1
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Stefanucci L, Collins J, Sims MC, Barrio-Hernandez I, Sun L, Burren OS, Perfetto L, Bender I, Callahan TJ, Fleming K, Guerrero JA, Hermjakob H, Martin MJ, Stephenson J, Paneerselvam K, Petrovski S, Porras P, Robinson PN, Wang Q, Watkins X, Frontini M, Laskowski RA, Beltrao P, Di Angelantonio E, Gomez K, Laffan M, Ouwehand WH, Mumford AD, Freson K, Carss K, Downes K, Gleadall N, Megy K, Bruford E, Vuckovic D. The effects of pathogenic and likely pathogenic variants for inherited hemostasis disorders in 140 214 UK Biobank participants. Blood 2023; 142:2055-2068. [PMID: 37647632 PMCID: PMC10733830 DOI: 10.1182/blood.2023020118] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 08/04/2023] [Accepted: 08/04/2023] [Indexed: 09/01/2023] Open
Abstract
Rare genetic diseases affect millions, and identifying causal DNA variants is essential for patient care. Therefore, it is imperative to estimate the effect of each independent variant and improve their pathogenicity classification. Our study of 140 214 unrelated UK Biobank (UKB) participants found that each of them carries a median of 7 variants previously reported as pathogenic or likely pathogenic. We focused on 967 diagnostic-grade gene (DGG) variants for rare bleeding, thrombotic, and platelet disorders (BTPDs) observed in 12 367 UKB participants. By association analysis, for a subset of these variants, we estimated effect sizes for platelet count and volume, and odds ratios for bleeding and thrombosis. Variants causal of some autosomal recessive platelet disorders revealed phenotypic consequences in carriers. Loss-of-function variants in MPL, which cause chronic amegakaryocytic thrombocytopenia if biallelic, were unexpectedly associated with increased platelet counts in carriers. We also demonstrated that common variants identified by genome-wide association studies (GWAS) for platelet count or thrombosis risk may influence the penetrance of rare variants in BTPD DGGs on their associated hemostasis disorders. Network-propagation analysis applied to an interactome of 18 410 nodes and 571 917 edges showed that GWAS variants with large effect sizes are enriched in DGGs and their first-order interactors. Finally, we illustrate the modifying effect of polygenic scores for platelet count and thrombosis risk on disease severity in participants carrying rare variants in TUBB1 or PROC and PROS1, respectively. Our findings demonstrate the power of association analyses using large population datasets in improving pathogenicity classifications of rare variants.
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Affiliation(s)
- Luca Stefanucci
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- British Heart Foundation, BHF Centre of Research Excellence, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Janine Collins
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Haematology, Barts Health NHS Trust, London, United Kingdom
| | - Matthew C. Sims
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Haematology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Sheffield, United Kingdom
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - Inigo Barrio-Hernandez
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Luanluan Sun
- Department of Public Health and Primary Care, BHF Cardiovascular Epidemiology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Oliver S. Burren
- Centre for Genomics Research, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
| | - Livia Perfetto
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
- Department of Biology and Biotechnology “C.Darwin,” Sapienza University of Rome, Rome, Italy
| | - Isobel Bender
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Tiffany J. Callahan
- Department of Biomedical Informatics, Columbia University Irving Medical Center, New York, NY
| | - Kathryn Fleming
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Jose A. Guerrero
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Haematology, Barts Health NHS Trust, London, United Kingdom
| | - Henning Hermjakob
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Maria J. Martin
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - James Stephenson
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - NIHR BioResource
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- British Heart Foundation, BHF Centre of Research Excellence, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Haematology, Barts Health NHS Trust, London, United Kingdom
- Department of Haematology, Sheffield Teaching Hospitals NHS Foundation Trust, Royal Hallamshire Hospital, Sheffield, United Kingdom
- Department of Oncology and Metabolism, University of Sheffield, Sheffield, United Kingdom
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
- Department of Public Health and Primary Care, BHF Cardiovascular Epidemiology Unit, University of Cambridge, Cambridge, United Kingdom
- Centre for Genomics Research, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
- Department of Biology and Biotechnology “C.Darwin,” Sapienza University of Rome, Rome, Italy
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- Department of Biomedical Informatics, Columbia University Irving Medical Center, New York, NY
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- Centre for Genomics Research, Discovery Sciences, AstraZeneca, Cambridge, United Kingdom
- Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Australia
- Genomic Medicine, The Jackson Laboratory, Farmington, CT
- Institute for Systems Genomics, University of Connecticut, Farmington, CT
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences RILD Building, University of Exeter Medical School, Exeter, United Kingdom
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
- Heart and Lung Research Institute, University of Cambridge, Cambridge, United Kingdom
- NIHR Blood and Transplant Research Unit in Donor Health and Behaviour, Cambridge, United Kingdom
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, United Kingdom
- Health Data Science Centre, Human Technopole, Milan, Italy
- Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, United Kingdom
- Department of Haematology, Imperial College Healthcare NHS Trust, London, United Kingdom
- Department of Immunology and Inflammation, Centre for Haematology, Imperial College London, London, United Kingdom
- Department of Haematology, University College London Hospitals NHS Trust, London, United Kingdom
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KULeuven, Leuven, Belgium
- Cambridge Genomics Laboratory, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Epidemiology and Biostatistics, Imperial College London, London, United Kingdom
| | - Kalpana Paneerselvam
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Slavé Petrovski
- Centre for Genomics Research, Discovery Sciences, AstraZeneca, Cambridge, United Kingdom
- Department of Medicine, Austin Health, The University of Melbourne, Melbourne, Australia
| | - Pablo Porras
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Peter N. Robinson
- Genomic Medicine, The Jackson Laboratory, Farmington, CT
- Institute for Systems Genomics, University of Connecticut, Farmington, CT
| | - Quanli Wang
- Centre for Genomics Research, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
| | - Xavier Watkins
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Mattia Frontini
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- British Heart Foundation, BHF Centre of Research Excellence, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences RILD Building, University of Exeter Medical School, Exeter, United Kingdom
| | - Roman A. Laskowski
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Pedro Beltrao
- Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
| | - Emanuele Di Angelantonio
- British Heart Foundation, BHF Centre of Research Excellence, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Public Health and Primary Care, BHF Cardiovascular Epidemiology Unit, University of Cambridge, Cambridge, United Kingdom
- Heart and Lung Research Institute, University of Cambridge, Cambridge, United Kingdom
- NIHR Blood and Transplant Research Unit in Donor Health and Behaviour, Cambridge, United Kingdom
- Health Data Research UK Cambridge, Wellcome Genome Campus and University of Cambridge, Cambridge, United Kingdom
- Health Data Science Centre, Human Technopole, Milan, Italy
| | - Keith Gomez
- Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, United Kingdom
| | - Mike Laffan
- Department of Haematology, Imperial College Healthcare NHS Trust, London, United Kingdom
- Department of Immunology and Inflammation, Centre for Haematology, Imperial College London, London, United Kingdom
| | - Willem H. Ouwehand
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Department of Haematology, University College London Hospitals NHS Trust, London, United Kingdom
| | - Andrew D. Mumford
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Kathleen Freson
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KULeuven, Leuven, Belgium
| | - Keren Carss
- Centre for Genomics Research, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, Cambridge, United Kingdom
| | - Kate Downes
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Cambridge Genomics Laboratory, Cambridge University Hospitals National Health Service Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Nick Gleadall
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- National Health Service Blood and Transplant, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Karyn Megy
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Elspeth Bruford
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Dragana Vuckovic
- Department of Epidemiology and Biostatistics, Imperial College London, London, United Kingdom
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2
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Germeshausen M, Ballmaier M. CAMT-MPL: congenital amegakaryocytic thrombocytopenia caused by MPL mutations - heterogeneity of a monogenic disorder - a comprehensive analysis of 56 patients. Haematologica 2021; 106:2439-2448. [PMID: 32703794 PMCID: PMC8409039 DOI: 10.3324/haematol.2020.257972] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Indexed: 11/17/2022] Open
Abstract
Congenital amegakaryocytic thrombocytopenia caused by deleterious homozygous or compound heterozygous mutations in MPL (CAMT-MPL) is a rare inherited bone marrow failure syndrome presenting as an isolated thrombocytopenia at birth progressing to pancytopenia due to exhaustion of hematopoietic progenitors. The analysis of samples and clinical data from a large cohort of 56 patients with CAMT-MPL resulted in a detailed description of the clinical picture and reliable genotype-phenotype correlations for this rare disease. We extended the spectrum of CAMT causing MPL mutations regarding number (17 novel mutations) and impact. Clinical courses showed great variability with respect to the severity of thrombocytopenia, the development of pancytopenia and the consequences from bleedings. The most severe clinical problems were (i) intracranial bleedings pre- and perinatally and the resulting long-term consequences, and (ii) the development of aplastic anemia in the later course of the disease. An important and new finding was that thrombocytopenia was not detected at birth in a quarter of the patients. The rate of non-hematological abnormalities in CAMT-MPL was higher than described so far. Most of the anomalies were related to the head region (brain anomalies, ocular and orbital anomalies) and consequences of intracranial bleedings. The present study demonstrates a higher variability of clinical courses than described so far and has important implications on diagnosis and therapy. The diagnosis CAMT-MPL has to be considered even for those patients who are inconspicuous in the first months of life or show somatic anomalies typical for other inherited bone marrow failure syndromes.
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Affiliation(s)
- Manuela Germeshausen
- Central Research Facility Cell Sorting, Hannover Medical School, Hannover, Germany.
| | - Matthias Ballmaier
- Central Research Facility Cell Sorting, Hannover Medical School, Hannover, Germany.
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3
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Paul M, Killikulangara Sadanandan A, Abraham L, Madany Pathrose S, Varghese D. An Unusual Case of Severe Persistent Neonatal Thrombocytopenia in an Extremely Low Birth Weight, Extreme Preterm Neonate. Glob Pediatr Health 2021; 8:2333794X211038724. [PMID: 34414253 PMCID: PMC8369956 DOI: 10.1177/2333794x211038724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 07/21/2021] [Indexed: 11/15/2022] Open
Abstract
Neonatal thrombocytopenia is a common hematological problem but refractory thrombocytopenia is very rare in neonates. A systematic and diligent workup will result in arriving at the proper diagnosis and providing accurate management in rare causes of neonatal thrombocytopenia. We report a case of severe refractory thrombocytopenia in an extremely low birth weight (ELBW)/extreme preterm baby who presented with early onset severe thrombocytopenia associated with anemia and required multiple platelet transfusions. After ruling out COVID-19 infection, sepsis and neonatal alloimmune thrombocytopenia (NAIT), the cause for severe refractory thrombocytopenia was diagnosed as Type II congenital amegakaryocytic thrombocytopenia (CAMT) by bone marrow examination and MPL gene mutation studies.
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4
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Congenital amegakaryocytic thrombocytopenia - Not a single disease. Best Pract Res Clin Haematol 2021; 34:101286. [PMID: 34404532 DOI: 10.1016/j.beha.2021.101286] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 01/05/2023]
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare inherited bone marrow failure syndrome (IBMFS) that is characterized by severe thrombocytopenia at birth due to ineffective megakaryopoiesis and development towards aplastic anemia during the first years of life. CAMT is not a single monogenetic disorder; rather, many descriptions of CAMT include different entities with different etiologies. CAMT in a narrow sense, which is primarily restricted to the hematopoietic system, is caused mainly by mutations in the gene for the thrombopoietin receptor (MPL), sometimes in the gene for its ligand (THPO). CAMT in association with radio-ulnar synostosis, which is not always clinically apparent, is mostly caused by mutations in MECOM, rarely in HOXA11. Patients affected by other IBMFS - especially Fanconi anemia or dyskeratosis congenita - may be misdiagnosed as having CAMT when they lack typical disease features of these syndromes or have only mild symptoms. This article reviews scientific and clinical aspects of the various disorders associated with the term "CAMT" with a main focus on the disease caused by mutations in the MPL gene.
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5
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Agarwal N, Mangla A. Thrombopoietin receptor agonist for treatment of immune thrombocytopenia in pregnancy: a narrative review. Ther Adv Hematol 2021; 12:20406207211001139. [PMID: 33796239 PMCID: PMC7983475 DOI: 10.1177/20406207211001139] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 02/09/2021] [Indexed: 12/26/2022] Open
Abstract
The treatment of immune thrombocytopenia (ITP) in adults has evolved rapidly over the past decade. The second-generation thrombopoietin receptor agonists (TPO-RAs), romiplostim, eltrombopag, and avatrombopag are approved for the treatment of chronic ITP in adults. However, their use in pregnancy is labeled as category C by the United States Food and Drug Administration (FDA) due to the lack of clinical data on human subjects. ITP is a common cause of thrombocytopenia in the first and second trimester of pregnancy, which not only affects the mother but can also lead to thrombocytopenia in the neonatal thrombocytopenia secondary to maternal immune thrombocytopenia (NMITP). Corticosteroids, intravenous immunoglobulins (IVIGs) are commonly used for treating acute ITP in pregnant patients. Drugs such as rituximab, anti-D, and azathioprine that are used to treat ITP in adults, are labeled category C and seldom used in pregnant patients. Cytotoxic chemotherapy (vincristine, cyclophosphamide), danazol, and mycophenolate are contraindicated in pregnant women. In such a scenario, TPO-RAs present an attractive option to treat ITP in pregnant patients. Current evidence on the use of TPO-RAs in pregnant women with ITP is limited. In this narrative review, we will examine the preclinical and the clinical literature regarding the use of TPO-RAs in the management of ITP in pregnancy and their effect on neonates with NMITP.
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Affiliation(s)
- Nikki Agarwal
- Division of Pediatric Hematology and Oncology, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Ankit Mangla
- Division of Hematology and Oncology, Seidman Cancer Center, University Hospitals, 11100 Euclid Avenue, Cleveland, OH 44106, USA
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6
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Spivak JL, Moliterno AR. The Thrombopoietin Receptor, MPL, Is a Therapeutic Target of Opportunity in the MPN. Front Oncol 2021; 11:641613. [PMID: 33777803 PMCID: PMC7987816 DOI: 10.3389/fonc.2021.641613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/28/2021] [Indexed: 12/12/2022] Open
Abstract
The myeloproliferative neoplasms, polycythemia vera, essential thrombocytosis and primary myelofibrosis share driver mutations that either activate the thrombopoietin receptor, MPL, or indirectly activate it through mutations in the gene for JAK2, its cognate tyrosine kinase. Paradoxically, although the myeloproliferative neoplasms are classified as neoplasms because they are clonal hematopoietic stem cell disorders, the mutations affecting MPL or JAK2 are gain-of-function, resulting in increased production of normal erythrocytes, myeloid cells and platelets. Constitutive JAK2 activation provides the basis for the shared clinical features of the myeloproliferative neoplasms. A second molecular abnormality, impaired posttranslational processing of MPL is also shared by these disorders but has not received the recognition it deserves. This abnormality is important because MPL is the only hematopoietic growth factor receptor expressed in hematopoietic stem cells; because MPL is a proto-oncogene; because impaired MPL processing results in chronic elevation of plasma thrombopoietin, and since these diseases involve normal hematopoietic stem cells, they have proven resistant to therapies used in other myeloid neoplasms. We hypothesize that MPL offers a selective therapeutic target in the myeloproliferative neoplasms since impaired MPL processing is unique to the involved stem cells, while MPL is required for hematopoietic stem cell survival and quiescent in their bone marrow niches. In this review, we will discuss myeloproliferative neoplasm hematopoietic stem cell pathophysiology in the context of the behavior of MPL and its ligand thrombopoietin and the ability of thrombopoietin gene deletion to abrogate the disease phenotype in vivo in a JAK2 V617 transgenic mouse model of PV.
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Affiliation(s)
- Jerry L Spivak
- Hematology Division, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, Baltimore, MD, United States
| | - Alison R Moliterno
- Hematology Division, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, Baltimore, MD, United States
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7
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Zhao TY, Chen M. [Congenital amegakaryocytic thrombocytopenia with inflammatory disease of ascending colon and ileocecum: a case report and literature review]. ZHONGHUA XUE YE XUE ZA ZHI = ZHONGHUA XUEYEXUE ZAZHI 2021; 41:762-765. [PMID: 33113609 PMCID: PMC7595868 DOI: 10.3760/cma.j.issn.0253-2727.2020.09.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- T Y Zhao
- Endocrinology Department, Peking Union Medical College Hospital, CAMS & PUMC, Beijing 100730, China
| | - M Chen
- Hematology Department, Peking Union Medical College Hospital, CAMS & PUMC, Beijing 100730, China
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8
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Xu L, Liu X, Peng F, Zhang W, Zheng L, Ding Y, Gu T, Lv K, Wang J, Ortinau L, Hu T, Shi X, Shi G, Shang G, Sun S, Iwawaki T, Ji Y, Li W, Rosen JM, Zhang XHF, Park D, Adoro S, Catic A, Tong W, Qi L, Nakada D, Chen X. Protein quality control through endoplasmic reticulum-associated degradation maintains haematopoietic stem cell identity and niche interactions. Nat Cell Biol 2020; 22:1162-1169. [PMID: 32958856 PMCID: PMC7888538 DOI: 10.1038/s41556-020-00581-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 08/21/2020] [Indexed: 12/19/2022]
Abstract
Stem cells need to be protected from genotoxic and proteotoxic stress to maintain a healthy pool throughout life1–3. Little is known about the proteostasis mechanism that safeguards the stem cells. Here, we report Endoplasmic Reticulum-Associated Degradation (ERAD) as a protein quality checkpoint that controls hematopoietic stem cell (HSC)-niche interaction and determines the fate of HSC. SEL1L-HRD1 complex, the most conserved branch of ERAD4, is highly expressed in HSC. Deletion of Sel1l led to niche displacement of HSC, complete loss of HSC identity, and allowed highly efficient donor-HSC engraftment without irradiation. Mechanistic studies identified MPL, the master regulator of HSC identity5, as a bona-fide ERAD substrate that became aggregated in the ER upon ERAD deficiency. Restoration of MPL signaling with an agonist partially rescued the number and reconstitution capacity of Sel1l-deficient HSCs. Our study defines ERAD as an essential proteostasis mechanism to safeguard a healthy stem cell pool through regulating the stem cell-niche interaction.
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Affiliation(s)
- Longyong Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Xia Liu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Fanglue Peng
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Weijie Zhang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Liting Zheng
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Yao Ding
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Tianpeng Gu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Stem Cells and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX, USA
| | - Kaosheng Lv
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jin Wang
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, USA
| | - Laura Ortinau
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Tianyuan Hu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Xiangguo Shi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Guojun Shi
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ge Shang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Shengyi Sun
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Takao Iwawaki
- Division of Cell Medicine, Department of Life Science, Medical Research Institute, Kanazawa Medical University, Uchinada, Japan
| | - Yewei Ji
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Wei Li
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Jeffrey M Rosen
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Xiang H-F Zhang
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Dongsu Park
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Stanley Adoro
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Andre Catic
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Wei Tong
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ling Qi
- Department of Molecular and Integrative Physiology and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Daisuke Nakada
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Xi Chen
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA. .,Lester and Sue Smith Breast Center and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, USA.
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9
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Spivak JL, Merchant A, Williams DM, Rogers O, Zhao W, Duffield A, Resar LS, Moliterno AR, Zhao ZJ. Thrombopoietin is required for full phenotype expression in a JAK2V617F transgenic mouse model of polycythemia vera. PLoS One 2020; 15:e0232801. [PMID: 32479500 PMCID: PMC7263591 DOI: 10.1371/journal.pone.0232801] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/21/2020] [Indexed: 12/30/2022] Open
Abstract
The myeloproliferative neoplasms, polycythemia vera, essential thrombocytosis and primary myelofibrosis are hematopoietic stem cell disorders and share driver mutations that either directly activate the thrombopoietin receptor, MPL, or activate it indirectly through gain-of-function mutations in the gene for JAK2, its cognate tyrosine kinase. Paradoxically, MPL surface expression in hematopoietic stem cells is also reduced in the myeloproliferative neoplasms due to abnormal post-translational glycosylation and premature destruction of JAK2, suggesting that the myeloproliferative neoplasms are disorders of MPL processing since MPL is the only hematopoietic growth factor receptor in hematopoietic stem cells. To examine this possibility, we genetically manipulated MPL expression and maturation in a JAK2V617F transgenic mouse model of polycythemia vera. Elimination of MPL expression completely abrogated the polycythemia vera phenotype in this JAK2V617F transgenic mouse model, which could only be partially restored by expression of one MPL allele. Most importantly, elimination of thrombopoietin gene expression abrogated the polycythemia vera phenotype in this JAK2V617F transgenic mouse model, which could be completely restored by expression of a single thrombopoietin allele. These data indicate that polycythemia vera is in part a thrombopoietin-dependent disorder and that targeting the MPL-thrombopoietin axis could be an effective, nonmyelotoxic therapeutic strategy in this disorder.
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Affiliation(s)
- Jerry L. Spivak
- Hematology Division, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
| | - Akil Merchant
- Samuel Oschin Comprehensive Cancer Institute, Blood and Marrow Transplant Program, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Donna M. Williams
- Hematology Division, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Ophelia Rogers
- Hematology Division, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Wanke Zhao
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Amy Duffield
- Department of Pathology, Hematologic Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Linda S. Resar
- Hematology Division, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Alison R. Moliterno
- Hematology Division, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Zhizhuang J. Zhao
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
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10
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Zebrafish for thrombocytopoiesis- and hemostasis-related researches and disorders. BLOOD SCIENCE 2020; 2:44-49. [PMID: 35402814 PMCID: PMC8975081 DOI: 10.1097/bs9.0000000000000043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 03/05/2020] [Indexed: 11/30/2022] Open
Abstract
Platelets play vital roles in hemostasis, inflammation, and vascular biology. Platelets are also active participants in the immune responses. As vertebrates, zebrafish have a highly conserved hematopoietic system in the developmental, cellular, functional, biochemical, and genetic levels with mammals. Thrombocytes in zebrafish are functional homologs of mammalian platelets. Here, we summarized thrombocyte development, function, and related research techniques in zebrafish, and reviewed available zebrafish models of platelet-associated disorders, including congenital amegakaryocytic thrombocytopenia, inherited thrombocytopenia, essential thrombocythemia, and blood coagulation disorders such as gray platelet syndrome. These elegant zebrafish models and methods are crucial for understanding the molecular and genetic mechanisms of thrombocyte development and function, and provide deep insights into related human disease pathophysiology and drug development.
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11
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Bussel J, Kulasekararaj A, Cooper N, Verma A, Steidl U, Semple JW, Will B. Mechanisms and therapeutic prospects of thrombopoietin receptor agonists. Semin Hematol 2019; 56:262-278. [PMID: 31836033 DOI: 10.1053/j.seminhematol.2019.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 07/30/2019] [Accepted: 09/30/2019] [Indexed: 12/13/2022]
Abstract
The second-generation thrombopoietin (TPO) receptor agonists eltrombopag and romiplostim are potent activators of megakaryopoiesis and represent a growing treatment option for patients with thrombocytopenic hematological disorders. Both TPO receptor agonists have been approved worldwide for the treatment of children and adults with chronic immune thrombocytopenia. In the EU and USA, eltrombopag is approved for the treatment of patients with severe aplastic anemia who have had an insufficient response to immunosuppressive therapy and in the USA for the first-line treatment of severe aplastic anemia in combination with immunosuppressive therapy. Eltrombopag has also shown efficacy in several other disease settings, for example, chemotherapy-induced thrombocytopenia, selected inherited thrombocytopenias, and myelodysplastic syndromes. While both TPO receptor agonists stimulate TPO receptor signaling and enhance megakaryopoiesis, their vastly different biochemical structures bestow upon them markedly different molecular and functional properties. Here, we review and discuss results from preclinical and clinical studies on the functional and molecular mechanisms of action of this new class of drug.
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Affiliation(s)
- James Bussel
- Pediatric Hematology/Oncology, Weill Cornell Medicine, New York, NY.
| | | | | | - Amit Verma
- Albert Einstein College of Medicine, New York, NY
| | | | - John W Semple
- Division of Hematology and Transfusion Medicine, Lund University, Lund, Sweden
| | - Britta Will
- Albert Einstein College of Medicine, New York, NY.
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12
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MECOM-associated syndrome: a heterogeneous inherited bone marrow failure syndrome with amegakaryocytic thrombocytopenia. Blood Adv 2019. [PMID: 29540340 DOI: 10.1182/bloodadvances.2018016501] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Heterozygous mutations in MECOM (MDS1 and EVI1 complex locus) have been reported to be causative of a rare association of congenital amegakaryocytic thrombocytopenia and radioulnar synostosis. Here we report on 12 patients with congenital hypomegakaryocytic thrombocytopenia caused by MECOM mutations (including 10 novel mutations). The mutations affected different functional domains of the EVI1 protein. The spectrum of phenotypes was much broader than initially reported for the first 3 patients; we found familial as well as sporadic cases, and the clinical spectrum ranged from isolated radioulnar synostosis with no or mild hematological involvement to severe bone marrow failure without obvious skeletal abnormality. The clinical picture included radioulnar synostosis, bone marrow failure, clinodactyly, cardiac and renal malformations, B-cell deficiency, and presenile hearing loss. No single clinical manifestation was detected in all patients affected by MECOM mutations. Radioulnar synostosis and B-cell deficiency were observed only in patients with mutations affecting a short region in the C-terminal zinc finger domain of EVI1. We propose the term MECOM-associated syndrome for this heterogeneous hereditary disease and inclusion of MECOM sequencing in the diagnostic workup of congenital bone marrow failure.
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13
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Pecci A, Ragab I, Bozzi V, De Rocco D, Barozzi S, Giangregorio T, Ali H, Melazzini F, Sallam M, Alfano C, Pastore A, Balduini CL, Savoia A. Thrombopoietin mutation in congenital amegakaryocytic thrombocytopenia treatable with romiplostim. EMBO Mol Med 2019; 10:63-75. [PMID: 29191945 PMCID: PMC5760853 DOI: 10.15252/emmm.201708168] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is an inherited disorder characterized at birth by thrombocytopenia with reduced megakaryocytes, which evolves into generalized bone marrow aplasia during childhood. Although CAMT is genetically heterogeneous, mutations of MPL, the gene encoding for the receptor of thrombopoietin (THPO), are the only known disease‐causing alterations. We identified a family with three children affected with CAMT caused by a homozygous mutation (p.R119C) of the THPO gene. Functional studies showed that p.R119C affects not only ability of the cytokine to stimulate MPL but also its release, which is consistent with the relatively low serum THPO levels measured in patients. In all the three affected children, treatment with the THPO‐mimetic romiplostim induced trilineage hematological responses, remission of bleeding and infections, and transfusion independence, which were maintained after up to 6.5 years of observation. Recognizing patients with THPO mutations among those with juvenile bone marrow failure is essential to provide them with appropriate substitutive therapy and prevent the use of invasive and unnecessary treatments, such as hematopoietic stem cell transplantation or immunosuppression.
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Affiliation(s)
- Alessandro Pecci
- Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy
| | - Iman Ragab
- Hematology-Oncology Unit, Pediatric Hospital, Ain Shams University, Cairo, Egypt
| | - Valeria Bozzi
- Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy
| | - Daniela De Rocco
- Institute for Maternal and Child Health - IRCCS Burlo Garofolo, Trieste, Italy
| | - Serena Barozzi
- Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy
| | | | - Heba Ali
- Hematology-Oncology Unit, Pediatric Hospital, Ain Shams University, Cairo, Egypt
| | - Federica Melazzini
- Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy
| | - Mohamed Sallam
- Department of Clinical Pathology, Ain Shams University, Cairo, Egypt
| | - Caterina Alfano
- Maurice Wohl Clinical Neuroscience Institute, King's College, London, UK.,Fondazione Ri.MED, Palermo, Italy
| | - Annalisa Pastore
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Carlo L Balduini
- Department of Internal Medicine, IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy
| | - Anna Savoia
- Institute for Maternal and Child Health - IRCCS Burlo Garofolo, Trieste, Italy .,Department of Medical Sciences, University of Trieste, Trieste, Italy
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14
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15
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Jameson-Lee M, Chen K, Ritchie E, Shore T, Al-Khattab O, Gergis U. Acute myeloid leukemia in a patient with thrombocytopenia with absent radii: A case report and review of the literature. Hematol Oncol Stem Cell Ther 2018; 11:245-247. [DOI: 10.1016/j.hemonc.2017.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 01/04/2017] [Accepted: 02/06/2017] [Indexed: 10/20/2022] Open
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16
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Case Report: Clinical Variation in Children With Thrombopoietin Receptor (C-MPL) Mutations: Report of 2 Cases. J Pediatr Hematol Oncol 2018; 40:67-70. [PMID: 28859041 DOI: 10.1097/mph.0000000000000944] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT, MIM# 604498) is a rare congenital bone marrow failure syndrome which presents early in life with abnormal bleeding because of thrombocytopenia. Classically, megakaryocytes are decreased to absent in the bone marrow. The development of aplastic anemia early in childhood has led to the recommendation for early stem cell transplantation. Quantitative or loss-of-function mutations in the myeloproliferative leukemia gene (c-mpl), whose gene product functions as the thrombopoietin receptor, have been identified as causative for CAMT. Approximately 100 cases of CAMT are published in the medical literature. We describe 2 cases of CAMT who demonstrate disparate clinical courses, thereby highlighting phenotypic differences and increasing awareness of this clinical entity.
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17
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Abstract
Thrombopoietin (THPO) has been well characterized as a key regulator of platelet production. THPO also plays an important role in the maintenance and regulation of hematopoietic stem cells (HSCs). In this issue of EMBO Molecular Medicine, Pecci et al (2018) describe a newly identified homozygous mutation in THPO causing congenital amegakaryocytic thrombocytopenia, a disease characterized by a significant impairment in platelet production with rapid onset of aplastic anemia within a few years. The paper nicely investigates the underlying pathogenic mechanisms of this disease. Importantly, this study, in tandem with other recent ones, shows that this rare genetic form of aplastic anemia is treatable with THPO receptor agonists, emphasizing the paramount role of genetic testing in cases of aplastic anemia and other bone marrow failure disorders. This report also refines our understanding of the role of THPO in human HSC function and illustrates the important biological insight that can be gained through studies of such rare genetic disorders.
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Affiliation(s)
- Ah Ram Kim
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Vijay G Sankaran
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
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18
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Melazzini F, Zaninetti C, Balduini CL. Bleeding is not the main clinical issue in many patients with inherited thrombocytopaenias. Haemophilia 2017; 23:673-681. [PMID: 28594466 DOI: 10.1111/hae.13255] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2017] [Indexed: 02/01/2023]
Abstract
Bleeding diathesis has been considered for a long time the main clinical issue impacting the lives of patients affected by inherited thrombocytopaenias. However, the number of known inherited thrombocytopaenias greatly increased in recent years, and careful evaluation of hundreds of patients affected by these 'new' disorders revealed that most of them are at risk of developing additional life-threatening disorders during childhood or adult life. These additional disorders are usually more serious and dangerous than low platelet count. For instance, it is known that mutations in RUNX1, ANKRD26 and ETV6 cause congenital thrombocytopaenia, but we now know that they also predispose to haematological malignancies. Similarly, MYH9 mutations result in congenital thrombocytopaenia and increase the risk of developing kidney failure, cataracts and hearing loss at a later stage, while MPL mutations cause a congenital thrombocytopaenia that almost always evolves into deadly bone marrow failure. Thus, identification of patients with these disorders is essential for evaluation of their prognosis, enabling effective genetic counselling, personalizing follow-up and giving appropriate treatments in case of development of additional diseases. Careful clinical evaluation and peripheral blood film examination are extremely useful tools in guiding the diagnostic process and identifying the candidate genes to be sequenced.
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Affiliation(s)
- F Melazzini
- IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy
| | - C Zaninetti
- IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy
| | - C L Balduini
- IRCCS Policlinico San Matteo Foundation and University of Pavia, Pavia, Italy
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19
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Ok Bozkaya İ, Yaralı N, Işık P, Ünsal Saç R, Tavil B, Tunç B. Severe Clinical Course in a Patient with Congenital Amegakaryocytic Thrombocytopenia Due to a Missense Mutation of the c-MPL Gene. Turk J Haematol 2017; 32:172-4. [PMID: 26316487 PMCID: PMC4451487 DOI: 10.4274/tjh.2013.0191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) generally begins at birth with severe thrombocytopenia and progresses to pancytopenia. It is caused by mutations in the thrombopoietin receptor gene, the myeloproliferative leukemia virus oncogene (c-MPL). The association between CAMT and c-MPL mutation type has been reported in the literature. Patients with CAMT have been categorized according to their clinical symptoms caused by different mutations. Missense mutations of c-MPL have been classified as type II and these patients have delayed onset of bone marrow failure compared to type I patients. Here we present a girl with severe clinical course of CAMT II having a missense mutation in exon 4 of the c-MPL gene who was admitted to our hospital with intracranial hemorrhage during the newborn period.
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Affiliation(s)
- İkbal Ok Bozkaya
- Ankara Children's Hematology Oncology Hospital, Clinic of Pediatric Hematology, Ankara, Turkey Phone: +90 312 396 99 70 E-mail:
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20
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Cremer M, Sallmon H, Kling PJ, Bührer C, Dame C. Thrombocytopenia and platelet transfusion in the neonate. Semin Fetal Neonatal Med 2016; 21:10-8. [PMID: 26712568 DOI: 10.1016/j.siny.2015.11.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Neonatal thrombocytopenia is widespread in preterm and term neonates admitted to neonatal intensive care units, with up to one-third of infants demonstrating platelet counts <150 × 10(9)/L. Thrombocytopenia may arise from maternal, placental or fetal/neonatal origins featuring decreased platelet production, increased consumption, or both mechanisms. Over the past years, innovations in managing neonatal thrombocytopenia were achieved from prospectively obtained clinical data on thrombocytopenia and bleeding events, animal studies on platelet life span and production rate and clinical use of fully automated measurement of reticulated platelets (immature platelet fraction). This review summarizes the pathophysiology of neonatal thrombocytopenia, current management including platelet transfusion thresholds and recent developments in megakaryopoietic agents. Furthermore, we propose a novel index score for bleeding risk in thrombocytopenic neonates to facilitate clinician's decision-making when to transfuse platelets.
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Affiliation(s)
- Malte Cremer
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany.
| | - Hannes Sallmon
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - Pamela J Kling
- Department of Pediatrics, University of Wisconsin - Madison, Madison, WI, USA
| | - Christoph Bührer
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - Christof Dame
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
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21
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Ouchi-Uchiyama M, Sasahara Y, Kikuchi A, Goi K, Nakane T, Ikeno M, Noguchi Y, Uike N, Miyajima Y, Matsubara K, Koh K, Sugita K, Imaizumi M, Kure S. Analyses of Genetic and Clinical Parameters for Screening Patients With Inherited Thrombocytopenia with Small or Normal-Sized Platelets. Pediatr Blood Cancer 2015; 62:2082-8. [PMID: 26175287 DOI: 10.1002/pbc.25668] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 06/17/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND Childhood thrombocytopenias include immune thrombocytopenic purpura (ITP) and inherited thrombocytopenia; the former is caused by autoantibodies to platelets, whereas the latter can be distinguished by platelet size and underlying genetic mutations. Due to limited methods for the definite diagnosis of ITP, genetic and clinical parameters are required for diagnosing inherited thrombocytopenias with small or normal-sized platelets. PROCEDURE In total, 32 Japanese patients with thrombocytopenia with small or normal-sized platelets from 29 families were enrolled. All the patients were under 20 years of age, with family histories of early-onset thrombocytopenia and/or poor response to conventional therapies for ITP. Genotypes and clinical parameters were retrospectively evaluated according to the disease type. RESULTS Twelve cases of inherited thrombocytopenia were observed. We identified chromosomal deletions within the WASP gene in two patients with Wiskott-Aldrich syndrome; a missense mutation in a patient with X-linked thrombocytopenia; and mutations in the RUNX1 gene of five patients with familial platelet disorder with propensity to acute myelogenous leukemia, and in the ANKRD26 gene of four patients with autosomal dominant thrombocytopenia-2. All 12 carried germline mutations, three of which were de novo. Furthermore, we observed significantly elevated serum thrombopoietin (TPO) levels and dysplasia of megakaryocytes in patients carrying the RUNX1 and ANKRD26 mutations. CONCLUSIONS Genetic analyses and detection of TPO levels and dysmegakaryopoiesis were clinically useful for screening patients with inherited thrombocytopenias, irrespective of the family history. We hypothesize that the WASP, RUNX1, and ANKRD26 genes are important for normal TPO signaling and the network underlying thrombopoiesis.
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Affiliation(s)
- Meri Ouchi-Uchiyama
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Miyagi, Japan.,Department of Hematology and Oncology, Miyagi Children's Hospital, Miyagi, Japan
| | - Yoji Sasahara
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Atsuo Kikuchi
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Kumiko Goi
- Department of Pediatrics, University of Yamanashi, Yamanashi, Japan
| | - Takaya Nakane
- Department of Pediatrics, University of Yamanashi, Yamanashi, Japan
| | - Mitsuru Ikeno
- Department of Pediatrics and Adolescent Medicine, Juntendo University School of Medicine, Tokyo, Japan
| | - Yasushi Noguchi
- Department of Pediatrics, Japanese Red Cross Narita Hospital, Chiba, Japan
| | - Naokuni Uike
- Department of Hematology, National Hospital Organization, Kyushu Cancer Center, Fukuoka, Japan
| | - Yuji Miyajima
- Department of Pediatrics, Anjoh Kosei Hospital, Aichi, Japan
| | | | - Katsuyoshi Koh
- Department of Hematology/Oncology, Saitama Children's Medical Center, Saitama, Japan
| | - Kanji Sugita
- Department of Pediatrics, University of Yamanashi, Yamanashi, Japan
| | - Masue Imaizumi
- Department of Hematology and Oncology, Miyagi Children's Hospital, Miyagi, Japan
| | - Shigeo Kure
- Department of Pediatrics, Tohoku University Graduate School of Medicine, Miyagi, Japan
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22
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Mouse prenatal platelet-forming lineages share a core transcriptional program but divergent dependence on MPL. Blood 2015; 126:807-16. [DOI: 10.1182/blood-2014-12-616607] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 05/15/2015] [Indexed: 01/15/2023] Open
Abstract
Key Points
Prenatal platelet-forming lineages are subject to common transcription factor controls despite distinct spatial and ancestral origins. Platelet-forming lineage production is MPL-independent on emergence, but MPL is required in the late fetus for efficient thrombopoiesis.
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23
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Ballmaier M, Holter W, Germeshausen M. Flow cytometric detection of MPL (CD110) as a diagnostic tool for differentiation of congenital thrombocytopenias. Haematologica 2015; 100:e341-4. [PMID: 25911549 DOI: 10.3324/haematol.2015.125963] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Matthias Ballmaier
- Dept. of Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
| | - Wolfgang Holter
- Dept. of Pediatric Hematology and Oncology, University Hospital Erlangen, Germany, present address: St. Anna Children's Hospital, Vienna, Austria
| | - Manuela Germeshausen
- Dept. of Pediatric Hematology and Oncology, Hannover Medical School, Hannover, Germany
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24
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25
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Svensson T, Chowdhury O, Garelius H, Lorenz F, Saft L, Jacobsen SE, Hellström-Lindberg E, Cherif H. A pilot phase I dose finding safety study of the thrombopoietin-receptor agonist, eltrombopag, in patients with myelodysplastic syndrome treated with azacitidine. Eur J Haematol 2014; 93:439-45. [DOI: 10.1111/ejh.12383] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2014] [Indexed: 01/03/2023]
Affiliation(s)
- Tobias Svensson
- Department of Medical Sciences; Section of Hematology; Uppsala University Hospital; Uppsala Sweden
| | - Onima Chowdhury
- Haematopoietic Stem Cell Laboratory and MRC Molecular Haematology Unit; Weatherall Institute of Molecular Medicine; Oxford University; Oxford UK
| | - Hege Garelius
- Department of Medicine; Section of Hematology and Coagulation; Sahlgrenska University Hospital; Gothenburg Sweden
| | - Fryderyk Lorenz
- Department of Hematology; Umeå University Hospital; Umeå Sweden
| | - Leonie Saft
- Department of Pathology; Division of Hematopathology; Karolinska University Hospital; Solna Sweden
| | - Sten-Eirik Jacobsen
- Haematopoietic Stem Cell Laboratory and MRC Molecular Haematology Unit; Weatherall Institute of Molecular Medicine; Oxford University; Oxford UK
| | - Eva Hellström-Lindberg
- Center for Hematology and Regenerative Medicine; Karolinska Institutet; Karolinska University Hospital; Huddinge Sweden
| | - Honar Cherif
- Department of Medical Sciences; Section of Hematology; Uppsala University Hospital; Uppsala Sweden
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26
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Kumar R, Kahr WHA. Congenital thrombocytopenia: clinical manifestations, laboratory abnormalities, and molecular defects of a heterogeneous group of conditions. Hematol Oncol Clin North Am 2013; 27:465-94. [PMID: 23714308 DOI: 10.1016/j.hoc.2013.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Once considered exceptionally rare, congenital thrombocytopenias are increasingly recognized as a heterogeneous group of disorders characterized by a reduction in platelet number and a bleeding tendency that may range from very mild to life threatening. Although some of these disorders affect only megakaryocytes and platelets, others involve different cell types and may result in characteristic phenotypic abnormalities. This review elaborates the clinical presentation and laboratory manifestations of common congenital thrombocytopenias in addition to exploring our understanding of the molecular basis of these disorders and therapeutic interventions available.
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Affiliation(s)
- Riten Kumar
- Division of Haematology/Oncology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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27
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Stoddart MT, Connor P, Germeshausen M, Ballmaier M, Steward CG. Congenital amegakaryocytic thrombocytopenia (CAMT) presenting as severe pancytopenia in the first month of life. Pediatr Blood Cancer 2013; 60:E94-6. [PMID: 23625800 DOI: 10.1002/pbc.24566] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 03/21/2013] [Indexed: 11/07/2022]
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is characterised by neonatal thrombocytopenia, with reduced or absent bone marrow megakaryocytes, leading eventually to pancytopenia. The mean age for progression to bone marrow failure is four years, with the earliest reported being six months. We describe a CAMT patient with compound heterozygous mutations of the causative MPL gene (one being a previously unreported splice site mutation in intron 11) who developed pancytopenia within the first month of life. This report emphasises the importance of considering CAMT in the differential diagnosis of congenital aplastic anaemia or idiopathic aplastic anaemia in babies.
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28
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Diz-Küçükkaya R. Inherited platelet disorders including Glanzmann thrombasthenia and Bernard-Soulier syndrome. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2013; 2013:268-275. [PMID: 24319190 DOI: 10.1182/asheducation-2013.1.268] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Inherited platelet disorders (IPDs) are a heterogeneous group of diseases affecting platelet production, morphology, and function. The degree of thrombocytopenia and functional abnormality of platelets determines the clinical manifestations. Although severe deficiencies may cause excessive bleeding beginning in early childhood, most of IPDs have mild bleeding tendencies and therefore are not always easy to distinguish from acquired platelet disorders. The diagnosis of IPD may require extensive laboratory investigation, because current routine laboratory tests are not satisfactory for differential diagnosis in some cases, and most of the specific tests are not readily available in many countries. This review summarizes the classification and clinical and molecular characteristics of known IPDs, including Bernard-Soulier syndrome and Glanzmann thrombasthenia, with a focus on current challenges in the laboratory diagnosis and management of bleeding in these patients.
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Affiliation(s)
- Reyhan Diz-Küçükkaya
- 1Department of Internal Medicine, Division of Hematology, Faculty of Medicine, Istanbul Bilim University, Istanbul, Turkey
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29
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The microtubule plus-end tracking protein CLASP2 is required for hematopoiesis and hematopoietic stem cell maintenance. Cell Rep 2012; 2:781-8. [PMID: 23084744 DOI: 10.1016/j.celrep.2012.08.040] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 07/09/2012] [Accepted: 08/31/2012] [Indexed: 12/22/2022] Open
Abstract
Mammalian CLASPs are microtubule plus-end tracking proteins whose essential function as regulators of microtubule behavior has been studied mainly in cultured cells. We show here that absence of murine CLASP2 in vivo results in thrombocytopenia, progressive anemia, and pancytopenia, due to defects in megakaryopoiesis, in erythropoiesis, and in the maintenance of hematopoietic stem cell activity. Furthermore, microtubule stability and organization are affected upon attachment of Clasp2 knockout hematopoietic stem-cell-enriched populations, and these cells do not home efficiently toward their bone marrow niche. Strikingly, CLASP2-deficient hematopoietic stem cells contain severely reduced mRNA levels of c-Mpl, which encodes the thrombopoietin receptor, an essential factor for megakaryopoiesis and hematopoietic stem cell maintenance. Our data suggest that thrombopoietin signaling is impaired in Clasp2 knockout mice. We propose that the CLASP2-mediated stabilization of microtubules is required for proper attachment, homing, and maintenance of hematopoietic stem cells and that this is necessary to sustain c-Mpl transcription.
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Chromosome anomalies in bone marrow as primary cause of aplastic or hypoplastic conditions and peripheral cytopenia: disorders due to secondary impairment of RUNX1 and MPL genes. Mol Cytogenet 2012; 5:39. [PMID: 23025896 PMCID: PMC3542585 DOI: 10.1186/1755-8166-5-39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 09/06/2012] [Indexed: 11/18/2022] Open
Abstract
Background Chromosome changes in the bone marrow (BM) of patients with persistent cytopenia are often considered diagnostic for a myelodysplastic syndrome (MDS). Comprehensive cytogenetic evaluations may give evidence of the real pathogenetic role of these changes in cases with cytopenia without morphological signs of MDS. Results Chromosome anomalies were found in the BM of three patients, without any morphological evidence of MDS: 1) an acquired complex rearrangement of chromosome 21 in a boy with severe aplastic anaemia (SAA); the rearrangement caused the loss of exons 2–8 of the RUNX1 gene with subsequent hypoexpression. 2) a constitutional complex rearrangement of chromosome 21 in a girl with congenital thrombocytopenia; the rearrangement led to RUNX1 disruption and hypoexpression. 3) an acquired paracentric inversion of chromosome 1, in which two regions at the breakpoints were shown to be lost, in a boy with aplastic anaemia; the MPL gene, localized in chromosome 1 short arms was not mutated neither disrupted, but its expression was severely reduced: we postulate that the aplastic anaemia was due to position effects acting both in cis and in trans, and causing Congenital Amegakaryocytic Thrombocytopenia (CAMT). Conclusions A clonal anomaly in BM does not imply per se a diagnosis of MDS: a subgroup of BM hypoplastic disorders is directly due to chromosome structural anomalies with effects on specific genes, as was the case of RUNX1 and MPL in the patients here reported with diagnosis of SAA, thrombocytopenia, and CAMT. The anomaly may be either acquired or constitutional, and it may act by deletion/disruption of the gene, or by position effects. Full cytogenetic investigations, including a-CGH, should always be part of the diagnostic evaluation of patients with BM aplasia/hypoplasia and peripheral cytopenias.
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Thrombopoietin/MPL participates in initiating and maintaining RUNX1-ETO acute myeloid leukemia via PI3K/AKT signaling. Blood 2012; 120:868-79. [PMID: 22613795 DOI: 10.1182/blood-2012-03-414649] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Oncogenic mutations in components of cytokine signaling pathways elicit ligand-independent activation of downstream signaling, enhancing proliferation and survival in acute myeloid leukemia (AML). The myeloproliferative leukemia virus oncogene, MPL, a homodimeric receptor activated by thrombopoietin (THPO), is mutated in myeloproliferative disorders but rarely in AML. Here we show that wild-type MPL expression is increased in a fraction of human AML samples expressing RUNX1-ETO, a fusion protein created by chromosome translocation t(8;21), and that up-regulation of Mpl expression in mice induces AML when coexpressed with RUNX1-ETO. The leukemic cells are sensitive to THPO, activating survival and proliferative responses. Mpl expression is not regulated by RUNX1-ETO in mouse hematopoietic progenitors or leukemic cells. Moreover, we find that activation of PI3K/AKT but not ERK/MEK pathway is a critical mediator of the MPL-directed antiapoptotic function in leukemic cells. Hence, this study provides evidence that up-regulation of wild-type MPL levels promotes leukemia development and maintenance through activation of the PI3K/AKT axis, and suggests that inhibitors of this axis could be effective for treatment of MPL-positive AML.
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Samarasinghe S, Webb DKH. How I manage aplastic anaemia in children. Br J Haematol 2012; 157:26-40. [PMID: 22348483 DOI: 10.1111/j.1365-2141.2012.09058.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 01/09/2012] [Indexed: 01/09/2023]
Abstract
Aplastic anaemia (AA) is a rare heterogeneous condition in children. 15-20% of cases are constitutional and correct diagnosis of these inherited causes of AA is important for appropriate management. For idiopathic severe aplastic anaemia, a matched sibling donor (MSD) haematopoietic stem cell transplant (HSCT) is the treatment of choice. If a MSD is not available, the options include immunosuppressive therapy (IST) or unrelated donor HSCT. IST with horse anti-thymocyte globulin (ATG) is superior to rabbit ATG and has good long-term results. In contrast, IST with rabbit ATG has an overall response of only 30-40%. Due to improvements in outcome over the last two decades in matched unrelated donor (MUD) HSCT, results are now similar to that of MSD HSCT. The decision to proceed with IST with ATG or MUD HSCT will depend on the likelihood of finding a MUD and the differing risks and benefits that each therapy provides.
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Affiliation(s)
- Sujith Samarasinghe
- Paediatric Haematopoietic Stem Cell Transplant Unit, Department of Adolescent and Paediatric Haematology and Oncology, Great North Children's Hospital, Royal Victoria Infirmary, Newcastle Upon Tyne, UK.
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Walne AJ, Dokal A, Plagnol V, Beswick R, Kirwan M, de la Fuente J, Vulliamy T, Dokal I. Exome sequencing identifies MPL as a causative gene in familial aplastic anemia. Haematologica 2011; 97:524-8. [PMID: 22180433 DOI: 10.3324/haematol.2011.052787] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The primary cause of aplastic anemia remains unknown in many patients. The aim of this study was to clarify the genetic cause of familial aplastic anemia. Genomic DNA of an affected individual from a multiplex consanguineous family was hybridized to a Nimblegen exome library before being sequenced on a GAIIx genome analyzer. Once the disease causing homozygous mutation had been confirmed in the consanguineous family, this gene was then analyzed for mutation in 33 uncharacterized index cases of aplastic anemia (<13 years) using denaturing HPLC. Abnormal traces were confirmed by direct sequencing. Exome sequencing identified a novel homozygous nonsense mutation in the thrombopoietin receptor gene MPL. An additional novel homozygous MPL mutation was identified in the screen of 33 aplastic anemia patients. This study shows for the first time a link between homozygous MPL mutations and familial aplastic anemia. It also highlights the important role of MPL in trilineage hematopoiesis.
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Affiliation(s)
- Amanda J Walne
- Centre for Paediatrics, Blizard Institute of Cell and Molecular Science, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, London, UK.
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Jalas C, Anderson SL, Laufer T, Martimucci K, Bulanov A, Xie X, Ekstein J, Rubin BY. A founder mutation in the MPL gene causes congenital amegakaryocytic thrombocytopenia (CAMT) in the Ashkenazi Jewish population. Blood Cells Mol Dis 2011; 47:79-83. [DOI: 10.1016/j.bcmd.2011.03.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 03/17/2011] [Accepted: 03/17/2011] [Indexed: 11/27/2022]
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Mutations in ANKRD26 are responsible for a frequent form of inherited thrombocytopenia: analysis of 78 patients from 21 families. Blood 2011; 117:6673-80. [PMID: 21467542 DOI: 10.1182/blood-2011-02-336537] [Citation(s) in RCA: 196] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Until recently, thrombocytopenia 2 (THC2) was considered an exceedingly rare form of autosomal dominant thrombocytopenia and only 2 families were known. However, we recently identified mutations in the 5'-untranslated region of the ANKRD26 gene in 9 THC2 families. Here we report on 12 additional pedigrees with ANKRD26 mutations, 6 of which are new. Because THC2 affected 21 of the 210 families in our database, it has to be considered one of the less rare forms of inherited thrombocytopenia. Analysis of all 21 families with ANKRD26 mutations identified to date revealed that thrombocytopenia and bleeding tendency were usually mild. Nearly all patients had no platelet macrocytosis, and this characteristic distinguishes THC2 from most other forms of inherited thrombocytopenia. In the majority of cases, platelets were deficient in glycoprotein Ia and α-granules, whereas in vitro platelet aggregation was normal. Bone marrow examination and serum thrombopoietin levels suggested that thrombocytopenia was derived from dysmegakaryopoiesis. Unexplained high values of hemoglobin and leukocytes were observed in a few cases. An unexpected finding that warrants further investigation was a high incidence of acute leukemia. Given the scarcity of distinctive characteristics, the ANKRD26-related thrombocytopenia has to be taken into consideration in the differential diagnosis of isolated thrombocytopenias.
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Teofili L, Larocca LM. Advances in understanding the pathogenesis of familial thrombocythaemia. Br J Haematol 2011; 152:701-12. [DOI: 10.1111/j.1365-2141.2010.08500.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Chung HS, Koh KN, Kim HJ, Kim HJ, Lee KO, Park CJ, Chi HS, Kim SH, Seo JJ, Im HJ. A novel nonsense mutation in the MPL gene in congenital amegakaryocytic thrombocytopenia. Pediatr Blood Cancer 2011; 56:304-6. [PMID: 21162090 DOI: 10.1002/pbc.22842] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare autosomal recessive disorder characterized by thrombocytopenia from failure of megakaryopoiesis. CAMT is one of the bone marrow failure syndromes, and the disease progression may involve other lineages leading to pancytopenia. The genetic background of CAMT is mutations in the MPL gene encoding the thrombopoietin receptor. Here, we describe a Korean male with CAMT. Molecular genetic analyses by direct sequencing revealed that he was compound heterozygous for two nonsense mutations in MPL, Tyr63X (c.189C>A), and Arg357X (c.1069C>T), the latter being a novel mutation.
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Affiliation(s)
- Hae-Sun Chung
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Bizzetto R, Bonfim C, Rocha V, Socié G, Locatelli F, Chan K, Ramirez O, Stein J, Nabhan S, Miranda E, Passweg J, de Souza CA, Gluckman E. Outcomes after related and unrelated umbilical cord blood transplantation for hereditary bone marrow failure syndromes other than Fanconi anemia. Haematologica 2010; 96:134-41. [PMID: 21071499 DOI: 10.3324/haematol.2010.027839] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Allogeneic stem cell transplantation is the only curative option for patients with hereditary bone marrow failure syndromes. Umbilical cord blood is an alternative source of stem cells for allogeneic transplantation. DESIGN AND METHODS This multicenter, retrospective study is based on data reported to the Eurocord Registry about patients with hereditary bone marrow failure syndrome who underwent umbilical cord blood transplantation. RESULTS Sixty-four patients with hereditary bone marrow failure syndromes were transplanted from related (n = 20) or unrelated donors (n = 44). Diagnoses were Diamond-Blackfan anemia (21 patients), congenital amegakaryocytic thrombocytopenia (16 patients), dyskeratosis congenita (8 patients), Shwachman-Diamond syndrome (2 patients), severe congenital neutropenia (16 patients) and unclassified (1 patient). In the group of patients who received grafts from related donors, all patients but one received an HLA-matched sibling transplant. The median number of total nucleated cells infused was 5 × 10⁷/kg. The cumulative incidence of neutrophil recovery at 60 days was 95%. Two patients had grade II-IV acute graft-versus-host disease, while the 2-year cumulative incidence of chronic graft-versus-host disease was 11%. The 3-year overall survival rate was 95%. In the group of patients who received grafts from unrelated donors, 86% had HLA-mismatched grafts and three received two umbilical cord blood units. The median number of total nucleated cells infused was 6.1 × 10⁷/kg. The cumulative incidence of neutrophil recovery at day 60 in this group was 55%. The 100-day cumulative incidence of grade II-IV acute graft-versus-host disease was 24%, while the 2-year cumulative incidence of chronic graft-versus-host disease was 53%. The 3-year overall survival rate was 61%; better overall survival was associated with age less than 5 years (P = 0.01) and 6.1 × 10⁷/kg or more total nucleated cells infused (P = 0.05). CONCLUSIONS In patients with hereditary bone marrow failure syndromes, related umbilical cord blood transplantation is associated with excellent outcomes while increasing cell dose and better HLA matching might provide better results in unrelated umbilical cord blood transplantation.
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Ivanova A, Wuerfel J, Zhang J, Hoffmann O, Ballmaier M, Dame C. Expression pattern of the thrombopoietin receptor (Mpl) in the murine central nervous system. BMC DEVELOPMENTAL BIOLOGY 2010; 10:77. [PMID: 20667107 PMCID: PMC2921376 DOI: 10.1186/1471-213x-10-77] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2009] [Accepted: 07/28/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Thrombopoietin (Thpo) and its receptor (Mpl), which regulate megakaryopoiesis, are expressed in the central nervous system (CNS), where Thpo is thought to exert pro-apoptotic effects on newly generated neurons. Mpl expression has been analysed in brain tissue on transcript level and in cultured primary rat neurons and astrocytes on protein level. Herein, we analysed Mpl expression in the developing and adult murine CNS by immunohistochemistry and investigated the brain of mice with homozygous Mpl deficiency (Mpl-/-) by MRI. RESULTS Mpl was not detectable at developmental stages E12 to E15 in any resident cells of the CNS. From E18 onwards, robust Mpl expression was found in various brain areas, including cerebral cortex, olfactory bulb, thalamus, hypothalamus, medulla, pons, and the grey matter of spinal cord. However, major developmental changes became obvious: In the subventricular zone of the cerebral cortex Mpl expression occurred only during late gestation, while in the hippocampus Mpl expression was detectable for first time at stage P4. In the white matter of the cerebellum Mpl expression was restricted to the perinatal period. In the adult cerebellum, Mpl expression switched to Purkinje cell. The majority of other Mpl-positive cells were NeuN-positive neurons. None of the cells could be double-labelled with astrocyte marker GFAP. Mpl-/- mice showed no gross abnormalities of the brain. CONCLUSIONS Our data locate Mpl expression to neurons at different subdivisions of the spinal cord, rhombencephalon, midbrain and prosencephalon. Besides neuronal cells Mpl protein is also expressed in Purkinje cells of the adult cerebellum.
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Affiliation(s)
- Anna Ivanova
- Department of Neonatology, Charité - Universitätsmedizin, Germany
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Abstract
The inherited marrow failure syndromes are a diverse set of genetic disorders characterized by hematopoietic aplasia and cancer predisposition. The clinical phenotypes are highly variable and much broader than previously recognized. The medical management of the inherited marrow failure syndromes differs from that of acquired aplastic anemia or malignancies arising in the general population. Diagnostic workup, molecular pathogenesis, and clinical treatment are reviewed.
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Recent advances in bone marrow biopsy pathology. J Hematop 2009; 2:151-6. [PMID: 20309423 PMCID: PMC2766445 DOI: 10.1007/s12308-009-0045-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 08/26/2009] [Indexed: 11/04/2022] Open
Abstract
The second quarter of 2009 saw steady advances in bone marrow biopsy (BMB) pathology. The following publications are a personal selection of the highlights. Quality issues in diagnostic immunohistochemistry for BMB have largely been ignored in external quality assurance programmes, and this issue is highlighted. In other areas, publications reflecting advances in flow cytometry and aspirate morphology are discussed where translation to the BMB is possible. Classifications undergo constant change, and several publications address the redefinition of the cut off points between malignancy, benign, and normal. Lastly, current scientific research is presented where it is relevant to the understanding of BMB pathobiology.
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