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Mohan S, Koshy T, Vekatachalam P, Nampoothiri S, Yesodharan D, Gowrishankar K, Kumar J, Ravichandran L, Joseph S, Chandrasekaran A, Paul SFD. Subtelomeric rearrangements in Indian children with idiopathic intellectual disability/developmental delay: Frequency estimation & clinical correlation using fluorescence in situ hybridization (FISH). Indian J Med Res 2017; 144:206-214. [PMID: 27934799 PMCID: PMC5206871 DOI: 10.4103/0971-5916.195031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022] Open
Abstract
Background & objectives: Subtelomeres are prone to deleterious rearrangements owing to their proximity to unique sequences on the one end and telomeric repetitive sequences, which increase their tendency to recombine, on the other end. These subtelomeric rearrangements resulting in segmental aneusomy are reported to contribute to the aetiology of idiopathic intellectual disability/developmental delay (ID/DD). We undertook this study to estimate the frequency of subtelomeric rearrangements in children with ID/DD. Methods: One hundred and twenty seven children with idiopathic ID/DD were tested for subtelomeric rearrangements using karyotyping and FISH. Blood samples were cultured, harvested, fixed and GTG-banded using the standard protocols. Results: Rearrangements involving the subtelomeres were observed in 7.8 per cent of the tested samples. Detection of rearrangements visible at the resolution of the karyotype constituted 2.3 per cent, while those rearrangements detected only with FISH constituted 5.5 per cent. Five deletions and five unbalanced translocations were detected. Analysis of parental samples wherever possible was informative regarding the inheritance of the rearrangement. Interpretation & conclusions: The frequency of subtelomeric rearrangements observed in this study was within the reported range of 0-35 per cent. All abnormal genotypes were clinically correlated. Further analysis with array technologies presents a future prospect. Our results suggest the need to test individuals with ID/DD for subtelomeric rearrangements using sensitive methods such as FISH.
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Affiliation(s)
- Shruthi Mohan
- Department of Human Genetics, Sri Ramachandra University, Porur, India
| | - Teena Koshy
- Department of Human Genetics, Sri Ramachandra University, Porur, India
| | | | - Sheela Nampoothiri
- Department of Paediatric Genetics, Amrita Institute of Medical Sciences, Kochi, India
| | - Dhanya Yesodharan
- Department of Paediatric Genetics, Amrita Institute of Medical Sciences, Kochi, India
| | - Kalpana Gowrishankar
- Department of Medical Genetics, CHILDS Trust Medical Research Foundation, Kanchi Kamakoti CHILDS Trust Hospital, Chennai, India
| | - Jeevan Kumar
- Department of Medical Genetics, CHILDS Trust Medical Research Foundation, Kanchi Kamakoti CHILDS Trust Hospital, Chennai, India
| | | | - Santhosh Joseph
- Department of Radiology, Sri Ramachandra University, Porur, India
| | | | - Solomon F D Paul
- Department of Human Genetics, Sri Ramachandra University, Porur, India
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2
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Poot M, Haaf T. Mechanisms of Origin, Phenotypic Effects and Diagnostic Implications of Complex Chromosome Rearrangements. Mol Syndromol 2015; 6:110-34. [PMID: 26732513 DOI: 10.1159/000438812] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2015] [Indexed: 01/08/2023] Open
Abstract
Complex chromosome rearrangements (CCRs) are currently defined as structural genome variations that involve more than 2 chromosome breaks and result in exchanges of chromosomal segments. They are thought to be extremely rare, but their detection rate is rising because of improvements in molecular cytogenetic technology. Their population frequency is also underestimated, since many CCRs may not elicit a phenotypic effect. CCRs may be the result of fork stalling and template switching, microhomology-mediated break-induced repair, breakage-fusion-bridge cycles, or chromothripsis. Patients with chromosomal instability syndromes show elevated rates of CCRs due to impaired DNA double-strand break responses during meiosis. Therefore, the putative functions of the proteins encoded by ATM, BLM, WRN, ATR, MRE11, NBS1, and RAD51 in preventing CCRs are discussed. CCRs may exert a pathogenic effect by either (1) gene dosage-dependent mechanisms, e.g. haploinsufficiency, (2) mechanisms based on disruption of the genomic architecture, such that genes, parts of genes or regulatory elements are truncated, fused or relocated and thus their interactions disturbed - these mechanisms will predominantly affect gene expression - or (3) mixed mutation mechanisms in which a CCR on one chromosome is combined with a different type of mutation on the other chromosome. Such inferred mechanisms of pathogenicity need corroboration by mRNA sequencing. Also, future studies with in vitro models, such as inducible pluripotent stem cells from patients with CCRs, and transgenic model organisms should substantiate current inferences regarding putative pathogenic effects of CCRs. The ramifications of the growing body of information on CCRs for clinical and experimental genetics and future treatment modalities are briefly illustrated with 2 cases, one of which suggests KDM4C (JMJD2C) as a novel candidate gene for mental retardation.
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Affiliation(s)
- Martin Poot
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Thomas Haaf
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
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3
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Pellestor F, Anahory T, Lefort G, Puechberty J, Liehr T, Hedon B, Sarda P. Complex chromosomal rearrangements: origin and meiotic behavior. Hum Reprod Update 2011; 17:476-94. [DOI: 10.1093/humupd/dmr010] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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4
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Fauth C, Gribble SM, Porter KM, Codina-Pascual M, Ng BL, Kraus J, Uhrig S, Leifheit J, Haaf T, Fiegler H, Carter NP, Speicher MR. Micro-array analyses decipher exceptional complex familial chromosomal rearrangement. Hum Genet 2006; 119:145-53. [PMID: 16395598 DOI: 10.1007/s00439-005-0103-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Accepted: 11/03/2005] [Indexed: 10/25/2022]
Abstract
Recently there has been an increased interest in large-scale genomic variation and clinically in the consequences of haploinsufficiency of genomic segments or disruption of normal gene function by chromosome rearrangements. Here, we present an extraordinary case in which both mother and daughter presented with unexpected chromosomal rearrangement complexity, which we characterized with array-CGH, array painting and multicolor large insert clone hybridizations. We found the same 12 breakpoints involving four chromosomes in both mother and daughter. In addition, the daughter inherited a microdeletion from her father. We mapped all breakpoints to the resolution level of breakpoint spanning clones. Genes were found within 7 of the 12 breakpoint regions, some of which were disrupted by the chromosome rearrangement. One of the rearrangements disrupted a locus, which has been discussed as a quantitative trait locus for fetal hemoglobin expression in adults. Interestingly, both mother and daughter show persistent fetal hemoglobin levels. We detail the most complicated familial complex chromosomal rearrangement reported to date and thus an extreme example of inheritance of chromosomal rearrangements without error in meiotic segregation.
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MESH Headings
- Child
- Chromosome Banding
- Chromosome Breakage
- Chromosome Disorders/genetics
- Chromosome Disorders/pathology
- Chromosomes, Human, Pair 11
- Chromosomes, Human, Pair 20
- Chromosomes, Human, Pair 6
- Chromosomes, Human, Pair 9
- Female
- Humans
- In Situ Hybridization, Fluorescence/methods
- Karyotyping
- Microarray Analysis/methods
- Models, Genetic
- Nucleic Acid Hybridization/methods
- Translocation, Genetic/genetics
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Affiliation(s)
- Christine Fauth
- Institut für Humangenetik, Technische Universität München, Trogerstr. 32, 81675 München, Germany
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5
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Kline AD, Griffin CA, Haddadin MH, Chudoba I, Morsberger LA, Hawkins AL, Amato RS, Munshi G, Cohen MM. A de novo complex karyotype with two independent balanced translocations and a double inversion of chromosome 6 presenting with multiple congenital anomalies. Am J Med Genet A 2005; 129A:124-9. [PMID: 15316975 DOI: 10.1002/ajmg.a.30130] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We report a 4-year-old female with a de novo complex karyotype with multiple chromosomal rearrangements and a distinctive phenotype. Her medical history is significant for having been a twin born at 35 weeks gestation, breech presentation, with feeding problems and poor growth as an infant, gastroesophageal reflux disease, peripheral pulmonic stenosis, omphalocele, high myopia, and severe mental retardation. She is small for her age with microcephaly, posteriorly sloping forehead, shallow orbits, long palpebral fissures, prominent nose, wide mouth, absent uvula, kyphosis, brachydactyly, bridged palmar crease, and hypertonia. Peripheral blood lymphocytes revealed a karyotype of 46,XX,t(1;12)(p22.3;q21.3),inv(6)(p24q23),t(7;18)(q11.2;q21.2) in all cells. Parental karyotypes and that of her twin were normal. Spectral Karyotyping (SKY) and fluorescence in situ hybridization (FISH) with whole chromosome paints for chromosomes 1, 6, 7, 12, and 18 did not reveal additional rearrangements. Prometaphase G-banding analysis suggested that the "inverted" chromosome 6 might contain a cryptic rearrangement. Although no deletion nor duplication was detected using metaphase comparative genomic hybridization (CGH), multicolor high resolution banding (mBAND) demonstrated a double inversion of chromosome 6, resulting in a final karyotype as above but including der(6)(pter --> p23::q21 --> q22.3::q21 --> p23::q22.3 --> qter).
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Affiliation(s)
- Antonie D Kline
- Department of Pediatrics, Greater Baltimore Medical Center, Baltimore, Maryland 21204, USA.
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6
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Rosenberg C, Knijnenburg J, Chauffaille MDL, Brunoni D, Catelani AL, Sloos W, Szuhai K, Tanke HJ. Array CGH detection of a cryptic deletion in a complex chromosome rearrangement. Hum Genet 2005; 116:390-4. [PMID: 15726417 DOI: 10.1007/s00439-004-1248-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Accepted: 12/12/2004] [Indexed: 11/28/2022]
Abstract
Balanced complex chromosome rearrangements (CCR) are extremely rare in humans. They are usually ascertained either by abnormal phenotype or reproductive failure in carriers. These abnormalities are attributed to disruption of genes at the breakpoints, position effect or cryptic imbalances in the genome. However, little is known about possible imbalances at the junction points. We report here a patient with a CCR involving three chromosomes (2;10;11) and eight breakpoints. The patient presented with behavioural problems as the sole phenotypic abnormality. The rearrangement, which is apparently balanced in G-banding and multicolour FISH, was shown by genomic array analysis to include a deletion of 0.15-1.5 Mb associated with one of the breakpoints. To explain the formation of this rearrangement through the smallest possible number of breakage-and-reunion events, one has to assume that the breaks have not occurred simultaneously, but in a temporal order within the span of a single cell division. We demonstrate that array comparative genomic hybridisation (CGH) is a useful complementary tool to cytogenetic analysis for detecting and mapping cryptic imbalances associated with chromosome rearrangement.
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Affiliation(s)
- Carla Rosenberg
- Laboratory of Cytochemistry and Cytometry, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
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7
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Coco R, Rahn MI, Estanga PG, Antonioli G, Solari AJ. A constitutional complex chromosome rearrangement involving meiotic arrest in an azoospermic male: Case report. Hum Reprod 2004; 19:2784-90. [PMID: 15513983 DOI: 10.1093/humrep/deh506] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Complex chromosome rearrangements are rare aberrations that frequently lead to reproductive failure and that may hinder assisted reproduction. A 25-year-old azoospermic male was studied cytogenetically with synaptonemal complex analysis of spermatocytes from a testicular biopsy and fluorescence in situ hybridization (FISH) of lymphocytes. The spermatocytes showed a pentavalent plus a univalent chromosome. Cell death occurred mainly at advanced pachytene stages. The sex chromosomes were involved in the multiple, as shown by their typical axial excrescences. Two autosomal pairs, including an acrocentric chromosome (15), were also involved in the multiple. FISH allowed the definite identification of all the involved chromosomes. An inverted chromosome 12 is translocated with most of one long arm of chromosome 15, while the centromeric piece of this chromosome 15 is translocated with Yqh, forming a small marker chromosome t(15;Y). The euchromatic part of the Y chromosome is joined to the remaining piece of chromosome 12, forming a neo-Y chromosome. The patient shows azoospermia and a normal phenotype. The disruption of spermatogenesis is hypothetically due to the extent of asynaptic segments and to sex-body association during pachytene. This CCR occurred 'de novo' during paternal spermatogenesis. Meiotic analysis and FISH are valuable diagnostic tools in these cases.
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Affiliation(s)
- R Coco
- FECUNDITAS, Instituto de Medicina Reproductiva, Larrea 790, Buenos Aires, Argentina
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8
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Vermeulen S, Menten B, Van Roy N, Van Limbergen H, De Paepe A, Mortier G, Speleman F. Molecular cytogenetic analysis of complex chromosomal rearrangements in patients with mental retardation and congenital malformations: delineation of 7q21.11 breakpoints. Am J Med Genet A 2004; 124A:10-8. [PMID: 14679581 DOI: 10.1002/ajmg.a.20378] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Constitutional de novo complex chromosomal rearrangements (CCRs) are a rare finding in patients with mild to severe mental retardation. CCRs pose a challenge to the clinical cytogeneticist: generally CCRs are assumed to be the cause of the observed phenotypic abnormalities, but the complex nature of these chromosomal changes often hamper the accurate delineation of the chromosomal breakpoints and the identification of possible imbalances. In a first step towards a more detailed molecular cytogenetic characterization of CCRs, we studied four de novo CCRs using multicolor fluorescent in situ hybridization (M-FISH), comparative genomic hybridization (CGH), and FISH with region specific probes. These methods allowed a more refined characterization of the breakpoints in three of the four CCRs. The occurrence of 7q breakpoints in three out of these four CCRs and in 30% of reported CCRs suggested preferential involvement of this chromosomal region in the formation of CCRs. Further analysis of these 7q breakpoints revealed a 2 Mb deletion at 7q21.11 in one patient and involvement of the same region in a cryptic insertion in a second patient. This particular region contains at least 5 candidate genes for mental retardation. The other patient had a breakpoint more proximal to this region. The present data together with these from the literature provide evidence that a region within 7q21.11 may be prone to breakage and formation of CCRs.
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Affiliation(s)
- Stefan Vermeulen
- Center for Medical Genetics, Ghent University Hospital 0K5, De Pintelaan 185, 9000 Ghent, Belgium.
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Grasshoff U, Singer S, Liehr T, Starke H, Fode B, Schöning M, Dufke A. A complex chromosomal rearrangement with a translocation 4;10;14 in a fertile male carrier: ascertainment through an offspring with partial trisomy 14q13-->q24.1 and partial monosomy 4q27-->q28 [corrected]. Cytogenet Genome Res 2004; 103:17-23. [PMID: 15004458 DOI: 10.1159/000076282] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Accepted: 10/13/2003] [Indexed: 11/19/2022] Open
Abstract
Complex chromosomal rearrangements (CCRs) are usually associated with infertility or subfertility in male carriers. If fertility is maintained, there is a high risk of abnormal pregnancy outcome. Few male carriers have been identified by children presenting with mental retardation/congenital malformations (MR/CM) or by spontaneous abortions of the spouses. We report a de novo CCR with five breakpoints involving chromosomes 4, 10 and 14 in a male carrier who was ascertained through a son presenting with MR/CM due to an unbalanced karyotype with partial trisomy 14 and partial monosomy 4. The child has a healthy elder brother. In the family history no abortions were reported. No fertility treatment was necessary. Cytogenetic analysis from the affected son showed a reciprocal translocation t(4;10) with additional chromosomal material inserted between the translocation junctions in the derivative chromosome 10. The father showed the same derivative chromosome 10 but had additionally one aberrant chromosome 14. Further molecular cytogenetic analyses determined the inserted material in the aberrant chromosome 10 as derived from chromosome 14 and revealed a small translocation with material of chromosome 4 inserted into the derivative chromosome 14. Thus the phenotype of the son is supposed to be associated with a partial duplication 14q13-->q24.1 and a partial monosomy 4q27-->q28. Including our case we are aware of eleven CCR cases with fertile male carriers. In eight of these families normal offspring have been reported. We propose that exceptional CCRs in fertile male carriers might form comparatively simple pachytene configurations increasing the chance of healthy offspring.
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Affiliation(s)
- U Grasshoff
- Department of Medical Genetics, Eberhard-Karls-University of Tübingen Medical School, Tübingen, Germany
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10
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Battisti C, Bonaglia MC, Giglio S, Anichini C, Pucci L, Dotti MT, Zuffardi O, Federico A. De novo double translocation 3;13 and 4;8;18 in a patient with mental retardation and skeletal abnormalities. Am J Med Genet A 2003; 117A:207-11. [PMID: 12599183 DOI: 10.1002/ajmg.a.10149] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A de novo, apparently balanced complex chromosome rearrangement (CCR) involving five chromosomes and six chromosome breakpoints was found in a child with Marfanoid habitus, kyphoscoliosis, axillary pterygium, camptodactyly, joint laxity, and mild mental retardation. Fluorescence in situ hybridization (FISH) revealed a simple translocation involving chromosomes 3 and 13, and a complex rearrangement involving chromosomes 4, 8, and 18 with four breakpoints.
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MESH Headings
- Abnormalities, Multiple/genetics
- Abnormalities, Multiple/pathology
- Bone and Bones/abnormalities
- Child
- Chromosomes, Human, Pair 13/genetics
- Chromosomes, Human, Pair 18/genetics
- Chromosomes, Human, Pair 3/genetics
- Chromosomes, Human, Pair 4/genetics
- Chromosomes, Human, Pair 8/genetics
- Fingers/abnormalities
- Humans
- In Situ Hybridization, Fluorescence
- Intellectual Disability/pathology
- Male
- Translocation, Genetic
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Affiliation(s)
- C Battisti
- O.U. of Neurometabolic Diseases, Policlinico Le Scotte, Research Center for Diagnosis, Therapy and Prevention of Neurohandicap, University of Siena, Viale Bracci 2, 53100 Siena, Italy
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Abstract
Aim of this review is to present the latest advances in the identification of the genetic determinants of intellectual deficiency. Mental retardation (MR) is often associated with other neurologic symptoms, metabolic disorders, or malformation syndromes. The purpose of the review is to subdivide the large field of MR into categories that may help professionals in making a diagnosis. Nonspecific MR can also segregate in families and the mapping and cloning of corresponding mutant genes will eventually advance our understanding of normal and abnormal brain functioning. Several genes responsible for nonspecific X-linked mental retardation have been identified in the last 12 to 24 months and are being intensively investigated. This will hopefully lead to new possibilities of either genetic or pharmacological therapy.
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Affiliation(s)
- P Chiurazzi
- Department of Clinical Genetics, Erasmus University, Rotterdam, The Netherlands
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