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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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Brand BA, Blesson AE, Smith-Hicks CL. The Impact of X-Chromosome Inactivation on Phenotypic Expression of X-Linked Neurodevelopmental Disorders. Brain Sci 2021; 11:brainsci11070904. [PMID: 34356138 PMCID: PMC8305405 DOI: 10.3390/brainsci11070904] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/16/2021] [Accepted: 06/20/2021] [Indexed: 12/20/2022] Open
Abstract
Nearly 20% of genes located on the X chromosome are associated with neurodevelopmental disorders (NDD) due to their expression and role in brain functioning. Given their location, several of these genes are either subject to or can escape X-chromosome inactivation (XCI). The degree to which genes are subject to XCI can influence the NDD phenotype between males and females. We provide a general review of X-linked NDD genes in the context of XCI and detailed discussion of the sex-based differences related to MECP2 and FMR1, two common X-linked causes of NDD that are subject to XCI. Understanding the effects of XCI on phenotypic expression of NDD genes may guide the development of stratification biomarkers in X-linked disorders.
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Affiliation(s)
- Boudewien A Brand
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA; (B.A.B.); (A.E.B.)
| | - Alyssa E Blesson
- Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA; (B.A.B.); (A.E.B.)
| | - Constance L. Smith-Hicks
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Correspondence:
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3
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Haase S, Garcia-Fabiani MB, Carney S, Altshuler D, Núñez FJ, Méndez FM, Núñez F, Lowenstein PR, Castro MG. Mutant ATRX: uncovering a new therapeutic target for glioma. Expert Opin Ther Targets 2018; 22:599-613. [PMID: 29889582 PMCID: PMC6044414 DOI: 10.1080/14728222.2018.1487953] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/08/2018] [Indexed: 12/29/2022]
Abstract
INTRODUCTION ATRX is a chromatin remodeling protein whose main function is the deposition of the histone variant H3.3. ATRX mutations are widely distributed in glioma, and correlate with alternative lengthening of telomeres (ALT) development, but they also affect other cellular functions related to epigenetic regulation. Areas covered: We discuss the main molecular characteristics of ATRX, from its various functions in normal development to the effects of its loss in ATRX syndrome patients and animal models. We focus on the salient consequences of ATRX mutations in cancer, from a clinical to a molecular point of view, focusing on both adult and pediatric glioma. Finally, we will discuss the therapeutic opportunities future research perspectives. Expert opinion: ATRX is a major component of various essential cellular pathways, exceeding its functions as a histone chaperone (e.g. DNA replication and repair, chromatin higher-order structure regulation, gene transcriptional regulation, etc.). However, it is unclear how the loss of these functions in ATRX-null cancer cells affects cancer development and progression. We anticipate new treatments and clinical approaches will emerge for glioma and other cancer types as mechanistic and molecular studies on ATRX are only just beginning to reveal the many critical functions of this protein in cancer.
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Affiliation(s)
- Santiago Haase
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
| | - María Belén Garcia-Fabiani
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
| | - Stephen Carney
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
| | - David Altshuler
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
| | - Felipe J Núñez
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
| | - Flor M Méndez
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
| | - Fernando Núñez
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
| | - Pedro R Lowenstein
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
| | - Maria G Castro
- a Department of Neurosurgery , The University of Michigan School of Medicine , Ann Arbor , MI , USA
- b Department of Cell & Developmental Biology , The University of Michigan School of Medicine , Ann Arbor , MI , USA
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4
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Cantone I, Fisher AG. Human X chromosome inactivation and reactivation: implications for cell reprogramming and disease. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0358. [PMID: 28947657 DOI: 10.1098/rstb.2016.0358] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2017] [Indexed: 11/12/2022] Open
Abstract
X-chromosome inactivation (XCI) is an exemplar of epigenetic regulation that is set up as pluripotent cells differentiate. Once established, XCI is stably propagated, but can be reversed in vivo or by pluripotent reprogramming in vitro Although reprogramming provides a useful model for inactive X (Xi) reactivation in mouse, the relative instability and heterogeneity of human embryonic stem (ES) cells and induced pluripotent stem cells hampers comparable progress in human. Here we review studies aimed at reactivating the human Xi using different reprogramming strategies. We outline our recent results using mouse ES cells to reprogramme female human fibroblasts by cell-cell fusion. We show that pluripotent reprogramming induces widespread and rapid chromatin remodelling in which the human Xi loses XIST and H3K27m3 enrichment and selected Xi genes become reactivated, ahead of mitotic division. Using RNA sequencing to map the extent of human Xi reactivation, and chromatin-modifying drugs to potentiate reactivation, we outline how this approach could be used to better design strategies to re-express human X-linked loci. As cell fusion induces the expression of human pluripotency genes that represent both the 'primed' and 'naive' states, this approach may also offer a fresh opportunity to segregate human pluripotent states with distinct Xi expression profiles, using single-cell-based approaches.This article is part of the themed issue 'X-chromosome inactivation: a tribute to Mary Lyon'.
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Affiliation(s)
- Irene Cantone
- Lymphocyte Development, MRC London Institute of Medical Sciences (LMS), Du Cane Road, London W12 0NN, UK
| | - Amanda G Fisher
- Lymphocyte Development, MRC London Institute of Medical Sciences (LMS), Du Cane Road, London W12 0NN, UK .,Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
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5
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Dyer MA, Qadeer ZA, Valle-Garcia D, Bernstein E. ATRX and DAXX: Mechanisms and Mutations. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a026567. [PMID: 28062559 DOI: 10.1101/cshperspect.a026567] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent genome sequencing efforts in a variety of cancers have revealed mutations and/or structural alterations in ATRX and DAXX, which together encode a complex that deposits histone variant H3.3 into repetitive heterochromatin. These regions include retrotransposons, pericentric heterochromatin, and telomeres, the latter of which show deregulation in ATRX/DAXX-mutant tumors. Interestingly, ATRX and DAXX mutations are often found in pediatric tumors, suggesting a particular developmental context in which these mutations drive disease. Here we review the functions of ATRX and DAXX in chromatin regulation as well as their potential contributions to tumorigenesis. We place emphasis on the chromatin remodeler ATRX, which is mutated in the developmental disorder for which it is named, α-thalassemia, mental retardation, X-linked syndrome, and at high frequency in a number of adult and pediatric tumors.
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Affiliation(s)
- Michael A Dyer
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Zulekha A Qadeer
- Departments of Oncological Sciences and Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - David Valle-Garcia
- Departments of Oncological Sciences and Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Emily Bernstein
- Departments of Oncological Sciences and Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029
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6
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Vacca M, Della Ragione F, Scalabrì F, D'Esposito M. X inactivation and reactivation in X-linked diseases. Semin Cell Dev Biol 2016; 56:78-87. [PMID: 26994527 DOI: 10.1016/j.semcdb.2016.03.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/22/2022]
Abstract
X chromosome inactivation (XCI) is the phenomenon by which mammals compensate for dosage of X-linked genes in females (XX) versus males (XY). XCI patterns can be random or show extreme skewing, and can modify the mode of inheritance of X-driven phenotypes, which contributes to the variability of human pathologies. Recent findings have shown reversibility of the XCI process, which has opened new avenues in the approaches used for the treatment of X-linked diseases.
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Affiliation(s)
- Marcella Vacca
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy.
| | - Floriana Della Ragione
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy; IRCCS Neuromed, Pozzilli, Isernia, Italy
| | | | - Maurizio D'Esposito
- Institute of Genetics and Biophysics "A. Buzzati Traverso", CNR, via Pietro Castellino, 111, 80131, Naples, Italy; IRCCS Neuromed, Pozzilli, Isernia, Italy
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7
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Chandrasekaran P, Doss CGP, Nisha J, Sethumadhavan R, Shanthi V, Ramanathan K, Rajasekaran R. In silico analysis of detrimental mutations in ADD domain of chromatin remodeling protein ATRX that cause ATR-X syndrome: X-linked disorder. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s13721-013-0031-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Shimada S, Okamoto N, Ito M, Arai Y, Momosaki K, Togawa M, Maegaki Y, Sugawara M, Shimojima K, Osawa M, Yamamoto T. MECP2 duplication syndrome in both genders. Brain Dev 2013; 35:411-9. [PMID: 22877836 DOI: 10.1016/j.braindev.2012.07.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Revised: 07/07/2012] [Accepted: 07/15/2012] [Indexed: 12/21/2022]
Abstract
BACKGROUND Duplications involving the methyl-CpG-binding protein 2 gene (MECP2) locus at Xq28 have been frequently identified in male patients who exhibit a phenotype unique from that of Rett syndrome, which is mainly characterized by severe mental retardation, recurrent infections, and epilepsy. This combination of features is recognized as MECP2 duplication syndrome. METHODS Genomic copy number was investigated for patients with unexplained mental retardation, and phenotypic features of the patients having interstitial duplications including MECP2 were analyzed. RESULTS Three male and one female patients with MECP2 duplication were identified. The phenotypic features of all the four patients were compatible with MECP2 duplication syndrome. The X-chromosome inactivation (XCI) pattern was analyzed in the female patient, identifying a skewed XCI that activated the X-chromosome containing the MECP2 duplication. Her mother possessed the same MECP2 duplication and a random XCI pattern but exhibited no phenotypic features, indicating a nonsymptomatic carrier. The brain magnetic resonance imaging revealed periventricular cystic lesions in all four patients, including the female patient. CONCLUSION This study suggested clinical implications of the MECP2 duplication syndrome not only in the male but also in female patients with unexplained mental retardation.
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Affiliation(s)
- Shino Shimada
- Tokyo Women's Medical University Institute for Integrated Medical Sciences, Tokyo, Japan
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9
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Herbaux C, Badens C, Guidez S, Lacoste C, Maboudou P, Rose C. A NewATRXMutation in a Patient With Acquiredα-Thalassemia Myelodysplastic Syndrome. Hemoglobin 2012; 36:581-5. [DOI: 10.3109/03630269.2012.724040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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10
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De La Fuente R, Baumann C, Viveiros MM. Role of ATRX in chromatin structure and function: implications for chromosome instability and human disease. Reproduction 2011; 142:221-34. [PMID: 21653732 PMCID: PMC3253860 DOI: 10.1530/rep-10-0380] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Functional differentiation of chromatin structure is essential for the control of gene expression, nuclear architecture, and chromosome stability. Compelling evidence indicates that alterations in chromatin remodeling proteins play an important role in the pathogenesis of human disease. Among these, α-thalassemia mental retardation X-linked protein (ATRX) has recently emerged as a critical factor involved in heterochromatin formation at mammalian centromeres and telomeres as well as facultative heterochromatin on the murine inactive X chromosome. Mutations in human ATRX result in an X-linked neurodevelopmental condition with various degrees of gonadal dysgenesis (ATRX syndrome). Patients with ATRX syndrome may exhibit skewed X chromosome inactivation (XCI) patterns, and ATRX-deficient mice exhibit abnormal imprinted XCI in the trophoblast cell line. Non-random or skewed XCI can potentially affect both the onset and severity of X-linked disease. Notably, failure to establish epigenetic modifications associated with the inactive X chromosome (Xi) results in several conditions that exhibit genomic and chromosome instability such as fragile X syndrome as well as cancer development. Insight into the molecular mechanisms of ATRX function and its interacting partners in different tissues will no doubt contribute to our understanding of the pathogenesis of ATRX syndrome as well as the epigenetic origins of aneuploidy. In turn, this knowledge will be essential for the identification of novel drug targets and diagnostic tools for cancer progression as well as the therapeutic management of global epigenetic changes commonly associated with malignant neoplastic transformation.
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Affiliation(s)
- Rabindranath De La Fuente
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602, USA.
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11
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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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12
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Skewed X inactivation and IVF-conceived infants. Reprod Biomed Online 2010; 20:660-3. [PMID: 20207584 DOI: 10.1016/j.rbmo.2010.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 09/18/2009] [Accepted: 12/17/2009] [Indexed: 01/19/2023]
Abstract
The objective of this study was to investigate whether skewed X chromosome inactivation (XCI) is associated with IVF. A retrospective cohort study was performed comprising 30 female infants conceived by IVF and 44 naturally conceived control infants matched for gestational age and sex. Cord blood DNA samples were obtained and XCI patterns were analysed using a methylation-sensitive assay. Eight IVF samples and 13 control samples were excluded from the study because they were either homozygous or alleles were too similar for the assay to determine skewing. Mildly skewed XCI (80-90% inactivation of one allele) was present in two of 22 (9.1%) IVF samples and two of 31 (6.5%) control samples. Extremely skewed XCI (>90% inactivation of one allele) was found in two of 22 (9.1%) IVF samples and none of 31 control samples. Neither difference was statistically significant. However, the mean degree of skewed XCI in the IVF group was 72.0% and in the control group was 62.4% (P=0.002). Larger studies are needed to clarify the relationship between IVF and skewed XCI.
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13
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Orstavik KH. X chromosome inactivation in clinical practice. Hum Genet 2009; 126:363-73. [PMID: 19396465 DOI: 10.1007/s00439-009-0670-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2009] [Accepted: 04/07/2009] [Indexed: 01/19/2023]
Abstract
X chromosome inactivation (XCI) is the transcriptional silencing of the majority of genes on one of the two X chromosomes in mammalian females. Females are, therefore, mosaics for two cell lines, one with the maternal X and one with the paternal X as the active chromosome. The relative proportion of the two cell lines, the X inactivation pattern, may be analyzed by simple assays in DNA from available tissues. This review focuses on medical issues related to XCI in X-linked disorders, and on the value of X inactivation analysis in clinical practice.
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Affiliation(s)
- Karen Helene Orstavik
- Department of Medical Genetics, Oslo University Hospital, Rikshospitalet and Faculty Division Rikshospitalet, University of Oslo, Forskningsveien 2B, 0027, Oslo, Norway.
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Huntriss J, Picton HM. Epigenetic consequences of assisted reproduction and infertility on the human preimplantation embryo. HUM FERTIL 2008; 11:85-94. [PMID: 18569063 DOI: 10.1080/14647270802116250] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Epigenetic information, which is essential for normal mammalian development, is acquired during gametogenesis and further regulated during preimplantation development. The epigenetic consequences of assisted reproductive technologies (ARTs) and infertility on the health and quality of the human preimplantation embryo are considered in this review. In the zygote, the epigenetic information that is inherited from the sperm and the oocyte intersects and must be appropriately recognized, regulated and then propagated during preimplantation development so as to regulate gene expression in an appropriate manner. A growing body of evidence suggests that ARTs and/or infertility itself may affect these complex processes leading to epigenetic diseases that include disorders of genomic imprinting. The epigenetic safety of human gametes and embryos is of paramount importance. Unfortunately, morphological methods of assessing embryo quality are incapable of detecting epigenetic errors. Further research is therefore critical to resolve these issues.
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Affiliation(s)
- John Huntriss
- Reproduction and Early Development Research Group, Leeds Institute of Genetics, Health and Therapeutics, The LIGHT Laboratories, University of Leeds, Leeds, UK.
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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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