1
|
Sun Q, Zhang X, Zhan P, Tian W, Wang Y, Yang X. Analysis of 2 men with t(8;22)(q13;q13) and t(8;14)(q13;q22) chromosomal translocation karyotypes. Medicine (Baltimore) 2022; 101:e31091. [PMID: 36254019 PMCID: PMC9575810 DOI: 10.1097/md.0000000000031091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Male infertility is a multifactorial condition that is closely associated with chromosomal abnormalities. Reciprocal chromosomal translocation (RCT) is a significant structural genetic abnormality. The specific mechanisms of forms of RCT affecting male infertility include the product of chromosomally unbalanced gametes, thereby disrupting the structure and function of important genes responsible for spermatogenesis. RCT breakpoints have been found to disrupt gene structure and function in many medical fields However, the relationship between RCT breakpoints and male infertility remains to be determined. The purpose of this study is to describe 2 male carriers of RCTs 46,XY,t(8;22)(q13;q13) and 46,XY,t(8;14)(q13;q22). Both patients were collected from the second hospital of Jilin University. Semen parameters were detected using the computer-aided semen analysis system. Cytogenetic analysis was performed using standard operating procedure. Related genes on chromosomal breakpoints were searched using Online Mendelian Inheritance in Man. One man had semen parameters within the normal range, but the couple was infertile after 5 years of marriage. The other man showed normal semen parameters, and his wife had experienced 2 spontaneous miscarriages. Using a literature search, the association between chromosome 22q13 breakpoint and fertility were investigated. The results suggest that physicians should focus on the clinical phenotype of the patients and the breakpoints of RCT in genetic counseling. An important gene related to human male infertility is clearly located in chromosome region 22q13, and its function is worthy of further study.
Collapse
Affiliation(s)
- Qijia Sun
- Department of Urology, The Second Hospital of Jilin University, Changchun, China
| | - Xiaoyu Zhang
- Department of Urology, The Second Hospital of Jilin University, Changchun, China
| | - Peng Zhan
- Department of Urology, The Second Hospital of Jilin University, Changchun, China
- * Correspondence: Peng Zhan, Department of Urology, The Second Hospital of Jilin University, 218 Ziqiang Street, Nanguan District, Changchun, Jilin Province 130041, China (e-mail: )
| | - Wenjie Tian
- Department of Urology, The Second Hospital of Jilin University, Changchun, China
| | - Yanli Wang
- Department of Urology, The Second Hospital of Jilin University, Changchun, China
| | - Xiao Yang
- Department of Urology, The Second Hospital of Jilin University, Changchun, China
| |
Collapse
|
2
|
Osei-Owusu IA, Norris AL, Joynt AT, Thorpe J, Cho S, Tierney E, Schmidt J, Hagopian L, Harris J, Pevsner J. Characterization of an unbalanced translocation causing 3q28qter duplication and 10q26.2qter deletion in a patient with global developmental delay and self-injury. Cold Spring Harb Mol Case Stud 2020; 6:mcs.a005884. [PMID: 33335013 PMCID: PMC7784495 DOI: 10.1101/mcs.a005884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/08/2020] [Indexed: 01/17/2023] Open
Abstract
Chromosomal structural variation can cause severe neurodevelopmental and neuropsychiatric phenotypes. Here we present a nonverbal female adolescent with severe stereotypic movement disorder with severe problem behavior (e.g., self-injurious behavior, aggression, and disruptive and destructive behaviors), autism spectrum disorder, severe intellectual disability, attention deficit hyperactivity disorder, and global developmental delay. Previous cytogenetic analysis revealed balanced translocations present in the patient's apparently normal mother. We hypothesized the presence of unbalanced translocations in the patient due to maternal history of spontaneous abortions. Whole-genome sequencing and whole-genome optical mapping, complementary next-generation genomic technologies capable of the accurate and robust detection of structural variants, identified t(3;10), t(10;14), and t(3;14) three-way balanced translocations in the mother and der(10)t(3;14;10) and der(14)t(3;14;10) translocations in the patient. Instead of a t(3;10), she inherited a normal maternal copy of Chromosome 3, resulting in an unbalanced state of a 3q28qter duplication and 10q26.2qter deletion. Copy-imbalanced genes in one or both of these regions, such as DLG1, DOCK1, and EBF3, may contribute to the patient's phenotype that spans neurodevelopmental, musculoskeletal, and psychiatric domains, with the possible contribution of a maternally inherited 15q13.2q13.3 deletion.
Collapse
Affiliation(s)
- Ikeoluwa A Osei-Owusu
- Program in Human Genetics, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.,Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA
| | - Alexis L Norris
- Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA
| | - Anya T Joynt
- Program in Human Genetics, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Jeremy Thorpe
- Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA.,Program in Biochemistry, Cellular and Molecular Biology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Soonweng Cho
- Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA.,Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Elaine Tierney
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.,Department of Psychiatry, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA
| | - Jonathan Schmidt
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.,Department of Behavioral Psychology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA
| | - Louis Hagopian
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.,Department of Behavioral Psychology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA
| | - Jacqueline Harris
- Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA.,Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Jonathan Pevsner
- Program in Human Genetics, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.,Department of Neurology, Kennedy Krieger Institute, Baltimore, Maryland 21205, USA.,Program in Biochemistry, Cellular and Molecular Biology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA.,Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| |
Collapse
|
3
|
Oudelaar AM, Higgs DR. The relationship between genome structure and function. Nat Rev Genet 2020; 22:154-168. [PMID: 33235358 DOI: 10.1038/s41576-020-00303-x] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2020] [Indexed: 02/06/2023]
Abstract
Precise patterns of gene expression in metazoans are controlled by three classes of regulatory elements: promoters, enhancers and boundary elements. During differentiation and development, these elements form specific interactions in dynamic higher-order chromatin structures. However, the relationship between genome structure and its function in gene regulation is not completely understood. Here we review recent progress in this field and discuss whether genome structure plays an instructive role in regulating gene expression or is a reflection of the activity of the regulatory elements of the genome.
Collapse
Affiliation(s)
| | - Douglas R Higgs
- Laboratory of Gene Regulation, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
| |
Collapse
|
4
|
Prediction of a rare chromosomal aberration simultaneously with next generation sequencing-based comprehensive chromosome screening in human preimplantation embryos for recurrent pregnancy loss. J Assist Reprod Genet 2017; 35:171-176. [PMID: 28965243 DOI: 10.1007/s10815-017-1044-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 09/07/2017] [Indexed: 11/27/2022] Open
Abstract
Preimplantation genetic testing has been used widely in recent years as a part of assisted reproductive technology (ART) owing to the breakthrough development of deoxyribonucleic acid (DNA) sequencing. With the advancement of technology and increased resolution of next generation sequencing (NGS), extensive comprehensive chromosome screening along with small clinically significant deletions and duplications can possibly be performed simultaneously. Here, we present a case of rare chromosomal aberrations: 46,XY,dup(15)(q11.2q13),t(16;18)(q23;p11.2), which resulted in a normally developed adult but abnormal gametes leading to recurrent pregnancy loss (RPL). To our best knowledge, this is the first report of t(16;18) translocation with such a small exchanged segment detected by NGS platform of MiSeq system in simultaneous 24-chromosome aneuploidy screening.
Collapse
|
5
|
Weckselblatt B, Hermetz KE, Rudd MK. Unbalanced translocations arise from diverse mutational mechanisms including chromothripsis. Genome Res 2015; 25:937-47. [PMID: 26070663 PMCID: PMC4484391 DOI: 10.1101/gr.191247.115] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/15/2015] [Indexed: 12/17/2022]
Abstract
Unbalanced translocations are a relatively common type of copy number variation and a major contributor to neurodevelopmental disorders. We analyzed the breakpoints of 57 unique unbalanced translocations to investigate the mechanisms of how they form. Fifty-one are simple unbalanced translocations between two different chromosome ends, and six rearrangements have more than three breakpoints involving two to five chromosomes. Sequencing 37 breakpoint junctions revealed that simple translocations have between 0 and 4 base pairs (bp) of microhomology (n = 26), short inserted sequences (n = 8), or paralogous repeats (n = 3) at the junctions, indicating that translocations do not arise primarily from nonallelic homologous recombination but instead form most often via nonhomologous end joining or microhomology-mediated break-induced replication. Three simple translocations fuse genes that are predicted to produce in-frame transcripts of SIRPG-WWOX, SMOC2-PROX1, and PIEZO2-MTA1, which may lead to gain of function. Three complex translocations have inversions, insertions, and multiple breakpoint junctions between only two chromosomes. Whole-genome sequencing and fluorescence in situ hybridization analysis of two de novo translocations revealed at least 18 and 33 breakpoints involving five different chromosomes. Breakpoint sequencing of one maternally inherited translocation involving four chromosomes uncovered multiple breakpoints with inversions and insertions. All of these breakpoint junctions had 0-4 bp of microhomology consistent with chromothripsis, and both de novo events occurred on paternal alleles. Together with other studies, these data suggest that germline chromothripsis arises in the paternal genome and may be transmitted maternally. Breakpoint sequencing of our large collection of chromosome rearrangements provides a comprehensive analysis of the molecular mechanisms behind translocation formation.
Collapse
Affiliation(s)
- Brooke Weckselblatt
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Karen E Hermetz
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - M Katharine Rudd
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| |
Collapse
|
6
|
Dupont C, Baumann C, Le Du N, Schaefer E, Guimiot F, Boutaud L, Capri Y, Spaggiari E, Aboura A, Benzacken B, Tabet AC. COL2A1 gene disruption by a balanced translocation t(12;15)(q13;q22.2) in familial Stickler syndrome. Am J Med Genet A 2013; 161A:2663-5. [PMID: 23918474 DOI: 10.1002/ajmg.a.36081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 05/05/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Céline Dupont
- AP-HP, Department of Genetic-Cytogenetic Unit, Robert Debre Hospital, Paris, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Balanced into array: genome-wide array analysis in 54 patients with an apparently balanced de novo chromosome rearrangement and a meta-analysis. Eur J Hum Genet 2011; 19:1152-60. [PMID: 21712853 DOI: 10.1038/ejhg.2011.120] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022] Open
Abstract
High-resolution genome-wide array analysis enables detailed screening for cryptic and submicroscopic imbalances of microscopically balanced de novo rearrangements in patients with developmental delay and/or congenital abnormalities. In this report, we added the results of genome-wide array analysis in 54 patients to data on 117 patients from seven other studies. A chromosome imbalance was detected in 37% of all patients with two-breakpoint rearrangements. In 49% of these patients, the imbalances were located in one or both breakpoint regions. Imbalances were more frequently (90%) found in complex rearrangements, with the majority (81%) having deletions in the breakpoint regions. The size of our own cohort enabled us to relate the presence of an imbalance to the clinical features of the patients by using a scoring system, the De Vries criteria, that indicates the complexity of the phenotype. The median De Vries score was significantly higher (P=0.002) in those patients with an imbalance (5, range 1-9) than in patients with a normal array result (3, range 0-7). This study provides accurate percentages of cryptic imbalances that can be detected by genome-wide array analysis in simple and complex de novo microscopically balanced chromosome rearrangements and confirms that these imbalances are more likely to occur in patients with a complex phenotype.
Collapse
|
8
|
Neill NJ, Ballif BC, Lamb AN, Parikh S, Ravnan JB, Schultz RA, Torchia BS, Rosenfeld JA, Shaffer LG. Recurrence, submicroscopic complexity, and potential clinical relevance of copy gains detected by array CGH that are shown to be unbalanced insertions by FISH. Genome Res 2011; 21:535-44. [PMID: 21383316 DOI: 10.1101/gr.114579.110] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Insertions occur when a segment of one chromosome is translocated and inserted into a new region of the same chromosome or a non-homologous chromosome. We report 71 cases with unbalanced insertions identified using array CGH and FISH in 4909 cases referred to our laboratory for array CGH and found to have copy-number abnormalities. Although the majority of insertions were non-recurrent, several recurrent unbalanced insertions were detected, including three der(Y)ins(Y;18)(q?11.2;p11.32p11.32)pat inherited from parents carrying an unbalanced insertion. The clinical significance of these recurrent rearrangements is unclear, although the small size, limited gene content, and inheritance pattern of each suggests that the phenotypic consequences may be benign. Cryptic, submicroscopic duplications were observed at or near the insertion sites in two patients, further confounding the clinical interpretation of these insertions. Using FISH, linear amplification, and array CGH, we identified a 126-kb duplicated region from 19p13.3 inserted into MECP2 at Xq28 in a patient with symptoms of Rett syndrome. Our results demonstrate that although the interpretation of most non-recurrent insertions is unclear without high-resolution insertion site characterization, the potential for an otherwise benign duplication to result in a clinically relevant outcome through the disruption of a gene necessitates the use of FISH to determine whether copy-number gains detected by array CGH represent tandem duplications or unbalanced insertions. Further follow-up testing using techniques such as linear amplification or sequencing should be used to determine gene involvement at the insertion site after FISH has identified the presence of an insertion.
Collapse
|
9
|
Miller DT, Adam MP, Aradhya S, Biesecker LG, Brothman AR, Carter NP, Church DM, Crolla JA, Eichler EE, Epstein CJ, Faucett WA, Feuk L, Friedman JM, Hamosh A, Jackson L, Kaminsky EB, Kok K, Krantz ID, Kuhn RM, Lee C, Ostell JM, Rosenberg C, Scherer SW, Spinner NB, Stavropoulos DJ, Tepperberg JH, Thorland EC, Vermeesch JR, Waggoner DJ, Watson MS, Martin CL, Ledbetter DH. Consensus statement: chromosomal microarray is a first-tier clinical diagnostic test for individuals with developmental disabilities or congenital anomalies. Am J Hum Genet 2010; 86:749-64. [PMID: 20466091 PMCID: PMC2869000 DOI: 10.1016/j.ajhg.2010.04.006] [Citation(s) in RCA: 1811] [Impact Index Per Article: 129.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 04/12/2010] [Accepted: 04/19/2010] [Indexed: 12/11/2022] Open
Abstract
Chromosomal microarray (CMA) is increasingly utilized for genetic testing of individuals with unexplained developmental delay/intellectual disability (DD/ID), autism spectrum disorders (ASD), or multiple congenital anomalies (MCA). Performing CMA and G-banded karyotyping on every patient substantially increases the total cost of genetic testing. The International Standard Cytogenomic Array (ISCA) Consortium held two international workshops and conducted a literature review of 33 studies, including 21,698 patients tested by CMA. We provide an evidence-based summary of clinical cytogenetic testing comparing CMA to G-banded karyotyping with respect to technical advantages and limitations, diagnostic yield for various types of chromosomal aberrations, and issues that affect test interpretation. CMA offers a much higher diagnostic yield (15%-20%) for genetic testing of individuals with unexplained DD/ID, ASD, or MCA than a G-banded karyotype ( approximately 3%, excluding Down syndrome and other recognizable chromosomal syndromes), primarily because of its higher sensitivity for submicroscopic deletions and duplications. Truly balanced rearrangements and low-level mosaicism are generally not detectable by arrays, but these are relatively infrequent causes of abnormal phenotypes in this population (<1%). Available evidence strongly supports the use of CMA in place of G-banded karyotyping as the first-tier cytogenetic diagnostic test for patients with DD/ID, ASD, or MCA. G-banded karyotype analysis should be reserved for patients with obvious chromosomal syndromes (e.g., Down syndrome), a family history of chromosomal rearrangement, or a history of multiple miscarriages.
Collapse
Affiliation(s)
- David T. Miller
- Division of Genetics and Department of Laboratory Medicine, Children's Hospital Boston and Harvard Medical School, Boston, MA, USA
| | - Margaret P. Adam
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
| | | | - Leslie G. Biesecker
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Arthur R. Brothman
- Department of Pediatrics, Human Genetics, Pathology and ARUP Laboratories, University of Utah School of Medicine, Salt Lake City, UT, USA
| | | | - Deanna M. Church
- National Center for Biotechnology Information, Bethesda, MD, USA
| | - John A. Crolla
- National Genetics Reference Laboratory (Wessex), Salisbury UK
| | - Evan E. Eichler
- Department of Genome Sciences and Howard Hughes Medical Institute, University of Washington School of Medicine, Seattle, WA, USA
| | - Charles J. Epstein
- Institute for Human Genetics and Department of Pediatrics, University of California, San Francisco, San Francisco, CA, USA
| | - W. Andrew Faucett
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Lars Feuk
- Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Jan M. Friedman
- Department of Medical Genetics, University of British Columbia, and Child & Family Research Institute, Vancouver, British Columbia, Canada
| | - Ada Hamosh
- Department of Pediatrics and McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Laird Jackson
- Department of Obstetrics and Gynecology, Drexel University College of Medicine and Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Erin B. Kaminsky
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Klaas Kok
- Department of Genetics, University Medical Centre Groningen, University of Groningen, The Netherlands
| | - Ian D. Krantz
- Department of Pediatrics/Human Genetics, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Robert M. Kuhn
- Center for Biomolecular Science and Engineering, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Charles Lee
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - James M. Ostell
- National Center for Biotechnology Information, Bethesda, MD, USA
| | - Carla Rosenberg
- Department of Genetics and Evolutionary Biology, University Sao Paulo, Brazil
| | - Stephen W. Scherer
- The Centre for Applied Genomics and Program in Genetics and Genetic Biology, The Hospital for Sick Children and Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Nancy B. Spinner
- Department of Pediatrics/Human Genetics, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Dimitri J. Stavropoulos
- Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Erik C. Thorland
- Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | | | - Darrel J. Waggoner
- Department of Human Genetics and Pediatrics, University of Chicago, Chicago, IL, USA
| | | | - Christa Lese Martin
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - David H. Ledbetter
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| |
Collapse
|
10
|
Lindstrand A, Schoumans J, Gustavsson P, Hanemaaijer N, Malmgren H, Blennow E. Improved structural characterization of chromosomal breakpoints using high resolution custom array-CGH. Clin Genet 2010; 77:552-62. [DOI: 10.1111/j.1399-0004.2009.01341.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
11
|
Gajecka M, Gentles AJ, Tsai A, Chitayat D, Mackay KL, Glotzbach CD, Lieber MR, Shaffer LG. Unexpected complexity at breakpoint junctions in phenotypically normal individuals and mechanisms involved in generating balanced translocations t(1;22)(p36;q13). Genome Res 2008; 18:1733-42. [PMID: 18765821 DOI: 10.1101/gr.077453.108] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Approximately one in 500 individuals carries a reciprocal translocation. Balanced translocations are usually associated with a normal phenotype unless the translocation breakpoints disrupt a gene(s) or cause a position effect. We investigated breakpoint junctions at the sequence level in phenotypically normal balanced translocation carriers. Eight breakpoint junctions derived from four nonrelated subjects with apparently balanced translocation t(1;22)(p36;q13) were examined. Additions of nucleotides, deletions, duplications, and a triplication identified at the breakpoints demonstrate high complexity at the breakpoint junctions and indicate involvement of multiple mechanisms in the DNA breakage and repair process during translocation formation. Possible detailed nonhomologous end-joining scenarios for t(1;22) cases are presented. We propose that cryptic imbalances in phenotypically normal, balanced translocation carriers may be more common than currently appreciated.
Collapse
Affiliation(s)
- Marzena Gajecka
- School of Molecular Biosciences, Washington State University, Spokane, Washington 99202, USA
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Jiang YH, Martinez JE, Ou Z, Cooper ML, Kang SHL, Pursley A, Cheung SW. De novo and complex imbalanced chromosomal rearrangements revealed by array CGH in a patient with an abnormal phenotype and apparently "balanced" paracentric inversion of 14(q21q23). Am J Med Genet A 2008; 146A:1986-93. [PMID: 18627051 DOI: 10.1002/ajmg.a.32408] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Paracentric inversions are one of the common chromosomal rearrangements typically associated with a normal phenotype. However, if dosage-sensitive genes are disrupted by the breakpoints, an abnormal phenotype could result. Detection of paracentric inversions often relies on careful high resolution banding, which has limited sensitivity. We report here cytogenetic studies performed on a 4-year-old female patient with global developmental delay, hypotonia, and dysmorphic features. The initial cytogenetic evaluation by G-banding revealed a de novo inversion of chromosome 14. Subsequent array CGH analysis using both a targeted BAC array and a high-resolution oligonucleotide array revealed microdeletions at the breakpoints of 14q21.1 (0.8 Mb) and 14q23.1 (0.9 Mb). Unexpectedly, a microdeletion in the region of 16q23.1 (1.3 Mb) was also identified, which overlaps with the common fragile site FRA16D. Parental chromosome and FISH analyses were normal, supporting the conclusion that these microdeletions were de novo in the patient and likely contributed to her abnormal phenotype. The case report presented illustrates the value of using high-resolution microarray analysis for phenotypically abnormal individuals with apparently balanced chromosomal rearrangements, including inversions.
Collapse
Affiliation(s)
- Yong-Hui Jiang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas TX 77030, USA
| | | | | | | | | | | | | |
Collapse
|
13
|
Baptista J, Mercer C, Prigmore E, Gribble SM, Carter NP, Maloney V, Thomas NS, Jacobs PA, Crolla JA. Breakpoint mapping and array CGH in translocations: comparison of a phenotypically normal and an abnormal cohort. Am J Hum Genet 2008; 82:927-36. [PMID: 18371933 DOI: 10.1016/j.ajhg.2008.02.012] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Revised: 02/13/2008] [Accepted: 02/19/2008] [Indexed: 01/22/2023] Open
Abstract
We report the analyses of breakpoints in 31 phenotypically normal and 14 abnormal carriers of balanced translocations. Our study assesses the differences between balanced translocations in normal carriers and those in abnormal carriers, focusing on the presence of genomic imbalances at the breakpoints or elsewhere in the genome, presence of cryptic chromosome rearrangements, and gene disruption. Our hypothesis is that all four features will be associated with phenotypic abnormalities and absent or much less frequent in a normal population. In the normal cohort, we identified neither genomic imbalances at the breakpoints or elsewhere in the genome nor cryptic chromosome rearrangements. In contrast, we identified candidate disease-causing imbalances in 4/14 abnormal patients. These were three breakpoint associated deletions and three deletions unrelated to the breakpoints. All six de novo deletions originated on the paternally inherited chromosome. Additional complexity was also present in one of these cases. Gene disruption by the breakpoints was present in 16/31 phenotypically normal individuals and in 5/14 phenotypically abnormal patients. Our results show that translocations in phenotypically abnormal patients are molecularly distinct from those in normal individuals: the former are more likely to be associated with genomic imbalances at the breakpoints or elsewhere and with chromosomal complexity, whereas the frequency of gene disruption is similar in both normal and abnormal translocation carriers.
Collapse
|
14
|
Cantagrel V, Lossi AM, Lisgo S, Missirian C, Borges A, Philip N, Fernandez C, Cardoso C, Figarella-Branger D, Moncla A, Lindsay S, Dobyns WB, Villard L. Truncation of NHEJ1 in a patient with polymicrogyria. Hum Mutat 2007; 28:356-64. [PMID: 17191205 DOI: 10.1002/humu.20450] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Polymicrogyria (PMG) is a common malformation of the human cerebral cortex for which both acquired and genetic causes are known. Although genetic heterogeneity is documented, only one gene is currently known to cause isolated PMG. To clone new genes involved in this type of cerebral malformation, we studied a fetus presenting a defect of cortical organization consisting of a polymicrogyric cortex and neuronal heterotopia within the white matter. Karyotype analysis revealed that the fetus was carrier of a balanced, de novo, chromosomal translocation t(2;7)(q35;p22). Cloning and sequencing of the two translocation breakpoints reveals that the chromosomal rearrangement disrupts the coding region of a single gene, called NHEJ1, Cernunnos, or XLF, in 2q35. The NHEJ1 gene was recently identified as being responsible for autosomal recessive immunodeficiency with microcephaly. Using quantitative PCR experiments, we show that a truncated transcript is expressed in the polymicrogyric patient cells, suggesting a potential dominant negative effect possibly leading to a different phenotype. We performed in situ hybridization on human embryos and showed that the NHEJ1 transcript is preferentially expressed in the telencephalic ventricular and subventricular zones, consistent with the phenotype of the affected individual. In the human adult central nervous system (CNS), NHEJ1 is mainly expressed in the cerebral cortex and in the cerebellum. The association of PMG with the disruption of its transcript suggests that, in addition to its recently uncovered function in the immune system, the NHEJ1 protein may also play a role during development of the human cerebral cortex.
Collapse
|
15
|
Bernardini L, Palka C, Ceccarini C, Capalbo A, Bottillo I, Mingarelli R, Novelli A, Dallapiccola B. Complex rearrangement of chromosomes 7q21.13-q22.1 confirms the ectrodactyly-deafness locus and suggests new candidate genes. Am J Med Genet A 2007; 146A:238-44. [DOI: 10.1002/ajmg.a.32093] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
16
|
Abstract
Genetic abnormalities frequently give rise to a mental retardation phenotype. Recent advances in resolution of comparative genomic hybridization and genomic sequence annotation has identified new syndromes at chromosome 3q29 and 9q34. The finding of a significant number of copy number polymorphisms in the genome in the normal population, means that assigning pathogenicity to deletions and duplications in patients with mental retardation can be difficult but has been identified for duplications of MECP2 and L1CAM. Novel autosomal genes that cause mental retardation have been identified recently including CC2D1A identified by homozygosity mapping. Several new genes and pathways have been identified in the field of X-linked mental retardation but many more still await identification. Analysis of families where only a single male is affected reveals that the chance of this being due to a single X-linked gene abnormality is significantly less than would be expected if the excess of males in the population is entirely due to X-linked disease. Recent identification of novel X-linked mental retardation genes has identified components of the post-synaptic density and multiple zinc finger transcription factors as disease causing suggesting new mechanisms of disease causation. The first therapeutic treatments of animal models of mental retardation have been reported, a Drosophila model of Fragile X syndrome has been treated with lithium or metabotropic glutamate receptor (mGluR) antagonists and a mouse model of NF1 has been treated with the HMG-CoA reductase inhibitor lavastatin, which improves the learning and memory skills in these models.
Collapse
Affiliation(s)
- F Lucy Raymond
- Department of Medical Genetics, Cambridge Institute of Medical Research, University of Cambridge, Addenbrookes Hospital, Cambridge CB2 2XY, UK.
| | | |
Collapse
|
17
|
Gribble SM, Kalaitzopoulos D, Burford DC, Prigmore E, Selzer RR, Ng BL, Matthews NSW, Porter KM, Curley R, Lindsay SJ, Baptista J, Richmond TA, Carter NP. Ultra-high resolution array painting facilitates breakpoint sequencing. J Med Genet 2006; 44:51-8. [PMID: 16971479 PMCID: PMC2597908 DOI: 10.1136/jmg.2006.044909] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
OBJECTIVE To describe a considerably advanced method of array painting, which allows the rapid, ultra-high resolution mapping of translocation breakpoints such that rearrangement junction fragments can be amplified directly and sequenced. METHOD Ultra-high resolution array painting involves the hybridisation of probes generated by the amplification of small numbers of flow-sorted derivative chromosomes to oligonucleotide arrays designed to tile breakpoint regions at extremely high resolution. RESULTS AND DISCUSSION How ultra-high resolution array painting of four balanced translocation cases rapidly and efficiently maps breakpoints to a point where junction fragments can be amplified easily and sequenced is demonstrated. With this new development, breakpoints can be mapped using just two array experiments: the first using whole-genome array painting to tiling resolution large insert clone arrays, the second using ultra-high-resolution oligonucleotide arrays targeted to the breakpoint regions. In this way, breakpoints can be mapped and then sequenced in a few weeks.
Collapse
Affiliation(s)
- S M Gribble
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Gajecka M, Glotzbach CD, Jarmuz M, Ballif BC, Shaffer LG. Identification of cryptic imbalance in phenotypically normal and abnormal translocation carriers. Eur J Hum Genet 2006; 14:1255-62. [PMID: 16941016 DOI: 10.1038/sj.ejhg.5201710] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Approximately one in 500 individuals carries a reciprocal translocation. Of the 121 monosomy 1p36 subjects ascertained by our laboratory, three independent cases involved unbalanced translocations of 1p and 9q, all of which were designated t(1;9)(p36.3;q34). These derivative chromosomes were inherited from balanced translocation carrier parents. To understand better the causes and consequences of chromosome breakage and rearrangement in the human genome, we characterized each derivative chromosome at the DNA sequence level and identified the junctions between 1p36 and 9q34. The breakpoint regions were unique in all individuals. Insertions and duplications were identified in two balanced translocation carrier parents and their unbalanced offspring. Sequence analyses revealed that the translocation breakpoints disrupted genes. This study demonstrates that apparently balanced reciprocal translocations in phenotypically normal carriers may have cryptic imbalance at the breakpoints. Because disrupted genes were identified in the phenotypically normal translocation carriers, caution should be exercised when interpreting data on phenotypically abnormal carriers with apparently balanced rearrangements that disrupt putative candidate genes.
Collapse
Affiliation(s)
- Marzena Gajecka
- Health Research and Education Center, Washington State University Spokane, Spokane, WA 99210, USA
| | | | | | | | | |
Collapse
|
19
|
Abstract
PURPOSE OF REVIEW Microarray-based comparative genomic hybridization (array-CGH) which detects aneuploidies and submicroscopic deletions and duplications in one assay is now offered for genetic diagnosis in children and adults. Its application to prenatal diagnosis is still limited, but very promising. We predict that array-CGH on fetal DNA obtained through amniocentesis or chorionic villus sampling and in the future possibly through noninvasive collection from the maternal cervix or blood, will transform the practice of prenatal diagnosis. RECENT FINDINGS The power of array-CGH for genetic diagnosis and gene discovery is supported by recent studies. Most arrays for clinical use carry large DNA fragments, but alternative designs containing oligonucleotides will move into the clinic. Some oligonucleotide arrays can simultaneously analyze DNA copy number and single nucleotide polymorphisms, thereby adding potential assessment of uniparental disomy and paternity. Recent array-CGH studies have revealed extensive interindividual copy number variation of genomic segments, unanticipated complexity of apparently balanced translocations, and new phenotypes associated with DNA deletions and duplications. These observations affect counseling for prenatal diagnosis by array-CGH. SUMMARY We believe that array-CGH will be embraced as a tool for prenatal diagnosis of chromosomal defects, but its introduction into clinical practice should proceed with caution by experienced laboratories.
Collapse
|
20
|
Mansouri MR, Carlsson B, Davey E, Nordenskjöld A, Wester T, Annerén G, Läckgren G, Dahl N. Molecular genetic analysis of a de novo balanced translocation t(6;17)(p21.31;q11.2) associated with hypospadias and anorectal malformation. Hum Genet 2006; 119:162-8. [PMID: 16395596 DOI: 10.1007/s00439-005-0122-9] [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: 10/23/2005] [Accepted: 12/09/2005] [Indexed: 10/25/2022]
Abstract
We report a young boy with penoscrotal hypospadias, anal atresia (AA) with a recto-urethral fistula, a hypoplastic kidney and a balanced translocation t(6;17)(p21.31;q11.2). Physical mapping of the breakpoints localized the chromosome 6 breakpoint within an intron of the gene lipoma HMGIC fusion partner-like 5 (LHFPL5) whereas the chromosome 17 breakpoint was mapped to the first intron of the 182-FIP gene encoding the Fragile X Mental Retardation Protein Interacting Protein. Sequence analysis across the breakpoints revealed an almost perfectly balanced translocation with a 2 bp deletion on the derivative chromosome 6 and a 7 bp duplication on the derivative chromosome 17. We identified a fusion transcript consisting of the first exon of 182-FIP and the last exon of LHFPL5 in patient-derived cells. Quantitative expression analysis of the genes flanking the breakpoints, revealed increased transcript levels for SFRS protein kinase 1 (SRPK1) and TAO kinase 1 (TAOK1) which suggests a positional effect due to the translocation. We hypothesize that the urogenital and anorectal malformations in the patient result from one or several mechanisms including disruption of the genes 182-FIP and LHFPL5, altered expression of the genes flanking the translocation breakpoints and, a gain of function mechanism mediated by the 182-FIP-LHFPL5 fusion transcript.
Collapse
Affiliation(s)
- Mahmoud Reza Mansouri
- Department of genetics and pathology, Section of Clinical Genetics The Rudbeck laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | | | | | | | | | | | | | | |
Collapse
|