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Jajodia E, Menghani H, Arora N, Jitani A. De-novo ATR-16 syndrome associated with inherited hemoglobin Evanston causing HbH phenotype: a rare occurrence. Ann Hematol 2024:10.1007/s00277-024-05876-9. [PMID: 38990295 DOI: 10.1007/s00277-024-05876-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2024] [Accepted: 07/02/2024] [Indexed: 07/12/2024]
Abstract
Abnormality of three α-globin genes, either deletion or point mutation results in symptomatic Hemoglobin H (HbH) phenotype. Most of such cases of α-globin defects are inherited from the parents, de-novo cases are exceedingly rare. Herein, a case of HbH is reported where the proband inherited one α-globin gene with a point mutation (αEvanston) from the mother. This was associated with large de-novo deletion of chromosome 16p13.3 resulting in α-thalassemia and mental retardation (ATR-16) syndrome. This deletion also encompassed two α-globin genes from chromosome 16, eventually leading to --/ααEvanston genotype, explaining the clinical presentation of the proband. The challenges in screening of such cases and confirming the molecular diagnosis along with the mode of inheritance has been discussed.
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Affiliation(s)
- Ekta Jajodia
- Molecular Genetics, Unipath Specialty Laboratory, Ahmedabad, Gujarat, India
| | - Hemant Menghani
- Hematology and Bone Marrow Transplant, Marengo CIMS Hospital, Ahmedabad, Gujarat, India
| | - Neeraj Arora
- Molecular Genetics, Unipath Specialty Laboratory, Ahmedabad, Gujarat, India
| | - Ankit Jitani
- Hematology and Bone Marrow Transplant, Marengo CIMS Hospital, Ahmedabad, Gujarat, India.
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2
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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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3
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Tsai RX, Fang KC, Yang PC, Hsieh YH, Chiang IT, Chen Y, Lee HG, Lee J, Chu HPC. TERRA regulates DNA G-quadruplex formation and ATRX recruitment to chromatin. Nucleic Acids Res 2022; 50:12217-12234. [PMID: 36440760 PMCID: PMC9757062 DOI: 10.1093/nar/gkac1114] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/31/2022] [Accepted: 11/08/2022] [Indexed: 11/29/2022] Open
Abstract
The genome consists of non-B-DNA structures such as G-quadruplexes (G4) that are involved in the regulation of genome stability and transcription. Telomeric-repeat containing RNA (TERRA) is capable of folding into G-quadruplex and interacting with chromatin remodeler ATRX. Here we show that TERRA modulates ATRX occupancy on repetitive sequences and over genes, and maintains DNA G-quadruplex structures at TERRA target and non-target sites in mouse embryonic stem cells. TERRA prevents ATRX from binding to subtelomeric regions and represses H3K9me3 formation. G4 ChIP-seq reveals that G4 abundance decreases at accessible chromatin regions, particularly at transcription start sites (TSS) after TERRA depletion; such G4 reduction at TSS is associated with elevated ATRX occupancy and differentially expressed genes. Loss of ATRX alleviates the effect of gene repression caused by TERRA depletion. Immunostaining analyses demonstrate that knockdown of TERRA diminishes DNA G4 signals, whereas silencing ATRX elevates G4 formation. Our results uncover an epigenetic regulation by TERRA that sequesters ATRX and preserves DNA G4 structures.
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Affiliation(s)
| | | | | | - Yu-Hung Hsieh
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - I-Tien Chiang
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Yunfei Chen
- Institute of Molecular and Cellular Biology, National Taiwan University, No. 1 Sec. 4 Roosevelt Road, Taipei, Taiwan
| | - Hun-Goo Lee
- Department of Molecular Biology, Massachusetts General Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
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Gaspar TB, Macedo S, Sá A, Soares MA, Rodrigues DF, Sousa M, Mendes N, Martins RS, Cardoso L, Borges I, Canberk S, Gärtner F, Miranda-Alves L, Sobrinho-Simões M, Lopes JM, Soares P, Vinagre J. Characterisation of an Atrx Conditional Knockout Mouse Model: Atrx Loss Causes Endocrine Dysfunction Rather Than Pancreatic Neuroendocrine Tumour. Cancers (Basel) 2022; 14:cancers14163865. [PMID: 36010860 PMCID: PMC9406167 DOI: 10.3390/cancers14163865] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 12/22/2022] Open
Abstract
Simple Summary ATRX and DAXX mutations occur in 30–40% of pancreatic neuroendocrine tumours (PanNETs), and there are no reports in the literature of any genetically engineered mouse model (GEMM) evaluating the effect of Atrx disruption as a putative driver event on PanNET initiation. We created a novel GEMM with Atrx conditional disruption in β cells. We observed that this genetic alteration, per se, was not tumourigenic, but we reported novel roles of Atrx on endocrine function, which resulted in dysglycaemia and the exacerbation of inflammageing (increased pancreatic inflammation and hepatic steatosis). Abstract ATRX is a chromatin remodeller that maintains telomere homeostasis. Loss of ATRX is described in approximately 10% of pancreatic neuroendocrine tumours (PanNETs) and associated with poorer prognostic features. Here, we present a genetically engineered mouse model (GEMM) addressing the role of Atrx loss (AtrxKO) in pancreatic β cells, evaluating a large cohort of ageing mice (for up to 24 months (mo.)). Atrx loss did not cause PanNET formation but rather resulted in worsening of ageing-related pancreatic inflammation and endocrine dysfunction in the first year of life. Histopathological evaluation highlighted an exacerbated prevalence and intensity of pancreatic inflammation, ageing features, and hepatic steatosis in AtrxKO mice. Homozygous floxed mice presented hyperglycaemia, increased weights, and glucose intolerance after 6 months, but alterations in insulinaemia were not detected. Floxed individuals presented an improper growth of their pancreatic endocrine fraction that may explain such an endocrine imbalance. A pilot study of BRACO-19 administration to AtrxKO mice resulted in telomere instability, reinforcing the involvement of Atrx in the maintenance of β cell telomere homeostasis. Thereby, a non-obese dysglycaemic GEMM of disrupted Atrx is here presented as potentially useful for metabolic studies and putative candidate for inserting additional tumourigenic genetic events.
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Affiliation(s)
- Tiago Bordeira Gaspar
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, 4050-313 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
| | - Sofia Macedo
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, 4050-313 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
| | - Ana Sá
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
| | - Mariana Alves Soares
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Laboratório de Endocrinologia Experimental (LEEx), Instituto de Ciências Biomédicas (ICB), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-912, Brazil
- Programa de Pós-Graduação em Endocrinologia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-905, Brazil
| | - Daniela Ferreira Rodrigues
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute for Molecular and Cell Biology (IBMC), University of Porto, 4200-135 Porto, Portugal
| | - Mafalda Sousa
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute for Molecular and Cell Biology (IBMC), University of Porto, 4200-135 Porto, Portugal
| | - Nuno Mendes
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
| | - Rui Sousa Martins
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Faculty of Sciences of the University of Porto (FCUP), 4169-007 Porto, Portugal
| | - Luís Cardoso
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Department of Endocrinology, Diabetes and Metabolism, Centro Hospitalar e Universitário de Coimbra, 3000-075 Coimbra, Portugal
| | - Inês Borges
- Centro de Diagnóstico Veterinário (Cedivet), 4200-071 Porto, Portugal
| | - Sule Canberk
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, 4050-313 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
| | - Fátima Gärtner
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
| | - Leandro Miranda-Alves
- Laboratório de Endocrinologia Experimental (LEEx), Instituto de Ciências Biomédicas (ICB), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-912, Brazil
- Programa de Pós-Graduação em Endocrinologia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-905, Brazil
| | - Manuel Sobrinho-Simões
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
- Department of Pathology, Centro Hospitalar Universitário de São João (CHUSJ), 4200-319 Porto, Portugal
| | - José Manuel Lopes
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
- Department of Pathology, Centro Hospitalar Universitário de São João (CHUSJ), 4200-319 Porto, Portugal
| | - Paula Soares
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
| | - João Vinagre
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, 4200-135 Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (Ipatimup), 4200-135 Porto, Portugal
- Faculty of Medicine of the University of Porto (FMUP), 4200-319 Porto, Portugal
- Correspondence: ; Tel.: +351-225-570-700
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Jiwu L, Manna S, Ying Z, Youqing F, Haiyang C, Wanfang X, Yanhui L. Two large novel alpha-globin gene cluster deletions causing alpha(0)-thalassemia in two Chinese families. Gene 2022; 840:146767. [PMID: 35905847 DOI: 10.1016/j.gene.2022.146767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 06/28/2022] [Accepted: 07/24/2022] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Monosomy of terminal 16p13.3 is a relatively common subtelomeric abnormality, most affected individuals presented α-thalassemia, some also have mental retardation, developmental abnormalities and/or speech delay and facial dysmorphism, which is termed ATR-16 syndrome. Here, we reported two novel 16p13.3 deletions involving the α-globin gene cluster and multispecies conserved sequences (MCSs), causing only a phenotype of α-thalassemia. METHODS Samples were collected from members of the two families and were subjected to haematological and comprehensive genetic analysis. RESULTS The novel 108 Kb deletion in family A extends from the non-protein coding RNA gene (WASIR2) to the NPRL3 gene, removing MCS-R1 to R3. This deletion should arise de novo because it wasn't detected in both parents. The novel 336 Kb deletion in family B should extend from telomere to ∼ chr16:336000, removing the entire α-globin gene cluster. Carriers of these two deletions presented with microcytosis and hypochromic red cells, in accordance with a phenotype of α0-thalassemia carrier. CONCLUSION Our study increases the mutation spectrum of α-thalassemia. MCSs deletion should be considered in clinical practice of thalassemia screening and diagnosis.
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Affiliation(s)
- Lou Jiwu
- Prenatal Diagnostic Center, Affiliated Dongguan Maternal and Child Health Care Hospital, Southern Medical University, Dongguan, China
| | - Sun Manna
- Department of Obstetrics & Gynecologic, Affiliated Dongguan Maternal and Child Health Care Hospital, Southern Medical University, Dongguan, China
| | - Zhao Ying
- Prenatal Diagnostic Center, Affiliated Dongguan Maternal and Child Health Care Hospital, Southern Medical University, Dongguan, China
| | - Fu Youqing
- Prenatal Diagnostic Center, Affiliated Dongguan Maternal and Child Health Care Hospital, Southern Medical University, Dongguan, China
| | - Chen Haiyang
- Department of Laboratory, Affiliated Dongguan Maternal and Child Health Care Hospital, Southern Medical University, Dongguan, China
| | - Xu Wanfang
- Prenatal Diagnostic Center, Affiliated Dongguan Maternal and Child Health Care Hospital, Southern Medical University, Dongguan, China.
| | - Liu Yanhui
- Prenatal Diagnostic Center, Affiliated Dongguan Maternal and Child Health Care Hospital, Southern Medical University, Dongguan, China.
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Tamura K, Awaya T, Wada T, Fujii T, Yoshida T. Noniron deficiency microcytic anemia, dysmorphic features, and intellectual disability: Diagnostic clues for α-thalassemia/mental retardation associated with chromosome 16 syndrome. Pediatr Neonatol 2022; 63:298-300. [PMID: 35246371 DOI: 10.1016/j.pedneo.2021.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/06/2021] [Accepted: 11/26/2021] [Indexed: 11/19/2022] Open
Affiliation(s)
- Kentaro Tamura
- Division of Neonatology, Maternal and Perinatal Center, Toyama University Hospital, Toyama, Japan.
| | - Tomonari Awaya
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takahito Wada
- Department of Medical Ethics and Medical Genetics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tatsuya Fujii
- Department of Pediatrics, Shiga Medical Center for Children, Moriyama, Japan
| | - Taketoshi Yoshida
- Division of Neonatology, Maternal and Perinatal Center, Toyama University Hospital, Toyama, Japan
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Shahbazi Z, Rostami G, Hamid M. New heritable ATRX mutation identified by whole exome sequencing and review. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2022. [DOI: 10.1186/s43042-022-00227-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
The mutations in the ATRX gene have been shown to cause two types of disorders: inherited mutations lead to alpha thalassemia X-linked mental retardation (ATR-X) syndrome and acquired somatic mutations cause alpha thalassemia myelodysplastic syndrome (ATMDS). Here we report a case of ATRX gene mutation without completely features of ATR-X or ATMDS syndromes. Moreover we review previous reports of ATRX gene mutations in both ATR-X syndrome and ATMDS.
Methods
After sample collection and DNA extraction, whole exome sequencing was performed using Illumina HiSeq PE150 apparatus. The results were confirmed using Sanger sequencing for the patients and his relatives. Literature review was performed based on the published data in Web of science, Science direct, Springer link and Pubmed databases.
Results
We identified a hemizygous missense ATRX gene mutation (ATRX, c.2388A > C, p. K796N) as a new disease-causing variant in the patient, heterozygous situation for his mother and his father was hemizygous for wild type allele. The literatures of patients were reviewed regarding the ATR-X syndrome.
Conclusions
According to previous findings, inherited ATRX mutations are associated with a broad spectrum of clinical presentations. Therefore a person with a mild α-thalassemia phenotype may also has mutation in ATRX gene. Accordingly, it is critical for geneticist and physicians to increase awareness in molecular diagnosis of α-thalassemia patients.
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Abstract
Neuroblastoma (NB) is a pediatric cancer of the sympathetic nervous system and one of the most common solid tumors in infancy. Amplification of MYCN, copy number alterations, numerical and segmental chromosomal aberrations, mutations, and rearrangements on a handful of genes, such as ALK, ATRX, TP53, RAS/MAPK pathway genes, and TERT, are attributed as underlying causes that give rise to NB. However, the heterogeneous nature of the disease-along with the relative paucity of recurrent somatic mutations-reinforces the need to understand the interplay of genetic factors and epigenetic alterations in the context of NB. Epigenetic mechanisms tightly control gene expression, embryogenesis, imprinting, chromosomal stability, and tumorigenesis, thereby playing a pivotal role in physio- and pathological settings. The main epigenetic alterations include aberrant DNA methylation, disrupted patterns of posttranslational histone modifications, alterations in chromatin composition and/or architecture, and aberrant expression of non-coding RNAs. DNA methylation and demethylation are mediated by DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) proteins, respectively, while histone modifications are coordinated by histone acetyltransferases and deacetylases (HATs, HDACs), and histone methyltransferases and demethylases (HMTs, HDMs). This article focuses predominately on the crosstalk between the epigenome and NB, and the implications it has on disease diagnosis and treatment.
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9
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Liu J, Huang L, He Z, Lin S, Wang Y, Luo Y. Clinical value of genetic analysis in prenatal diagnosis of short femur. Mol Genet Genomic Med 2019; 7:e978. [PMID: 31566912 PMCID: PMC6825856 DOI: 10.1002/mgg3.978] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 08/26/2019] [Accepted: 08/29/2019] [Indexed: 12/31/2022] Open
Abstract
Background Fetal femur length (FL) is an important biometric index in prenatal screening. The etiology of short femur is diverse, with some pathogenic causes leading to adverse outcomes. To improve the accuracy and practicability of diagnosis, we investigated the value of genetic analysis in prenatal diagnosis of short femur. Methods We examined chromosomal microarray analysis (CMA) (64 fetuses) and karyotyping (59 fetuses) data retrospectively for short femur without fetal growth restriction (FGR). Genetic testing was conducted for 15 fetuses. Results Karyotyping and CMA detected chromosomal aberrations at rates of 13.6% and 27.2%, respectively. Among fetuses with other abnormalities, detection rates were 21.0% higher with CMA than karyotyping. CMA identified chromosomal abnormalities in 36.4% of cases with a FL 2–4 standard deviations (SDs) below the gestational age (GA) mean. Abnormality detection by CMA reached 38.5% in the second trimester. Duplication of 12p, 16p13.1 deletion, and uniparental disomy 16 were identified by CMA in three cases of short femur. Gene sequencing detected clinically notable mutations in 12/15 fetuses, among which 9/12 fetuses had FLs >4 SDs below the GA mean. Conclusions CMA yielded a higher detection value than karyotyping in fetuses with other abnormalities or a FL 2–4 SDs below the GA mean during the second trimester. Gene sequencing should be performed when FL is >4 SDs below the mean.
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Affiliation(s)
- Jialiu Liu
- Department of Obstetrics & Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Linhuan Huang
- Department of Obstetrics & Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Zhiming He
- Department of Obstetrics & Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Shaobin Lin
- Department of Obstetrics & Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Ye Wang
- Department of Obstetrics & Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Yanmin Luo
- Department of Obstetrics & Gynecology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, People's Republic of China
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Wykretowicz J, Song Y, McKnight B, Choi SW, Magenau J, Takiar R, Tomb PE, Ginsburg D, Bixby D, Khoriaty R. A diagnosis of discernment: Identifying a novel ATRX mutation in myelodysplastic syndrome with acquired α-thalassemia. Cancer Genet 2019; 231-232:36-40. [PMID: 30803555 DOI: 10.1016/j.cancergen.2019.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 12/15/2018] [Accepted: 01/07/2019] [Indexed: 12/15/2022]
Abstract
Myelodysplastic syndromes (MDS) are a heterogeneous category of myeloid neoplasms that represent the most common class of acquired bone marrow failure syndromes in adults. MDS is typically associated with a hypoproliferative macrocytic anemia, but atypical findings on initial diagnostic evaluations can raise concern for a distinct pathophysiological process and lead to the investigation of alternative etiologies. Here, we report a case of MDS with a concomitant hypoproliferative microcytic and hypochromic anemia that led to the identification of acquired hemoglobin H due to a novel somatic ATRX mutation.
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Affiliation(s)
- Jedrzej Wykretowicz
- Department of Internal Medicine, University of Michigan, 1524 Basic Science Research Building, Ann Arbor, MI 48109, USA
| | - Yeohan Song
- University of Michigan Medical School, University of Michigan, Ann Arbor, MI, USA
| | - Brooke McKnight
- College of Literature Science and the Arts, University of Michigan, Ann Arbor, MI, USA
| | - Sung Won Choi
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA
| | - John Magenau
- Department of Internal Medicine, University of Michigan, 1524 Basic Science Research Building, Ann Arbor, MI 48109, USA
| | - Radhika Takiar
- Department of Internal Medicine, University of Michigan, 1524 Basic Science Research Building, Ann Arbor, MI 48109, USA
| | - Paul El Tomb
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - David Ginsburg
- Department of Internal Medicine, University of Michigan, 1524 Basic Science Research Building, Ann Arbor, MI 48109, USA; Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA; Howard Hughes Medical Institute, Ann Arbor, MI, USA
| | - Dale Bixby
- Department of Internal Medicine, University of Michigan, 1524 Basic Science Research Building, Ann Arbor, MI 48109, USA
| | - Rami Khoriaty
- Department of Internal Medicine, University of Michigan, 1524 Basic Science Research Building, Ann Arbor, MI 48109, USA; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, USA.
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11
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Hnoonual A, Thammachote W, Tim-Aroon T, Rojnueangnit K, Hansakunachai T, Sombuntham T, Roongpraiwan R, Worachotekamjorn J, Chuthapisith J, Fucharoen S, Wattanasirichaigoon D, Ruangdaraganon N, Limprasert P, Jinawath N. Chromosomal microarray analysis in a cohort of underrepresented population identifies SERINC2 as a novel candidate gene for autism spectrum disorder. Sci Rep 2017; 7:12096. [PMID: 28935972 PMCID: PMC5608768 DOI: 10.1038/s41598-017-12317-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 09/07/2017] [Indexed: 01/11/2023] Open
Abstract
Chromosomal microarray (CMA) is now recognized as the first-tier genetic test for detection of copy number variations (CNVs) in patients with autism spectrum disorder (ASD). The aims of this study were to identify known and novel ASD associated-CNVs and to evaluate the diagnostic yield of CMA in Thai patients with ASD. The Infinium CytoSNP-850K BeadChip was used to detect CNVs in 114 Thai patients comprised of 68 retrospective ASD patients (group 1) with the use of CMA as a second line test and 46 prospective ASD and developmental delay patients (group 2) with the use of CMA as the first-tier test. We identified 7 (6.1%) pathogenic CNVs and 22 (19.3%) variants of uncertain clinical significance (VOUS). A total of 29 patients with pathogenic CNVs and VOUS were found in 22% (15/68) and 30.4% (14/46) of the patients in groups 1 and 2, respectively. The difference in detected CNV frequencies between the 2 groups was not statistically significant (Chi square = 1.02, df = 1, P = 0.31). In addition, we propose one novel ASD candidate gene, SERINC2, which warrants further investigation. Our findings provide supportive evidence that CMA studies using population-specific reference databases in underrepresented populations are useful for identification of novel candidate genes.
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Affiliation(s)
- Areerat Hnoonual
- Graduate Program in Biomedical Sciences, Prince of Songkla University, Songkhla, Thailand
| | - Weerin Thammachote
- Program in Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Thipwimol Tim-Aroon
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Kitiwan Rojnueangnit
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine, Thammasart University, Pathumthani, Thailand
| | - Tippawan Hansakunachai
- Division of Child Development, Department of Pediatrics, Faculty of Medicine, Thammasart University, Pathumthani, Thailand
| | - Tasanawat Sombuntham
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Rawiwan Roongpraiwan
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Juthamas Worachotekamjorn
- Division of Child Development, Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Jariya Chuthapisith
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Suthat Fucharoen
- Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Duangrurdee Wattanasirichaigoon
- Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Nichara Ruangdaraganon
- Division of Developmental-Behavioral Pediatrics, Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Pornprot Limprasert
- Division of Human Genetics, Department of Pathology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
| | - Natini Jinawath
- Program in Translational Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. .,Integrative Computational Bioscience Center, Mahidol University, Salaya, Nakhon Pathom, Thailand.
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12
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Ferrão J, Silva M, Gonçalves L, Gomes S, Loureiro P, Coelho A, Miranda A, Seuanes F, Reis AB, Pina F, Maia R, Kjöllerström P, Monteiro E, Lacerda JF, Lavinha J, Gonçalves J, Faustino P. Widening the spectrum of deletions and molecular mechanisms underlying alpha-thalassemia. Ann Hematol 2017; 96:1921-1929. [DOI: 10.1007/s00277-017-3090-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 08/01/2017] [Indexed: 10/18/2022]
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13
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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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14
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Abstract
Alpha-thalassemia (α-thal) is a disorder caused by the deletion of single or double α-globin genes, and/or point mutations in the α-globin genes. There are 2 common types of α-globin genes; HBA2 and HBA1. Recently, it has been discovered that the HBA2 gene is replaced by a unique HBA12 gene convert in 5.7% of the Saudi population. The α-globin genes have been emerging as a molecular target for the treatment of β-thalassemia (β-thal). Hence, it is essential to understand the molecular nature of α-globin genes to treat the most prevalent hemoglobin disorders, such as sickle cell disease, α-thal, and β-thal prevalent in the Kingdom of Saudi Arabia. Thirty-two different α-globin genotypes have been observed in the Saudi population. This review outlines the classification of the α-globin genes on the basis of their molecular nature and complex combinations of α-globin genes, and their variants predominant in Saudis.
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Affiliation(s)
- J Francis Borgio
- Center for Research and Medical Consultation, University of Dammam, Dammam, Kingdom of Saudi Arabia. E-mail.
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15
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Scheps KG, Francipane L, Nevado J, Basack N, Attie M, Bergonzi MF, Cerrone GE, Lapunzina P, Varela V. Multiple copy number variants in a pediatric patient with Hb H disease and intellectual disability. Am J Med Genet A 2016; 170A:986-91. [PMID: 26753516 DOI: 10.1002/ajmg.a.37532] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 12/11/2015] [Indexed: 11/09/2022]
Abstract
Two distinct syndromes that link α-thalassemia and intellectual disability (ID) have been described: ATR-X, due to mutations in the ATRX gene, and ATR-16, a contiguous gene deletion syndrome in the telomeric region of the short arm of chromosome 16. A critical region where the candidate genes for the ID map has been established. In a pediatric patient with Hemoglobin H disease, dysmorphic features and ID, 4 novel and clinically relevant Copy Number Variants were identified. PCR-GAP, MLPA and FISH analyses established the cause of the α-thalassemia. SNP-array analysis revealed the presence of 4 altered loci: 3 deletions (arr[hg19]Chr16(16p13.3; 88,165-1,507,988) x1; arr[hg19]Chr6(6p21.1; 44,798,701-45,334,537) x1 and arr[hg19]Chr17(17q25.3; 80,544,855-81,057,996) x1) and a terminal duplication (arr[hg19]Chr7(7p22.3-p22.2; 4,935-4,139,785) x3). The -α(3.7) mutation and the ∼1.51 Mb in 16p13.3 are involved in the alpha-thalassemic phenotype. However, the critical region for ATR-16 cannot be narrowed down. The deletion affecting 6p21.1 removes the first 2 exons and part of intron 2 of the RUNX2 gene. Although heterozygous loss of function mutations affecting this gene have been associated with cleidocranial dysplasia, the patient does not exhibit pathognomonic signs of this syndrome, possibly due to the fact that the isoform d of the transcription factor remains unaffected. This work highlights the importance of searching for cryptic deletions in patients with ID and reiterates the need of the molecular analysis when it is associated to microcytic hypochromic anemia with normal iron status.
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Affiliation(s)
- Karen G Scheps
- Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina.,INIGEM (Instituto de Inmunología, Genética y Metabolismo), CONICET- Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Liliana Francipane
- División Genética, Hospital de Clínicas "José de San Martín", Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Julián Nevado
- INGEMM (Instituto de Genética Médica y Molecular), Hospital Universitario La Paz-IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain.,CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Madrid, Spain
| | - Nora Basack
- División Hematología, Hospital de Niños "Dr. Ricardo Gutiérrez", Ciudad de Buenos Aires, Buenos Aires, Argentina
| | - Myriam Attie
- División Hematología, Hospital de Niños "Dr. Ricardo Gutiérrez", Ciudad de Buenos Aires, Buenos Aires, Argentina
| | - María Fernanda Bergonzi
- División Genética, Hospital de Clínicas "José de San Martín", Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Gloria E Cerrone
- Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina.,INIGEM (Instituto de Inmunología, Genética y Metabolismo), CONICET- Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Pablo Lapunzina
- INGEMM (Instituto de Genética Médica y Molecular), Hospital Universitario La Paz-IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain.,CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Madrid, Spain
| | - Viviana Varela
- Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina.,INIGEM (Instituto de Inmunología, Genética y Metabolismo), CONICET- Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
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16
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Abstract
Non-immune hemolytic anemia (NIHA) is characterized by positive routine hemolytic tests but negative anti-human immunoglobulin (Coombs) test. Hereditary non-immune hemolysis includes disorders of erythrocytic enzymes, membrane, hemoglobin (qualitative and quantitative disorders), as well as the rare hereditary forms of thrombotic microangiopathies. Acquired NIHA includes paroxysmal nocturnal hemolysis (PNH), infections, drug and metal intoxications with as a target red blood cells or endothelium of capillaries, the rare acquired forms of thalassemia or erythrocytic membrane disorders, and hemolysis secondary to a dysfunctioning artificial (prosthetic) cardiac valve. Identification of the specific cause of NIHA is sometimes difficult and requires not only a good knowledge of this entity but mainly a qualified specialized hematologic laboratory. An algorithm to be used in every new patient consulting for NIHA is proposed in the last part of this article.
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Affiliation(s)
- Photis Beris
- Service d'Hématologie, Département de Médecine Interne, Centre Médical Universitaire Genève Suisse, Geneva, Switzerland; Département d'hématologie, Laboratoire central Unilabs, Coppet, Switzerland.
| | - Véronique Picard
- Service d'Hématologie biologique, Hôpital Bicêtre, AP-HP, Le Kremlin Bicêtre, France; Laboratoire d'Hématologie, Faculté de Pharmacie, Université Paris-Sud, France
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17
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Tan WH, Bird LM, Thibert RL, Williams CA. If not Angelman, what is it? A review of Angelman-like syndromes. Am J Med Genet A 2014; 164A:975-92. [PMID: 24779060 DOI: 10.1002/ajmg.a.36416] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Angelman syndrome (AS) is caused by a lack of expression of the maternally inherited UBE3A gene in the brain. However, about 10% of individuals with a clinical diagnosis of AS do not have an identifiable molecular defect. It is likely that most of those individuals have an AS-like syndrome that is clinically and molecularly distinct from AS. These AS-like syndromes can be broadly classified into chromosomal microdeletion and microduplication syndromes, and single-gene disorders. The microdeletion/microduplication syndromes are now easily identified by chromosomal microarray analysis and include Phelan–McDermid syndrome (chromosome 22q13.3 deletion), MBD5 haploinsufficiency syndrome (chromosome 2q23.1 deletion), and KANSL1 haploinsufficiency syndrome (chromosome 17q21.31 deletion). The single-gene disorders include Pitt–Hopkins syndrome (TCF4), Christianson syndrome (SLC9A6), Mowat–Wilson syndrome (ZEB2), Kleefstra syndrome (EHMT1), and Rett (MECP2) syndrome. They also include disorders due to mutations in HERC2, adenylosuccinase lyase (ADSL), CDKL5, FOXG1, MECP2 (duplications), MEF2C, and ATRX. Although many of these single-gene disorders can be caused by chromosomal microdeletions resulting in haploinsufficiency of the critical gene, the individual disorders are often caused by intragenic mutations that cannot be detected by chromosomal microarray analysis. We provide an overview of the clinical features of these syndromes, comparing and contrasting them with AS, in the hope that it will help guide clinicians in the diagnostic work-up of individuals with AS-like syndromes.
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18
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López-Falcón B, Meyer-Nava S, Hernández-Rodríguez B, Campos A, Montero D, Rudiño E, Vázquez M, Zurita M, Valadez-Graham V. Characterization of the Drosophila group ortholog to the amino-terminus of the alpha-thalassemia and mental retardation X-Linked (ATRX) vertebrate protein. PLoS One 2014; 9:e113182. [PMID: 25437195 PMCID: PMC4249797 DOI: 10.1371/journal.pone.0113182] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/21/2014] [Indexed: 12/11/2022] Open
Abstract
The human ATRX gene encodes hATRX, a chromatin-remodeling protein harboring an helicase/ATPase and ADD domains. The ADD domain has two zinc fingers that bind to histone tails and mediate hATRX binding to chromatin. dAtrx, the putative ATRX homolog in Drosophila melanogaster, has a conserved helicase/ATPase domain but lacks the ADD domain. A bioinformatic search of the Drosophila genome using the human ADD sequence allowed us to identify the CG8290 annotated gene, which encodes three ADD harboring- isoforms generated by alternative splicing. This Drosophila ADD domain is highly similar in structure and in the amino acids which mediate the histone tail contacts to the ADD domain of hATRX as shown by 3D modeling. Very recently the CG8290 annotated gene has been named dadd1. We show through pull-down and CoIP assays that the products of the dadd1 gene interact physically with dAtrxL and HP1a and all of them mainly co-localize in the chromocenter, although euchromatic localization can also be observed through the chromosome arms. We confirm through ChIP analyses that these proteins are present in vivo in the same heterochromatic regions. The three isoforms are expressed throughout development. Flies carrying transheterozygous combinations of the dadd1 and atrx alleles are semi-viable and have different phenotypes including the appearance of melanotic masses. Interestingly, the dAdd1-b and c isoforms have extra domains, such as MADF, which suggest newly acquired functions of these proteins. These results strongly support that, in Drosophila, the atrx gene diverged and that the dadd1-encoded proteins participate with dAtrx in some cellular functions such as heterochromatin maintenance.
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Affiliation(s)
- Brenda López-Falcón
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Silvia Meyer-Nava
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Benjamín Hernández-Rodríguez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Adam Campos
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Daniel Montero
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Enrique Rudiño
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Martha Vázquez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Mario Zurita
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- * E-mail: (VVG); (MZ)
| | - Viviana Valadez-Graham
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- * E-mail: (VVG); (MZ)
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19
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Basehore MJ, Michaelson-Cohen R, Levy-Lahad E, Sismani C, Bird LM, Friez MJ, Walsh T, Abidi F, Holloway L, Skinner C, McGee S, Alexandrou A, Syrrou M, Patsalis PC, Raymond G, Wang T, Schwartz CE, King MC, Stevenson RE. Alpha-thalassemia intellectual disability: variable phenotypic expression among males with a recurrent nonsense mutation - c.109C>T (p.R37X). Clin Genet 2014; 87:461-6. [PMID: 24805811 DOI: 10.1111/cge.12420] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/02/2014] [Accepted: 05/05/2014] [Indexed: 11/30/2022]
Abstract
Alpha-thalassemia intellectual disability, one of the recognizable X-linked disability syndromes, is characterized by short stature, microcephaly, distinctive facies, hypotonic appearance, cardiac and genital anomalies, and marked skewing of X-inactivation in female carriers. With the advent of next generation sequencing, mutations have been identified that result in less severe phenotypes lacking one or more of these phenotypic manifestations. Here we report five unrelated kindreds in which a c.109C>T (p.R37X) mutation segregates with a variable but overall milder phenotype. The distinctive facial appearance of alpha-thalassemia intellectual disability was present in only one of the 18 affected males evaluated beyond the age of puberty, although suggestive facial appearance was present in several during infancy or early childhood. Although the responsible genetic alteration is a nonsense mutation in exon 2 of ATRX, the phenotype appears to be partially rescued by the production of alternative transcripts and/or other molecular mechanisms.
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Affiliation(s)
- M J Basehore
- Greenwood Genetic Center, Molecular Diagnostic, Greenwood, SC, USA
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20
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Meeker A, Heaphy C. Gastroenteropancreatic endocrine tumors. Mol Cell Endocrinol 2014; 386:101-20. [PMID: 23906538 DOI: 10.1016/j.mce.2013.07.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 02/06/2023]
Abstract
Gastroenteropancreatic endocrine tumors (GEP-NETs) are relatively uncommon; comprising approximately 0.5% of all human cancers. Although they often exhibit relatively indolent clinical courses, GEP-NETs have the potential for lethal progression. Due to their scarcity and various technical challenges, GEP-NETs have been understudied. As a consequence, we have few diagnostic, prognostic and predictive biomarkers for these tumors. Early detection and surgical removal is currently the only reliable curative treatment for GEP-NET patients; many of whom, unfortunately, present with advanced disease. Here, we review the genetics and epigenetics of GEP-NETs. The last few years have witnessed unprecedented technological advances in these fields, and their application to GEP-NETS has already led to important new information on the molecular abnormalities underlying them. As outlined here, we expect that "omics" studies will provide us with new diagnostic and prognostic biomarkers, inform the development of improved pre-clinical models, and identify novel therapeutic targets for GEP-NET patients.
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Affiliation(s)
- Alan Meeker
- The Johns Hopkins University School of Medicine, Department of Pathology, Bond Street Research Annex Bldg., Room B300, 411 North Caroline Street, Baltimore, MD 21231, United States.
| | - Christopher Heaphy
- The Johns Hopkins University School of Medicine, Department of Pathology, Bond Street Research Annex Bldg., Room B300, 411 North Caroline Street, Baltimore, MD 21231, United States
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21
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Weatherall DJ. The Role of the Inherited Disorders of Hemoglobin, the First “Molecular Diseases,” in the Future of Human Genetics. Annu Rev Genomics Hum Genet 2013; 14:1-24. [DOI: 10.1146/annurev-genom-091212-153500] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- David J. Weatherall
- Weatherall Institute of Molecular Medicine, Oxford University, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom;
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22
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Abstract
Iron deficiency anemia arises when the balance of iron intake, iron stores, and the body's loss of iron are insufficient to fully support production of erythrocytes. Iron deficiency anemia rarely causes death, but the impact on human health is significant. In the developed world, this disease is easily identified and treated, but frequently overlooked by physicians. In contrast, it is a health problem that affects major portions of the population in underdeveloped countries. Overall, the prevention and successful treatment for iron deficiency anemia remains woefully insufficient worldwide, especially among underprivileged women and children. Here, clinical and laboratory features of the disease are discussed, and then focus is placed on relevant economic, environmental, infectious, and genetic factors that converge among global populations.
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Affiliation(s)
- Jeffery L Miller
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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23
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Ratnakumar K, Bernstein E. ATRX: the case of a peculiar chromatin remodeler. Epigenetics 2012; 8:3-9. [PMID: 23249563 DOI: 10.4161/epi.23271] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The SWI/SNF-like chromatin remodeler ATRX has recently garnered renewed attention. ATRX mutations were first identified in patients bearing the syndrome after which it is named, alpha thalassemia/mental retardation, X-linked. While ATRX has long been implicated in transcriptional regulation through multiple mechanisms, recent studies have identified a role for ATRX in the regulation of histone variant deposition. In addition, current reports describe ATRX to be mutated at high percentages in multiple tumor types, suggestive of a potential 'driver' role in cancer. Here we discuss the numerous and seemingly diverse roles for ATRX in transcriptional regulation and histone deposition and suggest that ATRX's effects are mediated by its regulation of histones within the chromatin template.
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Affiliation(s)
- Kajan Ratnakumar
- Department of Oncological Sciences, Mount Sinai School of Medicine, New York, NY, USA
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