Duplication 9p due to unequal sister chromatid exchange.

Mattina, Teresa; Sorge, Giovanni; Milone, Giuseppe; Garozzo, Rosaria; Conti, Letizia

doi:10.1136/jmg.24.5.303

Cited by 14 publications

(15 citation statements)

References 3 publications

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“…In such a case of de novo pure trisomy 9p, an intriguing mechanism has been proposed that the trisomy is due to a 3:1 segregation of a de novo given translocation involving chromosome 9p at gametogenesis [Mattina et al, 1986]. However, the microsatellite polymorphism study in the girl we described provided evidence for another mechanism resulting in the particular extra chromosome.…”

Section: Discussionmentioning

confidence: 74%

Maternal origin of a unique extra chromosome, der(9)(pter?q13::q13?q12:) in a girl with typical trisomy 9p syndrome

et al. 2001

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We report on a girl with the typical trisomy 9p syndrome who had an additional E-sized metacentric chromosome. On the basis of GTG- and CBG-banding, her karyotype was considered to be 47,XX,+der(9)(pter-->q13::q13-->q12:) de novo. Results of a fluorescence in situ hybridization study using a chromosome 9-specific painting probe were compatible with this cytogenetic interpretation. Molecular analyses of six highly polymorphic dinucleotide repeat loci on the short arm and the proximal long arm of chromosome 9 demonstrated that the girl inherited one allele from her father and two identical or different alleles from the mother. We speculated that the extra chromosome may have resulted from either nondisjunction of chromosome 9 followed by a U-type exchange and a crossing-over between different sister chromatids during maternal meiosis I and subsequent breakage and malsegregation during meiosis II, or nondisjunction during meiosis II followed by isochromosome formation in one of the two maternal chromosomes 9 and subsequent breakage.

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Section: Discussionmentioning

confidence: 74%

Maternal origin of a unique extra chromosome, der(9)(pter?q13::q13?q12:) in a girl with typical trisomy 9p syndrome

et al. 2001

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“…Several cases of tandem 9p duplications [Chiyo et al, 1976: case 8;Baccichetti et al, 1979: case 1;Fryns et al, 1979;Zadeh et al, 1981: case 1; Coco and Penchaszadeh, 1982: case 192;Cuoco et al, 1982: case 2; Motegi et al, 1985;Mattina et al, 1987;Haddad et al, 1996;Fujimoto et al, 1998;Guanciali et al, 2000;Kotzot et al, 2000: cases 11 and 12) or inverted 9p duplications [Teebi et al, 1993;Seghezzi et al, 1999] have been reported. The breakpoints range from the entire short arm to smaller 9p regions including either distal or interstitial segments.…”

Section: Discussion the Rearrangementmentioning

confidence: 96%

20‐Mb duplication of chromosome 9p in a girl with minimal physical findings and normal IQ: Narrowing of the 9p duplication critical region to 6 Mb

et al. 2002

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We studied the case of a girl with a partial 9p duplication, dup(9)(p22.1 --> p13.1). Molecular cytogenetics studies defined the chromosome 9 rearrangement as a direct duplication of 20 Mb from D9S1213 to D9S52. Microsatellite analysis demonstrated the presence of a double dosage of the paternal alleles and demonstrated that the duplication occurred between sister chromatids. The patient's phenotype was almost normal, with a few minor anomalies (dolichocephaly, crowded teeth, high arched palate) and normal IQ. The breakpoint's location in this patient and previously reported cases suggest that the critical region for the 9p duplication syndrome lies within a 6-Mb portion of chromosome 9p22 between markers D9S267 and D9S1213.

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“…In only two of the previously reported cases, the origin could be clarified. In both cases, one of the parents was an inversion carrier (one paternal paracentric inversion [Phelan et al, 1993] and one maternal pericentric inversion [Mattina et al, 1987]), and unequal sister chromatid exchange was found to be the most likely mechanism of formation in both cases. In our two de novo cases, the origin of the duplication was maternal in the first case and paternal in the second.…”

Section: Discussionmentioning

confidence: 93%

“…Duplications may be formed by various mechanisms, like unequal meiotic crossing over, unequal exchange between homologous chromosomes before meiosis, or unequal sister chromatid exchange (Mattina et al, 1987). In only two of the previously reported cases, the origin could be clarified.…”

Section: Discussionmentioning

confidence: 96%

Molecular cytogenetic characterization and origin of two de novo duplication 9p cases

Tsezou¹,

Kitsiou²,

Galla³

et al. 2000

Am. J. Med. Genet.

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We report on two additional cases with duplication of 9p, minor with facial anomalies and developmental delay. Using fluorescence in situ hybridization and single-copy probes, we showed that the first case was a direct duplication, whereas the second case was inverted. The extent of the direct duplication was defined as 9p12 --> p24 by microdissection and microcloning of the aberrant chromosome and subsequent chromosome-specific comparative genomic hybridization. DNA polymorphism analysis with eight microsatellite markers revealed that the origin of the dup(9p) was maternal in the first case, whereas it was paternal in the second.

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Duplication 9p due to unequal sister chromatid exchange.

Abstract: A case of trisomy 9p syndrome is reported. The karyotype showed a tandem duplicatiQn of the short arm and of the inverted heterochromatic block of chromosome 9. Unequal sister chromatid exchange seems to be the only possible cause of this finding.

Cited by 14 publications

References 3 publications

Maternal origin of a unique extra chromosome, der(9)(pter?q13::q13?q12:) in a girl with typical trisomy 9p syndrome

Maternal origin of a unique extra chromosome, der(9)(pter?q13::q13?q12:) in a girl with typical trisomy 9p syndrome

20‐Mb duplication of chromosome 9p in a girl with minimal physical findings and normal IQ: Narrowing of the 9p duplication critical region to 6 Mb

Molecular cytogenetic characterization and origin of two de novo duplication 9p cases

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