstract

Chromosomes forming a corresponding ring cannot be clearly defined by conventional cytogenetics or FISH. Karyotypic analyses using whole-genome single nucleotide polymorphism arrays (SNP-A) may result in the identification of previously cryptic lesions and allow for more precise definition of breakpoints. We describe a case of AML with metaphase cells bearing -5, del(11)(q22), and +r. With SNP-A, a 5p-terminal deletion (11 megabases [Mb]), a 5q-terminal deletion (27 Mb), an 11q-interstitial deletion (29 Mb), and a 21q gain (3 Mb) were identified. Therefore, the G-banded karyotype was revised as 46, XY, r(5)(p15. 2q33.2), del(11)(q14.1q23.2), dup(21)(q22.13q22.2)[18]/46,XY[2]. SNP-A could be a powerful tool for characterizing ring chromosomes in which the involved chromosomes or bands cannot be precisely identified by conventional cytogenetics or FISH.

Keyword

Ring; Chromosome 5; Single nucleotide polymorphism; Array; AML

MeSH Terms

Chromosome Deletion
*Chromosomes, Human, Pair 5
Humans
In Situ Hybridization, Fluorescence
Karyotyping
Leukemia, Myeloid, Acute/*diagnosis/genetics
Male
Metaphase
Middle Aged
Oligonucleotide Array Sequence Analysis
*Polymorphism, Single Nucleotide
*Ring Chromosomes

Figure

• 

  Fig. 1 G-banded karyogram showing 46,XY,r(5)(p14q35),del(11) (q13q22). Arrows stand for abnormal chromosome 5 and abnormal chromosome 11, respectively.

• 

  Fig. 2 Single nucleotide polymorphisms array (SNP-A) and FISH results. By SNP-A, the allele difference at the top of each panel represents genotyping calls or the frequency of the A and B alleles. The CN state represents the copy number status (CN=1, copy number 1; CN=2, copy number 2; and CN=3, copy number 3). (A) A decrease in the copy number of 5p15.33-p15.2 (423,554-11,003,428) and 5q33.2-q35.3 (153,225,007-180,652,396). (B) Interphase FISH using EGR1/D5S23, D5S721. One green (D5S23, D5S721) and 2 red (EGR1) signal patterns suggested deleted 5p15.2 and retained 5q31 regions. (C) A decrease in the copy number of 11q14.1-q23.2 (84,514,776-113,765,153). (D) An increased copy number of 21q22.13-q22.2 (37,018,986-39,492,610).

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