Ring chromosome 4.

McDermott, Alan; Voyce, M A; Romain, D R

doi:10.1136/jmg.14.3.228

Cited by 44 publications

(32 citation statements)

References 7 publications

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“…Dynamic mosaicism is referred to as occurrence of new genetic imbalances from an already abnormal cell or mosaicism resulting from behavioral peculiarities of a rearranged chromosome (McDermott et al, 1977;Gutiérrez-Angulo et al, 2002). In the recent literature, this term is usually used to describe occurrence of additional structural chromosome rearrangements resulting from an already structurally abnormal karyotype (Gutiérrez-Angulo et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…However, it appears apposite to extend this term to numerical chromosome abnormalities produced by loss/gain of a rearranged chromosome. Moreover, this term was earlier used to describe mosaic ring chromosome losses and gains (McDermott et al, 1977). Finally, previous observations have shown alterations to chromosome Y structure underlying the loss during mitotic cell division and, consequently, mosaicism formation (Haaf and Schmid, 1990;Maraschio et al, 1990;Hsu, 1994).…”

Section: Discussionmentioning

confidence: 99%

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Dynamic mosaicism manifesting as loss, gain and rearrangement of an isodicentric Y chromosome in a male child with growth retardation and abnormal external genitalia

Iourov

Sg²,

Liehr

et al. 2008

Cytogenet Genome Res

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Isodicentric chromosomes are considered the most common structural abnormality of the human Y chromosome. Because of their instability during cell division, loss of an isodicentric Y seems mainly to lie at the origin of mosaicism in previously reported patients with a 45,X cell line. Here, we report on a similar case, which, however, turned out to be an example of dynamic mosaicism involving isodicentric chromosome Y and isochromosome Y after FISH with a set of chromosome Y-specific probes and multicolor banding. Cytogenetic analyses (GTG-, C-, and Q-banding) have shown three different cell lines: 45,X/46, X,idic(Y)(q12)/46,X,+mar. The application of molecular cytogenetic techniques established the presence of four cell lines: 45,X (48%), 46,X,idic(Y)(q11.23) (42%), 46,X,i(Y)(p10) (6%) and 47,X,idic(Y)(q11.23),+idic(Y)(q11.23) (4%). According to the available literature, this is the first case of dynamic mosaicism with up to four different cell lines involving loss, gain, and rearrangement of an idic(Y)(q11.23). The present report indicates that cases of mosaicism involving isodicentric and isochromosome Ys can be more dynamic in terms of somatic intercellular variability that probably has an underappreciated effect on the phenotype.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Dynamic mosaicism manifesting as loss, gain and rearrangement of an isodicentric Y chromosome in a male child with growth retardation and abnormal external genitalia

Iourov

Sg²,

Liehr

et al. 2008

Cytogenet Genome Res

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“…These unstable chromosomes can lead to ring chromosome loss, producing monosomic cells, which may or may not be viable (Niss and Passarge, 1975;Ledbetter et al, 1980;Fang et al, 1995;Kosztolányi, 2009). Thus, ring chromosomes can vary in structure and number in an individual's somatic cells, resulting in a mosaic karyotype, a process called "dynamic tissue-specific mosaicism" (McDermott et al, 1977;Speevak et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Ring chromosome instability evaluation in six patients with autosomal rings

Sodré¹,

Guilherme²,

Meloni³

et al. 2010

Genet. Mol. Res.

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ABSTRACT. Ring chromosomes are often associated with abnormal phenotypes due to loss of genomic material and also because of ring instability at mitosis after sister chromatid exchange events. We investigated ring chromosome instability in six patients with ring chromosomes 4, 14, 15, and 18 by examining 48-and 72-h lymphocyte cultures at the first, second and subsequent cell divisions after bromodeoxyuridine incorporation. Although most cells from all patients showed only one monocentric ring chromosome, ring chromosome loss and secondary aberrations were observed both in 48-and 72-h lymphocyte cultures and in 135©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 9 (1): 134-143 (2010) Ring chromosome instability metaphase cells of the different cell generations. We found no clear-cut correlation between ring size and ring instability; we also did not find differences between apparently complete rings and rings with genetic material loss. The cytogenetic findings revealed secondary aberrations in all ring chromosome patients. We concluded that cells with ring chromosome instability can multiply and survive in vivo, and that they can influence the patient's phenotype.

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“…Côté et al [1981] proposed the term "ring syndrome" for this group of patients, and more recently Kosztolá nyi reviewed 207 cases with a ring autosome and found that a fifth of the group had the "ring syndrome" phenotype. Most previous reports [McDermott et al, 1977;Zuffardi et al, 1980;Côté et al, 1981;MacDermot et al, 1990;Freyberger et al, 1991;Migliori et al, 1994] have relied on standard cytogenetic banding techniques to exclude deletions in the ring chromosomes. We report on two cases with complete ring (4) and ring (9) chromosomes, respectively, and the "ring syndrome" phenotype.…”

Section: Introductionmentioning

confidence: 99%

Clinical, cytogenetic, and fluorescence in situ hybridization findings in two cases of ?complete ring? syndrome

et al. 1999

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The term "ring syndrome" was proposed to describe a phenotype of growth failure without major malformations due to a ring autosome. The growth failure is thought to be caused by instability of the ring chromosome leading to aneusomy and cell death. Most previous studies of ring chromosomes were based on standard cytogenetic banding techniques and were limited to microscopically detectable deletions in the ring chromosomes. We report on two patients with complete ring (4) and ring (9) chromosomes, respectively. The first was a 15-month-old girl and the second was a 16-month-old boy. They both presented with severe, symmetrical growth failure and normal psychomotor development in the absence of malformations. Their parents had a normal phenotype. The first case had a whorled pattern of hyperpigmentation and hypopigmentation on part of the face and chest, and the second case had a patchy hyperpigmented rash on the trunk. Peripheral blood karyotype of the first patient was 46,XX, r(4)(p16.3q35.2) and of the second 45,XY,-9/46,XY,r(9)(p24q34.3). G-band analysis suggested no loss of material in the ring chromosomes. These findings were confirmed by fluorescence in situ hybridization (FISH) analysis using chromosome-specific subtelomeric probes. The common human telomeric sequences were intact in the first patient but absent in the second patient. The cytogenetic and FISH data in our two cases provide further evidence for the existence of a "complete ring" phenotype independent of the autosome involved. Pigmentary skin changes are a useful clinical sign of mosaicism caused by the ring instability.

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Ring chromosome 4.

Cited by 44 publications

References 7 publications

Dynamic mosaicism manifesting as loss, gain and rearrangement of an isodicentric Y chromosome in a male child with growth retardation and abnormal external genitalia

Dynamic mosaicism manifesting as loss, gain and rearrangement of an isodicentric Y chromosome in a male child with growth retardation and abnormal external genitalia

Ring chromosome instability evaluation in six patients with autosomal rings

Clinical, cytogenetic, and fluorescence in situ hybridization findings in two cases of ?complete ring? syndrome

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