True telomeric translocation in a baby with the Prader‐Willi phenotype

Reeve, Ann; Norman, Andrew; Sinclair, Paul; Whittington‐Smith, Ruth; Hamey, Yvonne; Read, Andrew P.

doi:10.1002/ajmg.1320470102

Cited by 21 publications

(8 citation statements)

References 25 publications

(9 reference statements)

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“…"6 Involvement of the same chromosomal region has led to the suggestion that in this chromosomal region specific DNA sequences must be present, with an affinity for recombination with telomeres.4 6 On the other hand, in the two other patients with a constitutional jumping translocation investigated so far, interstitial telomeric sequences were also found, as in the present case (case 1 of Park et al,5 case 3 of Rossi et at). The detection of interstitial telomeres in the present patient with a breakpoint in 15q24 suggests that the jumping process could be related to the presence of interstitial telomeric sequences and not merely to the chromosomal region involved.…”

Section: Discussionsupporting

confidence: 49%

Trisomy 15 rescue with jumping translocation of distal 15q in Prader-Willi syndrome.

Devriendt

Petit

Matthijs

et al. 1997

Journal of Medical Genetics

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We report a patient with Prader-Willi syndrome (PWS) and mosaicism for a de novo jumping translocation of distal chromosome 15q, resulting in partial trisomy for 15q24-qter. A maternal uniparental heterodisomy for chromosome 15 was present in all cells, defining the molecular basis for the PWS in this patient. The translocated distal 15q fragment was of paternal origin and was present as a jumping translocation, involving three different translocation partners, chromosomes 14q, 4q, and 16p. The recipient chromosomes appeared cytogenetically intact and interstitial telomere DNA sequences were present at the breakpoint junctions. This strongly suggests that the initial event leading to the translocation of distal 15q was a non-reciprocal translocation, with fusion between the 15q24 breakpoint and the telomeres of the recipient chromosomes. These observations are best explained by a partial zygotic trisomy rescue and comprise a previously undescribed mechanism leading to partial trisomy.

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Section: Discussionsupporting

confidence: 49%

Trisomy 15 rescue with jumping translocation of distal 15q in Prader-Willi syndrome.

Devriendt

Petit

Matthijs

et al. 1997

Journal of Medical Genetics

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“…Azzalin et al [1997] used a long synthetic (TTAGGG)n probe and localized telomere-like repeats at internal sites of normal human chromosomes. However, there is no evidence of telomere-related sequence at 15q11 to Normal Huang et al [2004] account for the recombination with a true telomere [Wells et al, 1990;Park et al, 1992;Reeve et al, 1993;Gardner and Sutherland, 1996;Azzalin et al, 1997]. Similarly, the 22q11.2 region is a hot-spot for unequal homologous recombination events leading to deletions, duplications, and telomeric translocations.…”

Section: Discussionmentioning

confidence: 90%

A constitutional telomeric translocation showing meiotic instability

Josifova

Mazzaschi

Ballard³

et al. 2006

American J of Med Genetics Pt A

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Constitutional telomeric translocations are rare chromosome rearrangements. They are thought to occur as a result of chromosome breakage and subsequent ligation with the telomeric sequence of a different chromosome. Most frequently they occur as de novo events and, depending on the donor chromosome breakpoint, may be associated with an abnormal phenotype. We report a case of an unbalanced translocation involving the long arm of chromosome 15 and the short arm of chromosome 8 [45,XY, der(8)t(8;15)(p23.3;q11.2),-15], diagnosed prenatally; the father carried an unbalanced translocation of the long arm of chromosome 15 and the short arm of chromosome 2 [45,XY,der(2)t(2;15)(p25.3;q11.2),-15]. Both translocations were shown to have telomere repeat sequences at the translocation breakpoints. There was no apparent imbalance of euchromatic material in either translocation, and no associated abnormal phenotype.

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“…A rearrangement occurs in ~5% of individuals with PWS (25). These structural rearrangements may be balanced or unbalanced, the commonest being Robertsonian translocations (14;15) and (15;15) (25)(26)(27)(28)(29)(30).…”

Section: The Genetic Abnormality In Pwsmentioning

confidence: 99%

The dilemma of diagnostic testing for Prader-Willi syndrome

Smith

Hung

2017

Transl. Pediatr.

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Although Prader-Willi syndrome (PWS) is a well-described clinical dysmorphic syndrome, DNA testing is required for a definitive diagnosis. A definitive diagnosis can be made in approximately 99% of cases using DNA testing; there are a number of DNA tests that can be used for this purpose, although there is no set standard algorithm of testing. The dilemma arises because of the complex genetic mechanisms at the basis of PWS, which need to be elucidated. To establish the molecular mechanism with a complete work up, involves at least 2 tests. Here we discuss the commonly used tests currently available and suggest a costeffective approach to diagnostic testing.

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True telomeric translocation in a baby with the Prader‐Willi phenotype

Cited by 21 publications

References 25 publications

Trisomy 15 rescue with jumping translocation of distal 15q in Prader-Willi syndrome.

Trisomy 15 rescue with jumping translocation of distal 15q in Prader-Willi syndrome.

A constitutional telomeric translocation showing meiotic instability

The dilemma of diagnostic testing for Prader-Willi syndrome

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