Ring syndrome caused by ring chromosome 7 without loss of subtelomeric sequences

Vermeesch, Joris Robert; Baten, E; Devriendt, Koenraad

doi:10.1034/j.1399-0004.2002.620511.x

Cited by 34 publications

(25 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The syndrome could also include severe growth retardation and would be due to mitotic instability of cells carrying the aberration, with subsequent loss of the ring leading to cell death [Kosztolá nyi, 1987;Wintle et al, 1995]. However, not all ring chromosomes are associated with seizures [Vermeesch et al, 2002;Ishmael et al, 2003]. Thus, selected ring chromosome abnormalities can provide important clues in the mapping of genes involved in this disorder [Singh et al, 2002].…”

Section: Discussionmentioning

confidence: 95%

FISH‐mapping of telomeric 14q32 deletions: Search for the cause of seizures

Schlade-Bartusiak

Costa

Summers

et al. 2005

American J of Med Genetics Pt A

View full text Add to dashboard Cite

Ring chromosome 14 is a rare cytogenetic disorder. Individuals with r(14) generally have developmental delay and seizures. Other features include hypotonia, microcephaly, mild facial dysmorphism, and retinal pigmentation. Most of these features are also found in patients with linear terminal deletions of chromosome 14, except for seizures and retinal abnormalities. The objective of the study was to determine if deletion of a specific chromosome region is a possible explanation for the occurrence of seizures in patients with ring chromosome 14. Patients diagnosed either with r(14) (six patients) or a deletion of distal 14q (three patients) were analyzed by FISH (fluorescence in situ hybridization) with BAC probes. We observed differences in the size of deletions in the studied group. In two r(14) patients, we did not detect any deletion; the four other patients had deletions of various sizes, ranging from 0.8 Mb to 5 Mb. Two linear deletions were 3.2 Mb and 5.3 Mb in length, respectively; the third case had an interstitial deletion that did not overlap with the others. The deleted regions in ring chromosomes showed overlap with those in the two linear terminal deletions. We conclude that there is unlikely to be a specific deleted locus in 14q32.3 that predisposes r(14) patients to seizures or retinal pigmentation. The cause is probably related to the formation of the ring itself and the effect this may have on local chromatin structure.

show abstract

Section: Discussionmentioning

confidence: 95%

FISH‐mapping of telomeric 14q32 deletions: Search for the cause of seizures

Schlade-Bartusiak

Costa

Summers

et al. 2005

American J of Med Genetics Pt A

View full text Add to dashboard Cite

show abstract

“…This event typically results in partial monosomy for the distal ends of the short and long arms of a chromosome and often results in mental retardation and malformations (Kosztolanyi 1987). However, rare telomere-telomere fusions generating a ring chromosome may result in no loss of euchromatin with variable phenotypic effect (Pezzolo et al 1993;Vermeesch et al 2002). Formation of rings is uncommon and has been reported for all chromosomes.…”

Section: Introductionmentioning

confidence: 99%

Ring chromosome 15: characterization by array CGH

et al. 2005

View full text Add to dashboard Cite

Ring chromosome 15 [r(15)] is an uncommon finding with less than 50 patients reported. Precise genotype-phenotype correlations are problematic because of the difficulties in determining the extent of euchromatic loss, the level of mosaicism, and the influence of the timing of ascertainment. We report two discordant examples of r(15) patients. In the first case, prenatal diagnosis of a de novo r(15) was made during the second trimester: mos 46,XX,r(15)(p11.2q26)[32]/45,XX,-15[13]/47,XX,r(15)(p11.2q26)x2[3]/46,XX,dic r(15)(p11.2q26p11.2q26[1]/46,XX[2]. Postnatal follow-up revealed extremely small stature, heart defects, and developmental delay. Patient 2 was a 31-year-old short-statured female who was living independently: 46,XX,r(15)(p11q26). Both cases showed loss of the 15q subtelomeric region by fluorescence in situ hybridization (FISH). To investigate the discordance in phenotypes between the two patients, we undertook array comparative genomic hybridization (array CGH) analyses to more fully characterize the deletions associated with these otherwise structurally indistinguishable r(15) chromosomes from conventional cytogenetic analyses and fluorescence in situ hybridization (FISH) studies. By array CGH, patient 1 showed deletion of multiple contiguous clones predicting an approximately 6 Mb deletion of distal 15q. In contrast, patient 2 showed loss of just the 15q subtelomeric clone and an interstitial clone by array CGH confirming that the severity of the phenotype correlated with the size of the deletion at the molecular level. These cases illustrate the utility of array CGH characterization for determining the size of the associated deletion in ring chromosomes and for facilitating phenotype-genotype correlations.

show abstract

“…Alternatively, they can be formed by subtelomeric sequence fusion or telomere-telomere fusion with no loss of genetic material, resulting in complete ring chromosomes (Henegariu et al, 1997;Sigurdardottir et al, 1999;Vermeesch et al, 2002;Le Caigne et al, 2004). Based on high-resolution molecular karyotyping, other mechanisms of the formation of ring chromosomes have been proposed, such as rings originating from an inverted duplication with a terminal deletion rearrangement (Knijnenburg et al, 2007;Rossi et al, 2008a).…”

Section: Introductionmentioning

confidence: 99%

Ring chromosome instability evaluation in six patients with autosomal rings

Sodré¹,

Guilherme²,

Meloni³

et al. 2010

Genet. Mol. Res.

View full text Add to dashboard Cite

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.

show abstract

Ring syndrome caused by ring chromosome 7 without loss of subtelomeric sequences

Cited by 34 publications

References 12 publications

FISH‐mapping of telomeric 14q32 deletions: Search for the cause of seizures

FISH‐mapping of telomeric 14q32 deletions: Search for the cause of seizures

Ring chromosome 15: characterization by array CGH

Ring chromosome instability evaluation in six patients with autosomal rings

Contact Info

Product

Resources

About