1
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Fernandez DI, Provenzale I, Canault M, Fels S, Lenz A, Andresen F, Krümpel A, Dupuis A, Heemskerk JWM, Boeckelmann D, Zieger B. High-throughput microfluidic blood testing to phenotype genetically linked platelet disorders: an aid to diagnosis. Blood Adv 2023; 7:6163-6177. [PMID: 37389831 PMCID: PMC10582840 DOI: 10.1182/bloodadvances.2023009860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/12/2023] [Accepted: 05/30/2023] [Indexed: 07/01/2023] Open
Abstract
Linking the genetic background of patients with bleeding diathesis and altered platelet function remains challenging. We aimed to assess how a multiparameter microspot-based measurement of thrombus formation under flow can help identify patients with a platelet bleeding disorder. For this purpose, we studied 16 patients presenting with bleeding and/or albinism and suspected platelet dysfunction and 15 relatives. Genotyping of patients revealed a novel biallelic pathogenic variant in RASGRP2 (splice site c.240-1G>A), abrogating CalDAG-GEFI expression, compound heterozygosity (c.537del, c.571A>T) in P2RY12, affecting P2Y12 signaling, and heterozygous variants of unknown significance in the P2RY12 and HPS3 genes. Other patients were confirmed to have Hermansky-Pudlak syndrome type 1 or 3. In 5 patients, no genetic variant was found. Platelet functions were assessed via routine laboratory measurements. Blood samples from all subjects and day controls were screened for blood cell counts and microfluidic outcomes on 6 surfaces (48 parameters) in comparison with those of a reference cohort of healthy subjects. Differential analysis of the microfluidic data showed that the key parameters of thrombus formation were compromised in the 16 index patients. Principal component analysis revealed separate clusters of patients vs heterozygous family members and control subjects. Clusters were further segregated based on inclusion of hematologic values and laboratory measurements. Subject ranking indicated an overall impairment in thrombus formation in patients carrying a (likely) pathogenic variant of the genes but not in asymptomatic relatives. Taken together, our results indicate the advantages of testing for multiparametric thrombus formation in this patient population.
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Affiliation(s)
- Delia I. Fernandez
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
- Platelet Proteomics Group, Center for Research in Molecular Medicine and Chronic Diseases, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Isabella Provenzale
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
- Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom
| | - Matthias Canault
- Institut National de la Santé et de la Recherche Médicale, UMR_INRA 1260, Faculté de Medecine, Aix Marseille Université, Marseille, France
| | - Salome Fels
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Antonia Lenz
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Felicia Andresen
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Anne Krümpel
- Practice for Pediatric and Youth Medicine, Wettringen, Germany
| | - Arnaud Dupuis
- Université de Strasbourg, Etablissement Français du Sang Grand Est, UMR_S 1255, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Johan W. M. Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
- Synapse Research Institute, Maastricht, The Netherlands
| | - Doris Boeckelmann
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Barbara Zieger
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Center, University of Freiburg, Freiburg, Germany
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2
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Mortensen Ó, Thomsen E, Lydersen LN, Apol KD, Weihe P, Steig BÁ, Andorsdóttir G, Als TD, Gregersen NO. FarGen: Elucidating the distribution of coding variants in the isolated population of the Faroe Islands. Eur J Hum Genet 2023; 31:329-337. [PMID: 36404349 PMCID: PMC9995356 DOI: 10.1038/s41431-022-01227-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/30/2022] [Accepted: 10/27/2022] [Indexed: 11/22/2022] Open
Abstract
Here we present results from FarGen Phase I exomes. This dataset is based on the FarGen cohort, which consists of 1,541 individuals from the isolated population of the Faroe Islands. The purpose of this cohort is to serve as a reference catalog of coding variants, and to conduct population genetic studies to better understand the genetic contribution to various diseases in the Faroese population. The first whole-exome data set comprise 465 individuals and a total of 148,267 genetic variants were discovered. Principle Component Analysis indicates that the population is isolated and weakly structured. The distribution of variants in various functional classes was compared with populations in the gnomAD dataset; the results indicated that the proportions were consistent across the cohorts, but probably due to a small sample size, the FarGen dataset contained relatively few rare variants. We identified 19 variants that are classified as pathogenic or likely pathogenic in ClinVar; several of these variants are associated with monogenetic diseases with increased prevalence in the Faroe Islands. The results support previous studies, which indicate that the Faroe Islands is an isolated and weakly structured population. Future studies may elucidate the significance of the 19 pathogenic variants that were identified. The FarGen Phase I dataset is an important step for genetic research in the Faroese population, and the next phase of FarGen will increase the sample size and broaden the scope.
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Affiliation(s)
- Ólavur Mortensen
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands
| | - Elisabet Thomsen
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands
| | | | - Katrin D Apol
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands
| | - Pál Weihe
- Department of Occupational Medicine and Public Health, National Hospital of the Faroe Islands Tórshavn, Tórshavn, Faroe Islands
| | - Bjarni Á Steig
- Medical Department, National Hospital of the Faroe Islands, Tórshavn, Faroe Islands
| | - Guðrið Andorsdóttir
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands
- Centre of Health Science, Faculty of Health, University of the Faroe Islands, Tórshavn, Faroe Islands
| | - Thomas D Als
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus, Denmark
- Center for Genomics and Personalized Medicine, Aarhus, Denmark
| | - Noomi O Gregersen
- The Genetic Biobank of the Faroe Islands, Tórshavn, Faroe Islands.
- Centre of Health Science, Faculty of Health, University of the Faroe Islands, Tórshavn, Faroe Islands.
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3
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Wang H, Lin Z, Nian Z, Zhang W, Liu W, Yan F, Xiao Z, Wang X, Zhang Z, Ma Z, Liu Z. Hematopoietic transcription factor GFI1 promotes anchorage independence by sustaining ERK activity in cancer cells. J Clin Invest 2022; 132:149551. [PMID: 35819844 PMCID: PMC9433100 DOI: 10.1172/jci149551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/07/2022] [Indexed: 11/26/2022] Open
Abstract
The switch from anchorage-dependent to anchorage-independent growth is essential for epithelial metastasis. The underlying mechanism, however, is not fully understood. In this study, we identified growth factor independent-1 (GFI1), a transcription factor that drives the transition from adherent endothelial cells to suspended hematopoietic cells during hematopoiesis, as a critical regulator of anchorage independence in lung cancer cells. GFI1 elevated the numbers of circulating and lung-infiltrating tumor cells in xenograft models and predicted poor prognosis of patients with lung cancer. Mechanistically, GFI1 inhibited the expression of multiple adhesion molecules and facilitated substrate detachment. Concomitantly, GFI1 reconfigured the chromatin structure of the RASGRP2 gene and increased its expression, causing Rap1 activation and subsequent sustained ERK activation upon detachment, and this led to ERK signaling dependency in tumor cells. Our studies unveiled a mechanism by which carcinoma cells hijacked a hematopoietic factor to gain anchorage independence and suggested that the intervention of ERK signaling may suppress metastasis and improve the therapeutic outcome of patients with GFI1-positive lung cancer.
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Affiliation(s)
- Hao Wang
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Zhenzhen Lin
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Zhe Nian
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Wei Zhang
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Wenxu Liu
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Fei Yan
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Zengtuan Xiao
- Department of Lung Cancer Surgery, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Xia Wang
- Department of Gastrointestinal Oncology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Zhenfa Zhang
- Department of Lung Cancer Surgery, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Zhenyi Ma
- Department of Immunology, Tianjin Medical University, Tianjin, China
| | - Zhe Liu
- Department of Immunology, Tianjin Medical University, Tianjin, China
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4
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Pluthero FG, Westbury SK, Kahr WHA. Inherited platelet disorders: From new variants to new knowledge. Br J Haematol 2022; 197:245-246. [PMID: 35187641 DOI: 10.1111/bjh.18074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Fred G Pluthero
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sarah K Westbury
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Walter H A Kahr
- Cell Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.,Division of Haematology/Oncology, The Hospital for Sick Children, Toronto, Ontario, Canada.,Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada
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5
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Kawankar N, Shetty S, Kulkarni B. Novel RASGRP2 variants in platelet function defects: Indian study. Br J Haematol 2022; 197:377-380. [PMID: 35122233 DOI: 10.1111/bjh.18049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/29/2021] [Accepted: 01/05/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Nikesh Kawankar
- ICMR-National Institute of Immunohaematology, K.E.M. Hospital campus, Parel, Mumbai, India
| | - Shrimati Shetty
- ICMR-National Institute of Immunohaematology, K.E.M. Hospital campus, Parel, Mumbai, India
| | - Bipin Kulkarni
- ICMR-National Institute of Immunohaematology, K.E.M. Hospital campus, Parel, Mumbai, India
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6
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CalDAG-GEFI Deficiency in a Family with Symptomatic Heterozygous and Homozygous Carriers of a Likely Pathogenic Variant in RASGRP2. Int J Mol Sci 2021; 22:ijms222212423. [PMID: 34830306 PMCID: PMC8618213 DOI: 10.3390/ijms222212423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 11/28/2022] Open
Abstract
RASGRP2 encodes the calcium and diacylglycerol (DAG)-regulated guanine nucleotide exchange factor I (CalDAG-GEFI) identified as a Rap1-activating molecule. Pathogenic variants previously identified in RASGRP2 allowed the characterization of CalDAG-GEFI deficiency as a non-syndromic, autosomal recessive platelet function disease. We report on the clinical manifestations and laboratory features of a Portuguese family with a likely pathogenic variant in RASGRP2 (c.999G>C leading to a p.Lys333Asn change in the CDC25 catalytic domain of CalDAG-GEFI) and discuss the contribution of this variant to the disease manifestations. Based on the study of this family with one homozygous patient and five heterozygous carriers and on a critical analysis of the literature, we challenge previous knowledge that CalDAG-GEFI deficiency only manifests in homozygous patients. Our data suggest that at least for the RASGRP2 variant reported herein, there is a phenotypic expression, albeit milder, in heterozygous carriers.
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7
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Tsai FD, Battinelli EM. Inherited Platelet Disorders. Hematol Oncol Clin North Am 2021; 35:1069-1084. [PMID: 34391603 DOI: 10.1016/j.hoc.2021.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Bleeding disorders due to platelet dysfunction are a common hematologic complication affecting patients, and typically present with mucocutaneous bleeding or hemorrhage. An inherited platelet disorder should be suspected in individuals with a suggestive family history and no identified secondary causes of bleeding. Genetic defects have been described at all levels of platelet activation, including receptor binding, signaling, granule release, cytoskeletal remodeling, and platelet hematopoiesis. Management of these disorders is typically supportive, with an emphasis on awareness, patient education, and anticipatory guidance to prevent future episodes of bleeding.
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Affiliation(s)
- Frederick D Tsai
- Division of Hematology, Department of Medicine, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA; Division of Hematologic Neoplasia, Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Harvard Medical School, 25 Shattuck St, Boston, MA 02115, USA
| | - Elisabeth M Battinelli
- Division of Hematology, Department of Medicine, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA; Harvard Medical School, 25 Shattuck St, Boston, MA 02115, USA.
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8
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Platelet transfusion for patients with platelet dysfunction: effectiveness, mechanisms, and unanswered questions. Curr Opin Hematol 2021; 27:378-385. [PMID: 32868672 DOI: 10.1097/moh.0000000000000608] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE OF REVIEW In this review, we discuss current clinical guidelines and potential underlying mechanisms regarding platelet transfusion therapy in patients at risk of bleeding, comparing management of patients with thrombocytopenia versus those with qualitative platelet disorders. RECENT FINDINGS Platelet transfusion therapy is highly effective in managing bleeding in patients with hypoproliferative thrombocytopenia. Clinical trials have demonstrated that platelet transfusion can be used at a lower trigger threshold and reduced platelet doses, and may be used therapeutically rather than prophylactically in some situations, although additional data are needed. In patients with inherited platelet disorders such as Glanzmann's Thrombasthenia or those with RASGRP2 mutations, platelet transfusion may be ineffective because of competition between transfused and endogenous platelets at the site of vascular injury. Successful management of these patients may require transfusion of additional platelet units, or mechanism-driven combination therapy with other pro-hemostatic agents. In patients on antiplatelet therapy, timing of transfusion and inhibitor mechanism-of-action are key in determining therapeutic success. SUMMARY Expanding our understanding of the mechanisms by which transfused platelets exert their pro-hemostatic function in various bleeding disorders will improve the appropriate use of platelet transfusion.
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9
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Rosenberg N, Dardik R, Hauschner H, Nakav S, Barel O, Luboshitz J, Yacobovich J, Tamary H, Kenet G. Mutations in RASGRP2 gene identified in patients misdiagnosed as Glanzmann thrombasthenia patients. Blood Cells Mol Dis 2021; 89:102560. [PMID: 33711653 DOI: 10.1016/j.bcmd.2021.102560] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/24/2021] [Accepted: 03/01/2021] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Glanzmann thrombasthenia (GT) is a severe inherited platelet function disorder (IPFD), presenting with bleeding diathesis and impaired platelet aggregation, is caused by mutations in the genes ITGA2B or ITGB3. AIM We aimed to study the genetic cause of IPFD mimicking GT. METHODS During 2017-2019, 16 patients were referred to our tertiary center with bleeding symptoms, impaired platelet aggregation and normal platelet count and size. RESULTS Using flow cytometry, 13/16 patients were diagnosed with GT, yet three patients displayed normal surface expression of the integrins αIIbβ3 and αvβ3, as well as normal integrin αIIbβ3 activation following incubation with the activating monoclonal antibody anti-LIBS6, while platelet activation following ADP or epinephrine was impaired. Whole exome sequencing detected 2 variants in RASGRP2 gene in all 3 patients. DISCUSSION Both RASGRP2 mutations predicted frameshift, premature stop codon (p. I427Mfs*92 and p. R494Afs*54, respectively) and truncated calcium-sensing guanine nucleotide exchange factor [CalDAG-GEFI]- the major signaling molecule that regulates integrin-mediated aggregation and granule secretion, causing IPFD-18. CONCLUSION Patients who suffer from bleeding diathesis without immune dysregulation, may be mistakenly diagnosed as GT. Further studies are required to confirm the diagnosis of specific IPFD.
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Affiliation(s)
- Nurit Rosenberg
- The Israeli National Hemophilia Center and Thrombosis Institute, Sheba Medical Center, Tel Hashomer, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Amalia Biron Research Institute of Thrombosis and Hemostasis, Sheba Medical Center, Tel Hashomer, and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rima Dardik
- The Israeli National Hemophilia Center and Thrombosis Institute, Sheba Medical Center, Tel Hashomer, Israel
| | - Hagit Hauschner
- The Israeli National Hemophilia Center and Thrombosis Institute, Sheba Medical Center, Tel Hashomer, Israel; Amalia Biron Research Institute of Thrombosis and Hemostasis, Sheba Medical Center, Tel Hashomer, and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sigal Nakav
- Coagulation and Hemostasis Laboratory, Hematology Laboratories, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Ortal Barel
- Bioinformatic Unit, Sheba Cancer Research Center, Tel-Hashomer, Israel
| | - Jacob Luboshitz
- The Israeli National Hemophilia Center and Thrombosis Institute, Sheba Medical Center, Tel Hashomer, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Joanne Yacobovich
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Pediatric Hematology, Schneider Children's Medical Center, Petach-Tikva; Israel
| | - Hannah Tamary
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Pediatric Hematology, Schneider Children's Medical Center, Petach-Tikva; Israel
| | - Gili Kenet
- The Israeli National Hemophilia Center and Thrombosis Institute, Sheba Medical Center, Tel Hashomer, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; Amalia Biron Research Institute of Thrombosis and Hemostasis, Sheba Medical Center, Tel Hashomer, and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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10
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Al-Hebshi A. Inherited Platelet Function Disorder From Novel Mutations in RAS Guanyl-Releasing Protein-2 Confirmed by Sanger Sequencing. Cureus 2020; 12:e11708. [PMID: 33391941 PMCID: PMC7769792 DOI: 10.7759/cureus.11708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Inherited platelet disorders (IPDs) are genetically heterogeneous rare disorders due to quantitative and/or qualitative abnormalities of the platelet. IPDs are often predisposed to significant medical complications. RAS guanyl-releasing protein-2 (RASGRP2) was recently identified as a gene affected in patients with platelet function defects and a bleeding complication. RASGRP2 codes for the protein CalDAG-GEFI RAS (guanyl-releasing protein-2), a guanine nucleotide exchange factor for small guanosine triphosphate(GTP)ase Rap1. We used Sanger sequencing to identify a novel function-disrupting homozygous mutation in RASGRP2 responsible for bleeding diathesis and platelet dysfunction in a patient.
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Affiliation(s)
- Abdulqader Al-Hebshi
- Pediatric Hematology Oncology, Prince Mohammed Bin Abdulaziz Hospital, Medina, SAU.,Pediatric Hematology Oncology, Ministry of National Guard Health Affairs, Medina, SAU.,Pediatric Hematology Oncology, King Abdullah International Medical Research Center, Riyadh, SAU.,Pediatric Hematology Oncology, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, SAU
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11
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Alharby E, Bakhsh MA, Albalawi AM, Almutairi SO, Hashmi JA, Basit S. A novel missense variant in the RASGRP2 gene in patients with moderate to severe bleeding disorder. Platelets 2020; 31:646-651. [PMID: 32609603 DOI: 10.1080/09537104.2019.1663803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Inherited platelet function disorder-18 (IPD-18) is a relatively new non-syndromic autosomal recessive bleeding disorder. It is characterized by deficient or dysfunctional CalDAG-GEFI protein. The distinctive feature of the disease is impaired platelet aggregation in response to multiple physiologic agonists. We here report a family with a platelet-type bleeding disorder and a novel mutation in the RASGRP2 gene. The overall bleeding score for the affected individuals was 15 and 12. Based on the initial diagnosis of Glanzmann thrombasthenia, targeted sequencing of integrin subunit alpha 2b and integrin subunit beta 3 encoding genes ITGA2B and ITGB3 were carried out in both affected members of a family. Sequence alignment failed to identify the disease-causing variant(s) in both genes. Therefore, whole exome sequencing in one affected individual was performed. Data analysis detected a novel homozygous missense variant (c.956C>T; p.Pro319Leu) in the exon 9 of the RASGRP2 gene. Five additional individuals of a family including both parents, an affected individual and two asymptomatic individuals were Sanger sequenced for the variant (c.956C>T). The variant segregates in the family in an autosomal recessive manner. Several in silico tools predicted the variant as pathogenic. Protein modeling studies suggest that the mutation (p.Pro319Leu) cause a conformational change in the loop structure of the RasGEF domain of the CalDAG-GEFI protein. Reported variants in the RasGEF domain impair expression and/or nucleotide exchange activity of CalDAG-GEFI protein and thus inhibit the activation of Rap1 protein required for platelet adhesion and hemostatic plug formation.
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Affiliation(s)
- Essa Alharby
- Center for Genetics and Inherited Diseases, Taibah University Medina, Almadinah Almunawwarah , Saudi Arabia
| | - Mohammad A Bakhsh
- College of Applied Medical Science, Taibah University Medina, Almadinah Almunawwarah , Saudi Arabia
| | - Alia M Albalawi
- Center for Genetics and Inherited Diseases, Taibah University Medina, Almadinah Almunawwarah , Saudi Arabia
| | - Sultan O Almutairi
- College of Applied Medical Science, Taibah University Medina, Almadinah Almunawwarah , Saudi Arabia
| | - Jamil A Hashmi
- Center for Genetics and Inherited Diseases, Taibah University Medina, Almadinah Almunawwarah , Saudi Arabia
| | - Sulman Basit
- Center for Genetics and Inherited Diseases, Taibah University Medina, Almadinah Almunawwarah , Saudi Arabia
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12
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Turro E, Astle WJ, Megy K, Gräf S, Greene D, Shamardina O, Allen HL, Sanchis-Juan A, Frontini M, Thys C, Stephens J, Mapeta R, Burren OS, Downes K, Haimel M, Tuna S, Deevi SVV, Aitman TJ, Bennett DL, Calleja P, Carss K, Caulfield MJ, Chinnery PF, Dixon PH, Gale DP, James R, Koziell A, Laffan MA, Levine AP, Maher ER, Markus HS, Morales J, Morrell NW, Mumford AD, Ormondroyd E, Rankin S, Rendon A, Richardson S, Roberts I, Roy NBA, Saleem MA, Smith KGC, Stark H, Tan RYY, Themistocleous AC, Thrasher AJ, Watkins H, Webster AR, Wilkins MR, Williamson C, Whitworth J, Humphray S, Bentley DR, Kingston N, Walker N, Bradley JR, Ashford S, Penkett CJ, Freson K, Stirrups KE, Raymond FL, Ouwehand WH. Whole-genome sequencing of patients with rare diseases in a national health system. Nature 2020; 583:96-102. [PMID: 32581362 PMCID: PMC7610553 DOI: 10.1038/s41586-020-2434-2] [Citation(s) in RCA: 277] [Impact Index Per Article: 69.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 05/05/2020] [Indexed: 02/02/2023]
Abstract
Most patients with rare diseases do not receive a molecular diagnosis and the aetiological variants and causative genes for more than half such disorders remain to be discovered1. Here we used whole-genome sequencing (WGS) in a national health system to streamline diagnosis and to discover unknown aetiological variants in the coding and non-coding regions of the genome. We generated WGS data for 13,037 participants, of whom 9,802 had a rare disease, and provided a genetic diagnosis to 1,138 of the 7,065 extensively phenotyped participants. We identified 95 Mendelian associations between genes and rare diseases, of which 11 have been discovered since 2015 and at least 79 are confirmed to be aetiological. By generating WGS data of UK Biobank participants2, we found that rare alleles can explain the presence of some individuals in the tails of a quantitative trait for red blood cells. Finally, we identified four novel non-coding variants that cause disease through the disruption of transcription of ARPC1B, GATA1, LRBA and MPL. Our study demonstrates a synergy by using WGS for diagnosis and aetiological discovery in routine healthcare.
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Affiliation(s)
- Ernest Turro
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK.
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK.
| | - William J Astle
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
| | - Karyn Megy
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Stefan Gräf
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Daniel Greene
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Olga Shamardina
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Hana Lango Allen
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Alba Sanchis-Juan
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Mattia Frontini
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK
- British Heart Foundation Cambridge Centre of Excellence, University of Cambridge, Cambridge, UK
| | - Chantal Thys
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Leuven, Belgium
| | - Jonathan Stephens
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Rutendo Mapeta
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Oliver S Burren
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Kate Downes
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Matthias Haimel
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Salih Tuna
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Sri V V Deevi
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Timothy J Aitman
- MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, UK
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - David L Bennett
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
| | - Paul Calleja
- High Performance Computing Service, University of Cambridge, Cambridge, UK
| | - Keren Carss
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Mark J Caulfield
- Genomics England Ltd, London, UK
- William Harvey Research Institute, NIHR Biomedical Research Centre at Barts, Queen Mary University of London, London, UK
| | - Patrick F Chinnery
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Clinical Neurosciences, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Cambridge, UK
| | - Peter H Dixon
- Women and Children's Health, School of Life Course Sciences, King's College London, London, UK
| | - Daniel P Gale
- Department of Renal Medicine, University College London, London, UK
- Rare Renal Disease Registry, UK Renal Registry, Bristol, UK
| | - Roger James
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Ania Koziell
- King's College London, London, UK
- Department of Paediatric Nephrology, Evelina London Children's Hospital, Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - Michael A Laffan
- Department of Haematology, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK
- Centre for Haematology, Imperial College London, London, UK
| | - Adam P Levine
- Department of Renal Medicine, University College London, London, UK
| | - Eamonn R Maher
- Department of Medical Genetics, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK
- Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Hugh S Markus
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Bristol, UK
| | - Joannella Morales
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
| | - Nicholas W Morrell
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Andrew D Mumford
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
- University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Elizabeth Ormondroyd
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
- Department of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Stuart Rankin
- High Performance Computing Service, University of Cambridge, Cambridge, UK
| | - Augusto Rendon
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Genomics England Ltd, London, UK
| | - Sylvia Richardson
- MRC Biostatistics Unit, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Irene Roberts
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Department of Paediatrics, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Noemi B A Roy
- NIHR Oxford Biomedical Research Centre, Oxford University Hospitals Trust, Oxford, UK
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Moin A Saleem
- Bristol Renal and Children's Renal Unit, Bristol Medical School, University of Bristol, Bristol, UK
- Bristol Royal Hospital for Children, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Kenneth G C Smith
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Hannah Stark
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Rhea Y Y Tan
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Bristol, UK
| | - Andreas C Themistocleous
- The Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | | | - Hugh Watkins
- Department of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Andrew R Webster
- Moorfields Eye Hospital NHS Trust, London, UK
- UCL Institute of Opthalmology, University College London, London, UK
| | | | - Catherine Williamson
- Women and Children's Health, School of Life Course Sciences, King's College London, London, UK
- Institute of Reproductive and Developmental Biology, Department of Surgery and Cancer, Faculty of Medicine, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - James Whitworth
- Department of Medical Genetics, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK
- Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
| | | | | | - Nathalie Kingston
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Neil Walker
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - John R Bradley
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK
- Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
- Department of Renal Medicine, Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Sofie Ashford
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Christopher J Penkett
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - Kathleen Freson
- Department of Cardiovascular Sciences, Center for Molecular and Vascular Biology, KU Leuven, Leuven, Belgium
| | - Kathleen E Stirrups
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK
| | - F Lucy Raymond
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK.
- Department of Medical Genetics, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
| | - Willem H Ouwehand
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
- NIHR BioResource, Cambridge University Hospitals NHS Foundation, Cambridge Biomedical Campus, Cambridge, UK.
- NHS Blood and Transplant, Cambridge Biomedical Campus, Cambridge, UK.
- British Heart Foundation Cambridge Centre of Excellence, University of Cambridge, Cambridge, UK.
- Wellcome Sanger Institute, Cambridge, UK.
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13
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Diagnostic high-throughput sequencing of 2396 patients with bleeding, thrombotic, and platelet disorders. Blood 2020; 134:2082-2091. [PMID: 31064749 DOI: 10.1182/blood.2018891192] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/22/2019] [Indexed: 12/17/2022] Open
Abstract
A targeted high-throughput sequencing (HTS) panel test for clinical diagnostics requires careful consideration of the inclusion of appropriate diagnostic-grade genes, the ability to detect multiple types of genomic variation with high levels of analytic sensitivity and reproducibility, and variant interpretation by a multidisciplinary team (MDT) in the context of the clinical phenotype. We have sequenced 2396 index patients using the ThromboGenomics HTS panel test of diagnostic-grade genes known to harbor variants associated with rare bleeding, thrombotic, or platelet disorders (BTPDs). The molecular diagnostic rate was determined by the clinical phenotype, with an overall rate of 49.2% for all thrombotic, coagulation, platelet count, and function disorder patients and a rate of 3.2% for patients with unexplained bleeding disorders characterized by normal hemostasis test results. The MDT classified 745 unique variants, including copy number variants (CNVs) and intronic variants, as pathogenic, likely pathogenic, or variants of uncertain significance. Half of these variants (50.9%) are novel and 41 unique variants were identified in 7 genes recently found to be implicated in BTPDs. Inspection of canonical hemostasis pathways identified 29 patients with evidence of oligogenic inheritance. A molecular diagnosis has been reported for 894 index patients providing evidence that introducing an HTS genetic test is a valuable addition to laboratory diagnostics in patients with a high likelihood of having an inherited BTPD.
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14
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Botero JP, Lee K, Branchford BR, Bray PF, Freson K, Lambert MP, Luo M, Mohan S, Ross JE, Bergmeier W, Di Paola J. Glanzmann thrombasthenia: genetic basis and clinical correlates. Haematologica 2020; 105:888-894. [PMID: 32139434 PMCID: PMC7109743 DOI: 10.3324/haematol.2018.214239] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 02/07/2020] [Indexed: 01/23/2023] Open
Abstract
Glanzmann thrombasthenia (GT) is an autosomal recessive disorder of platelet aggregation caused by quantitative or qualitative defects in integrins αIIb and β3. These integrins are encoded by the ITGA2B and ITGB3 genes and form platelet glycoprotein (GP)IIb/IIIa, which acts as the principal platelet receptor for fibrinogen. Although there is variability in the clinical phenotype, most patients present with severe mucocutaneous bleeding at an early age. A classic pattern of abnormal platelet aggregation, platelet glycoprotein expression and molecular studies confirm the diagnosis. Management of bleeding is based on a combination of hemostatic agents including recombinant activated factor VII with or without platelet transfusions and antifibrinolytic agents. Refractory bleeding and platelet alloimmunization are common complications. In addition, pregnant patients pose unique management challenges. This review highlights clinical and molecular aspects in the approach to patients with GT, with particular emphasis on the significance of multidisciplinary care.
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Affiliation(s)
- Juliana Perez Botero
- Versiti and Division of Hematology/Oncology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Kristy Lee
- Department of Genetics, University of North Carolina at Chapel Hill, NC, USA
| | - Brian R Branchford
- University of Colorado School of Medicine, Department of Pediatrics, Division of Hematology/Oncology/Bone Marrow Transplant, Aurora, CO, USA
| | - Paul F Bray
- Molecular Medicine Program, Division of Hematology and Hematologic Malignancies, Department of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Kathleen Freson
- Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium
| | - Michele P Lambert
- The Children's Hospital of Philadelphia and Department of Pediatrics, Perelman School of Medicine, Philadelphia, PA, USA
| | - Minjie Luo
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA, USA
| | - Shruthi Mohan
- Department of Genetics, University of North Carolina at Chapel Hill, NC, USA
| | - Justyne E Ross
- Department of Genetics, University of North Carolina at Chapel Hill, NC, USA
| | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics and UNC Blood Research Center, University of North Carolina at Chapel Hill, NC, USA
| | - Jorge Di Paola
- Division of Pediatric Hematology Oncology, Department of Pediatrics, Washington University School of Medicine in St. Louis, MO, USA
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15
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Sarker M, Goliaei A, Golesi F, Poggi M, Cook A, Khan MAI, Temple BR, Stefanini L, Canault M, Bergmeier W, Campbell SL. Subcellular localization of Rap1 GTPase activator CalDAG-GEFI is orchestrated by interaction of its atypical C1 domain with membrane phosphoinositides. J Thromb Haemost 2020; 18:693-705. [PMID: 31758832 PMCID: PMC7050387 DOI: 10.1111/jth.14687] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 10/17/2019] [Accepted: 11/14/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND The small GTPase Rap1 and its guanine nucleotide exchange factor, CalDAG-GEFI (CDGI), are critical for platelet function and hemostatic plug formation. CDGI function is regulated by a calcium binding EF hand regulatory domain and an atypical C1 domain with unknown function. OBJECTIVE Here, we investigated whether the C1 domain controls CDGI subcellular localization, both in vitro and in vivo. METHODS CDGI interaction with phosphoinositides was studied by lipid co-sedimentation assays and molecular dynamics simulations. Cellular localization of CDGI was studied in heterologous cells by immunofluorescence and subcellular fractionation assays. RESULTS Lipid co-sedimentation studies demonstrated that the CDGI C1 domain associates with membranes through exclusive recognition of phosphoinositides, phosphatidylinositol (4,5)-biphosphate (PIP2) and phosphatidylinositol (3,4,5)-triphosphate (PIP3). Molecular dynamics simulations identified a phospholipid recognition motif consisting of residues exclusive to the CDGI C1 domain. Mutation of those residues abolished co-sedimentation of the C1 domain with lipid vesicles and impaired membrane localization of CDGI in heterologous cells. CONCLUSION Our studies identify a novel interaction between an atypical C1 domain and phosphatidylinositol (4,5)-biphosphate and phosphatidylinositol (3,4,5)-triphosphate in cellular membranes, which is critical for Rap1 signaling in health and disease.
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Affiliation(s)
- Muzaddid Sarker
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ardeshir Goliaei
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - Marjorie Poggi
- Aix Marseille University, INSERM, INRA, Marseille, France
| | - Aaron Cook
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mohammad A. I. Khan
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Brenda R. Temple
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- RL Juliano Structural Bioinformatics Core, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Lucia Stefanini
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | | | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Sharon L. Campbell
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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16
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Canault M, Alessi MC. RasGRP2 Structure, Function and Genetic Variants in Platelet Pathophysiology. Int J Mol Sci 2020; 21:E1075. [PMID: 32041177 PMCID: PMC7037602 DOI: 10.3390/ijms21031075] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 12/18/2022] Open
Abstract
RasGRP2 is calcium and diacylglycerol-regulated guanine nucleotide exchange factor I that activates Rap1, which is an essential signaling-knot in "inside-out" αIIbβ3 integrin activation in platelets. Inherited platelet function disorder caused by variants of RASGRP2 represents a new congenital bleeding disorder referred to as platelet-type bleeding disorder-18 (BDPLT18). We review here the structure of RasGRP2 and its functions in the pathophysiology of platelets and of the other cellular types that express it. We will also examine the different pathogenic variants reported so far as well as strategies for the diagnosis and management of patients with BDPLT18.
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Affiliation(s)
- Matthias Canault
- Aix Marseille University, INSERM, INRAE, C2VN, 13005 Marseille, France
| | - Marie-Christine Alessi
- Aix Marseille University, INSERM, INRAE, C2VN, 13005 Marseille, France
- Hematology laboratory, APHM, CHU Timone, 13005 Marseille, France
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17
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Southgate L, Machado RD, Gräf S, Morrell NW. Molecular genetic framework underlying pulmonary arterial hypertension. Nat Rev Cardiol 2020; 17:85-95. [PMID: 31406341 DOI: 10.1038/s41569-019-0242-x] [Citation(s) in RCA: 163] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/12/2019] [Indexed: 02/02/2023]
Abstract
Pulmonary arterial hypertension (PAH) is a rare, progressive disorder typified by occlusion of the pulmonary arterioles owing to endothelial dysfunction and uncontrolled proliferation of pulmonary artery smooth muscle cells and fibroblasts. Vascular occlusion can lead to increased pressure in the pulmonary arteries, often resulting in right ventricular failure with shortness of breath and syncope. Since the identification of BMPR2, which encodes a receptor in the transforming growth factor-β superfamily, the development of high-throughput sequencing approaches to identify novel causal genes has substantially advanced our understanding of the molecular genetics of PAH. In the past 6 years, additional pathways involved in PAH susceptibility have been described through the identification of deleterious genetic variants in potassium channels (KCNK3 and ABCC8) and transcription factors (TBX4 and SOX17), among others. Although familial PAH most often has an autosomal-dominant pattern of inheritance, cases of incomplete penetrance and evidence of genetic heterogeneity support a model of PAH as a Mendelian disorder with complex disease features. In this Review, we outline the latest advances in the detection of rare and common genetic variants underlying PAH susceptibility and disease progression. These findings have clinical implications for lung vascular function and can help to identify mechanistic pathways amenable to pharmacological intervention.
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Affiliation(s)
- Laura Southgate
- Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK.,Department of Medical and Molecular Genetics, King's College London, London, UK
| | - Rajiv D Machado
- Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Stefan Gräf
- Department of Medicine, University of Cambridge, Cambridge, UK.,Department of Haematology, University of Cambridge, Cambridge, UK.,NIHR BioResource, Cambridge, UK
| | - Nicholas W Morrell
- Department of Medicine, University of Cambridge, Cambridge, UK. .,NIHR BioResource, Cambridge, UK.
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18
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Lee RH, Piatt R, Dhenge A, Lozano ML, Palma-Barqueros V, Rivera J, Bergmeier W. Impaired hemostatic activity of healthy transfused platelets in inherited and acquired platelet disorders: Mechanisms and implications. Sci Transl Med 2019; 11:eaay0203. [PMID: 31826978 PMCID: PMC10824274 DOI: 10.1126/scitranslmed.aay0203] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 10/11/2019] [Indexed: 12/21/2022]
Abstract
Platelet transfusions can fail to prevent bleeding in patients with inherited platelet function disorders (IPDs), such as Glanzmann's thrombasthenia (GT; integrin αIIbβ3 dysfunction), Bernard-Soulier syndrome [BSS; glycoprotein (GP) Ib/V/IX dysfunction], and the more recently identified nonsyndromic RASGRP2 variants. Here, we used IPD mouse models and real-time imaging of hemostatic plug formation to investigate whether dysfunctional platelets impair the hemostatic function of healthy donor [wild-type (WT)] platelets. In Rasgrp2-/- mice or mice with platelet-specific deficiency in the integrin adaptor protein TALIN1 ("GT-like"), WT platelet transfusion was ineffective unless the ratio between mutant and WT platelets was ~2:1. In contrast, thrombocytopenic mice or mice lacking the extracellular domain of GPIbα ("BSS-like") required very few transfused WT platelets to normalize hemostasis. Both Rasgrp2-/- and GT-like, but not BSS-like, platelets effectively localized to the injury site. Mechanistic studies identified at least two mechanisms of interference by dysfunctional platelets in IPDs: (i) delayed adhesion of WT donor platelets due to reduced access to GPIbα ligands exposed at sites of vascular injury and (ii) impaired consolidation of the hemostatic plug. We also investigated the hemostatic activity of transfused platelets in the setting of dual antiplatelet therapy (DAPT), an acquired platelet function disorder (APD). "DAPT" platelets did not prolong the time to initial hemostasis, but plugs were unstable and frequent rebleeding was observed. Thus, we propose that the endogenous platelet count and the ratio of transfused versus endogenous platelets should be considered when treating select IPD and APD patients with platelet transfusions.
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Affiliation(s)
- Robert H Lee
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
- UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Raymond Piatt
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Ankita Dhenge
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
- UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - María L Lozano
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia 30003, Spain
| | - Verónica Palma-Barqueros
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia 30003, Spain
| | - José Rivera
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Murcia 30003, Spain
| | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
- UNC Blood Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
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19
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Takino JI, Sato T, Nagamine K, Hori T. The inhibition of Bax activation-induced apoptosis by RasGRP2 via R-Ras-PI3K-Akt signaling pathway in the endothelial cells. Sci Rep 2019; 9:16717. [PMID: 31723205 PMCID: PMC6854084 DOI: 10.1038/s41598-019-53419-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/15/2019] [Indexed: 12/31/2022] Open
Abstract
Apoptosis of endothelial cells is a very important event in various diseases and angiogenesis. We recently reported that ras guanyl nucleotide releasing protein 2 (RasGRP2), which is a guanine nucleotide exchange factor, was expressed in the human umbilical vein endothelial cells (HUVECs) and that Rap1 activation by its overexpression inhibited apoptosis by suppressing tumor necrosis factor-α induced-reactive oxygen species (ROS) production. However, other signaling pathways and roles of RasGRP2 not mediated via Rap1 are not well understood. Therefore, we compared the Mock (M) and the RasGRP2-stable overexpression (R) immortalized HUVECs using BAM7 and anisomycin, which are apoptosis inducers. BAM7 and anisomycin induced apoptosis without causing ROS production, and such apoptosis was significantly increased in M cells, but not in R cells. RasGRP2 suppressed BAM7- and anisomycin-induced apoptosis, but not via the Rap1 pathway as observed using Rap1 knockdown. Furthermore, RasGRP2 activated not only Rap1 but also R-Ras, and suppressed apoptosis by activating R-Ras-phosphoinositide 3-kinase (PI3K)-Akt signaling pathway. The phosphorylation of Akt by RasGRP2 inhibited Bax translocation by promoting translocation of hexokinase-2 (HK-2) from cytoplasm to mitochondria. Taken together, it was suggested that RasGRP2 suppresses the Bax activation-induced apoptosis by promoting HK-2 translocation to mitochondria via R-Ras-PI3K-Akt signaling pathway.
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Affiliation(s)
- Jun-Ichi Takino
- Laboratory of Biochemistry, Hiroshima International University, Hiroshima, Japan.
| | - Takuma Sato
- Laboratory of Biochemistry, Hiroshima International University, Hiroshima, Japan
| | - Kentaro Nagamine
- Laboratory of Biochemistry, Hiroshima International University, Hiroshima, Japan
- Department of Clinical Nutrition, Hiroshima International University, Hiroshima, Japan
| | - Takamitsu Hori
- Laboratory of Biochemistry, Hiroshima International University, Hiroshima, Japan
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20
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Lunghi B, Lecchi A, Santacroce R, Scavone M, Paniccia R, Artoni A, Gachet C, Castaman G, Margaglione M, Bernardi F, Cattaneo M. Severe bleeding and absent ADP-induced platelet aggregation associated with inherited combined CalDAG-GEFI and P2Y 12 deficiencies. Haematologica 2019; 105:e361-e364. [PMID: 31649128 DOI: 10.3324/haematol.2019.232850] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Barbara Lunghi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Anna Lecchi
- Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy
| | - Rosa Santacroce
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Mariangela Scavone
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
| | - Rita Paniccia
- Center for Bleeding Disorders and Coagulation, Department of Oncology, Careggi University Hospital, Florence, Italy
| | - Andrea Artoni
- Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy
| | - Christian Gachet
- Université de Strasbourg, INSERM, EFS Grand Est, BPPS UMR-S 1255, FMTS, Strasbourg, France
| | - Giancarlo Castaman
- Center for Bleeding Disorders and Coagulation, Department of Oncology, Careggi University Hospital, Florence, Italy
| | - Maurizio Margaglione
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Francesco Bernardi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Marco Cattaneo
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy .,Unità di Medicina, ASST Santi Paolo e Carlo, Presidio San Paolo, Milan, Italy
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21
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Vermeersch E, Nuyttens BP, Tersteeg C, Broos K, De Meyer SF, Vanhoorelbeke K, Deckmyn H. Functional Genomics for the Identification of Modulators of Platelet-Dependent Thrombus Formation. TH OPEN 2019; 2:e272-e279. [PMID: 31249951 PMCID: PMC6524883 DOI: 10.1055/s-0038-1670630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/06/2018] [Indexed: 11/17/2022] Open
Abstract
Despite the absence of the genome in platelets, transcription profiling provides important insights into platelet function and can help clarify abnormalities in platelet disorders. The Bloodomics Consortium performed whole-genome expression analysis comparing in vitro–differentiated megakaryocytes (MKs) with in vitro–differentiated erythroblasts and different blood cell types. This allowed the identification of genes with upregulated expression in MKs compared with all other cell lineages, among the receptors BAMBI, LRRC32, ESAM, and DCBLD2. In a later correlative analysis of genome-wide platelet RNA expression with interindividual human platelet reactivity, LLRFIP and COMMD7 were additionally identified. A functional genomics approach using morpholino-based silencing in zebrafish identified various roles for all of these selected genes in thrombus formation. In this review, we summarize the role of the six identified genes in zebrafish and discuss how they correlate with subsequently performed mouse experiments.
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Affiliation(s)
- Elien Vermeersch
- Laboratory for Thrombosis Research, KU Leuven Campus Kulak, Kortrijk, Belgium
| | | | - Claudia Tersteeg
- Laboratory for Thrombosis Research, KU Leuven Campus Kulak, Kortrijk, Belgium
| | - Katleen Broos
- Laboratory for Thrombosis Research, KU Leuven Campus Kulak, Kortrijk, Belgium
| | - Simon F De Meyer
- Laboratory for Thrombosis Research, KU Leuven Campus Kulak, Kortrijk, Belgium
| | - Karen Vanhoorelbeke
- Laboratory for Thrombosis Research, KU Leuven Campus Kulak, Kortrijk, Belgium
| | - Hans Deckmyn
- Laboratory for Thrombosis Research, KU Leuven Campus Kulak, Kortrijk, Belgium
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22
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Lambert MP. Inherited Platelet Disorders: A Modern Approach to Evaluation and Treatment. Hematol Oncol Clin North Am 2019; 33:471-487. [PMID: 31030814 DOI: 10.1016/j.hoc.2019.01.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The inherited platelet disorders are a heterogeneous group of disorders that can be pleotropic in their clinical presentations. They may present with variable platelet counts and bleeding, making their diagnosis difficult. New diagnostic tools range from flow cytometric platelet function assessments to next-generation sequencing. Several platelet disorders may now be treated with gene therapy or bone marrow transplant. Improved understanding of the molecular and biologic mechanisms of the inherited platelet disorders may lead to novel targeted therapies.
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Affiliation(s)
- Michele P Lambert
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Special Coagulation Laboratory, The Children's Hospital of Philadelphia, Philadelphia, PA, USA; Frontier Program in Immune Dysregulation, Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
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23
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Palma-Barqueros V, Ruiz-Pividal J, Bohdan N, Vicente V, Bastida JM, Lozano M, Rivera J. RASGRP2 gene variations associated with platelet dysfunction and bleeding. Platelets 2019; 30:535-539. [PMID: 30849270 DOI: 10.1080/09537104.2019.1585528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This manuscript reviews pathogenic variants in RASGRP2, which are the cause of a relatively new autosomal recessive and nonsyndromic inherited platelet function disorder, referred to as platelet-type bleeding disorder-18 (BDPLT18)(OMIM:615888). To date, 18 unrelated BDPLT18 pedigrees have been reported, harboring 19 different homozygous or compound heterozygous RASGRP2 variants. Patients with this disease present with lifelong moderate to severe bleeding, with epistaxis as the most common and relevant bleeding symptom. Biologically, they exhibit normal platelet count and morphology, reduced aggregation responses to ADP, epinephrine and low-dose collagen, and impaired αIIbβ3 integrin activation (fibrinogen or PAC-1 binding) in response to most agonists except PMA. Diagnosis is confirmed by genetic analysis of RASGRP2.
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Affiliation(s)
- Verónica Palma-Barqueros
- a Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación , Universidad de Murcia , Murcia , Spain
| | - Juan Ruiz-Pividal
- a Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación , Universidad de Murcia , Murcia , Spain
| | - Natalia Bohdan
- a Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación , Universidad de Murcia , Murcia , Spain
| | - Vicente Vicente
- a Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación , Universidad de Murcia , Murcia , Spain
| | - Jose Maria Bastida
- b Department of Hematology , IBSAL-Hospital Universitario de Salamanca , Salamanca , Spain
| | - María Lozano
- a Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación , Universidad de Murcia , Murcia , Spain.,c On behalf of the "Inherited Platelet Disorders Project", Hemorrhagic Diathesis Working Group SETH
| | - José Rivera
- a Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación , Universidad de Murcia , Murcia , Spain.,c On behalf of the "Inherited Platelet Disorders Project", Hemorrhagic Diathesis Working Group SETH
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24
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Yun JW, Lee KO, Jung CW, Oh SY, Kim SH, Choi CW, Kim HJ. Hereditary platelet function disorder from RASGRP2 gene mutations encoding CalDAG-GEFI identified by whole-exome sequencing in a Korean woman with severe bleeding. Haematologica 2019; 104:e274-e276. [PMID: 30846498 DOI: 10.3324/haematol.2019.218487] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Jae Won Yun
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul
| | - Ki-O Lee
- Samsung Biomedical Research Institute, Samsung Medical Center
| | - Chul Won Jung
- Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine
| | - Soo-Young Oh
- Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine
| | - Sun-Hee Kim
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul
| | - Chul Won Choi
- Division of Hematology and Oncology, Department of Internal Medicine, Korea University College of Medicine, Seoul, Korea
| | - Hee-Jin Kim
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul
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25
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26
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Cattaneo M. Inherited Disorders of Platelet Function. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00048-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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27
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Lyu SJ, Ren WR, Zhu HL, Liu T. [The clinical characteristics and molecular pathogenesis of a variant Glanzmann's thrombasthenia-like pedigree]. ZHONGHUA XUE YE XUE ZA ZHI = ZHONGHUA XUEYEXUE ZAZHI 2018; 39:807-811. [PMID: 30369200 PMCID: PMC7348282 DOI: 10.3760/cma.j.issn.0253-2727.2018.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Indexed: 02/05/2023]
Abstract
Objective: To review the clinical characteristics of a pedigree with inherited hemorrhagic disease to explore its molecular pathogenesis. Methods: The clinical data of the pedigree with inherited hemorrhagic disease were collected. After extracting DNA, next generation sequencing was utilized to detect the potential gene mutation. The changes of RASGRP2 transcript of this proband and his parents were detected using RT-PCR to compare with normal control. Results: The phenotype of the proband in this pedigree with inherited platelet dysfunction and bleeding disorder was similar to variant Glanzmann's thrombasthenia, the maximum aggregations of platelet in response to the physiological agonists including ADP, epinephrine and arachidonic acid were significantly lower, leading to severe spontaneous mucosal bleeding. Integrin αIIbβ3 gene mutation was not detected, but another gene mutation RASGRP2 IVS3-1 stood out. The mutation was homozygous in the proband and heterozygosis in both of his parents. Two transcript types were detected in the proband, without transcripts coding functional RASGRP2 protein, however, his parents had functional transcripts and abnormal transcripts, with the normal transcripts in the majority. Conclusions: The RASGRP2 IVS3-1 gene mutation was responsible for the inherited hemorrhagic disease. The RASGRP2 IVS3-1 gene mutation led to abnormal alternative splicing, without formation of functional RASGRP2 protein. The RASGRP2 protein is at the nexus of calcium-dependent platelet activation and hemostasis after damage of blood vessels. Spontaneous mucosal bleeding was a result of the lack of the functional RASGRP2 protein. This was the first report of RASGRP2 gene mutation resulting in bleeding disorder in China, and also the first report of the mutation type of RASGRP2 IVS3-1.
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Affiliation(s)
- S J Lyu
- Department of Hematology, West China Hospital, Sichuan University, Chengdu 610041, China
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28
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Functional redundancy between RAP1 isoforms in murine platelet production and function. Blood 2018; 132:1951-1962. [PMID: 30131434 DOI: 10.1182/blood-2018-03-838714] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 08/11/2018] [Indexed: 01/14/2023] Open
Abstract
RAP GTPases, important regulators of cellular adhesion, are abundant signaling molecules in the platelet/megakaryocytic lineage. However, mice lacking the predominant isoform, RAP1B, display a partial platelet integrin activation defect and have a normal platelet count, suggesting the existence of a RAP1-independent pathway to integrin activation in platelets and a negligible role for RAP GTPases in megakaryocyte biology. To determine the importance of individual RAP isoforms on platelet production and on platelet activation at sites of mechanical injury or vascular leakage, we generated mice with megakaryocyte-specific deletion (mKO) of Rap1a and/or Rap1b Interestingly, Rap1a/b-mKO mice displayed a marked macrothrombocytopenia due to impaired proplatelet formation by megakaryocytes. In platelets, RAP isoforms had redundant and isoform-specific functions. Deletion of RAP1B, but not RAP1A, significantly reduced α-granule secretion and activation of the cytoskeleton regulator RAC1. Both isoforms significantly contributed to thromboxane A2 generation and the inside-out activation of platelet integrins. Combined deficiency of RAP1A and RAP1B markedly impaired platelet aggregation, spreading, and clot retraction. Consistently, thrombus formation in physiological flow conditions was abolished in Rap1a/b-mKO, but not Rap1a-mKO or Rap1b-mKO, platelets. Rap1a/b-mKO mice were strongly protected from experimental thrombosis and exhibited a severe defect in hemostasis after mechanical injury. Surprisingly, Rap1a/b-mKO platelets were indistinguishable from controls in their ability to prevent blood-lymphatic mixing during development and hemorrhage at sites of inflammation. In summary, our studies demonstrate an essential role for RAP1 signaling in platelet integrin activation and a critical role in platelet production. Although important for hemostatic/thrombotic plug formation, platelet RAP1 signaling is dispensable for vascular integrity during development and inflammation.
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29
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Stefanini L, Bergmeier W. RAP GTPases and platelet integrin signaling. Platelets 2018; 30:41-47. [PMID: 29863951 PMCID: PMC6312509 DOI: 10.1080/09537104.2018.1476681] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/26/2018] [Accepted: 04/27/2018] [Indexed: 12/31/2022]
Abstract
Platelets are highly specialized cells that continuously patrol the vasculature to ensure its integrity (hemostasis). At sites of vascular injury, they are able to respond to trace amounts of agonists and to rapidly transition from an anti-adhesive/patrolling to an adhesive state (integrin inside-out activation) required for hemostatic plug formation. Pathological conditions that disturb the balance in the underlying signaling processes can lead to unwanted platelet activation (thrombosis) or to an increased bleeding risk. The small GTPases of the RAP subfamily, highly expressed in platelets, are critical regulators of cell adhesion, cytoskeleton remodeling, and MAP kinase signaling. Studies by our group and others demonstrate that RAP GTPases, in particular RAP1A and RAP1B, are the key molecular switches that turn on platelet activation/adhesiveness at sites of injury. In this review, we will summarize major findings on the role of RAP GTPases in platelet biology with a focus on the signaling pathways leading to the conversion of integrins to a high-affinity state.
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Affiliation(s)
- Lucia Stefanini
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - Wolfgang Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill (NC), USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill (NC), USA
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30
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Cook AA, Deng W, Ren J, Li R, Sondek J, Bergmeier W. Calcium-induced structural rearrangements release autoinhibition in the Rap-GEF CalDAG-GEFI. J Biol Chem 2018; 293:8521-8529. [PMID: 29622678 DOI: 10.1074/jbc.ra118.002712] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 03/22/2018] [Indexed: 11/06/2022] Open
Abstract
Platelets are recruited to sites of vascular injury, where they are activated and aggregate to form a hemostatic plug. This process requires the activation of the small GTPase Rap1B by its cognate guanine nucleotide exchange factor CalDAG-GEFI. Studies on platelet function suggest that CalDAG-GEFI activity is regulated by changes in cytosolic calcium, but the exact molecular mechanism is poorly understood. Here we show that purified CalDAG-GEFI is autoinhibited and directly regulated by calcium. Substitutions of putative calcium-binding residues within the canonical EF hands of CalDAG-GEFI diminish its capacity to activate Rap1B. Structural differences between active (WT) and inactive (EF hand variant) CalDAG-GEFI protein were determined by hydrogen-deuterium exchange MS. The highest differential rates of deuterium uptake in WT over EF hand variant CalDAG-GEFI were observed in regions within the catalytic Cdc25 domain and a putative autoinhibitory linker connecting the Cdc25 and EF hand domains. Exchange activity in the EF hand variant was fully restored by an additional substitution, valine 406 to glutamate, which is thought to disrupt the interface between the autoinhibitory linker and the Cdc25 domain. Overall, our results suggest a model for how CalDAG-GEFI remains in an autoinhibited state when levels of cytosolic calcium in resting platelets are low. In response to cellular stimulation, calcium mobilization and binding to the EF hands causes conformational rearrangements within CalDAG-GEFI, including the autoinhibitory linker that frees the catalytic surface of CalDAG-GEFI to engage and activate Rap1B. The data from this study are the first evidence linking CalDAG-GEFI activity directly to calcium.
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Affiliation(s)
- Aaron A Cook
- From the Departments of Biochemistry and Biophysics and
| | - Wei Deng
- the Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | | | - Renhao Li
- the Aflac Cancer and Blood Disorders Center, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - John Sondek
- From the Departments of Biochemistry and Biophysics and.,Pharmacology and.,the Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
| | - Wolfgang Bergmeier
- From the Departments of Biochemistry and Biophysics and .,the McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina 27516
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31
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Bergmeier W, Stefanini L. Platelets at the Vascular Interface. Res Pract Thromb Haemost 2018; 2:27-33. [PMID: 29457148 PMCID: PMC5810953 DOI: 10.1002/rth2.12061] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 10/19/2017] [Indexed: 02/01/2023] Open
Abstract
In this brief review paper, we will summarize the State-of-the-Art on how platelet reactivity is regulated in circulation and at sites of vascular injury. Our review discusses recent and ongoing work, presented at this year's International Society on Thrombosis and Haemostasis (ISTH) meeting, on the role of platelets in (1) classical hemostasis at sites of mechanical injury, and (2) the maintenance of vascular integrity at sites of inflammation.
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Affiliation(s)
- Wolfgang Bergmeier
- Department of Biochemistry and BiophysicsUniversity of North Carolina at Chapel HillChapel HillNCUSA
- McAllister Heart InstituteUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Lucia Stefanini
- Department of Internal Medicine and Medical SpecialtiesSapienza University of RomeRomeItaly
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32
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Bastida JM, Lozano ML, Benito R, Janusz K, Palma-Barqueros V, Del Rey M, Hernández-Sánchez JM, Riesco S, Bermejo N, González-García H, Rodriguez-Alén A, Aguilar C, Sevivas T, López-Fernández MF, Marneth AE, van der Reijden BA, Morgan NV, Watson SP, Vicente V, Hernández-Rivas JM, Rivera J, González-Porras JR. Introducing high-throughput sequencing into mainstream genetic diagnosis practice in inherited platelet disorders. Haematologica 2017; 103:148-162. [PMID: 28983057 PMCID: PMC5777202 DOI: 10.3324/haematol.2017.171132] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 09/29/2017] [Indexed: 12/30/2022] Open
Abstract
Inherited platelet disorders are a heterogeneous group of rare diseases, caused by inherited defects in platelet production and/or function. Their genetic diagnosis would benefit clinical care, prognosis and preventative treatments. Until recently, this diagnosis has usually been performed via Sanger sequencing of a limited number of candidate genes. High-throughput sequencing is revolutionizing the genetic diagnosis of diseases, including bleeding disorders. We have designed a novel high-throughput sequencing platform to investigate the unknown molecular pathology in a cohort of 82 patients with inherited platelet disorders. Thirty-four (41.5%) patients presented with a phenotype strongly indicative of a particular type of platelet disorder. The other patients had clinical bleeding indicative of platelet dysfunction, but with no identifiable features. The high-throughput sequencing test enabled a molecular diagnosis in 70% of these patients. This sensitivity increased to 90% among patients suspected of having a defined platelet disorder. We found 57 different candidate variants in 28 genes, of which 70% had not previously been described. Following consensus guidelines, we qualified 68.4% and 26.3% of the candidate variants as being pathogenic and likely pathogenic, respectively. In addition to establishing definitive diagnoses of well-known inherited platelet disorders, high-throughput sequencing also identified rarer disorders such as sitosterolemia, filamin and actinin deficiencies, and G protein-coupled receptor defects. This included disease-causing variants in DIAPH1 (n=2) and RASGRP2 (n=3). Our study reinforces the feasibility of introducing high-throughput sequencing technology into the mainstream laboratory for the genetic diagnostic practice in inherited platelet disorders.
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Affiliation(s)
- José M Bastida
- Servicio de Hematología, Hospital Universitario de Salamanca-IBSAL-USAL, Spain .,On behalf of the Project "Functional and Molecular Characterization of Patients with Inherited Platelet Disorders" of the Hemorrhagic Diathesis Working Group of the Spanish Society of Thrombosis and Haemostasis
| | - María L Lozano
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Spain.,On behalf of the Project "Functional and Molecular Characterization of Patients with Inherited Platelet Disorders" of the Hemorrhagic Diathesis Working Group of the Spanish Society of Thrombosis and Haemostasis
| | - Rocío Benito
- IBSAL, IBMCC, CIC, Universidad de Salamanca-CSIC, Spain
| | - Kamila Janusz
- IBSAL, IBMCC, CIC, Universidad de Salamanca-CSIC, Spain
| | - Verónica Palma-Barqueros
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Spain
| | | | | | - Susana Riesco
- Servicio de Pediatría, Hospital Universitario de Salamanca-IBSAL, Spain
| | - Nuria Bermejo
- Servicio de Hematología, Complejo Hospitalario San Pedro Alcántara, Cáceres, Spain
| | | | - Agustín Rodriguez-Alén
- Servicio de Hematología y Hemoterapia, Hospital Virgen de la Salud, Complejo Hospitalario de Toledo, Spain
| | - Carlos Aguilar
- Servicio de Hematología, Complejo Asistencial de Soria, Spain
| | - Teresa Sevivas
- Serviço de Imunohemoterapia, Sangue e Medicina Transfusional do Centro Hospitalar e Universitário de Coimbra, EPE, Portugal
| | | | - Anna E Marneth
- Department of Laboratory Medicine, Laboratory of Hematology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Bert A van der Reijden
- Department of Laboratory Medicine, Laboratory of Hematology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Neil V Morgan
- Birmingham Platelet Group, Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, UK
| | - Steve P Watson
- Birmingham Platelet Group, Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, UK
| | - Vicente Vicente
- On behalf of the Project "Functional and Molecular Characterization of Patients with Inherited Platelet Disorders" of the Hemorrhagic Diathesis Working Group of the Spanish Society of Thrombosis and Haemostasis
| | - Jesús M Hernández-Rivas
- Servicio de Hematología, Hospital Universitario de Salamanca-IBSAL-USAL, Spain.,IBSAL, IBMCC, CIC, Universidad de Salamanca-CSIC, Spain
| | - José Rivera
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, Universidad de Murcia, IMIB-Arrixaca, CB15/00055-CIBERER, Spain.,On behalf of the Project "Functional and Molecular Characterization of Patients with Inherited Platelet Disorders" of the Hemorrhagic Diathesis Working Group of the Spanish Society of Thrombosis and Haemostasis
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33
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Canault M, Saultier P, Fauré S, Poggi M, Nurden AT, Nurden P, Morange PE, Alessi MC, Gris JC. Peripartum bleeding management in a patient with CalDAG-GEFI deficiency. Haemophilia 2017; 23:e533-e535. [PMID: 28976076 DOI: 10.1111/hae.13352] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2017] [Indexed: 11/26/2022]
Affiliation(s)
- M Canault
- Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
| | - P Saultier
- Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
| | - S Fauré
- Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
| | - M Poggi
- Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France
| | - A T Nurden
- Institut-Hospitalo-Universitaire LIRYC, Plateforme Technologique et d'Innovation Biomédicale, Pessac, France
| | - P Nurden
- Institut-Hospitalo-Universitaire LIRYC, Plateforme Technologique et d'Innovation Biomédicale, Pessac, France
| | - P E Morange
- Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France.,APHM, CHU Timone, French Reference Centre for Rare Platelet Disorders, Marseille, France
| | - M-C Alessi
- Aix Marseille Univ, INSERM, INRA, NORT, Marseille, France.,APHM, CHU Timone, French Reference Centre for Rare Platelet Disorders, Marseille, France
| | - J-C Gris
- Laboratoire d'hématologie, Groupe Hospitalo-Universitaire Caremeau, Nîmes, France
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