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Kumar R, Bakeer N, Dawson J, Al-Mughairy A, Stanek J, Dunn A, Male C, Chan A, Williams S. Impact of SERPINC1 mutation on thrombotic phenotype in children with congenital antithrombin deficiency-first analysis of the International Society on Thrombosis and Haemostasis pediatric antithrombin deficiency database and biorepository. J Thromb Haemost 2023; 21:1248-1257. [PMID: 36764659 DOI: 10.1016/j.jtha.2023.01.037] [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] [Received: 07/25/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/11/2023]
Abstract
BACKGROUND The natural history and genotype-phenotype correlation of congenital antithrombin (AT) deficiency in children are unknown. OBJECTIVES To describe the clinical presentation of congenital AT deficiency in children and evaluate its correlation to specific mutations in SERPINC1. METHODS In 2017, a prospective pediatric database and DNA biorepository for congenital AT deficiency was established. During the pilot phase, the database was opened at 4 tertiary care centers in Canada and US. Approval from research ethics board was obtained at each participating center. Written consent/assent was obtained from guardians/subjects who met eligibility. Demographic/clinical data were uploaded into a database. DNA extraction and SERPINC1 sequencing were centralized for US centers. Standard statistical methods were used to summarize parameters. Probability of VTE-free survival was assessed using the Kaplan-Meier method. RESULTS Overall, 43 participants (25 females) from 31 unique kindreds were enrolled. Median age (range) at enrollment was 14.8 years (1-21 years). Median AT activity was 52% (24%-87%), and median AT antigen (n = 20) was 55% (38%-110%). Nineteen (44%) participants had a history of venous thromboembolism (VTE). Median age at VTE diagnosis was 12.8 years (0.1-19.2 years). SERPINC1 sequencing was completed for 31 participants and 21 unique mutations were identified, including 5 novel variants. Probability of 5-year VTE-free survival (95% CI) for carriers of missense mutations (92.0% [95% CI: 71.6%-97.9%]) was significantly higher compared with carriers of null mutations (66.7% [95% CI: 19.5%-90.4%]); p = .0012. CONCLUSION To our knowledge, this is the first pediatric study to document a severe thrombotic phenotype in carriers of null mutations in SERPINC1, when compared with carriers of missense mutations; underscoring the importance of genetic testing.
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Affiliation(s)
- Riten Kumar
- Dana Farber/Boston Children's Cancer and Blood Disorders Center, Boston, Massachusetts, USA; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA.
| | - Nihal Bakeer
- Indiana Hemophilia and Thrombosis Center, Indianapolis, Indianapolis, USA
| | - Jennifer Dawson
- Genomic Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Alyaa Al-Mughairy
- Division of Pediatric Hematology/Oncology, The Royal Hospital, Muscat, Oman
| | - Joseph Stanek
- Division of Pediatric Hematology, Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Amy Dunn
- Division of Pediatric Hematology, Nationwide Children's Hospital, Columbus, Ohio, USA; Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - Christoph Male
- Department of Pediatrics, Medical University of Vienne, Vienna, Austria
| | - Anthony Chan
- Division of Pediatric Hematology, McMaster Children's Hospital, Hamilton, Ontario, Canada; Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Suzan Williams
- Division of Pediatric Hematology, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
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Bravo‐Pérez C, Morena‐Barrio ME, Morena‐Barrio B, Miñano A, Padilla J, Cifuentes R, Garrido P, Vicente V, Corral J. Molecular and clinical characterization of transient antithrombin deficiency: A new concept in congenital thrombophilia. Am J Hematol 2022; 97:216-225. [PMID: 34800304 DOI: 10.1002/ajh.26413] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/13/2021] [Accepted: 11/16/2021] [Indexed: 11/07/2022]
Abstract
Antithrombin deficiency, the most severe thrombophilia, might be underestimated, since it is only investigated in cases with consistent functional deficiency or family history. We have analyzed 444 consecutive, unrelated cases, from 1998 to 2021, with functional results supporting antithrombin deficiency in at least one sample. Plasma antithrombin was evaluated by functional and biochemical methods in at least two samples. SERPINC1 gene was analyzed by sequencing and MPLA. Hypoglycosylation was studied by electrophoresis and high-performance liquid chromatography (HPLC). In 260 of 305 cases (85.2%) with constitutive deficiency (activity < 80% in all samples), a SERPINC1 (N = 250), or N-glycosylation defect (N = 10) was observed, while 45 remained undetermined. The other 139 cases had normal antithrombin activity (≥ 80%) in at least one sample, what we called transient deficiency. Sixty-one of these cases (43.9%) had molecular defects: 48 had SERPINC1 variants, with two recurrent mutations (p.Ala416Ser[Cambridge II], N = 15; p.Val30Glu[Dublin], N = 12), and 13 hypoglycosylation. Thrombotic complications occurred in transient deficiency, but were less frequent, latter-onset, and had a higher proportion of arterial events than in constitutive deficiency. Two mechanisms explained transient deficiency: The limitation of functional methods to detect some variants and the influence of external factors on the pathogenic consequences of these mutations. Our study reveals a molecular defect in a significant proportion of cases with transient antithrombin deficiency, and changes the paradigm of thrombophilia, as the pathogenic effect of some mutations might depend on external factors and be present only at certain timepoints. Antithrombin deficiency is underestimated, and molecular screening might be appropriate in cases with fluctuating laboratory findings.
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Affiliation(s)
- Carlos Bravo‐Pérez
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
| | - María Eugenia Morena‐Barrio
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
| | - Belén Morena‐Barrio
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
| | - Antonia Miñano
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
| | - José Padilla
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
| | - Rosa Cifuentes
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
| | - Pedro Garrido
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
| | - Vicente Vicente
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
| | - Javier Corral
- Servicio de Hematología y Oncología Médica, Hospital Universitario Morales Meseguer, Centro Regional de Hemodonación, IMIB, CIBERER Universidad de Murcia Murcia Spain
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Gaddh M, Rosovsky RP. Venous Thromboembolism: Genetics and Thrombophilias. Semin Respir Crit Care Med 2021; 42:271-283. [PMID: 33694139 DOI: 10.1055/s-0041-1723937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Venous thromboembolism (VTE) is a major cause of morbidity and mortality throughout the world. Up to one half of patients who present with VTE will have an underlying thrombophilic defect. This knowledge has led to a widespread practice of testing for such defects in patients who develop VTE. However, identifying a hereditary thrombophilia by itself does not necessarily change outcomes or dictate therapy. Furthermore, family history of VTE by itself can increase an asymptomatic person's VTE risk several-fold, independent of detecting a known inherited thrombophilia. In this article, we will describe the current validated hereditary thrombophilias including their history, prevalence, and association with VTE. With a focus on evaluating both risks and benefits of testing, we will also explore the controversies of why, who, and when to test as well as discuss contemporary societal guidelines. Lastly, we will share how these tests have been integrated into clinical practice and how to best utilize them in the future.
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Affiliation(s)
- Manila Gaddh
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, Georgia
| | - Rachel P Rosovsky
- Division of Hematology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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Antithrombin deficiency in pregnancy-the unresolved issues. LANCET HAEMATOLOGY 2020; 7:e276-e278. [PMID: 32112715 DOI: 10.1016/s2352-3026(20)30038-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 01/31/2020] [Indexed: 11/27/2022]
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Kovac M, Mitic G, Djilas I, Kuzmanovic M, Serbic O, Lekovic D, Tomic B, Bereczky Z. Genotype phenotype correlation in a pediatric population with antithrombin deficiency. Eur J Pediatr 2019; 178:1471-1478. [PMID: 31359133 DOI: 10.1007/s00431-019-03433-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 07/12/2019] [Accepted: 07/16/2019] [Indexed: 11/25/2022]
Abstract
Inherited antithrombin (AT) deficiency is a rare autosomal dominant disorder, caused by mutations in the AT gene (SERPINC1). Considering that the genotype phenotype relationship in AT deficiency patients remains unclear, especially in pediatric patients, the aim of our study was to evaluate genotype phenotype correlation in a Serbian pediatric population. A retrospective cohort study included 19 children younger than 18 years, from 15 Serbian families, with newly diagnosed AT deficiency. In 21% of the recruited families, mutations affecting exon 4, 5, and 6 of the SERPINC1 gene that causes type I AT deficiency were detected. In the remaining families, the mutation in exon 2 causing type II HBS (AT Budapest 3) was found. Thrombosis events were observed in 1 (33%) of those with type I, 11 (85%) of those with AT Budapest 3 in the homozygous respectively, and 1(33%) in the heterozygous form. Recurrent thrombosis was observed only in AT Budapest 3 in the homozygous form, in 27% during initial treatment of the first thrombotic event. Abdominal venous thrombosis and arterial ischemic stroke, observed in almost half of the children from the group with AT Budapest 3 in the homozygous form, were unprovoked in all cases.Conclusion: Type II HBS (AT Budapest 3) in the homozygous form is a strong risk factor for arterial and venous thrombosis in pediatric patients. What is Known: • Inherited AT deficiency is a rare autosomal dominant disorder, caused by mutations in the SERPINC1gene. • The genotype phenotype correlation in AT deficiency patients remains unclear, especially in pediatric patients. What is New: • The genetic results for our paediatric population predominantly showed the presence of a single specific mutation in exon 2, that causes type II HBS deficiency (AT Budapest 3). • In this group thrombosis mostly occurred as unprovoked, in almost half of them as abdominal thrombosis or stroke with high incidence of recurrent thrombosis, in 27% during initial treatment.
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Affiliation(s)
- Mirjana Kovac
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia. .,Blood Transfusion Institute of Serbia, Hemostasis Department, Sv. Save 39, Belgrade, 11000, Serbia.
| | - Gorana Mitic
- Institute of Laboratory Medicine, Clinical Center of Vojvodina, Faculty of Medicine Novi Sad, University of Novi Sad, Novi Sad, Serbia
| | - Iva Djilas
- Blood Transfusion Institute of Serbia, Hemostasis Department, Sv. Save 39, Belgrade, 11000, Serbia
| | - Milos Kuzmanovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia.,Institute for Health Care of Mother and Child of Serbia Dr Vukan Cupic, Belgrade, Serbia
| | - Olivera Serbic
- Institute for Health Care of Mother and Child of Serbia Dr Vukan Cupic, Belgrade, Serbia
| | - Danijela Lekovic
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia.,Clinic of Hematology, Clinical Center of Serbia, Belgrade, Serbia
| | - Branko Tomic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Zsuzsanna Bereczky
- Division of Clinical Laboratory Research, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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6
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Kovac M, Mitic G, Mikovic Z, Mandic V, Miljic P, Mitrovic M, Tomic B, Bereczky Z. The influence of specific mutations in the AT gene (SERPINC1) on the type of pregnancy related complications. Thromb Res 2018; 173:12-19. [PMID: 30458337 DOI: 10.1016/j.thromres.2018.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/17/2018] [Accepted: 11/07/2018] [Indexed: 10/27/2022]
Abstract
BACKGROUND Inherited antithrombin (AT) deficiency is a rare autosomal dominant disorder, caused by mutations in the SERPINC1 gene. The most common clinical presentation in AT deficient patients includes venous thrombosis and pulmonary embolism, while the association of AT deficiency and its effect on the development of pregnancy complications has been less studied. The aim of our research was to evaluate the effect of AT deficiency types, determined by genotyping, on pregnancy outcomes. METHODS A retrospective cohort study included 28 women with AT deficiency, and their 64 pregnancies were analyzed. RESULTS With regard to live birth rate, a significant difference was observed among women who were carriers of different SERPINC1 mutations, as the rate varied from 100% in cases of type I to the extremely low rate of 8% for women with type II HBS (AT Budapest 3) in the homozygous variant, P = 0.0005. All pregnancies from the type I group, even untreated ones, resulted in live births. In women with AT Budapest 3 in homozygous variant the overall live birth rate increased to 28.5% in the treated pregnancies. In this group the highest incidence of fetal death was observed of 62%; repeated fetal losses in 30%; fetal growth restriction in 22% and placental abruption in 7% of all pregnancies. CONCLUSION Our study results indicate a difference between type I and type II AT deficiency. The risk of pregnancy related VTE was equally present in both groups, except for AT Budapest 3 in the heterozygous variant, while adverse pregnancy outcomes were strictly related to type II, especially AT Budapest 3 in the homozygous variant.
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Affiliation(s)
- Mirjana Kovac
- Faculty of Medicine, University of Belgrade, Serbia; Blood Transfusion Institute of Serbia, Hemostasis Department, Belgrade, Serbia.
| | - Gorana Mitic
- Institute of Laboratory Medicine, Clinical Center of Vojvodina, Faculty of Medicine Novi Sad, University of Novi Sad, Serbia
| | - Zeljko Mikovic
- Faculty of Medicine, University of Belgrade, Serbia; Gynecology and Obstetrics Clinic Narodni Front, Belgrade, Serbia
| | - Vesna Mandic
- Faculty of Medicine, University of Belgrade, Serbia; Gynecology and Obstetrics Clinic Narodni Front, Belgrade, Serbia
| | - Predrag Miljic
- Faculty of Medicine, University of Belgrade, Serbia; Clinic of Hematology, Clinical Center of Serbia, Serbia
| | - Mirjana Mitrovic
- Faculty of Medicine, University of Belgrade, Serbia; Clinic of Hematology, Clinical Center of Serbia, Serbia
| | - Branko Tomic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Zsuzsanna Bereczky
- Division of Clinical Laboratory Research, Department of Laboratory Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Revilla N, de la Morena-Barrio ME, Miñano A, López-Gálvez R, Toderici M, Padilla J, García-Avello Á, Lozano ML, Lefeber DJ, Corral J, Vicente V. Transient desialylation in combination with a novel antithrombin deficiency causing a severe and recurrent thrombosis despite anticoagulation therapy. Sci Rep 2017; 7:44556. [PMID: 28303970 PMCID: PMC5355981 DOI: 10.1038/srep44556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 02/09/2017] [Indexed: 11/09/2022] Open
Abstract
An in-depth focused study of specific cases of patients with recurrent thrombosis may help to identify novel circumstances, genetic and acquired factors contributing to the development of this disorder. The aim of this study was to carry out a detailed and sequential analysis of samples from a patient suffering from early and recurrent venous and arterial thrombosis. We performed thrombophilic tests, biochemical, functional, genetic and glycomic analysis of antithrombin and other plasma proteins. The patient carried a new type I antithrombin mutation (p.Ile218del), whose structural relevance was verified in a recombinant model. Experiments with N-glycosidase F and neuraminidase suggested a nearly full desialylation of plasma proteins, which was confirmed by mass spectrometry analysis of transferrin glycoforms. However, partial desialylation and normal patterns were detected in samples collected at other time-points. Desialylation was noticeable after arterial events and was associated with low antithrombin activity, reduced platelet count and glomerular filtration rate. This is the first description of a global and transient desialylation of plasma proteins associated with thrombosis. The decrease in the strong electronegative charge of terminal glycans may modulate hemostatic protein-protein interactions, which in combination with a strong prothrombotic situation, such as antithrombin deficiency, could increase the risk of thrombosis.
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Affiliation(s)
- Nuria Revilla
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain
| | - María Eugenia de la Morena-Barrio
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII) Madrid, Spain
| | - Antonia Miñano
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain
| | - Raquel López-Gálvez
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain
| | - Mara Toderici
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain
| | - José Padilla
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain
| | - Ángel García-Avello
- Servicio de Hematología. Hospital Universitario Ramón y Cajal. Madrid, Spain
| | - María Luisa Lozano
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII) Madrid, Spain
| | - Dirk J Lefeber
- Department of Neurology, Laboratory for Genetic, Endocrine and Metabolic Diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Javier Corral
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII) Madrid, Spain
| | - Vicente Vicente
- Centro Regional de Hemodonación. Servicio de Hematología y Oncología Médica. Hospital Universitario Morales Meseguer. IMIB-Arrixaca. Universidad de Murcia, Murcia, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII) Madrid, Spain
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8
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de la Morena-Barrio M, Sandoval E, Llamas P, Wypasek E, Toderici M, Navarro-Fernández J, Rodríguez-Alen A, Revilla N, López-Gálvez R, Miñano A, Padilla J, de la Morena-Barrio B, Cuesta J, Corral J, Vicente V. High levels of latent antithrombin in plasma from patients with antithrombin deficiency. Thromb Haemost 2017; 117:880-888. [PMID: 28229161 DOI: 10.1160/th16-11-0866] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/02/2017] [Indexed: 11/05/2022]
Abstract
Antithrombin is an anticoagulant serpin that efficiently inhibits multiple procoagulant proteases. The cost for the structural flexibility required for this function is the vulnerability to mutations that impact its folding pathway. Most conformational mutations identified in serpins cause polymerisation. Only three mutations in SERPINC1 affecting two residues have been found to favour transformation to the latent conformation of antithrombin, another hyperstable non-anticoagulant form with strong antiangiogenic activity that constitutes 3 % of plasma antithrombin in healthy subjects. The analysis of latent antithrombin in 141 unrelated patients with antithrombin deficiency carrying 89 different SERPINC1 mutations identified four cases with higher levels than that of controls: p.Pro439Thr, p.Pro461Ser, p.Met283Val, and p.His401Tyr, the last also with circulating polymers. Heating of plasma at 42ºC exacerbated the transformation to the latent conformation in p.Pro439Thr and p.Pro461Ser. The conformational effect of p.Met283Val, the mutation associated with the highest levels of latent antithrombin detected in four members of a family, was verified in a recombinant model. Antithrombin deficiency in these cases should be classified as pleiotropic based on the impaired reactivity and low heparin affinity of the variant. Despite high levels of latent antithrombin (up to 80 µg/ml in p.Met283Val carriers), no vascular defects were described in carriers of these mutations. In conclusion, our study identifies new residues involved in the structural stability of antithrombin (and potentially of all serpins). High levels of endogenous latent antithrombin seem to play a minor antiangiogenic effect. Finally, pleiotropic deficiencies may be caused by mutations inducing transformation to the latent conformation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Javier Corral
- Dr. Javier Corral, University of Murcia, Centro Regional de Hemodonación, Calle Ronda de Garay s/n. Murcia 30003, Spain, Tel.: +34 968341990, Fax: +34 968261914, E-mail:
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Causative genetic mutations for antithrombin deficiency and their clinical background among Japanese patients. Int J Hematol 2016; 105:287-294. [PMID: 27858332 DOI: 10.1007/s12185-016-2142-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 11/07/2016] [Accepted: 11/07/2016] [Indexed: 10/20/2022]
Abstract
We summarize causative genetic mutations for antithrombin (AT) deficiency and their clinical background in Japanese patients. A total of 19 mutations, including seven novel mutations, were identified. We also summarize clinical symptoms of thrombosis, age at onset, family history, and contributing factors for thrombosis, and review the use of prophylactic anticoagulation in pregnant women with heterozygous type II heparin binding site defects (HBS) AT deficiency. The prevalence of thrombosis in probands with type I AT deficiency (88%) was double that observed in those with type II AT deficiency (50%). The prevalence of thrombotic episodes among family members was also higher for type I AT deficiency subjects (82%) than for those with type II AT deficiency (0%). The most common contributing factor for thrombosis among women with type I AT deficiency was pregnancy. Forty-five percent of women with type I AT deficiency developed thrombotic events before the 20th week of gestation. In contrast, women with type II (HBS) AT deficiency appear to be at a lower risk of thrombosis during pregnancy. In conclusion, thrombotic risk varies among different subtypes. Risk assessments based on genetic/clinical backgrounds may contribute to appropriate diagnosis, treatment, and prophylaxis for patients with AT deficiency.
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Zhao LX, Liu B, Li CS. Progress in research into the genes associated with venous thromboembolism. World J Emerg Med 2015; 6:100-4. [PMID: 26056539 DOI: 10.5847/wjem.j.1920-8642.2015.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 04/06/2015] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Venous thromboembolism (VTE), including both deep vein thrombosis (DVT) and pulmonary embolism (PE), is a common, lethal disorder that affects hospitalized and non-hospitalized patients. This study aimed to review the progress in the research into VTE. DATA SOURCES We reviewed the studies about VTE and verified different genetic polymoriphisms of VTE. RESULTS The pathogenesis of VTE involves hereditary and acquired factors. Many studies indicated that the disorder of coagulation and fibirnolytic system is of utmost importance to this disease. Genetic polymoriphism-related VTE demonstrated significant differences among geographies and ethnicities. CONCLUSION VTE has many risk factors, but genetic factors play an important role.
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Affiliation(s)
- Lian-Xing Zhao
- Department of Emergency Medicine, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
| | - Bo Liu
- Department of Emergency Medicine, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
| | - Chun-Sheng Li
- Department of Emergency Medicine, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
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11
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Aguila S, Navarro-Fernández J, Bohdan N, Gutiérrez-Gallego R, de la Morena-Barrio ME, Vicente V, Corral J, Martínez-Martínez I. Role of the C-sheet in the maturation of N-glycans on antithrombin: functional relevance of pleiotropic mutations. J Thromb Haemost 2014; 12:1131-40. [PMID: 24824609 DOI: 10.1111/jth.12606] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 04/15/2014] [Indexed: 12/01/2022]
Abstract
BACKGROUND The characterization of natural mutants identified in patients with antithrombin deficiency has helped to identify functional domains or regions of this key anticoagulant and the mechanisms involved in the deficiency, as well as to define the clinical prognosis. Recently, we described an abnormal glycosylation in a pleiotropic mutant (K241E) that explained the impaired heparin affinity and the mild risk of thrombosis in carriers. OBJECTIVES To evaluate the effects of different natural pleiotropic mutations on the glycosylation of antithrombin and their functional effects. METHODS Five pleiotropic mutations identified in patients with antithrombin deficiency and located at each one of the strands of the C-sheet were selected (K241E, M251I, M315K, F402L, and P429L). Recombinant mutants were generated and purified. Glycoform heterogeneity and conformational sensitivity were studied with electrophoresis, proteomic analysis, and glycomic analysis. Heparin affinity was evaluated from intrinsic fluorescence. Reactivity assays with factor Xa, thrombin and neutrophil elastase in the presence or absence of heparin were also performed. RESULTS AND CONCLUSIONS Pleiotropic mutants, except for that with the M315K mutation, which affects a non-exposed residue, showed two glycoforms. Variant 1, with abnormal glycosylation, had reduced heparin affinity and severely affected reactivity with the target proteases. In contrast, variant 2, with similar electrophoretic mobility and heparin affinity to wild-type antithrombin, had impaired inhibitory activity that was partially compensated for by activation with heparin. Our results suggest the C-sheet of antithrombin as a new region that is relevant for proper maturation of the N-glycans. Therefore, pleiotropic mutations lead to glycosylation defects that are responsible for the reduced heparin affinity.
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Affiliation(s)
- S Aguila
- Centro Regional de Hemodonación, Servicio de Hematología y Oncología Médica HU Morales Meseguer, University of Murcia, IMIB, Murcia, Spain
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Kumar R, Chan AKC, Dawson JE, Forman-Kay JD, Kahr WHA, Williams S. Clinical presentation and molecular basis of congenital antithrombin deficiency in children: a cohort study. Br J Haematol 2014; 166:130-9. [DOI: 10.1111/bjh.12842] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 01/10/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Riten Kumar
- Department of Pediatrics; Division of Hematology/Oncology; Nationwide Children's Hospital; The Ohio State University; OH USA
| | - Anthony K. C. Chan
- Department of Paediatrics; Division of Haematology/Oncology; McMaster Children's Hospital; McMaster University; Toronto ON USA
| | - Jennifer E. Dawson
- Program in Molecular Structure and Function; Research Institute; The Hospital for Sick Children; Toronto ON USA
- Department of Biochemistry; University of Toronto; Toronto ON USA
| | - Julie D. Forman-Kay
- Program in Molecular Structure and Function; Research Institute; The Hospital for Sick Children; Toronto ON USA
- Department of Biochemistry; University of Toronto; Toronto ON USA
| | - Walter H. A. Kahr
- Department of Biochemistry; University of Toronto; Toronto ON USA
- Program in Cell Biology; Research Institute; The Hospital for Sick Children; Toronto ON USA
- Department of Paediatrics; Division of Haematology, Oncology; The Hospital for Sick Children; University of Toronto; Toronto ON USA
| | - Suzan Williams
- Department of Paediatrics; Division of Haematology, Oncology; The Hospital for Sick Children; University of Toronto; Toronto ON USA
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13
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Déficit homozygote en antithrombine de type II HBS (99Leu-Phe) : une cause rare de thromboses artérielles récidivantes. Rev Med Interne 2011; 32:e29-31. [DOI: 10.1016/j.revmed.2009.08.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 08/14/2009] [Accepted: 08/22/2009] [Indexed: 11/20/2022]
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14
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Abstract
Serpins (serine protease inhibitors) have traditionally been grouped together based on structural homology. They share common structural features of primary sequence, but not all serpins require binding to cofactors in order to achieve maximal protease inhibition. In order to obtain physiologically relevant rates of inhibition of target proteases, some serpins utilize the unbranched sulfated polysaccharide chains known as glycosaminoglycans (GAGs) to enhance inhibition. These GAG-binding serpins include antithrombin (AT), heparin cofactor II (HCII), and protein C inhibitor (PCI). The GAGs heparin and heparan sulfate have been shown to bind AT, HCII, and PCI, while HCII is also able to utilize dermatan sulfate as a cofactor. Other serpins such as PAI-1, kallistatin, and α(1)-antitrypsin also interact with GAGs with different endpoints, some accelerating protease inhibition while others inhibit it. There are many serpins that bind or carry ligands that are unrelated to GAGs, which are described elsewhere in this work. For most GAG-binding serpins, binding of the GAG occurs in a conserved region of the serpin near or involving helix D, with the exception of PCI, which utilizes helix H. The binding of GAG to serpin can lead to a conformational change within the serpin, which can lead to increased or tighter binding to the protease, and can accelerate the rates of inhibition up to 10,000-fold compared to the unbound native serpin. In this chapter, we will discuss three major GAG-binding serpins with known physiological roles in modulating coagulation: AT (SERPINC1), HCII (SERPIND1), and PCI (SERPINA5). We will review methodologies implemented to study the structure of these serpins and those used to study their interactions with GAG's. We discuss novel techniques to examine the serpin-GAG interaction and finally we review the biological roles of these serpins by describing the mouse models used to study them.
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Affiliation(s)
- Chantelle M Rein
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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15
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Wang LP, Huang SW, Wang SS, Wang C, Mou TY, Zhong M. Mutation Screening of the AT-III Gene in Pregnant and Post-Partum Women With Venous Thromboembolism by DHPLC. Lab Med 2010. [DOI: 10.1309/lmwlz182fjrfyyft] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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16
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Wheeler DS, Wong HR, Shanley TP. Genetic Polymorphisms in Critical Care and Illness. SCIENCE AND PRACTICE OF PEDIATRIC CRITICAL CARE MEDICINE 2009. [PMCID: PMC7123127 DOI: 10.1007/978-1-84800-921-9_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Derek S. Wheeler
- Medical Center, Div. of Critical Care Medicine, Cincinnati Children's Hospital, Burnet Avenue 3333, Cincinnati, 45229 U.S.A
| | - Hector R. Wong
- Medical Center, Div. of Critical Care Medicine, Cincinnati Children's Hospital, Burnet Avenue 3333, Cincinnati, 45229 U.S.A
| | - Thomas P. Shanley
- C.S. Mott Children's Hospital , Pediatric Critical Care Medicine , University of Michigan, E. Medical Center Drive 1500, Ann Arbor, 48109-0243 U.S.A
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17
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Middeldorp S, van Hylckama Vlieg A. Does thrombophilia testing help in the clinical management of patients? Br J Haematol 2008; 143:321-35. [PMID: 18710381 DOI: 10.1111/j.1365-2141.2008.07339.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Saskia Middeldorp
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
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18
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Alhenc-Gelas M, Aiach M. Anomalies constitutionnelles de la coagulation prédisposant à la thrombose. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/s1155-1984(07)46642-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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Tran M, Spencer FA. Thromboepidemiology: identifying patients with heritable risk for thrombin-mediated thromboembolic events. Am Heart J 2005; 149:S9-18. [PMID: 15644796 DOI: 10.1016/j.ahj.2004.10.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Maichi Tran
- Department of Medicine, Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Mass 01655, USA
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20
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Carraro P. Guidelines for the laboratory investigation of inherited thrombophilias. Recommendations for the first level clinical laboratories. Clin Chem Lab Med 2003; 41:382-91. [PMID: 12705349 DOI: 10.1515/cclm.2003.059] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recent advances in the laboratory diagnostic approach to inherited thrombophilia call for an update on laboratory strategies and organization. The present paper therefore deals in particular with: the panel test choice, timing and test appropriateness, and analytical methods in several clinical conditions. Specific recommendations are supported by the state-of-the-art in this branch.
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Affiliation(s)
- Paolo Carraro
- Department of Laboratory Medicine, Padova University-Hospital, Padova, Italy.
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21
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Abstract
OBJECTIVE To review the current understanding of the pathophysiology of antithrombin deficiency and its role in congenital thrombophilia. Recommendations for diagnostic testing of antithrombin function and concentration, derived from the medical literature and consensus opinions of recognized experts in the field, are included. These recommendations specify whom, how, and when to test. DATA SOURCES Review of the published medical literature. DATA EXTRACTION AND SYNTHESIS A summary of the medical literature and proposed testing recommendations were prepared and presented at the College of American Pathologists Conference XXXVI: Diagnostic Issues in Thrombophilia. After discussion at the conference, consensus recommendations presented in this article were accepted after a two-thirds majority vote by the participants. CONCLUSIONS Antithrombin deficiency is an infrequent genetic abnormality that may be a significant contributing cause of thrombophilia. Antithrombin deficiency also may be observed in conjunction with other genetic or acquired risk factors. Assay of antithrombin plasma levels is appropriate in the laboratory evaluation of individuals with thrombophilia, preferably using a functional, amidolytic antithrombin assay. The diagnosis of antithrombin deficiency should be established only after other acquired causes of antithrombin deficiency, such as liver disease, consumptive coagulopathy, or heparin therapy, are excluded. A low antithrombin level should be confirmed with a subsequent assay on a fresh specimen, and family studies may be helpful to establish the diagnosis. Antigenic antithrombin assays may be of benefit in subclassification of the type of antithrombin deficiency and to confirm the decreased antithrombin level in patients with type I deficiency.
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22
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Pecheniuk NM, Walsh TP, Marsh NA. DNA technology for the detection of common genetic variants that predispose to thrombophilia. Blood Coagul Fibrinolysis 2000; 11:683-700. [PMID: 11132646 DOI: 10.1097/00001721-200012000-00001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
With the identification of common single locus point mutations as risk factors for thrombophilia, many DNA testing methodologies have been described for detecting these variations. Traditionally, functional or immunological testing methods have been used to investigate quantitative anticoagulant deficiencies. However, with the emergence of the genetic variations, factor V Leiden, prothrombin 20210 and, to a lesser extent, the methylene tetrahydrofolate reductase (MTHFR677) and factor V HR2 haplotype, traditional testing methodologies have proved to be less useful and instead DNA technology is more commonly employed in diagnostics. This review considers many of the DNA techniques that have proved to be useful in the detection of common genetic variants that predispose to thrombophilia. Techniques involving gel analysis are used to detect the presence or absence of restriction sites, electrophoretic mobility shifts, as in single strand conformation polymorphism or denaturing gradient gel electrophoresis, and product formation in allele-specific amplification. Such techniques may be sensitive, but are unwielding and often need to be validated objectively. In order to overcome some of the limitations of gel analysis, especially when dealing with larger sample numbers, many alternative detection formats, such as closed tube systems, microplates and microarrays (minisequencing, real-time polymerase chain reaction, and oligonucleotide ligation assays) have been developed. In addition, many of the emerging technologies take advantage of colourimetric or fluorescence detection (including energy transfer) that allows qualitative and quantitative interpretation of results. With the large variety of DNA technologies available, the choice of methodology will depend on several factors including cost and the need for speed, simplicity and robustness.
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Affiliation(s)
- N M Pecheniuk
- Co-operative Research Center for Diagnostic Technologies, School of Life Sciences, Queensland University of Technology, Brisbane, Australia.
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23
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Afibrinogenemia: first identification of a splicing mutation in the fibrinogen gamma chain gene leading to a major gamma chain truncation. Blood 2000. [DOI: 10.1182/blood.v96.7.2496] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractCongenital afibrinogenemia is a rare autosomal recessive disorder characterized by the complete absence of plasma fibrinogen and by a bleeding tendency ranging from mild to moderately severe. Beside a deletion of the almost entire Aα-chain gene, only 2 missense mutations in the C-terminal domain of the Bβ-chain have been very recently described as being associated with afibrinogenemia. We studied a Pakistani patient with unmeasurable plasma levels of functional and immunoreactive fibrinogen. Sequencing of the fibrinogen genes revealed a homozygous G→A transition at position +5 of intron 1 of the γ-chain gene. The predicted mutant fibrinogen γ-chain would contain the signal peptide, followed by a short stretch of aberrant amino acids, preceding a premature stop codon. To demonstrate the causal role of the identified mutation, we prepared expression vectors containing a region of the fibrinogen γ-chain gene spanning from exon 1 to intron 4 and carrying either a G or an A at position +5 of intron 1. Transient transfection of the mutated plasmid in HeLa cells, followed by RNA extraction and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, allowed us to demonstrate the production of an erroneously spliced messenger RNA (mRNA), retaining intron 1, as shown by direct sequencing. A normal splicing occurred in HeLa cells transfected with the wild-type plasmid. This is the first report of a mutation in the fibrinogen γ-chain gene causing afibrinogenemia and indicates that, in addition to the Aα and Bβ-chain genes, the γ-chain gene must also be considered in mutation screening for afibrinogenemia.
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24
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Afibrinogenemia: first identification of a splicing mutation in the fibrinogen gamma chain gene leading to a major gamma chain truncation. Blood 2000. [DOI: 10.1182/blood.v96.7.2496.h8002496_2496_2500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Congenital afibrinogenemia is a rare autosomal recessive disorder characterized by the complete absence of plasma fibrinogen and by a bleeding tendency ranging from mild to moderately severe. Beside a deletion of the almost entire Aα-chain gene, only 2 missense mutations in the C-terminal domain of the Bβ-chain have been very recently described as being associated with afibrinogenemia. We studied a Pakistani patient with unmeasurable plasma levels of functional and immunoreactive fibrinogen. Sequencing of the fibrinogen genes revealed a homozygous G→A transition at position +5 of intron 1 of the γ-chain gene. The predicted mutant fibrinogen γ-chain would contain the signal peptide, followed by a short stretch of aberrant amino acids, preceding a premature stop codon. To demonstrate the causal role of the identified mutation, we prepared expression vectors containing a region of the fibrinogen γ-chain gene spanning from exon 1 to intron 4 and carrying either a G or an A at position +5 of intron 1. Transient transfection of the mutated plasmid in HeLa cells, followed by RNA extraction and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, allowed us to demonstrate the production of an erroneously spliced messenger RNA (mRNA), retaining intron 1, as shown by direct sequencing. A normal splicing occurred in HeLa cells transfected with the wild-type plasmid. This is the first report of a mutation in the fibrinogen γ-chain gene causing afibrinogenemia and indicates that, in addition to the Aα and Bβ-chain genes, the γ-chain gene must also be considered in mutation screening for afibrinogenemia.
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25
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Kubo T, Tsuji H, Yamamoto T, Nakahara H, Nakagawa M, Hirasawa Y. Antithrombin III deficiency in a patient with multifocal osteonecrosis. Clin Orthop Relat Res 2000:306-11. [PMID: 10987006 DOI: 10.1097/00003086-200009000-00041] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The authors examined a 35-year-old man who had multifocal osteonecrosis on the right and left femoral heads, left humeral head, and right scaphoid. The patient previously had a diagnosis of Type I congenital antithrombin III deficiency but had no other risk factors for osteonecrosis. This patient was thought to have systemic thromboembolism because of the increased blood coagulability resulting from antithrombin III deficiency. Thrombophilia (increased likelihood of thrombosis) and hypofibrinolysis (reduced ability to lyse thrombi) have been implicated as causative factors for osteonecrosis. This case shows a possible relationship between thrombophilic antithrombin III deficiency and multifocal osteonecrosis.
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Affiliation(s)
- T Kubo
- Department of Orthopaedic Surgery, Kyoto Prefectural University of Medicine, Japan
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26
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Abstract
The inherited hypercoagulable states can be divided into those that are common and associated with a modest risk of thrombosis (i.e. factor V Leiden and G20210A prothrombin gene) and those that are uncommon but associated with a high risk of thrombosis. There is no convincing evidence that, independent of other clinical factors, the presence of factor V Leiden or the prothrombin gene mutation should influence the use of primary prophylaxis or the duration of anticoagulant therapy following an episode of thrombosis. Indirect evidence suggests that the presence of antithrombin, protein C deficiency, or protein S deficiency justifies avoiding additional risk factors for thrombosis, such as estrogen therapy, and justifies use of more aggressive primary prophylaxis when additional risk factors cannot readily be avoided (e.g. pregnancy). The presence of one of these three abnormalities also favors more prolonged anticoagulant therapy following venous thrombosis. However, their presence or absence appears to have less influence on the risk of recurrent venous thromboembolism than whether thrombosis was provoked by a major reversible risk factor, such as surgery.
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Affiliation(s)
- C Kearon
- McMaster Clinic, Henderson General Hospital, Hamilton, Ontario, Canada
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27
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Roman K, Rosenthal E, Razavi R. Pulmonary arterial thrombosis in a neonate with homozygous deficiency of antithrombin III: successful outcome following pulmonary thrombectomy and infusions of antithrombin III concentrate. Cardiol Young 2000; 10:275-8. [PMID: 10824912 DOI: 10.1017/s1047951100009240] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We report a newborn male who presented with severe central cyanosis on the third day of life. Partial thrombotic obstruction of the pulmonary trunk secondary to Antithrombin III (homozygous defect of heparin binding site) deficiency was subsequently diagnosed. Surgical thrombectomy, and infusions of Antithrombin III concentrate, led to a successful outcome. We postulate that intrauterine thrombosis occurred to give this unusual presentation.
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Affiliation(s)
- K Roman
- Department of Paediatric Cardiology, Guys Hospital, Guys and St. Thomas NHS Trust, London, UK.
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28
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Fairweather R. Hereditary and Acquired Causes of a Hypercoagulable State. Diagn Pathol 2000. [DOI: 10.1201/b13994-34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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29
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Meyer M, Kutscher G, Vogel G. The prothrombin nt20210 A allele as a risk factor for venous thromboembolism: detection of heterozygous and homozygous carriers by alternative methods. Thromb Res 2000; 97:359-63. [PMID: 10709912 DOI: 10.1016/s0049-3848(99)00177-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The A allele of a G/A dimorphism at position nt20210 in the 3'-untranslated region of the prothrombin gene has been recently identified as a common risk factor for venous thrombosis. It is detected mostly by PCR amplification using a mutagenic primer and subsequent restriction analysis. We have applied two alternative methods--DGGE and SSCP-to analyse the nt20210 dimorphism in a series of 383 consecutive patients with deep venous thrombosis and in 144 controls. Both screening methods resulted in the unambiguous identification of carriers of the nt20210 A allele not only in heterozygotes but in two cases as well in homozygous state. The frequency of the A allele was 0.7% in the control group but 3.7% in the patient group, demonstrating a substantial increase in risk for venous thrombosis in carriers of the 20210 A allele. Both methods have the potential to detect other DNA sequence variations in the vicinity of the 20210 G/A dimorphism. This was demonstrated by the identification of a new mutation T20122G in the 3'-untranslated region of the prothrombin gene in a single patient.
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Affiliation(s)
- M Meyer
- Department of Medical Engineering, University of Applied Sciences (FH) Jena, Germany.
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30
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Hypofibrinogenemia Associated With a Heterozygous Missense Mutation γ153Cys to Arg (Matsumoto IV): In Vitro Expression Demonstrates Defective Secretion of the Variant Fibrinogen. Blood 1999. [DOI: 10.1182/blood.v94.12.4122.424k35_4122_4131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We genetically analyzed a case of hypofibrinogenemia that showed no bleeding or thrombotic tendency. Direct sequencing of a polymerase chain reaction-amplified γ-chain gene segment showed a novel nucleotide substitution. This heterozygous mutation encodes both Cys (TGT) and Arg (CGT) at residue 153. To examine the basis for the fibrinogen deficiency, we prepared expression vectors containing mutant γ-chain DNAs encoding γ153R and γ153A for in vitro expression in Chinese hamster ovary (CHO) cells. Enzyme-linked immunosorbent assay and immunoblot analysis of the culture media and cell lysates showed that CHO cells transfected with γ153R or γ153A synthesized the variant γ-chain, but did not secrete variant fibrinogen into the culture medium. Metabolic pulse-chase experiments showed that fibrinogen assembly was impaired when either variant γ-chain was expressed. In cells expressing normal fibrinogen, assem- bly intermediates and intact fibrinogen were seen in cell lysates prepared after short (3 minutes) or long (1 hour) incubation with 35S-methionine. Neither intermediates nor intact fibrinogen was seen with the variant γ-chains. These data suggest that γ-chains have an important early role in fibrinogen assembly. Thus, our results support the model for fibrinogen assembly proposed by Huang et al (J Biol Chem 268:8919, 1993), in which the first step in assembly is the formation of γ or βγ dimers, or both. This model implies that γCys153 has a critical role in the formation of these early assembly intermediates. We concluded that the γ153Cys→Arg substitution does not allow fibrinogen assembly and secretion, and this is manifest in vivo as a fibrinogen deficiency. We designated this variant as fibrinogen Matsumoto IV.
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31
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Hypofibrinogenemia Associated With a Heterozygous Missense Mutation γ153Cys to Arg (Matsumoto IV): In Vitro Expression Demonstrates Defective Secretion of the Variant Fibrinogen. Blood 1999. [DOI: 10.1182/blood.v94.12.4122] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractWe genetically analyzed a case of hypofibrinogenemia that showed no bleeding or thrombotic tendency. Direct sequencing of a polymerase chain reaction-amplified γ-chain gene segment showed a novel nucleotide substitution. This heterozygous mutation encodes both Cys (TGT) and Arg (CGT) at residue 153. To examine the basis for the fibrinogen deficiency, we prepared expression vectors containing mutant γ-chain DNAs encoding γ153R and γ153A for in vitro expression in Chinese hamster ovary (CHO) cells. Enzyme-linked immunosorbent assay and immunoblot analysis of the culture media and cell lysates showed that CHO cells transfected with γ153R or γ153A synthesized the variant γ-chain, but did not secrete variant fibrinogen into the culture medium. Metabolic pulse-chase experiments showed that fibrinogen assembly was impaired when either variant γ-chain was expressed. In cells expressing normal fibrinogen, assem- bly intermediates and intact fibrinogen were seen in cell lysates prepared after short (3 minutes) or long (1 hour) incubation with 35S-methionine. Neither intermediates nor intact fibrinogen was seen with the variant γ-chains. These data suggest that γ-chains have an important early role in fibrinogen assembly. Thus, our results support the model for fibrinogen assembly proposed by Huang et al (J Biol Chem 268:8919, 1993), in which the first step in assembly is the formation of γ or βγ dimers, or both. This model implies that γCys153 has a critical role in the formation of these early assembly intermediates. We concluded that the γ153Cys→Arg substitution does not allow fibrinogen assembly and secretion, and this is manifest in vivo as a fibrinogen deficiency. We designated this variant as fibrinogen Matsumoto IV.
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32
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Abstract
In the past few years, important advances have been made in the identification of factors predisposing to familial thrombophilia. Particular attention has been paid to the characterization of known inherited defects and their genotype-phenotype relationship, and to studying the interaction between single or multiple inherited conditions and acquired risk factors for venous thrombosis. The recent discovery of 'new' and very common genetic lesions predisposing to thrombosis has greatly expanded the interest in this field. Hereditary predisposition to venous thrombosis may be related to lesions in one or more of 10-15 genes encoding antithrombin, Protein C, Protein S, Factor V, prothrombin, enzymes of the homocysteine metabolic pathway, fibrinogen, heparin cofactor II, plasminogen and thrombomodulin. About 500 different gene lesions (substitutions, deletions, insertions) have so far been reported to affect these genes in patients with thrombotic disease. Because there are potentially multiple interactions between genetic and environmental factors, familial thrombophilia is now considered to be a multifactorial disease. The aim of this chapter is to review aspects of the molecular genetics of familial thrombophilia. In particular, those gene/protein defects for which there is convincing evidence of an association with familial thrombosis will be examined in detail.
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Affiliation(s)
- P Simioni
- Department of Medical and Surgical Sciences, University of Padua Medical School, Italy
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33
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Tsuda H, Hattori S, Tanabe S, Iida H, Nakahara M, Nishioka S, Fujise M, Kinoshita S, Okubo K, Hamasaki N. Screening for aetiology of thrombophilia: a high prevalence of protein S abnormality. Ann Clin Biochem 1999; 36 ( Pt 4):423-32. [PMID: 10456203 DOI: 10.1177/000456329903600404] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We systematically screened for the aetiology of thrombophilia in 115 patients with venous, arterial and small vessel thromboses. Forty-one patients (36% of those we examined) suffering from a variety of thromboses, including deep vein thrombosis, pulmonary embolism, arterial occlusion, cerebral infarction, Moyamoya disease and ulcerative colitis, were characterized either with positive lupus anticoagulants or with decreased activities of protein S, protein C, antithrombin III and/or plasminogen. Eight mutation sites were confirmed in 11 thrombotic patients using gene analysis. Decreased protein S activity was found with a high incidence (23 out of 115) in Japanese patients who suffered from not only venous thrombosis but also arterial and small vessel thrombosis. We emphasize here the important role of protein S in the pathogenesis of thrombosis in the Japanese population.
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Affiliation(s)
- H Tsuda
- Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Faculty of Medicine, Fukuoka, Japan
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34
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Familial Overexpression of β Antithrombin Caused by an Asn135Thr Substitution. Blood 1999. [DOI: 10.1182/blood.v93.12.4242.412k02_4242_4247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have investigated the basis of antithrombin deficiency in an asymptomatic individual (and family) with borderline levels (≈70% antigen and activity) of antithrombin. Direct sequencing of amplified DNA showed a mutation in codon 135, AAC to ACC, predicting a heterozygous Asn135Thr substitution. This substitution alters the predicted consensus sequence for glycosylation, Asn-X-Ser, adjacent to the heparin interaction site of antithrombin. The antithrombin isolated from plasma of the proband by heparin-Sepharose chromatography contained amounts of β antithrombin (the very high affinity fraction) greatly increased (≈20% to 30% of total) above the trace levels found in normals. Expression of the residue 135 variant in both a cell-free system and COS-7 cells confirmed altered glycosylation arising as a consequence of the mutation. Wild-type and variant protein were translated and exported from COS-7 cells with apparently equal efficiency, in contrast to the reduced level of variant observed in plasma of the affected individual. This case represents a novel cause of antithrombin deficiency, removal of glycosylation concensus sequence, and highlights the potentially important role of β antithrombin in regulating coagulation.
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35
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Abstract
AbstractWe have investigated the basis of antithrombin deficiency in an asymptomatic individual (and family) with borderline levels (≈70% antigen and activity) of antithrombin. Direct sequencing of amplified DNA showed a mutation in codon 135, AAC to ACC, predicting a heterozygous Asn135Thr substitution. This substitution alters the predicted consensus sequence for glycosylation, Asn-X-Ser, adjacent to the heparin interaction site of antithrombin. The antithrombin isolated from plasma of the proband by heparin-Sepharose chromatography contained amounts of β antithrombin (the very high affinity fraction) greatly increased (≈20% to 30% of total) above the trace levels found in normals. Expression of the residue 135 variant in both a cell-free system and COS-7 cells confirmed altered glycosylation arising as a consequence of the mutation. Wild-type and variant protein were translated and exported from COS-7 cells with apparently equal efficiency, in contrast to the reduced level of variant observed in plasma of the affected individual. This case represents a novel cause of antithrombin deficiency, removal of glycosylation concensus sequence, and highlights the potentially important role of β antithrombin in regulating coagulation.
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Cumming AM, Shiach CR. The investigation and management of inherited thrombophilia. CLINICAL AND LABORATORY HAEMATOLOGY 1999; 21:77-92. [PMID: 10342066 DOI: 10.1046/j.1365-2257.1999.00210.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- A M Cumming
- University Department of Haematology, Royal Infirmary, Manchester, UK
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37
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Tarantino MD, Curtis SM, Johnson GS, Waye JS, Blajchman MA. A novel and de novo spontaneous point mutation (Glu271STOP) of the antithrombin gene results in a type I deficiency and thrombophilia. Am J Hematol 1999; 60:126-9. [PMID: 9929104 DOI: 10.1002/(sici)1096-8652(199902)60:2<126::aid-ajh7>3.0.co;2-l] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We describe a novel, de novo point mutation in one antithrombin (AT) allele resulting in type I AT deficiency and thrombophilia. Low plasma AT activity as well as low plasma AT antigen were documented in the propositus, but not in the parents, or in a male sibling. AT gene analysis by sequencing polymerase chain reaction-amplified genomic DNA from exon 5 of the propositus revealed a novel point mutation, GAG-->TAG at codon 271, resulting in a stop codon (Glu271STOP). This mutation was not demonstrable in the other members of his immediate family. DNA marker polymorphism analysis indicated the expected parentage. Based on allele frequency data for Caucasians in the United States the cumulative paternity index, or CPI, for the propositus and his father is 219,077. This corresponds to a probability of paternity of 99.9995% based on a prior probability of 50%. Included in this analysis is a linkage analysis of a trinucleotide repeat in intron 5 of the AT gene of the various family members, which also confirmed maternity and paternity. These studies provide documentation of the first spontaneous mutation of an AT gene in a thrombophilic individual, resulting in a type I AT deficiency.
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Affiliation(s)
- M D Tarantino
- Department of Pediatrics, University of Louisville, Kentucky, USA.
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38
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Epidemiologie der funktionellen Inhibitormängel und weiterer hereditärer Risikofaktoren für venöse Thromboembolien. Hamostaseologie 1999. [DOI: 10.1007/978-3-662-07673-6_35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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39
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Abstract
AbstractFive genetic defects have been established as risk factors for venous thrombosis. Three are protein C, protein S, and antithrombin deficiencies, defects in the anticoagulant pathways of blood coagulation. Together they can be found in ∼15% of families with inherited thrombophilia. Their laboratory diagnosis is hampered by the large genetic heterogeneity of these defects. The other two genetic risk factors, resistance to activated protein C associated with the factor V Leiden mutation and increased prothrombin associated with the prothrombin 20210 A allele, are much more prevalent and together can be found in 63% of the thrombophilia families. Because both defects are caused by a single mutation, DNA analysis is the basis of their laboratory diagnosis.
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40
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Abstract
The heritable defects which are at present accepted as proven to be associated with familial venous thrombosis are deficiency of antithrombin (AT), protein C (PC) or protein S (PS) and the FV Leiden mutation. In women from symptomatic kindred each of these defects is associated with increased risk of pregnancy-associated venous thrombosis and increased risk of fetal loss and other vascular complications of pregnancy. The risks appear to be greatest for some types of AT deficiency. These defects are very common but there is growing evidence that congenital thrombophilia is a multigene defect and abnormalities of AT or of the PC-PS system represent only part of the genetic thrombotic predisposition in symptomatic families. Currently it seems reasonable to focus resources on women with AT or PC-PS system abnormalities who are themselves already symptomatic or who come from symptomatic families rather than screen whole populations for these defects. In symptomatic families screening of females around the time of puberty allows time for education and counselling. Pregnancies should be planned, and each pregnancy in each patient managed individually. In general though, women with AT deficiency from symptomatic families require anticoagulant prophylaxis throughout pregnancy and for at least 3 months post-partum, whereas those with PC-PS system defects may require third-trimester plus post-partum prophylaxis or post-partum anticoagulant prophylaxis only.
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Affiliation(s)
- I D Walker
- Department of Haematology, Glasgow Royal Infirmary, UK
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41
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Tokunaga F, Shirotani H, Hara K, Kozuki D, Omura S, Koide T. Intracellular degradation of secretion defect-type mutants of antithrombin is inhibited by proteasomal inhibitors. FEBS Lett 1997; 412:65-9. [PMID: 9257691 DOI: 10.1016/s0014-5793(97)00745-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
To examine the cellular basis for secretion defect-type antithrombin deficiency, we expressed two mutants, P --> stop (Pro429 to stop codon) and deltaGlu (deletion of Glu313). Pulse-chase experiments using stably transfected BHK cells showed that little (< 5%) of P --> stop mutant as well as deltaGlu mutant was secreted and the total amount of radioactivity was significantly reduced, suggesting an intracellular degradation. The degradation was not inhibited by brefeldin A, indicating it occurring in a preGolgi apparatus. However, the degradation was strongly inhibited by proteasomal inhibitors, such as carbobenzoxy-L-leucyl-L-leucyl-L-leucinal (LLL), carbobenzoxy-L-leucyl-L-leucyl-L-norvalinal (LLnV) and lactacystin. By endoglycosidase H digestion and immunofluorescence staining, these mutants were shown to localize in the endoplasmic reticulum (ER). These results suggest that the secretion defect-type mutants of antithrombin are degraded by proteasome through the ER-associated quality control mechanism in the cells.
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Affiliation(s)
- F Tokunaga
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Hyogo, Japan
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42
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Laffan M, Tuddenham E. Thrombophilia: an expanding group of genetic defects that predispose to thrombosis. MOLECULAR MEDICINE TODAY 1997; 3:303-9. [PMID: 9257298 DOI: 10.1016/s1357-4310(97)01064-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Thrombophilia is a term recently coined to describe the increased tendency of some patients to develop thrombosis. Although the term was originally used as a clinical description, the abnormalities of the coagulation system responsible can now be identified in approximately 50% of cases of thrombosis. Many of these disorders are hereditary and it is this group that are generally referred to as thrombophilia. Recent studies have begun to establish the mutations responsible for the hereditary thrombophilias and to assess their interactions with one another. However, it is also clear that many other factors remain undiscovered.
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Affiliation(s)
- M Laffan
- Dept of Haematology, Royal Postgraduate Medical School, London, UK.
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43
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Ozawa T, Niiya K, Inoue N, Kawahara N, Nakatsuka M, Tada K, Kudo T, Sakuragawa N. A novel 4 base pair deletion mutation inducing type I antithrombin deficiency. Thromb Res 1997; 85:515-7. [PMID: 9101643 DOI: 10.1016/s0049-3848(97)00040-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- T Ozawa
- Department of Clinical Laboratory Medicine, Toyama Medical and Pharmaceutical University, Japan
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44
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45
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Stubbs JR. Coagulation for Blood Bankers. Clin Lab Med 1996. [DOI: 10.1016/s0272-2712(18)30242-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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46
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van der Bom JG, Bots ML, van Vliet HH, Pols HA, Hofman A, Grobbee DE. Antithrombin and atherosclerosis in the Rotterdam Study. Arterioscler Thromb Vasc Biol 1996; 16:864-7. [PMID: 8673561 DOI: 10.1161/01.atv.16.7.864] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Antithrombin is a potent inhibitor of thrombotic tendency. Whether atherosclerotic disease is associated with high or low antithrombin is unclear. Studies of the relation between antithrombin and presence of arterial disease have shown contrasting results. In the Rotterdam Study, a single-center, population-based cohort study of 7983 subjects aged 55 years and older, the association between atherosclerosis and antithrombin was evaluated. The ratio of ankle to arm blood pressure is a graded marker for atherosclerosis and provides the opportunity to investigate nonlinear associations. In the first 1427 participants of the Rotterdam Study who did not use anticoagulants, both antithrombin and the ratio of ankle to arm blood pressure were measured. In men the association between the two was quadratic: antithrombin activity was increased in men with moderate peripheral arterial atherosclerosis compared with those without, and in men with more severe atherosclerosis it was decreased. In women the association was linear: a decreased ratio of ankle to arm pressure was associated with increased antithrombin activity. These associations were independent of smoking, body mass index, serum lipids, fibrinogen, and factor VIIc. We propose that antithrombin activity rises in response to increased risk of cardiovascular disease and also in response to the presence of atherosclerosis, whereas antithrombin may decrease with increasing severity of the atherosclerotic process in men. This may explain the contrasting results found in previous studies. Changes in antithrombin over time might be useful in predicting the risk of cardiovascular disease and progression.
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Affiliation(s)
- J G van der Bom
- Department of Epidemiology, Erasmus University Medical School, Rotterdam, Netherlands
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Abstract
Antithrombin is the major proteinase inhibitor of thrombin and other blood coagulation proteinases. Antithrombin has two functional domains, a heparin binding site and a reactive centre (that complexes and inactivates the proteinase). Its deficiency results in an increased risk of venous thromboembolism. Appreciable progress has been made in recent years in understanding the structure and function of this protein, the genetic cause of inherited deficiency and its clinical consequence. The structure of antithrombin is now considered in terms of the models derived from X-ray crystallography, which have provided explanations for the function of its heparin interaction site and of its reactive loop. The structural organization of the antithrombin gene has been defined and numerous mutations have been identified that are responsible for antithrombin deficiency: these may reduce the level of the protein (Type I deficiency), alter the function of the protein (Type II deficiency, altering heparin binding or reactive sites), or even have multiple or 'pleiotropic effects' (Type II deficiency, altering both functional domains and the level of protein).
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Affiliation(s)
- D A Lane
- Department of Haematology, Charing Cross and Westminister Medical School, Hammersmith, London, UK
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Yamazaki T, Katsumi A, Tsuzuki S, Sugiura I, Kojima T, Takamatsu J, Saito H. Analysis for antithrombin gene polymorphisms in Japanese subjects and cosegregation studies in families with hereditary antithrombin deficiency. Thromb Res 1996; 82:275-80. [PMID: 8732631 DOI: 10.1016/0049-3848(96)00074-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- T Yamazaki
- First Department of Internal Medicine, Nagoya University School of Medicine, Japan
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49
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Arai T, Clarke J, Parker A, Busby W, Nam T, Clemmons DR. Substitution of specific amino acids in insulin-like growth factor (IGF) binding protein 5 alters heparin binding and its change in affinity for IGF-I response to heparin. J Biol Chem 1996; 271:6099-106. [PMID: 8626396 DOI: 10.1074/jbc.271.11.6099] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Heparin binding to insulin-like growth factor (IGF)-binding protein 5 (IGFBP-5) leads to a 17-fold decrease in its affinity for IGF-I, and a region that contains several basic amino acids (Arg201-Arg218) may be involved in this affinity shift. In the present study, mutagenesis was used to analyze the effect of substitutions for basic amino acids in the Arg201-Arg218 region of IGFBP-5 on heparin-binding and the heparin-induced affinity shift. Nine mutant forms were prepared. Their association constants (Ka) for IGF-I were similar to native IGFBP-5. When 10 microg/ml of heparin was added, the Ka of native IGFBP-5 decreased 17-fold, and the Ka of the K134A/R136A mutant decreased 16-fold. In contrast, substitutions for specific basic amino acids in the Arg2O1-Arg218 region decrease the affinity shift to 1.1-3.2-fold. Lys 211 was especially important. When a mutant containing that single substitution was tested, heparin caused only a 2.5-fold reduction in IGF-I affinity. Affinity cross-linking studies showed that heparin was equipotent in inhibiting the formation of 125I-IGF-I-K134A/Rl36A mutant complexes compared to native IGFBP-5. In contrast, heparin had minimal effects on the formation of complexes between 125I-IGF-I and the other mutants. The heparin-binding activity of each mutant was determined. Four mutants, R201A/K202N, K202A/K206A/R207A, R201A/K202N/K206N/K208N, and K211N/R214A/K217A/R218A, had reduced heparin binding compared to native IGFBP-5. The other five mutants, including the K21IN mutant, showed no change in heparin binding. The four mutants with reduced heparin binding could be dissociated from heparin-Sepharose with much lower NaCl concentrations, indicating that they had reduced affinity. These findings suggest that Arg201 Lys202, LysS206, and Arg214 are important for heparin binding. In contrast, LyS211 is not important for the binding of IGFBP-5 to heparin, but substitution for it reduced the heparin-induced affinity shift.
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Affiliation(s)
- T Arai
- Department of Medicine, University of North Carolina, School of Medicine, Chapel Hill 27599, USA
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50
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Abstract
Human antithrombin is the major plasma inhibitor of thrombin both in the presence and absence of heparin. Its physiological importance is emphasised by the recurrent thromboses that individuals with a deficient or functionally abnormal protein are prone to develop. Such deficiencies are estimated to affect as many as 1:630 of the general population and between 3% and 5% of patients with thrombotic disease. The gene for antithrombin (AT3) has been cloned and shown to map to the long arm of chromosome 1 at 1q23-25. The gene consists of seven exons and six introns and spans 13,477bp of DNA. Advances in molecular genetic techniques have facilitated identification of the underlying DNA mutation(s) in > 80 families with antithrombin deficiency. Such work has proved invaluable in structure-function studies and in helping to provide informed genetic counselling to "at-risk" individuals based upon the natural history of similar variants.
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Affiliation(s)
- D J Perry
- Department of Haematology, University of Cambridge, United Kingdom
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