A constitutional telomeric translocation showing meiotic instability

Josifova, Dragana; Mazzaschi, Roberto; Ballard, Terry; Ogilvie, Caroline Mackie; Splitt, Miranda

doi:10.1002/ajmg.a.31216

Cited by 3 publications

(5 citation statements)

References 29 publications

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“…TAs have been mostly reported in various leukemias and solid tumors (renal tumor, squamous cell carcinoma, cardiac myxoma, giant cell tumor of bone) and exceptionally in constitutional cells. To our knowledge, only seven patients from five different families carrying a constitutional TAs with TTAGGG telomeric sequences at the junction of the TAs have been previously published [Sawyer et al, ; Engelen et al, ; Zneimer et al, ; Huang et al, ; Josifova et al, ] (Table ). We did not include the rare cases for which the presence of telomeric sequences at the junction of the TA was not proven experimentally.…”

Section: Discussionmentioning

confidence: 99%

“…Three of these five different constitutional TAs were de novo events. The remaining two were inherited [Huang et al, ; Josifova et al, ]. Six out of seven patients with TAs involved an acrocentric suggesting that these chromosomes are preferentially involved in constitutional TAs.…”

Section: Discussionmentioning

confidence: 99%

“…The TAs were not responsible for infertility in males. Two of them had children [Huang et al, ; Josifova et al, ]. We have no data regarding the females since all of them were very young (less than 11 years).…”

Section: Discussionmentioning

confidence: 99%

“…TAs are also unstable in meioses because if most of TAs occurred de novo, two of them were familial but “jumped” during meiosis. Constitutional tas(Y;15) and (8;15) were inherited from their fathers who presented, respectively, a constitutional tas(Y;19) and a constitutional tas(2;15) [Huang et al, ; Josifova et al, ].…”

Section: Discussionmentioning

confidence: 99%

“…In contrast, constitutional TAs are rare events. To our knowledge, five different constitutional TAs have been reported to date [Sawyer et al, ; Engelen et al, ; Zneimer et al, ; Huang et al, ; Josifova et al, ], among them two involved the Y chromosome [Sawyer et al, ; Huang et al, ]. We report on a 6‐year‐old girl for whom a monosomy X was diagnosed during pregnancy.…”

Section: Introductionmentioning

confidence: 90%

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Constitutional telomeric association (Y;7) in a patient with a female phenotype

Bénéteau

Baron

David

et al. 2013

American J of Med Genetics Pt A

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Telomeric associations (TAs) are fusions between two telomeres of two different chromosomes without visible loss of chromosomal material. Constitutional telomeric associations are rare chromosomal anomalies. We report on the cytogenetic and molecular analyses of a TA involving chromosomes Y and 7 in a child with a female phenotype. Prenatal cytogenetic analysis showed a 45,X chromosome complement in all cells. No fetal abnormality was identified at ultrasound examinations and the pregnancy went to term. During childhood, the proband had gonadal dysgenesis but no other phenotypic manifestations of Turner syndrome. Molecular genetic analyses showed the presence of genomic DNA of the SRY gene without any mutation. Karyotyping and fluorescent in situ hybridization (FISH) analyses on blood showed two cell lines: one cell line with a TA involving chromosomes Y and 7 [46,X,tas(Y;7)(p11.32;q36.3)] and a second cell line with a 45,X pattern. A human pantelomeric repeat TTAGGG probe hybridized to the junction of the TA within the derivative chromosome. FISH and array comparative genomic hybridization (aCGH) analyses demonstrated that tas(Y;7) occurred without detectable loss of any sequence at the derivative chromosome. SNP array analysis excluded an uniparental isodisomy of chromosome 7. Knowing more about TAs will help geneticists to deliver accurate genetic counseling.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 90%

See 3 more Smart Citations

Constitutional telomeric association (Y;7) in a patient with a female phenotype

Bénéteau

Baron

David

et al. 2013

American J of Med Genetics Pt A

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A 9p13→p24 duplication coupled with a whole 22q translocation onto 9p24

et al. 2007

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We report on a 3-year-old girl with a typical 9p trisomy syndrome, whose 45-chromosome karyotype includes a 9p+. As assessed by G, C and Ag-NOR bands, the rearranged chromosome resulted from a 9p13-->p24 direct duplication coupled with a translocation of the whole 22q onto 9pter, had heterochromatin at the junction site, lacked both nucleolar organizing regions (NORs) and centromere dots at the unconstricted fusion point, and was present in all metaphases scored. FISH results: a 9p subtelomere probe gave a diminished signal on the 9p+ precisely at the duplication junction 9p24::9p13, but no labeling was observed at the 9;22 translocation site; a pancentromeric alphoid probe labeled all centromeres, and gave a distinct signal at the 9pter;22cen junction. Hence, her karyotype was 45,XX,rea(9;22)(9qter-->9p24::9p13-->9p24::22p10-->22qter).ish rea(9;22) (9psubtel+dim,pancen+). Parental chromosomes were normal. The distinctiveness of the present centromere-telomere fusion rests on the coupling of an intrachromosomal distal duplication with a whole-arm translocation including alphoid DNA onto the duplicated segment. The centromeric inertia of the residual alphoid DNA in the present case compares with the variable functional status of the chromosome 22 centromere in true heterodicentrics involving such a chromosome.

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Frequency of Chromosome Healing and Interstitial Telomeres in 40 Cases of Constitutional Abnormalities

Fortin¹,

Bergeron²,

Fetni³

et al. 2009

Cytogenet Genome Res

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Human telomeres play a major role in stabilizing chromosome ends and preventing fusions. Chromosomes bearing a broken end are rescued by the acquisition of a new telomeric cap without any subtelomeric sequences being present at the breakpoint, a process referred to as chromosome healing. Conversely, a loss of telomeric function or integrity can lead to the presence of interstitial telomeres at the junction site in translocations or ring chromosomes. In order to determine the frequency at which interstitial telomeres or chromosome healing events are observed in target chromosome abnormalities, we conducted a retrospective FISH study using pan-telomeric and chromosome-specific subtelomeric probes on archival material from 40 cases of terminal deletions, translocations or ring chromosomes. Of the 19 terminal deletions investigated, 17 were negative for the subtelomeric probe specific to the deleted arm despite being positive for the pan-telomeric probe. These 17 cases were thus considered as having been rescued through chromosome healing, suggesting that this process is frequent in terminal deletions. In addition, as 2 of these cases were inherited from a parent bearing the same deletion, chromosomes healed by this process are thus stable through mitosis and meiosis. Regarding the 13 cases of translocations and 8 ring chromosomes, 4 and 2 cases respectively demonstrated pan-telomeric sequences at the interstitial junction point. Furthermore, 2 cases of translocations and 1 ring chromosome had both interstitial pan-telomeres and subtelomeres, whereas 2 other cases of ring chromosomes and 1 case of translocation only showed interstitial subtelomeres. Therefore, interstitial (sub)telomeric sequences in translocations and ring chromosomes are more common than previously thought, as we found a frequency of 43% in this study. Moreover, our results illustrate the necessity of performing FISH with both subtelomeric and pan-telomeric probes when investigating these rearrangements, as the breakpoints can be either in the distal part of the pan-telomeres, or in between the 2 types of sequences.

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A constitutional telomeric translocation showing meiotic instability

Cited by 3 publications

References 29 publications

Constitutional telomeric association (Y;7) in a patient with a female phenotype

Constitutional telomeric association (Y;7) in a patient with a female phenotype

A 9p13→p24 duplication coupled with a whole 22q translocation onto 9p24

Frequency of Chromosome Healing and Interstitial Telomeres in 40 Cases of Constitutional Abnormalities

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