1
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Marneth AE, Mullally A. Busy signal: platelet-derived growth factor activation in myelofibrosis. Haematologica 2021; 105:1988-1990. [PMID: 32739885 DOI: 10.3324/haematol.2020.253708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Anna E Marneth
- Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston
| | - Ann Mullally
- Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston.,Dana-Farber Cancer Institute, Harvard Medical School, Boston.,Broad Institute, Cambridge, MA, USA
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2
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Wang Q, Cao L, Sheng G, Shen H, Ling J, Xie J, Ma Z, Yin J, Wang Z, Yu Z, Chen S, Zhao Y, Ruan C, Xia L, Jiang M. Application of High-Throughput Sequencing in the Diagnosis of Inherited Thrombocytopenia. Clin Appl Thromb Hemost 2018; 24:94S-103S. [PMID: 30103613 PMCID: PMC6714838 DOI: 10.1177/1076029618790696] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Inherited thrombocytopenia is a group of hereditary diseases with a reduction in platelet
count as the main clinical manifestation. Clinically, there is an urgent need for a
convenient and rapid diagnosis method. We introduced a high-throughput, next-generation
sequencing (NGS) platform into the routine diagnosis of patients with unexplained
thrombocytopenia and analyzed the gene sequencing results to evaluate the value of NGS
technology in the screening and diagnosis of inherited thrombocytopenia. From a cohort of
112 patients with thrombocytopenia, we screened 43 patients with hereditary features. For
the blood samples of these 43 patients, a gene sequencing platform for hemorrhagic and
thrombotic diseases comprising 89 genes was used to perform gene detection using NGS
technology. When we combined the screening results with clinical features and other
findings, 15 (34.9%) of 43patients were diagnosed with inherited thrombocytopenia. In
addition, 19 pathogenic variants, including 8 previously unreported variants, were
identified in these patients. Through the use of this detection platform, we expect to
establish a more effective diagnostic approach to such disorders.
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Affiliation(s)
- Qi Wang
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Lijuan Cao
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Guangying Sheng
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Hongjie Shen
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Jing Ling
- Department of Hematology and Oncology, Children's Hospital of Soochow University, Suzhou, China
| | - Jundan Xie
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Zhenni Ma
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Jie Yin
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Zhaoyue Wang
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Ziqiang Yu
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Suning Chen
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Yiming Zhao
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Changgeng Ruan
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
| | - Lijun Xia
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China.,Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Miao Jiang
- Jiangsu Institute of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, The First Affiliated Hospital of Soochow University, Suzhou, China.,Collaborative Innovation Center of Hematology, Soochow University, Suzhou, China
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3
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Fletcher SJ, Pisareva VP, Khan AO, Tcherepanov A, Morgan NV, Pisarev AV. Role of the novel endoribonuclease SLFN14 and its disease-causing mutations in ribosomal degradation. RNA (NEW YORK, N.Y.) 2018; 24:939-949. [PMID: 29678925 PMCID: PMC6004054 DOI: 10.1261/rna.066415.118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Platelets are anucleate and mostly ribosome-free cells within the bloodstream, derived from megakaryocytes within bone marrow and crucial for cessation of bleeding at sites of injury. Inherited thrombocytopenias are a group of disorders characterized by a low platelet count and are frequently associated with excessive bleeding. SLFN14 is one of the most recently discovered genes linked to inherited thrombocytopenia where several heterozygous missense mutations in SLFN14 were identified to cause defective megakaryocyte maturation and platelet dysfunction. Yet, SLFN14 was recently described as a ribosome-associated protein resulting in rRNA and ribosome-bound mRNA degradation in rabbit reticulocytes. To unveil the cellular function of SLFN14 and the link between SLFN14 and thrombocytopenia, we examined SLFN14 (WT/mutants) in in vitro models. Here, we show that all SLFN14 variants colocalize with ribosomes and mediate rRNA endonucleolytic degradation. Compared to SLFN14 WT, expression of mutants is dramatically reduced as a result of post-translational degradation due to partial misfolding of the protein. Moreover, all SLFN14 variants tend to form oligomers. These findings could explain the dominant negative effect of heterozygous mutation on SLFN14 expression in patients' platelets. Overall, we suggest that SLFN14 could be involved in ribosome degradation during platelet formation and maturation.
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Affiliation(s)
- Sarah J Fletcher
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Vera P Pisareva
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Abdullah O Khan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Andrew Tcherepanov
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Neil V Morgan
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Andrey V Pisarev
- Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
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4
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Mutation in GNE is associated with severe congenital thrombocytopenia. Blood 2018; 132:1855-1858. [PMID: 29941673 DOI: 10.1182/blood-2018-04-847798] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 06/19/2018] [Indexed: 01/27/2023] Open
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5
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Ferreira FLB, Colella MP, Medina SS, Costa-Lima C, Fiusa MML, Costa LNG, Orsi FA, Annichino-Bizzacchi JM, Fertrin KY, Gilberti MFP, Ozelo MC, De Paula EV. Evaluation of the immature platelet fraction contribute to the differential diagnosis of hereditary, immune and other acquired thrombocytopenias. Sci Rep 2017; 7:3355. [PMID: 28611471 PMCID: PMC5469896 DOI: 10.1038/s41598-017-03668-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/03/2017] [Indexed: 11/10/2022] Open
Abstract
The differential diagnosis of immune (ITP) and hereditary macrothrombocytopenia (HM) is key to patient management. The immature platelet fraction (IPF) represents the subset of circulating platelets with higher RNA content, and has been shown to distinguish hypo- from hyperproliferative thrombocytopenias. Here we evaluated the diagnostic accuracy of IPF in the differential diagnosis between HM and other thrombocytopenias in a population of patients with post-chemotherapy thrombocytopenia (n = 56), bone marrow failure (n = 22), ITP (n = 105) and HM (n = 27). TPO levels were also measured in HM and ITP matched for platelet counts. Platelet counts were similar in all patient groups. Higher IPF values were observed in both ITP (12.3%; 2.4–65.6%) and HM (29.8%; 4.6–65.9%) compared to hypoproliferative thrombocytopenias. IPF values were also higher in HM compared to ITP, yielding a diagnostic accuracy of 0.80 (95%CI 0.70–0.90; P < 0.0001) to distinguish these two conditions. Intra- and inter-assays reproducibility of IPF in HM patients revealed that this is a stable parameter. In conclusion, IPF is increased in HM compared to both ITP and other thrombocytopenias and contributes to the differentiation between ITP and HM. Further studies are warranted to understand the biological rationale of these findings and to its incorporation in diagnostic algorithms of HM.
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Affiliation(s)
- F L B Ferreira
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - M P Colella
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - S S Medina
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - C Costa-Lima
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - M M L Fiusa
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - L N G Costa
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - F A Orsi
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - J M Annichino-Bizzacchi
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | | | - M F P Gilberti
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - M C Ozelo
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil
| | - E V De Paula
- Faculty of Medical Sciences/Hematology and Hemotherapy Center, University of Campinas, Campinas, SP, Brazil.
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6
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Melhem M, Abu-Farha M, Antony D, Madhoun AA, Bacchelli C, Alkayal F, AlKhairi I, John S, Alomari M, Beales PL, Alsmadi O. Novel G6B gene variant causes familial autosomal recessive thrombocytopenia and anemia. Eur J Haematol 2017; 98:218-227. [PMID: 27743390 DOI: 10.1111/ejh.12819] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2016] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To characterize the underlying genetic and molecular defects in a consanguineous family with lifelong blood disorder manifested with thrombocytopenia (low platelets count) and anemia. METHODS Genetic linkage analysis, exome sequencing, and functional genomics were carried out to identify and characterize the defective gene. RESULTS We identified a novel truncation mutation (p.C108*) in chromosome 6 open reading frame 25 (C6orf25) gene in this family. We also showed the p.C108* mutation was responsible for destabilizing the encoded truncated G6B protein. Unlike the truncated form, wild-type G6B expression resulted in enhanced K562 differentiation into megakaryocytes and erythrocytes. C6orf25, also known as G6B, is an effector protein for the key hematopoiesis regulators, Src homology region 2 domain-containing phosphatases SHP-1 and SHP-2. CONCLUSION G6B seems to act through an autosomal recessive mode of disease transmission in this family and regarded as the gene responsible for the observed hematological disorder. This inference is well supported further by in vivo evidence where similar outcomes were reported from G6b-/- and SHP1/2 DKO mouse models.
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Affiliation(s)
- Motasem Melhem
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Mohamed Abu-Farha
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Dinu Antony
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Ashraf Al Madhoun
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Chiara Bacchelli
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Fadi Alkayal
- Pancreatic Islet Biology & Transplantation Unit, Dasman Diabetes Institute, Dasman, Kuwait
| | - Irina AlKhairi
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Sumi John
- Integrative Informatics, Dasman Diabetes Institute, Dasman, Kuwait
| | - Mohamad Alomari
- Department of Pathology, Windsor Regional Hospital, Windsor, ON, Canada
| | - Phillip L Beales
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Osama Alsmadi
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
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7
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Fletcher SJ, Johnson B, Lowe GC, Bem D, Drake S, Lordkipanidzé M, Guiú IS, Dawood B, Rivera J, Simpson MA, Daly ME, Motwani J, Collins PW, Watson SP, Morgan NV. SLFN14 mutations underlie thrombocytopenia with excessive bleeding and platelet secretion defects. J Clin Invest 2015; 125:3600-5. [PMID: 26280575 DOI: 10.1172/jci80347] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 07/08/2015] [Indexed: 01/08/2023] Open
Abstract
Inherited thrombocytopenias are a group of disorders that are characterized by a low platelet count and are sometimes associated with excessive bleeding that ranges from mild to severe. We evaluated 36 unrelated patients and 17 family members displaying thrombocytopenia that were recruited to the UK Genotyping and Phenotyping of Platelets (GAPP) study. All patients had a history of excessive bleeding of unknown etiology. We performed platelet phenotyping and whole-exome sequencing (WES) on all patients and identified mutations in schlafen 14 (SLFN14) in 12 patients from 3 unrelated families. Patients harboring SLFN14 mutations displayed an analogous phenotype that consisted of moderate thrombocytopenia, enlarged platelets, decreased ATP secretion, and a dominant inheritance pattern. Three heterozygous missense mutations were identified in affected family members and predicted to encode substitutions (K218E, K219N, and V220D) within an ATPase-AAA-4, GTP/ATP-binding region of SLFN14. Endogenous SLFN14 expression was reduced in platelets from all patients, and mutant SLFN14 expression was markedly decreased compared with that of WT SLFN14 when overexpressed in transfected cells. Electron microscopy revealed a reduced number of dense granules in affected patients platelets, correlating with a decreased ATP secretion observed in lumiaggregometry studies. These results identify SLFN14 mutations as cause for an inherited thrombocytopenia with excessive bleeding, outlining a fundamental role for SLFN14 in platelet formation and function.
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8
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Wang Z, Cao L, Su Y, Wang G, Wang R, Yu Z, Bai X, Ruan C. Specific macrothrombocytopenia/hemolytic anemia associated with sitosterolemia. Am J Hematol 2014; 89:320-4. [PMID: 24166850 DOI: 10.1002/ajh.23619] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 10/06/2013] [Accepted: 10/21/2013] [Indexed: 11/11/2022]
Abstract
Sitosterolemia (phytosterolemia) is a rare inherited sterol storage disorder, characterized by significantly elevated plasma levels of plant sterols. The clinical features of sitosterolemia are xanthomas, premature atherosclerosis, arthritis, and, occasionally, liver function impair and hematologic abnormalities. This disorder is caused by mutations of ABCG5/ABCG8 genes. We report here the clinical, laboratory, and molecular genetic features of 13 patients with sitosterolemia from eight unrelated families who had specific hematologic problems of macrothrombocytopenia, hemolytic anemia, and splenomegaly besides the major clinical manifestations. The peripheral blood films showed some unique features: large platelets surrounded by a circle of vacuoles, and various abnormal erythrocyte shapes, especially stomatocyte. According to these distinct changes of blood cell morphology, we identified two sitosterolemia patients who lacked the classical clinical phenomena. All the patients had been misdiagnosed with immune thrombocytopenia (ITP), Evans syndrome, or secondary ITP with delay being 28.8 years between symptom onset and correct diagnosis. These results indicate that sitosterolemia is certainly not as rare as originally thought. The phenomena of macrothrombocytopenia/hemolysis might represent a new platelet disorder. Plasma plant sterols and ABCG5/ABCG8 genes should be analyzed when such hematologic abnormalities are unexplained.
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Affiliation(s)
- Zhaoyue Wang
- Jiangsu Institute of Hematology; The First Affiliated Hospital of Soochow University; Key Lab of Thrombosis and Hemostasis of Ministry of Health; Suzhou China
| | - Lijuan Cao
- Jiangsu Institute of Hematology; The First Affiliated Hospital of Soochow University; Key Lab of Thrombosis and Hemostasis of Ministry of Health; Suzhou China
| | - Yanhua Su
- Jiangsu Institute of Hematology; The First Affiliated Hospital of Soochow University; Key Lab of Thrombosis and Hemostasis of Ministry of Health; Suzhou China
- Deparment of Hematology; The First Affiliated Hospital of Harbin Medical University; Harbin China
| | - Gaifeng Wang
- Jiangsu Institute of Hematology; The First Affiliated Hospital of Soochow University; Key Lab of Thrombosis and Hemostasis of Ministry of Health; Suzhou China
| | - Ruijuan Wang
- Jiangsu Institute of Hematology; The First Affiliated Hospital of Soochow University; Key Lab of Thrombosis and Hemostasis of Ministry of Health; Suzhou China
| | - Ziqiang Yu
- Jiangsu Institute of Hematology; The First Affiliated Hospital of Soochow University; Key Lab of Thrombosis and Hemostasis of Ministry of Health; Suzhou China
| | - Xia Bai
- Jiangsu Institute of Hematology; The First Affiliated Hospital of Soochow University; Key Lab of Thrombosis and Hemostasis of Ministry of Health; Suzhou China
| | - Changgeng Ruan
- Jiangsu Institute of Hematology; The First Affiliated Hospital of Soochow University; Key Lab of Thrombosis and Hemostasis of Ministry of Health; Suzhou China
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9
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LATGER-CANNARD V, HOARAU M, SALIGNAC S, BAUMGART D, NURDEN P, LECOMPTE T. Mean platelet volume: comparison of three analysers towards standardization of platelet morphological phenotype. Int J Lab Hematol 2012; 34:300-10. [DOI: 10.1111/j.1751-553x.2011.01396.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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10
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Mutations in the 5' UTR of ANKRD26, the ankirin repeat domain 26 gene, cause an autosomal-dominant form of inherited thrombocytopenia, THC2. Am J Hum Genet 2011; 88:115-20. [PMID: 21211618 DOI: 10.1016/j.ajhg.2010.12.006] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 12/11/2010] [Accepted: 12/16/2010] [Indexed: 11/24/2022] Open
Abstract
THC2, an autosomal-dominant thrombocytopenia described so far in only two families, has been ascribed to mutations in MASTL or ACBD5. Here, we show that ANKRD26, another gene within the THC2 locus, and neither MASTL nor ACBD5, is mutated in eight unrelated families. ANKRD26 was also found to be mutated in the family previously reported to have an ACBD5 mutation. We identified six different ANKRD26 mutations, which were clustered in a highly conserved 19 bp sequence located in the 5' untranslated region. Mutations were not detected in 500 controls and are absent from the 1000 Genomes database. Available data from an animal model and Dr. Watson's genome give evidence against haploinsufficiency as the pathogenetic mechanism for ANKRD26-mediated thrombocytopenia. The luciferase reporter assay suggests that these 5' UTR mutations might enhance ANKRD26 expression. ANKRD26 is the ancestor of a family of primate-specific genes termed POTE, which have been recently identified as a family of proapoptotic proteins. Dysregulation of apoptosis might therefore be the pathogenetic mechanism, as demonstrated for another thrombocytopenia, THC4. Further investigation is needed to provide evidence supporting this hypothesis.
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11
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Eltrombopag for the treatment of the inherited thrombocytopenia deriving from MYH9 mutations. Blood 2010; 116:5832-7. [DOI: 10.1182/blood-2010-08-304725] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Platelet transfusion is currently the primary medical treatment for reducing thrombocytopenia in patients with inherited thrombocytopenias. To evaluate whether stimulating megakaryopoiesis could increase platelet count in these conditions, we treated patients with a severe thrombocytopenia induced by MYH9 mutations (MYH9-related disease) with a nonpeptide thrombopoietin receptor agonist, eltrombopag. Twelve adult patients with MYH9-RD and platelet counts of less than 50 × 109/L received 50 mg of eltrombopag orally per day for 3 weeks. Patients who achieved a platelet count higher than 150 × 109/L stopped therapy, those with 100 to 150 platelets × 109/L continued treatment at the same eltrombopag dose for 3 additional weeks, while those with less than 100 platelets × 109/L increased the eltrombopag dose to 75 mg for 3 weeks. Major responses (platelet count of at least 100 × 109/L or 3 times the baseline value) were obtained in 8 patients, minor responses (platelet counts at least twice the baseline value) in 3. One patient did not respond. Bleeding tendency disappeared in 8 of 10 patients with bleeding symptoms at baseline. Mild adverse events were reported in 2 patients. The availability of thrombopoietin mimetics opened new prospects in the treatment of inherited thrombocytopenias. This study is registered at www.clinicaltrials.gov as NCT01133860 (European Union Drug Regulating Authorities Clinical Trials number 2008-001903-42).
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12
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13
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Abstract
The cellular and molecular mechanisms orchestrating the complex process by which bone marrow megakaryocytes form and release platelets remain poorly understood. Mature megakaryocytes generate long cytoplasmic extensions, proplatelets, which have the capacity to generate platelets. Although microtubules are the main structural component of proplatelets and microtubule sliding is known to drive proplatelet elongation, the role of actin dynamics in the process of platelet formation has remained elusive. Here, we tailored a mouse model lacking all ADF/n-cofilin-mediated actin dynamics in megakaryocytes to specifically elucidate the role of actin filament turnover in platelet formation. We demonstrate, for the first time, that in vivo actin filament turnover plays a critical role in the late stages of platelet formation from megakaryocytes and the proper sizing of platelets in the periphery. Our results provide the genetic proof that platelet production from megakaryocytes strictly requires dynamic changes in the actin cytoskeleton.
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14
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Noris P, Klersy C, Zecca M, Arcaini L, Pecci A, Melazzini F, Terulla V, Bozzi V, Ambaglio C, Passamonti F, Locatelli F, Balduini CL. Platelet size distinguishes between inherited macrothrombocytopenias and immune thrombocytopenia. J Thromb Haemost 2009; 7:2131-6. [PMID: 19740094 DOI: 10.1111/j.1538-7836.2009.03614.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Distinguishing inherited thrombocytopenias from immune thrombocytopenia (ITP) can be difficult, and patients are therefore at risk of misdiagnosis and inappropriate treatments. Although it is known that the most common inherited forms of thrombocytopenia are characterized by increased platelet size, the diagnostic power of this feature has never been investigated. OBJECTIVES The aim of this study was to test the hypothesis that platelet size can be used to differentiate ITP from inherited macrothrombocytopenias. PATIENTS/METHODS We measured mean platelet volume (MPV) and mean platelet diameter (MPD), within 2 h of blood sampling, in 35 patients with inherited macrothrombocytopenias [15 MYH9-related disease (MYH9-RD), three biallelic and 17 monoallelic Bernard-Soulier syndrome (BSS)], and 56 with ITP. Using receiving operating characteristic analysis, we searched for the best cut-off values to differentiate between these conditions. RESULTS As expected, platelets were larger in inherited macrothrombocytopenias than in ITP. An MPD larger than 3.3 mum differentiated MYH9-RD and BSS from ITP with 0.89 sensitivity and 0.88 specificity, and an MPV larger than 12.4 fL had 0.83 sensitivity and 0.89 specificity. Combining MPD with MPV increased sensitivity and specificity to 0.97 and 0.89, respectively. CONCLUSION Platelet size evaluation by both an appropriate cell counter and blood film examination is useful for differentiating inherited macrothrombocytopenias from ITP.
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Affiliation(s)
- P Noris
- Department of Internal Medicine, University of Pavia, Pavia, Italy.
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15
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Beltrame MP, Malvezzi M, Zanis J, Pasquini R. Flow cytometry as a tool in the diagnosis of Bernard-Soulier Syndrome in Brazilian patients. Platelets 2009; 20:229-34. [DOI: 10.1080/09537100902893784] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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The Montreal platelet syndrome kindred has type 2B von Willebrand disease with the VWF V1316M mutation. Blood 2008; 113:3348-51. [PMID: 19060241 DOI: 10.1182/blood-2008-06-165233] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Montreal platelet syndrome (MPS), hitherto described in only one kindred, is a hereditary thrombocytopenia associated with mucocutaneous bleeding, giant platelets, and spontaneous platelet aggregation in vitro. These are features shared with some forms of type 2B von Willebrand disease (VWD); however, the MPS kindred had not been investigated for VWD. We found that all affected MPS family members had borderline to normal von Willebrand factor antigen (VWF:Ag; 0.43-0.75 U/mL), discrepantly low ristocetin cofactor activity (VWF:RCo; 0.16-0.29 U/mL), and normal factor VIII coagulant activity (FVIII:C; 0.57-1.04 U/mL). Unaffected family members all had normal VWF:Ag, VWF:RCo, and FVIII:C levels. In addition, persons with MPS, but not unaffected family members, had loss of plasma (but not platelet) high molecular weight VWF multimers, and were heterozygous for the previously reported V1316M type 2B VWD mutation. Thus, in reevaluating this kindred, we determined that patients with MPS have type 2B VWD with the V1316M VWF mutation.
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[An asymptomatic thrombocytopenia in a 66-year-old man]. Rev Med Interne 2008; 30:282-6. [PMID: 19041164 DOI: 10.1016/j.revmed.2008.10.332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Boudreaux MK. Characteristics, diagnosis, and treatment of inherited platelet disorders in mammals. J Am Vet Med Assoc 2008; 233:1251-9, 1190. [DOI: 10.2460/javma.233.8.1251] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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