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Barra V, Fachinetti D. The dark side of centromeres: types, causes and consequences of structural abnormalities implicating centromeric DNA. Nat Commun 2018; 9:4340. [PMID: 30337534 PMCID: PMC6194107 DOI: 10.1038/s41467-018-06545-y] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 09/06/2018] [Indexed: 12/18/2022] Open
Abstract
Centromeres are the chromosomal domains required to ensure faithful transmission of the genome during cell division. They have a central role in preventing aneuploidy, by orchestrating the assembly of several components required for chromosome separation. However, centromeres also adopt a complex structure that makes them susceptible to being sites of chromosome rearrangements. Therefore, preservation of centromere integrity is a difficult, but important task for the cell. In this review, we discuss how centromeres could potentially be a source of genome instability and how centromere aberrations and rearrangements are linked with human diseases such as cancer.
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Affiliation(s)
- V Barra
- Institut Curie, PSL Research University, CNRS, UMR 144, 26 rue d'Ulm, F-75005, Paris, France
| | - D Fachinetti
- Institut Curie, PSL Research University, CNRS, UMR 144, 26 rue d'Ulm, F-75005, Paris, France.
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Villa N, Conconi D, Benussi DG, Tornese G, Crosti F, Sala E, Dalprà L, Pecile V. A complete duplication of X chromosome resulting in a tricentric isochromosome originated by centromere repositioning. Mol Cytogenet 2017. [PMID: 28630649 PMCID: PMC5470200 DOI: 10.1186/s13039-017-0323-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neocentromeres are rare and considered chromosomal aberrations, because a non-centromeric region evolves in an active centromere by mutation. The literature reported several structural anomalies of X chromosome and they influence the female reproductive capacity or are associated to Turner syndrome in the presence of monosomy X cell line. CASE PRESENTATION We report a case of chromosome X complex rearrangement found in a prenatal diagnosis. The fetal karyotype showed a mosaicism with a 45,X cell line and a 46 chromosomes second line with a big marker, instead of a sex chromosome. The marker morphology and fluorescence in situ hybridization (FISH) characterization allowed us to identify a tricentric X chromosome constituted by two complete X chromosome fused at the p arms telomere and an active neocentromere in the middle, at the union of the two Xp arms, where usually are the telomeric regions. FISH also showed the presence of a paracentric inversion of both Xp arms. Furthermore, fragility figures were found in 56% of metaphases from peripheral blood lymphocytes culture at birth: a shorter marker chromosome and an apparently acentric fragment frequently lost. CONCLUSIONS At our knowledge, this is the first isochromosome of an entire non-acrocentric chromosome. The neocentromere is constituted by canonical sequences but localized in an unusual position and the original centromeres are inactivated. We speculated that marker chromosome was the result of a double rearrangement: firstly, a paracentric inversion which involved the Xp arm, shifting a part of the centromere at the p end and subsequently a duplication of the entire X chromosome, which gave rise to an isochromosome. It is possible to suppose that the first event could be a result of a non-allelic homologous recombination mediated by inverted low-copy repeats. As expected, our case shows a Turner phenotype with mild facial features and no major skeletal deformity, normal psychomotor development and a spontaneous development of puberty and menarche, although with irregular menses since the last follow-up.
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Affiliation(s)
- N Villa
- Medical Genetics Laboratory, Clinical Pathology Department, S. Gerardo Hospital, Monza, Italy
| | - D Conconi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - D Gambel Benussi
- Medical Genetics, Institute for Maternal and Child Health I.R.C.C.S. "Burlo Garofolo", Trieste, Italy
| | - G Tornese
- Department of Pediatrics, Institute for Maternal and Child Health I.R.C.C.S. "Burlo Garofolo", Trieste, Italy
| | - F Crosti
- Medical Genetics Laboratory, Clinical Pathology Department, S. Gerardo Hospital, Monza, Italy
| | - E Sala
- Medical Genetics Laboratory, Clinical Pathology Department, S. Gerardo Hospital, Monza, Italy
| | - L Dalprà
- Medical Genetics Laboratory, Clinical Pathology Department, S. Gerardo Hospital, Monza, Italy.,School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - V Pecile
- Medical Genetics, Institute for Maternal and Child Health I.R.C.C.S. "Burlo Garofolo", Trieste, Italy
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Hemmat M, Yang X, Chan P, McGough RA, Ross L, Mahon LW, Anguiano AL, Boris WT, Elnaggar MM, Wang JCJ, Strom CM, Boyar FZ. Characterization of a complex chromosomal rearrangement using chromosome, FISH, and microarray assays in a girl with multiple congenital abnormalities and developmental delay. Mol Cytogenet 2014; 7:50. [PMID: 25478007 PMCID: PMC4255717 DOI: 10.1186/1755-8166-7-50] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/27/2014] [Indexed: 11/10/2022] Open
Abstract
Complex chromosomal rearrangements (CCRs) are balanced or unbalanced structural rearrangements involving three or more cytogenetic breakpoints on two or more chromosomal pairs. The phenotypic anomalies in such cases are attributed to gene disruption, superimposed cryptic imbalances in the genome, and/or position effects. We report a 14-year-old girl who presented with multiple congenital anomalies and developmental delay. Chromosome and FISH analysis indicated a highly complex chromosomal rearrangement involving three chromosomes (3, 7 and 12), seven breakpoints as a result of one inversion, two insertions, and two translocations forming three derivative chromosomes. Additionally, chromosomal microarray study (CMA) revealed two submicroscopic deletions at 3p12.3 (467 kb) and 12q13.12 (442 kb). We postulate that microdeletion within the ROBO1 gene at 3p12.3 may have played a role in the patient’s developmental delay, since it has potential activity-dependent role in neurons. Additionally, factors other than genomic deletions such as loss of function or position effects may also contribute to the abnormal phenotype in our patient.
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Affiliation(s)
- Morteza Hemmat
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Xiaojing Yang
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Patricia Chan
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Robert A McGough
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Leslie Ross
- Quest Diagnostics, 695 South Broadway, Denver, Colorado 80209, USA
| | - Loretta W Mahon
- Quest Diagnostics, 8401 Fallbrook Avenue , West, Hills, California 91304, USA
| | - Arturo L Anguiano
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Wang T Boris
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Mohamed M Elnaggar
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Jia-Chi J Wang
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Charles M Strom
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
| | - Fatih Z Boyar
- Cytogenetics Department, Quest Diagnostics Nichols Institute, 33608 Ortega Hwy, San Juan Capistrano, California 92675, USA
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A turner syndrome patient carrying a mosaic distal x chromosome marker. Case Rep Genet 2014; 2014:597314. [PMID: 24778889 PMCID: PMC3977098 DOI: 10.1155/2014/597314] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 02/05/2014] [Indexed: 11/22/2022] Open
Abstract
A skin sample from a 17-year-old female was received for routine karyotyping with a set of clinical features including clonic seizures, cardiomyopathy, hepatic adenomas, and skeletal dysplasia. Conventional karyotyping revealed a mosaic Turner syndrome karyotype with a cell line containing a small marker of X chromosome origin. This was later confirmed on peripheral blood cultures by conventional G-banding, fluorescence in situ hybridisation and microarray analysis. Similar Turner mosaic marker chromosome cases have been previously reported in the literature, with a variable phenotype ranging from the mild “classic” Turner syndrome to anencephaly, agenesis of the corpus callosum, complex heart malformation, and syndactyly of the fingers and toes. This case report has a phenotype that is largely discordant with previously published cases as it lies at the severe end of the Turner variant phenotype scale. The observed cytogenetic abnormalities in this study may represent a coincidental finding, but we cannot exclude the possibility that the marker has a nonfunctioning X chromosome inactivation locus, leading to functional disomy of those genes carried by the marker.
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