Eleven X Chromosome Breakpoints Associated with Premature Ovarian Failure (POF) Map to a 15-Mb YAC Contig Spanning Xq21

Sala, Cinzia; Arrigo, Giulia; Torri, G.; Martinazzi, Francesco; Riva, Paola; Larizza, Lidia; Philippe, Christophe; Jonveaux, Philippe; Sloan, Frederique; Labella, Tullio; Toniolo, Daniela

doi:10.1006/geno.1996.4542

Cited by 131 publications

(84 citation statements)

References 30 publications

(7 reference statements)

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“…Above ideogram, bars represent critical regions for ovarian dysgenesis suggested in different studies. Diagram modified from [14] dysgenesis related to chromosomal abnormalities can be due to disrupted expression of critical genes [34], inappropriate gene expression following incomplete paring of X chromosome at pachytene leading to meiotic arrest [34,35] or position effect of the breakpoints on the flanking X-linked gene or autosomal linked genes.…”

Section: Discussionmentioning

confidence: 99%

Molecular cytogenetic characterization of two Turner syndrome patients with mosaic ring X chromosome

Chauhan

Jaiswal

Lakhotia

et al. 2016

J Assist Reprod Genet

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Purpose In the present study, we reported two cases of TS with mosaic ring X chromosome showing common clinical characteristics of TS like growth retardation and ovarian dysfunction. The purpose of the present study was to cytogenetically characterize both cases. Methods Whole blood culture and G-banding were performed for karyotyping the cases following standard protocol. Origin of the ring chromosome and degree of mosaicism were further determined by fluorescence in situ hybridization (FISH). Breakpoints and loss of genetic material in formation of different ring X chromosomes r (X) in cases were determined with the help of cytogenetic microarray. Results Cases 1 and 2 with ring chromosome were cytogenetically characterized as 45, X [114]/46Xr (X) (p22.11q21.32) [116] and 45, X [170]/46, Xr (X) (p22.2q21.33) [92], respectively. Sizes of these ring X chromosomes were found to be~7 5 and~95 Mb in cases 1 and 2, respectively, using visual estimation as part of cytogenetic observation. In both cases, we observed breakpoints on Xq chromosome were within relatively narrow region between Xq21.33 and Xq22.1 compared to regions in previously reported cases associated with ovarian dysgenesis. Conclusions Our observation agrees with the fact that despite of large heterogeneity, severity of the cases with intact Xinactive specific transcript (XIST) is dependent on degree of mosaicism and extent of Xq deletion having crucial genes involved directly or indirectly in various physiological involving ovarian cyclicity.

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Section: Discussionmentioning

confidence: 99%

Molecular cytogenetic characterization of two Turner syndrome patients with mosaic ring X chromosome

Chauhan

Jaiswal

Lakhotia

et al. 2016

J Assist Reprod Genet

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“…Protein coding exons of COL4A6 (exons 1-45), insulin-like growth factor binding protein 7 (IGFBP7) (exons [1][2][3][4][5] and C14orf159 (exons 4-16) were screened by high-resolution melt analysis using LightCycler 480 system II (Roche Applied Science, Tokyo, Japan), except for exon 1 of IGFBP7, which were analyzed by direct sequencing. PCR mixture contained 20 ng genomic DNA, 1Â ExTaq buffer, 0.2 mM each dNTPs, 0. an aberrant melting curve pattern, the PCR product was purified using ExoSAP-IT (USB, Cleveland, OH, USA) and sequenced by a standard method using BigDye terminator ver.3 (Applied Biosystems, Foster City, CA, USA) on the ABI PRISM 3100 Genetic analyzer (Applied Biosystems).…”

Section: Mutation Analysismentioning

confidence: 99%

“…2,4 It was suggested that several X-linked loci expressing on both X chromosomes, which were required in a higher dosage for normal ovarian function, were involved in POF. 5 Furthermore, genetic factors for POF may be more complex as X;autosome translocations often disrupt no genes; therefore, other factors, such as position effects on autosomal genes, are proposed. 6 We had an opportunity to analyze four cases of POF each having t(X;autosome).…”

Section: Introductionmentioning

confidence: 99%

Breakpoint determination of X;autosome balanced translocations in four patients with premature ovarian failure

et al. 2010

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Premature ovarian failure (POF) is a disorder characterized by amenorrhea and elevated serum gonadotropins before 40 years of age. As X chromosomal abnormalities are often recognized in POF patients, defects of X-linked gene may contribute to POF. Four cases of POF with t(X;autosome) were genetically analyzed. All the translocation breakpoints were determined at the nucleotide level. Interestingly, COL4A6 at Xq22.3 encoding collagen type IV alpha 6 was disrupted by the translocation in one case, but in the remaining three cases, breakpoints did not involve any X-linked genes. According to the breakpoint sequences, two translocations had microhomology of a few nucleotides and the other two showed insertion of 3-8 nucleotides with unknown origin, suggesting that non-homologous end-joining is related to the formation of all the translocations.

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“…At Xq (Table 1), cases 1-3 have the same breakpoint between the two YACs 31HF3 (DXS1217, DXYS34, DXYS1, DXYS42) and 208A4 (DXYS107 and DXYS5). 18 The two YACs are separated by DXYS49. YAC 905A8, which covers DXYS49 and partially overlaps 31HF3 and 208A4, did not give clear hybridisation signals at Xq.…”

Section: Resultsmentioning

confidence: 99%

Opposite deletions/duplications of the X chromosome: two novel reciprocal rearrangements

et al. 2000

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Paralogous sequences on the same chromosome allow refolding of the chromosome into itself and homologous recombination. Recombinant chromosomes have microscopic or submicroscopic rearrangements according to the distance between repeats. Examples are the submicroscopic inversions of factor VIII, of the IDS gene and of the FLN1/emerin region, all resulting from misalignment of inverted repeats, and double recombination. Most of these inversions are of paternal origin possibly because the X chromosome at male meiosis is free to refold into itself for most of its length. We report on two de novo rearrangements of the X chromosome found in four hypogonadic females. Two of them had an X chromosome deleted for most of Xp and duplicated for a portion of Xq and two had the opposite rearrangement (class I and class II rearrangements, respectively). The breakpoints were defined at the level of contiguous YACs. The same Xp11.23 breakpoint was found in the four cases. That of the long arm coincided in three cases (Xq21.3) and was more proximal in case 4 (Xq21.1). Thus class I rearrangements (cases 1 and 2) are reciprocal to that of case 3, whilst that of case 4 shares only the Xp breakpoint. The abnormal X was paternal in the three cases investigated. Repeated inverted sequences located at the breakpoints of rearrangements are likely to favour the refolding of the paternal X chromosome and the recombination of the repeats. The repeat at the Xp11 may synapse with either that at Xq21.3 or that at Xq21.1. These rearrangements seem to originate as the Xq28 submicroscopic inversions but they are identifiable at the microscopic level and result from a single recombination event.

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Eleven X Chromosome Breakpoints Associated with Premature Ovarian Failure (POF) Map to a 15-Mb YAC Contig Spanning Xq21

Cited by 131 publications

References 30 publications

Molecular cytogenetic characterization of two Turner syndrome patients with mosaic ring X chromosome

Molecular cytogenetic characterization of two Turner syndrome patients with mosaic ring X chromosome

Breakpoint determination of X;autosome balanced translocations in four patients with premature ovarian failure

Opposite deletions/duplications of the X chromosome: two novel reciprocal rearrangements

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