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Marshall AE, Liang Y, Couse M, McConkey H, Sadikovic B, Boycott KM, Dyment DA, Kernohan KD. Integrated omics analyses clarifies ATRX copy number variant of uncertain significance. J Hum Genet 2024; 69:101-105. [PMID: 37904029 DOI: 10.1038/s10038-023-01203-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/12/2023] [Accepted: 10/16/2023] [Indexed: 11/01/2023]
Abstract
Partial duplications of genes can be challenging to detect and interpret and, therefore, likely represent an underreported cause of human disease. X-linked dominant variants in ATRX are associated with Alpha-thalassemia/impaired intellectual development syndrome, X-linked (ATR-X syndrome), a clinically heterogeneous disease generally presenting with intellectual disability, hypotonia, characteristic facies, genital anomalies, and alpha-thalassemia. We describe an affected male with a de novo hemizygous intragenic duplication of ~43.6 kb in ATRX, detected by research genome sequencing following non-diagnostic clinical testing. RNA sequencing and DNA methylation episignature analyses were central in variant interpretation, and this duplication was subsequently interpreted as disease-causing. This represents the smallest reported tandem duplication within ATRX associated with disease. This case demonstrates the diagnostic utility of integrating multiple omics technologies, which can ultimately lead to a definitive diagnosis for rare disease patients.
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Affiliation(s)
- Aren E Marshall
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, K1H 5B2, Canada
| | - Yijing Liang
- Centre for Computational Medicine, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Madeline Couse
- Centre for Computational Medicine, The Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Haley McConkey
- Department of Pathology and Laboratory Medicine, Western University, London, ON, N6A 3K7, Canada
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, N6A 5W9, Canada
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, ON, N6A 3K7, Canada
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, N6A 5W9, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, K1H 5B2, Canada
- Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, K1H 8L1, Canada
| | - David A Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, K1H 5B2, Canada.
- Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, K1H 8L1, Canada.
| | - Kristin D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, K1H 5B2, Canada.
- Newborn Screening Ontario, Ontario, ON, K1H 8L1, Canada.
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2
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Lomeli C. S, Kristin B. A. Epigenetic regulation of craniofacial development and disease. Birth Defects Res 2024; 116:e2271. [PMID: 37964651 PMCID: PMC10872612 DOI: 10.1002/bdr2.2271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/13/2023] [Accepted: 10/24/2023] [Indexed: 11/16/2023]
Abstract
BACKGROUND The formation of the craniofacial complex relies on proper neural crest development. The gene regulatory networks (GRNs) and signaling pathways orchestrating this process have been extensively studied. These GRNs and signaling cascades are tightly regulated as alterations to any stage of neural crest development can lead to common congenital birth defects, including multiple syndromes affecting facial morphology as well as nonsyndromic facial defects, such as cleft lip with or without cleft palate. Epigenetic factors add a hierarchy to the regulation of transcriptional networks and influence the spatiotemporal activation or repression of specific gene regulatory cascades; however less is known about their exact mechanisms in controlling precise gene regulation. AIMS In this review, we discuss the role of epigenetic factors during neural crest development, specifically during craniofacial development and how compromised activities of these regulators contribute to congenital defects that affect the craniofacial complex.
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Affiliation(s)
- Shull Lomeli C.
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Artinger Kristin B.
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN, USA
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Tillotson R, Yan K, Ruston J, DeYoung T, Córdova A, Turcotte-Cardin V, Yee Y, Taylor C, Visuvanathan S, Babbs C, Ivakine EA, Sled JG, Nieman BJ, Picketts DJ, Justice MJ. A new mouse model of ATR-X syndrome carrying a common patient mutation exhibits neurological and morphological defects. Hum Mol Genet 2023; 32:2485-2501. [PMID: 37171606 PMCID: PMC10360390 DOI: 10.1093/hmg/ddad075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/18/2023] [Accepted: 05/05/2023] [Indexed: 05/13/2023] Open
Abstract
ATRX is a chromatin remodelling ATPase that is involved in transcriptional regulation, DNA damage repair and heterochromatin maintenance. It has been widely studied for its role in ALT-positive cancers, but its role in neurological function remains elusive. Hypomorphic mutations in the X-linked ATRX gene cause a rare form of intellectual disability combined with alpha-thalassemia called ATR-X syndrome in hemizygous males. Clinical features also include facial dysmorphism, microcephaly, short stature, musculoskeletal defects and genital abnormalities. As complete deletion of ATRX in mice results in early embryonic lethality, the field has largely relied on conditional knockout models to assess the role of ATRX in multiple tissues. Given that null alleles are not found in patients, a more patient-relevant model was needed. Here, we have produced and characterized the first patient mutation knock-in model of ATR-X syndrome, carrying the most common causative mutation, R246C. This is one of a cluster of missense mutations located in the chromatin-binding domain and disrupts its function. The knock-in mice recapitulate several aspects of the patient disorder, including craniofacial defects, microcephaly, reduced body size and impaired neurological function. They provide a powerful model for understanding the molecular mechanisms underlying ATR-X syndrome and testing potential therapeutic strategies.
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Affiliation(s)
- Rebekah Tillotson
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital/Headley Way, Oxford OX3 9DS, UK
| | - Keqin Yan
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Julie Ruston
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
| | - Taylor DeYoung
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, ON M5T 3H7, Canada
| | - Alex Córdova
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
| | - Valérie Turcotte-Cardin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
- Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Yohan Yee
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, ON M5T 3H7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Christine Taylor
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
| | - Shagana Visuvanathan
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
| | - Christian Babbs
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital/Headley Way, Oxford OX3 9DS, UK
| | - Evgueni A Ivakine
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - John G Sled
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, ON M5T 3H7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
- Translational Medicine Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
| | - Brian J Nieman
- Mouse Imaging Centre, The Hospital for Sick Children, Toronto, ON M5T 3H7, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
- Translational Medicine Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
- Ontario Institute for Cancer Research, Toronto, ON M5G 0A3, Canada
| | - David J Picketts
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON K1H 8L6, Canada
- Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Monica J Justice
- Genetics and Genome Biology Program, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON M5G 0A4, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A1, Canada
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Electroencephalographic findings in ATRX syndrome: A new case series and review of literature. Eur J Paediatr Neurol 2022; 40:69-72. [PMID: 36031702 DOI: 10.1016/j.ejpn.2022.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/26/2022] [Accepted: 08/11/2022] [Indexed: 11/21/2022]
Abstract
Alpha-thalassemia X-linked intellectual disability syndrome (ATRX) is a rare genetic condition caused by mutations in the ATRX gene characterized by distinctive dysmorphic features, alpha thalassemia, mild-to-profound intellectual disability, and epilepsy, reported in nearly 30% of the patients. To date, different types of seizures are reported in patients with ATRX syndrome including either clonic, tonic, myoclonic seizures or myoclonic absences. However, an accurate analysis of electroencephalographic features is lacking in literature. We report on the epileptic and electroencephalographic phenotype of seven unpublished patients with ATRX syndrome, highlighting the presence of a peculiar EEG pattern characterized by diffuse background slowing with superimposed low voltage fast activity. Likewise, we also review the available literature on this topic.
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Dremsek P, Schwarz T, Weil B, Malashka A, Laccone F, Neesen J. Optical Genome Mapping in Routine Human Genetic Diagnostics-Its Advantages and Limitations. Genes (Basel) 2021; 12:1958. [PMID: 34946907 PMCID: PMC8701374 DOI: 10.3390/genes12121958] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 12/01/2022] Open
Abstract
In recent years, optical genome mapping (OGM) has developed into a highly promising method of detecting large-scale structural variants in human genomes. It is capable of detecting structural variants considered difficult to detect by other current methods. Hence, it promises to be feasible as a first-line diagnostic tool, permitting insight into a new realm of previously unknown variants. However, due to its novelty, little experience with OGM is available to infer best practices for its application or to clarify which features cannot be detected. In this study, we used the Saphyr system (Bionano Genomics, San Diego, CA, USA), to explore its capabilities in human genetic diagnostics. To this end, we tested 14 DNA samples to confirm a total of 14 different structural or numerical chromosomal variants originally detected by other means, namely, deletions, duplications, inversions, trisomies, and a translocation. Overall, 12 variants could be confirmed; one deletion and one inversion could not. The prerequisites for detection of similar variants were explored by reviewing the OGM data of 54 samples analyzed in our laboratory. Limitations, some owing to the novelty of the method and some inherent to it, were described. Finally, we tested the successful application of OGM in routine diagnostics and described some of the challenges that merit consideration when utilizing OGM as a diagnostic tool.
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Affiliation(s)
- Paul Dremsek
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University of Vienna, 1090 Vienna, Austria; (T.S.); (B.W.); (A.M.); (F.L.); (J.N.)
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6
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León NY, Harley VR. ATR-X syndrome: genetics, clinical spectrum, and management. Hum Genet 2021; 140:1625-1634. [PMID: 34524523 DOI: 10.1007/s00439-021-02361-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 08/30/2021] [Indexed: 12/13/2022]
Abstract
ATR-X, an acronym for alpha thalassemia and mental retardation X-linked, syndrome is a congenital condition predominantly affecting males, characterized by mild to severe intellectual disability, facial, skeletal, urogenital, and hematopoietic anomalies. Less common are heart defects, eye anomalies, renal abnormalities, and gastrointestinal dysfunction. ATR-X syndrome is caused by germline variants in the ATRX gene. Until recently, the diagnosis of the ATR-X syndrome had been guided by the classical clinical manifestations and confirmed by molecular techniques. However, our new systematic analysis shows that the only clinical sign shared by all affected individuals is intellectual disability, with the other manifestations varying even within the same family. More than 190 different germline ATRX mutations in some 200 patients have been analyzed. With improved and more frequent analysis by molecular technologies, more subtle deletions and insertions have been detected recently. Moreover, emerging technologies reveal non-classic phenotypes of ATR-X syndrome as well as the description of a new clinical feature, the development of osteosarcoma which suggests an increased cancer risk in ATR-X syndrome. This review will focus on the different types of inherited ATRX mutations and their relation to clinical features in the ATR-X syndrome. We will provide an update of the frequency of clinical manifestations, the affected organs, and the genotype-phenotype correlations. Finally, we propose a shift in the diagnosis of ATR-X patients, from a clinical diagnosis to a molecular-based approach. This may assist clinicians in patient management, risk assessment and genetic counseling.
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Affiliation(s)
- Nayla Y León
- Sex Development Laboratory, Centre for Endocrinology and Metabolism, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia.,Department of Molecular and Translational Science, Monash University, Melbourne, VIC, Australia
| | - Vincent R Harley
- Sex Development Laboratory, Centre for Endocrinology and Metabolism, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia. .,Department of Molecular and Translational Science, Monash University, Melbourne, VIC, Australia.
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Hartlieb SA, Sieverling L, Nadler-Holly M, Ziehm M, Toprak UH, Herrmann C, Ishaque N, Okonechnikov K, Gartlgruber M, Park YG, Wecht EM, Savelyeva L, Henrich KO, Rosswog C, Fischer M, Hero B, Jones DTW, Pfaff E, Witt O, Pfister SM, Volckmann R, Koster J, Kiesel K, Rippe K, Taschner-Mandl S, Ambros P, Brors B, Selbach M, Feuerbach L, Westermann F. Alternative lengthening of telomeres in childhood neuroblastoma from genome to proteome. Nat Commun 2021; 12:1269. [PMID: 33627664 PMCID: PMC7904810 DOI: 10.1038/s41467-021-21247-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 01/13/2021] [Indexed: 02/08/2023] Open
Abstract
Telomere maintenance by telomerase activation or alternative lengthening of telomeres (ALT) is a major determinant of poor outcome in neuroblastoma. Here, we screen for ALT in primary and relapsed neuroblastomas (n = 760) and characterize its features using multi-omics profiling. ALT-positive tumors are molecularly distinct from other neuroblastoma subtypes and enriched in a population-based clinical sequencing study cohort for relapsed cases. They display reduced ATRX/DAXX complex abundance, due to either ATRX mutations (55%) or low protein expression. The heterochromatic histone mark H3K9me3 recognized by ATRX is enriched at the telomeres of ALT-positive tumors. Notably, we find a high frequency of telomeric repeat loci with a neuroblastoma ALT-specific hotspot on chr1q42.2 and loss of the adjacent chromosomal segment forming a neo-telomere. ALT-positive neuroblastomas proliferate slowly, which is reflected by a protracted clinical course of disease. Nevertheless, children with an ALT-positive neuroblastoma have dismal outcome.
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Affiliation(s)
- Sabine A Hartlieb
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Lina Sieverling
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
- Applied Bioinformatics, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), Heidelberg, Germany
- Division of Translational Medical Oncology, National Center for Tumor Diseases (NCT), Heidelberg, Germany
| | - Michal Nadler-Holly
- Proteome Dynamics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Matthias Ziehm
- Proteome Dynamics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Umut H Toprak
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Carl Herrmann
- Health Data Science Unit, Medical Faculty Heidelberg and BioQuant, Heidelberg, Germany
| | - Naveed Ishaque
- Digital Health Centre, Berlin Institute of Health (BIH), Berlin, Germany
- Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Konstantin Okonechnikov
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Pediatric Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Moritz Gartlgruber
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Young-Gyu Park
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Elisa Maria Wecht
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Larissa Savelyeva
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Kai-Oliver Henrich
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Carolina Rosswog
- Department of Experimental Pediatric Oncology, University Children's Hospital of Cologne, Medical Faculty, Cologne, Germany
| | - Matthias Fischer
- Department of Experimental Pediatric Oncology, University Children's Hospital of Cologne, Medical Faculty, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
- Department of Pediatric Oncology and Hematology, University of Cologne, Cologne, Germany
| | - Barbara Hero
- Department of Pediatric Oncology and Hematology, University of Cologne, Cologne, Germany
| | - David T W Jones
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Pediatric Glioma Research Group, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Elke Pfaff
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Pediatric Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Pediatric Hematology and Oncology, University Hospital, Heidelberg, Germany
| | - Olaf Witt
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Department of Pediatric Hematology and Oncology, University Hospital, Heidelberg, Germany
- Clinical Cooperation Unit Pediatric Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stefan M Pfister
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany
- Pediatric Neurooncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Pediatric Hematology and Oncology, University Hospital, Heidelberg, Germany
| | - Richard Volckmann
- Department of Oncogenomics Amsterdam University Medical Centers (AUMC), Amsterdam, the Netherlands
| | - Jan Koster
- Department of Oncogenomics Amsterdam University Medical Centers (AUMC), Amsterdam, the Netherlands
| | - Katharina Kiesel
- Chromatin Networks, German Cancer Research Center (DKFZ) and BioQuant, Heidelberg, Germany
| | - Karsten Rippe
- Chromatin Networks, German Cancer Research Center (DKFZ) and BioQuant, Heidelberg, Germany
| | | | - Peter Ambros
- CCRI, St Anna Children's Cancer Research Institute, Vienna, Austria
| | - Benedikt Brors
- Applied Bioinformatics, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Matthias Selbach
- Proteome Dynamics, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Lars Feuerbach
- Applied Bioinformatics, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Frank Westermann
- Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany.
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
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Chen CP, Yip HK, Wang LK, Chern SR, Chen SW, Lai ST, Wu PS, Wang W. Molecular genetic characterization of a prenatally detected 1.484-Mb Xq13.3-q21.1 duplication encompassing ATRX and a literature review of syndromic intellectual disability and congenital abnormalities in males with a duplication at Xq13.3-q21.1. Taiwan J Obstet Gynecol 2017; 56:385-389. [PMID: 28600056 DOI: 10.1016/j.tjog.2017.04.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2017] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVE We present prenatal diagnosis of dup(X)(q13.3q21.1) in a male fetus and molecular genetic analysis in three generations and a literature review of syndromic intellectual disability and congenital abnormalities in males with a duplication at Xq13.3-q21.1. CASE REPORT A 35-year-old, primigravid woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. The woman and her mother were phenotypically normal, and there was no intellectual disability in the maternal family. Cytogenetic analysis of cultured amniocytes revealed a karyotype of 46,XY. Simultaneous array comparative genomic hybridization (aCGH) analysis on uncultured amniotic fluid incidentally detected a 1.484-Mb microduplication of Xq13.3-q21.1 encompassing ATRX. Subsequent aCGH analysis on fetal blood, maternal blood and grandmother's blood revealed the same 1.484-Mb dup(X)(q13.3q21.1). Prenatal ultrasound findings were unremarkable with no growth restriction and no short stature. After genetic counseling of syndromic intellectual disability in males with ATRX duplication, the woman elected to terminate the pregnancy. The fetus postnatally manifested hypoplastic male external genitalia, clinodactyly, hypertelorism, midface hypoplasia, epicanthic folds and micrognathia. CONCLUSION Simultaneous aCGH analysis on uncultured amniotic fluid in addition to conventional cytogenetics at amniocentesis is practical and may help in detecting unknown familial inheritance of subtle X chromosome aberrations.
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Affiliation(s)
- Chih-Ping Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Biotechnology, Asia University, Taichung, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
| | - Hoi-Kin Yip
- Department of Obstetrics and Gynecology, Cardinal Tien Hospital, Xindian, New Taipei City, Taiwan
| | - Liang-Kai Wang
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Schu-Rern Chern
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | - Shin-Wen Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Shih-Ting Lai
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | | | - Wayseen Wang
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Bioengineering, Tatung University, Taipei, Taiwan
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Sharma P, Gupta N, Chowdhury MR, Sapra S, Ghosh M, Gulati S, Kabra M. Application of chromosomal microarrays in the evaluation of intellectual disability/global developmental delay patients – A study from a tertiary care genetic centre in India. Gene 2016; 590:109-19. [DOI: 10.1016/j.gene.2016.06.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 01/21/2023]
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10
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625 kb microduplication at Xp22.12 including RPS6KA3 in a child with mild intellectual disability. J Hum Genet 2015; 60:777-80. [PMID: 26354035 DOI: 10.1038/jhg.2015.106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 07/09/2015] [Accepted: 07/13/2015] [Indexed: 11/09/2022]
Abstract
Here, we report on a patient with a 625 kb duplication in Xp22.12, detected by array comparative genomic hybridization (CGH). The duplicated region contains only one gene, RPS6KA3, that results in partial duplication. The same duplication was present in his mother and his maternal uncle. This partial duplication inhibits the RPS6KA3 expression, mimicking the effect of loss-of-function mutations associated with Coffin-Lowry syndrome (CLS). The phenotype of the patient here presented is not fully evocative of this syndrome because he does not present some of the facial, digital and skeletal abnormalities that are considered the main diagnostic features of CLS. This case is one of the few examples where RPS6KA3 mutations are associated with a non-specific X-linked mental retardation.
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Wada T, Ban H, Matsufuji M, Okamoto N, Enomoto K, Kurosawa K, Aida N. Neuroradiologic features in X-linked α-thalassemia/mental retardation syndrome. AJNR Am J Neuroradiol 2013; 34:2034-8. [PMID: 23681356 DOI: 10.3174/ajnr.a3560] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE X-linked α-thalassemia/mental retardation syndrome (Mendelian Inheritance in Man, 301040) is one of the X-linked intellectual disability syndromes caused by mutations of the ATRX gene and characterized by male predominance, central hypotonic facies, severe cognitive dysfunction, hemoglobin H disease (α-thalassemia), genital and skeletal abnormalities, and autistic and peculiar behavior. More than 200 patients in the world, including >70 Japanese patients, have been diagnosed with ATR-X syndrome. MATERIALS AND METHODS We reviewed the brain MRI and/or CT findings of 27 Japanese patients with ATR-X with ATRX mutations retrospectively. RESULTS The findings were categorized into 5 types: 1) nonspecific brain atrophy (17/27); 2) white matter abnormalities, especially around the trigones (11/27); 3) widespread and scattered white matter abnormalities (1/27); 4) delayed myelination (4/27); and 5) severe and rapidly progressive cortical brain atrophy (1/27). CONCLUSIONS This is the first report on a comprehensive study of brain MRI/CT findings of ATR-X syndrome. Our findings suggest that the ATRX protein seems to be involved in normal myelination. The classification will require revisions in the near future, but it will be helpful in establishing the relationship between ATRX mutation and brain development and understanding the ATRX protein function in the brain.
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Huidobro C, Fernandez AF, Fraga MF. The role of genetics in the establishment and maintenance of the epigenome. Cell Mol Life Sci 2013; 70:1543-73. [PMID: 23474979 PMCID: PMC11113764 DOI: 10.1007/s00018-013-1296-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 12/19/2022]
Abstract
Epigenetic mechanisms play an important role in gene regulation during development. DNA methylation, which is probably the most important and best-studied epigenetic mechanism, can be abnormally regulated in common pathologies, but the origin of altered DNA methylation remains unknown. Recent research suggests that these epigenetic alterations could depend, at least in part, on genetic mutations or polymorphisms in DNA methyltransferases and certain genes encoding enzymes of the one-carbon metabolism pathway. Indeed, the de novo methyltransferase 3B (DNMT3B) has been recently found to be mutated in several types of cancer and in the immunodeficiency, centromeric region instability and facial anomalies syndrome (ICF), in which these mutations could be related to the loss of global DNA methylation. In addition, mutations in glycine-N-methyltransferase (GNMT) could be associated with a higher risk of hepatocellular carcinoma and liver disease due to an unbalanced S-adenosylmethionine (SAM)/S-adenosylhomocysteine (SAH) ratio, which leads to aberrant methylation reactions. Also, genetic variants of chromatin remodeling proteins and histone tail modifiers are involved in genetic disorders like α thalassemia X-linked mental retardation syndrome, CHARGE syndrome, Cockayne syndrome, Rett syndrome, systemic lupus erythematous, Rubinstein-Taybi syndrome, Coffin-Lowry syndrome, Sotos syndrome, and facioescapulohumeral syndrome, among others. Here, we review the potential genetic alterations with a possible role on epigenetic factors and discuss their contribution to human disease.
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Affiliation(s)
- Covadonga Huidobro
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
| | - Agustin F. Fernandez
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
| | - Mario F. Fraga
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
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13
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Stefanova VT, Grifo JA, Hansis C. Derivation of novel genetically diverse human embryonic stem cell lines. Stem Cells Dev 2012; 21:1559-70. [PMID: 22204497 DOI: 10.1089/scd.2011.0642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human embryonic stem cells (hESCs) have the potential to revolutionize many biomedical fields ranging from basic research to disease modeling, regenerative medicine, drug discovery, and toxicity testing. A multitude of hESC lines have been derived worldwide since the first 5 lines by Thomson et al. 13 years ago, but many of these are poorly characterized, unavailable, or do not represent desired traits, thus making them unsuitable for application purposes. In order to provide the scientific community with better options, we have derived 12 new hESC lines at New York University from discarded genetically normal and abnormal embryos using the latest techniques. We examined the genetic status of the NYUES lines in detail as well as their molecular and cellular features and DNA fingerprinting profile. Furthermore, we differentiated our hESCs into the tissues most affected by a specific condition or into clinically desired cell types. To our knowledge, a number of characteristics of our hESCs have not been previously reported, for example, mutation for alpha thalassemia X-linked mental retardation syndrome, linkage to conditions with a genetic component such as asthma or poor sperm morphology, and novel combinations of ethnic backgrounds. Importantly, all of our undifferentiated euploid female lines tested to date did not show X chromosome inactivation, believed to result in superior potency. We continue to derive new hESC lines and add them to the NIH registry and other registries. This should facilitate the use of our hESCs and lead to advancements for patient-benefitting applications.
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Affiliation(s)
- Valentina T Stefanova
- Department of Obstetrics and Gynecology, New York University School of Medicine, New York, New York, USA
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14
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Breckpot J, Thienpont B, Arens Y, Tranchevent L, Vermeesch J, Moreau Y, Gewillig M, Devriendt K. Challenges of Interpreting Copy Number Variation in Syndromic and Non-Syndromic Congenital Heart Defects. Cytogenet Genome Res 2011; 135:251-9. [DOI: 10.1159/000331272] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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15
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Gijsbers ACJ, den Hollander NS, Helderman-van de Enden ATJM, Schuurs-Hoeijmakers JHM, Vijfhuizen L, Bijlsma EK, van Haeringen A, Hansson KBM, Bakker E, Breuning MH, Ruivenkamp CAL. X-chromosome duplications in males with mental retardation: pathogenic or benign variants? Clin Genet 2011; 79:71-8. [PMID: 20486941 DOI: 10.1111/j.1399-0004.2010.01438.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Studies to identify copy number variants (CNVs) on the X-chromosome have revealed novel genes important in the causation of X-linked mental retardation (XLMR). Still, for many CNVs it is unclear whether they are associated with disease or are benign variants. We describe six different CNVs on the X-chromosome in five male patients with mental retardation that were identified by conventional karyotyping and single nucleotide polymorphism array analysis. One deletion and five duplications ranging in size from 325 kb to 12.5 Mb were observed. Five CNVs were maternally inherited and one occurred de novo. We discuss the involvement of potential candidate genes and focus on the complexity of X-chromosomal duplications in males inherited from healthy mothers with different X-inactivation patterns. Based on size and/or the presence of XLMR genes we were able to classify CNVs as pathogenic in two patients. However, it remains difficult to decide if the CNVs in the other three patients are pathogenic or benign.
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Affiliation(s)
- A C J Gijsbers
- Center for Human and Clinical Genetics, Leiden University Medical Center (LUMC), Einthovenweg 20, Leiden, The Netherlands.
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16
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Yun KW, Chae SA, Lee JJ, Yun SW, Yoo BH, Lim IS, Choi ES, Lee MK. The first case of X-linked Alpha-thalassemia/mental retardation (ATR-X) syndrome in Korea. J Korean Med Sci 2011; 26:146-9. [PMID: 21218045 PMCID: PMC3012841 DOI: 10.3346/jkms.2011.26.1.146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2010] [Accepted: 04/30/2010] [Indexed: 11/20/2022] Open
Abstract
Mutation of the ATRX gene leads to X-linked alpha-thalassemia/mental retardation (ATR-X) syndrome and several other X-linked mental retardation syndromes. We report the first case of ATR-X syndrome documented here in Korea. A 32-month-old boy came in with irritability and fever. He showed dysmorphic features, mental retardation and epilepsy, so ATR-X syndrome was considered. Hemoglobin H inclusions in red blood cells supported the diagnosis and genetic studies confirmed it. Mutation analysis for our patient showed a point mutation of thymine to cytosine on the 9th exon in the ATRX gene, indicating that Trp(C), the 220th amino acid, was replaced by Ser(R). Furthermore, we investigated the same mutation in family members, and his mother and two sisters were found to be carriers.
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Affiliation(s)
- Ki Wook Yun
- Department of Pediatrics, Chung-Ang University College of Medicine, Seoul, Korea
| | - Soo Ahn Chae
- Department of Pediatrics, Chung-Ang University College of Medicine, Seoul, Korea
| | - Jung Ju Lee
- Department of Pediatrics, Chung-Ang University College of Medicine, Seoul, Korea
| | - Sin Weon Yun
- Department of Pediatrics, Chung-Ang University College of Medicine, Seoul, Korea
| | - Byoung Hoon Yoo
- Department of Pediatrics, Chung-Ang University College of Medicine, Seoul, Korea
| | - In Seok Lim
- Department of Pediatrics, Chung-Ang University College of Medicine, Seoul, Korea
| | - Eung Sang Choi
- Department of Pediatrics, Chung-Ang University College of Medicine, Seoul, Korea
| | - Mi-Kyung Lee
- Department of Laboratory Medicine, Chung-Ang University College of Medicine, Seoul, Korea
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17
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Breckpot J, Thienpont B, Peeters H, de Ravel T, Singer A, Rayyan M, Allegaert K, Vanhole C, Eyskens B, Vermeesch JR, Gewillig M, Devriendt K. Array comparative genomic hybridization as a diagnostic tool for syndromic heart defects. J Pediatr 2010; 156:810-7, 817.e1-817.e4. [PMID: 20138633 DOI: 10.1016/j.jpeds.2009.11.049] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 10/10/2009] [Accepted: 11/13/2009] [Indexed: 01/16/2023]
Abstract
OBJECTIVES To investigate different aspects of the introduction of array comparative genomic hybridization (aCGH) in clinical practice. STUDY DESIGN A total 150 patients with a syndromic congenital heart defect (CHD) of unknown cause were analyzed with aCGH at 1-Mb resolution. Twenty-nine of these patients, with normal results on 1Mb aCGH, underwent re-analysis with 244-K oligo-microarray. With a logistic regression model, we assessed the predictive value of patient characteristics for causal imbalance detection. On the basis of our earlier experience and the literature, we constructed an algorithm to evaluate the causality of copy number variants. RESULTS With 1-Mb aCGH, we detected 43 structural variants not listed as clinically neutral polymorphisms, 26 of which were considered to be causal. A systematic comparison of the clinical features of these 26 patients to the remaining 124 patients revealed dysmorphism as the only feature with a significant predictive value for reaching a diagnosis with 1-Mb aCGH. With higher resolution analysis in 29 patients, 75 variants not listed as clinically neutral polymorphisms were detected, 2 of which were considered to be causal. CONCLUSIONS Molecular karyotyping yields an etiological diagnosis in at least 18% of patients with a syndromic CHD. Higher resolution evaluation results in an increasing number of variants of unknown significance.
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Affiliation(s)
- Jeroen Breckpot
- Center of Human Genetics, University Hospitals Leuven, Leuven, Belgium
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18
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Cohn DM, Pagon RA, Hudgins L, Schwartz CE, Stevenson RE, Friez MJ. Partial ATRX gene duplication causes ATR-X syndrome. Am J Med Genet A 2009; 149A:2317-20. [PMID: 19764021 DOI: 10.1002/ajmg.a.33006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Dianne M Cohn
- Greenwood Genetic Center, Greenwood, South Carolina 29646, USA
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De Sario A. Clinical and molecular overview of inherited disorders resulting from epigenomic dysregulation. Eur J Med Genet 2009; 52:363-72. [PMID: 19632366 DOI: 10.1016/j.ejmg.2009.07.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 07/21/2009] [Indexed: 01/23/2023]
Abstract
Epigenetics is the study of heritable changes in gene expression that occur without a change in the DNA sequence. Most constitutional defects in genes encoding components of the machinery that regulates the epigenome lead to embryonic death. Hypomorphic mutations may be compatible with life, but lead to severe developmental disorders. Their study is of great importance to our understanding of epigenetics and may clarify the interplay between different epigenetic mechanisms. This review will briefly introduce DNA methylation, post-translational histone modifications, and non-coding small RNA transcription, which are the best known epigenetic mechanisms. Then it will describe five human disorders (RETT, ATRX, ICF, Coffin-Lowry, and Rubinstein-Taybi) resulting from mutations in genes responsible for DNA methylation and in genes involved in chromatin remodeling. Finally, it will discuss how research in medical genetics can elucidate fundamental epigenetic processes.
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Affiliation(s)
- Albertina De Sario
- Institut de Génétique Humaine, CNRS UPR 1142, 141 rue de la Cardonille, 34396 Montpellier, France.
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20
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Lugtenberg D, de Brouwer APM, Oudakker AR, Pfundt R, Hamel BCJ, van Bokhoven H, Bongers EMHF. Xq13.2q21.1 duplication encompassing the ATRX gene in a man with mental retardation, minor facial and genital anomalies, short stature and broad thorax. Am J Med Genet A 2009; 149A:760-6. [PMID: 19291773 DOI: 10.1002/ajmg.a.32742] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In a man with severe mental retardation, minor facial and genital anomalies, disproportionate short stature and a broad thorax, we identified a de novo Xq13.2q21.1 duplication by array CGH. This 7 Mb duplication encompasses 23 known genes, including the X-linked mental retardation (XLMR) genes ATRX and SLC16A2. The phenotype of this patient is similar to that described in more than 10 previously reported patients with overlapping Xq duplications. Detailed comparison of the clinical characteristics and the function of the genes located in the commonly duplicated regions of these patients led us to the hypothesis that an increased dosage of ATRX and perhaps of other genes is involved in the pathogenetic mechanism of this XLMR phenotype, including mental retardation, short stature, and genital abnormalities comprising cryptorchidism and/or a small penis.
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Affiliation(s)
- Dorien Lugtenberg
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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21
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Gibbons RJ, Wada T, Fisher CA, Malik N, Mitson MJ, Steensma DP, Fryer A, Goudie DR, Krantz ID, Traeger-Synodinos J. Mutations in the chromatin-associated protein ATRX. Hum Mutat 2008; 29:796-802. [PMID: 18409179 DOI: 10.1002/humu.20734] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
ATRX belongs to the SNF2 family of proteins, many of which have been demonstrated to have chromatin remodeling activity. Constitution mutations in the X-encoded gene give rise to alpha thalassemia mental retardation (ATR-X) syndrome and a variety of related conditions that are often associated with profound developmental delay, facial dysmorphism, genital abnormalities, and alpha thalassemia. Acquired mutations in ATRX are observed in the preleukemic condition alpha thalassemia myelodysplastic syndrome (ATMDS). Mutations in ATRX have been shown to perturb gene expression and DNA methylation. This is a comprehensive report of 127 mutations including 32 reported here for the first time. Missense mutations are shown to cluster in the two main functional domains. The truncating mutations appear to be "rescued" to some degree and so it appears likely that most if not all constitutional ATRX mutations are hypomorphs.
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Affiliation(s)
- Richard J Gibbons
- MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom.
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22
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Thienpont B, Breckpot J, Vermeesch JR, Gewillig M, Devriendt K. A complex submicroscopic chromosomal imbalance in 19p13.11 with one microduplication and two microtriplications. Eur J Med Genet 2008; 51:219-25. [PMID: 18282819 DOI: 10.1016/j.ejmg.2007.12.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Accepted: 12/28/2007] [Indexed: 01/30/2023]
Abstract
Complex chromosomal rearrangements [CCRs] are considered very rare, but are being detected with an increasing frequency because of the enhanced resolution of novel molecular karyotyping techniques like array-CGH. This report describes a patient carrying a unique CCR involving one duplication and two triplications in a 3.2 Mb region on 19p13.11. The patient presented with microcephaly, velopharyngeal insufficiency, dysmorphism, mental retardation and a muscular ventricular septal defect. We show that CCRs are likely to be more frequent than hitherto appreciated. This has important consequences for genotype-phenotype correlations and warrants caution before labelling imbalances as "simple".
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Affiliation(s)
- Bernard Thienpont
- Center for Human Genetics, Catholic University of Leuven, Herestraat 49, B-3000 Leuven, Belgium
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23
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Marques Pereira P, Heron D, Hanauer A. The first large duplication of the RSK2 gene identified in a Coffin-Lowry syndrome patient. Hum Genet 2007; 122:541-3. [PMID: 17717706 DOI: 10.1007/s00439-007-0424-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Accepted: 08/15/2007] [Indexed: 10/22/2022]
Abstract
Heterogeneous mutations in the X-linked gene RPS6KA3, encoding the protein kinase RSK2, are responsible for Coffin-Lowry Syndrome. Here we have further studied a male patient with a highly suggestive clinical diagnosis of CLS but in whom no mutation was found by exon sequencing. Western blot analysis revealed a protein much larger than the normal expected size. Sequencing of the RSK2 cDNA, showed the presence of an in-frame tandem duplication of exons 17-20. The mutated RSK2 protein was found to be inactive in an in-vitro kinase assay. This event, which was the result of a homologous unequal recombination between Alu sequences, is the first reported large duplication of the RPS6KA3 gene. Our finding provides further evidence that immunoblot analysis, or a molecular assay capable to detect large genomic mutational events, is essential for patients with a highly suggestive CLS clinical diagnosis but remaining without mutation after exon sequencing.
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Affiliation(s)
- Patricia Marques Pereira
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, B.P. 10142, 67404, Illkirch Cedex, C.U. de Strasbourg, France
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