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Sacco M, Testa MF, Ferretti A, Basso M, Lancellotti S, Tardugno M, Di Gennaro L, Concolino P, Minucci A, Spoliti C, Branchini A, De Cristofaro R. An integrated multitool analysis contributes elements to interpreting unclassified factor IX missense variants associated with hemophilia B. J Thromb Haemost 2024:S1538-7836(24)00425-2. [PMID: 39019441 DOI: 10.1016/j.jtha.2024.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 06/10/2024] [Accepted: 07/05/2024] [Indexed: 07/19/2024]
Abstract
BACKGROUND Dissection of genotype-phenotype relationships in hemophilia B (HB) is particularly relevant for challenging (mild HB) or for HB-associated but unclassified factor (F)IX missense variants. OBJECTIVE To contribute elements to interpret unclassified HB-associated FIX missense variants by a multiple-level approach upon identification of a reported, but uncharacterized, FIX missense variant associated with mild HB. METHODS Molecular modeling of wild-type and V92A FIX variants, expression studies in HEK293 cells with evaluation of protein (ELISA, western blotting) and activity (activated partial thromboplastin time-based/chromogenic assays) levels after recombinant expression, and multiple prediction tools. RESULTS The F9(NM_000133.4):c.275T>C (p.V92A) variant was found in a mild HB patient (antigen, 45.4 U/dL; coagulant activity, 23.6 IU/dL; specific activity, 0.52). Newly generated molecular models showed alterations in Gla/EGF1-EGF2 domain conformation impacting Ca++ affinity and protein-protein interactions with activated factor XI (FXIa). Multitool analysis indicated a moderate impact on protein structure/function of the valine-to-alanine substitution, in accordance with patient and modeling data. Expression studies on the V92A variant showed a specific activity (0.49 ± 0.07; wild-type, 1.0 ± 0.1) recapitulating that of the natural variant, and pointed toward a moderate activation impairment as the main determinant underlying the p.V92A defect. The validated multitool approach, integrated with evidence-based data, was challenged on a panel (n = 9) of unclassified FIX missense variants, which resulted in inferred protein (secretion/function) outputs and HB severity. CONCLUSION The rational integration of multitool and multiparameter analyses contributed elements to interpret genotype/phenotype relationships of unclassified FIX missense variants, with implications for diagnosis, management, and treatment of HB patients, and potentially translatable into other human disorders.
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Affiliation(s)
- Monica Sacco
- Department of Translational Medicine and Surgery, Catholic University of the Sacred Heart, Rome, Italy
| | - Maria Francesca Testa
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Antonietta Ferretti
- Center for Hemorrhagic and Thrombotic Diseases, Foundation University Hospital "A. Gemelli" IRCCS, Rome, Italy
| | - Maria Basso
- Center for Hemorrhagic and Thrombotic Diseases, Foundation University Hospital "A. Gemelli" IRCCS, Rome, Italy
| | - Stefano Lancellotti
- Center for Hemorrhagic and Thrombotic Diseases, Foundation University Hospital "A. Gemelli" IRCCS, Rome, Italy
| | - Maira Tardugno
- Department of Translational Medicine and Surgery, Catholic University of the Sacred Heart, Rome, Italy
| | - Leonardo Di Gennaro
- Center for Hemorrhagic and Thrombotic Diseases, Foundation University Hospital "A. Gemelli" IRCCS, Rome, Italy
| | - Paola Concolino
- Molecular and Genomic Diagnostics Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Angelo Minucci
- Molecular and Genomic Diagnostics Unit, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Claudia Spoliti
- Department of Translational Medicine and Surgery, Catholic University of the Sacred Heart, Rome, Italy
| | - Alessio Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
| | - Raimondo De Cristofaro
- Department of Translational Medicine and Surgery, Catholic University of the Sacred Heart, Rome, Italy; Center for Hemorrhagic and Thrombotic Diseases, Foundation University Hospital "A. Gemelli" IRCCS, Rome, Italy.
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Ljung R, Matino D, Shapiro AD. Recombinant factor IX Fc for the treatment of hemophilia B. Eur J Haematol 2024; 112:678-691. [PMID: 38369860 DOI: 10.1111/ejh.14176] [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: 10/17/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 02/20/2024]
Abstract
Current hemophilia B treatment guidelines recommend routine prophylaxis with factor IX (FIX) replacement products, tailored to maintain plasma activity at levels that will prevent bleeds. However, plasma FIX activity may not be the primary determinant or best indicator of hemostatic efficacy due to its extravascular distribution. FIX replacement therapy has evolved to include extended half-life (EHL) products that provide effective bleed protection when administered at intervals of 7 days or longer. rFIXFc is a recombinant fusion protein with an extended circulation time. rFIXFc has a biodistribution profile consistent with distribution into extravascular space, where it may support hemostasis at sites of vessel injury independent of circulating plasma activity levels. The safety and efficacy of rFIXFc prophylaxis is well established in adults, adolescents and children including previously untreated patients with hemophilia B, with substantial evidence from clinical trials and real-world clinical practice. This review describes the pharmacokinetic characteristics of rFIXFc, summarizes available safety and efficacy data, and evaluates the use of rFIXFc in special populations. Current hemophilia B treatment challenges, including target FIX plasma levels, perioperative use, and management of patients with comorbidities, are discussed together with the potential role of EHL products in the future treatment landscape of hemophilia B.
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Affiliation(s)
- Rolf Ljung
- Department of Clinical Sciences-Pediatrics, Lund University, Lund, Sweden
| | - Davide Matino
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Amy D Shapiro
- Indiana Hemophilia & Thrombosis Center, Inc, Indianapolis, Indiana, USA
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Bester C, Kloppers JF, van Rensburg WJJ. Genetic variant detection in a South African haemophilia B population. Haemophilia 2024; 30:765-773. [PMID: 38462783 DOI: 10.1111/hae.14978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/15/2024] [Accepted: 02/18/2024] [Indexed: 03/12/2024]
Abstract
BACKGROUND Haemophilia B is characterised by a deficiency of factor IX (FIX) protein due to genetic variants in the FIX gene (F9). Genetic testing may have a vital role in effectively managing haemophilia B. However, in many developing countries, comprehensive genetic variant detection is unavailable. This study aimed to address the lack of genetic data in our country by conducting genetic variant detection on people affected by haemophilia B in our region. METHODS Twenty-one participants were screened with a direct Sanger sequencing method to identify variants in the F9 gene. The identified variants were then compared to previously published variants and/or to a reference database. RESULTS AND DISCUSSION A total of ten F9 genetic changes were detected, with five of them being novel. These identified variants were distributed across different domains of the FIX protein. Only one participant had a history of inhibitor formation against FIX replacement therapy. Notably, this participant had two distinct genetic changes present adjacent to each other. Thus, we hypothesise that the presence of multiple variants within the same functional region of the gene may increase the risk for inhibitor development. CONCLUSION The discovery of novel pathogenic variations in the F9 gene highlights the importance of genetic analysis in specific geographical regions. The possible link between a complex variant and inhibitor formation illustrates the potential role that genetic screening has as a pre-treatment tool in predicting treatment reactions and outcomes.
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Affiliation(s)
- Chené Bester
- Faculty of Health Sciences, Human Molecular Biology Unit, School of Biomedical Sciences, University of the Free State, Bloemfontein, South Africa
| | - Jean F Kloppers
- Faculty of Health Sciences, Department of Haematology and Cell Biology, School of Pathology, University of the Free State, Bloemfontein, South Africa
- National Health Laboratory Service, Universitas Academic Business Unit, Bloemfontein, South Africa
| | - Walter J Janse van Rensburg
- Faculty of Health Sciences, Human Molecular Biology Unit, School of Biomedical Sciences, University of the Free State, Bloemfontein, South Africa
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Zhang H, Xin M, Lin L, Chen C, Balestra D, Ding Q. Pleiotropic effects of different exonic nucleotide changes at the same position contribute to hemophilia B phenotypic variation. J Thromb Haemost 2024; 22:975-989. [PMID: 38184202 DOI: 10.1016/j.jtha.2023.12.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/29/2023] [Accepted: 12/29/2023] [Indexed: 01/08/2024]
Abstract
BACKGROUND The disease-causing effects of genetic variations often depend on their location within a gene. Exonic changes generally lead to alterations in protein production, secretion, activity, or clearance. However, owing to the overlap between proteins and splicing codes, missense variants can also affect messenger RNA splicing, thus adding a layer of complexity and influencing disease phenotypes. OBJECTIVES To extensively characterize a panel of 13 exonic variants in the F9 gene occurring at 6 different factor IX positions and associated with varying severities of hemophilia B (HB). METHODS Computational predictions, splicing analysis, and recombinant factor IX assays were exploited to characterize F9 variants. RESULTS We demonstrated that 5 (38%) of 13 selected F9 exonic variants have pleiotropic effects. Although bioinformatic approaches accurately classified effects, extensive experimental assays were required to elucidate and deepen the molecular mechanisms underlying the pleiotropic effects. Importantly, their characterization was instrumental in developing tailored RNA therapeutics based on engineered U7 small nuclear RNA to mask cryptic splice sites and compensatory U1 small nuclear RNA to enhance exon definition. CONCLUSION Overall, albeit a multitool bioinformatic approach suggested the molecular effects of multiple HB variants, the deep investigation of molecular mechanisms revealed insights into the HB phenotype-genotype relationship, enabling accurate classification of HB variants. Importantly, knowledge of molecular mechanisms allowed the development of tailored RNA therapeutics, which can also be translated to other genetic diseases.
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Affiliation(s)
- Huayang Zhang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Min Xin
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Liya Lin
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Changming Chen
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Dario Balestra
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.
| | - Qiulan Ding
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; Collaborative Innovation Center of Hematology, Shanghai Jiaotong University School of Medicine, Shanghai, China.
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Gemmati D, D’Aversa E, Antonica B, Grisafi M, Salvatori F, Pizzicotti S, Pellegatti P, Ciccone M, Moratelli S, Serino ML, Tisato V. Gene Dosage of F5 c.3481C>T Stop-Codon (p.R1161Ter) Switches the Clinical Phenotype from Severe Thrombosis to Recurrent Haemorrhage: Novel Hypotheses for Readthrough Strategy. Genes (Basel) 2024; 15:432. [PMID: 38674367 PMCID: PMC11050146 DOI: 10.3390/genes15040432] [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: 02/20/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Inherited defects in the genes of blood coagulation essentially express the severity of the clinical phenotype that is directly correlated to the number of mutated alleles of the candidate leader gene (e.g., heterozygote vs. homozygote) and of possible additional coinherited traits. The F5 gene, which codes for coagulation factor V (FV), plays a two-faced role in the coagulation cascade, exhibiting both procoagulant and anticoagulant functions. Thus, defects in this gene can be predisposed to either bleeding or thrombosis. A Sanger sequence analysis detected a premature stop-codon in exon 13 of the F5 gene (c.3481C>T; p.R1161Ter) in several members of a family characterised by low circulating FV levels and contrasting clinical phenotypes. The propositus, a 29 y.o. male affected by recurrent haemorrhages, was homozygous for the F5 stop-codon and for the F5 c.1691G>A (p.R506Q; FV-Leiden) inherited from the heterozygous parents, which is suggestive of combined cis-segregation. The homozygous condition of the stop-codon completely abolished the F5 gene expression in the propositus (FV:Ag < 1%; FV:C < 1%; assessed by ELISA and PT-based one-stage clotting assay respectively), removing, in turn, any chance for FV-Leiden to act as a prothrombotic molecule. His father (57 y.o.), characterised by severe recurrent venous thromboses, underwent a complete molecular thrombophilic screening, revealing a heterozygous F2 G20210A defect, while his mother (56 y.o.), who was negative for further common coagulation defects, reported fully asymptomatic anamnesis. To dissect these conflicting phenotypes, we performed the ProC®Global (Siemens Helthineers) coagulation test aimed at assessing the global pro- and anticoagulant balance of each family member, investigating the responses to the activated protein C (APC) by means of an APC-sensitivity ratio (APC-sr). The propositus had an unexpectedly poor response to APC (APC-sr: 1.09; n.v. > 2.25), and his father and mother had an APC-sr of 1.5 and 2.0, respectively. Although ProC®Global prevalently detects the anticoagulant side of FV, the exceptionally low APC-sr of the propositus and his discordant severe-moderate haemorrhagic phenotype could suggest a residual expression of mutated FV p.506QQ through a natural readthrough or possible alternative splicing mechanisms. The coagulation pathway may be physiologically rebalanced through natural and induced strategies, and the described insights might be able to track the design of novel treatment approaches and rebalancing molecules.
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Affiliation(s)
- Donato Gemmati
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
- University Strategic Centre for Studies on Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
- Centre Haemostasis & Thrombosis, University of Ferrara, 44121 Ferrara, Italy
| | - Elisabetta D’Aversa
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Bianca Antonica
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Miriana Grisafi
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | - Francesca Salvatori
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
| | | | | | - Maria Ciccone
- Haematology Unit, Hospital-University of Ferrara, 44121 Ferrara, Italy
| | - Stefano Moratelli
- Centre Haemostasis & Thrombosis, University of Ferrara, 44121 Ferrara, Italy
| | - Maria Luisa Serino
- Centre Haemostasis & Thrombosis, University of Ferrara, 44121 Ferrara, Italy
| | - Veronica Tisato
- Department of Translational Medicine, University of Ferrara, 44121 Ferrara, Italy
- University Strategic Centre for Studies on Gender Medicine, University of Ferrara, 44121 Ferrara, Italy
- Laboratory of Technology for Advanced Therapies (LTTA) Centre, University of Ferrara, 44121 Ferrara, Italy
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6
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Li F, He L, Chen G, Lu Y, Li R, Zhang Y, Jing X, Ling R, Li D, Liao C. Variant spectrum of F8 and F9 in hemophilia patients from southern China and 26 novel variants. Front Genet 2023; 14:1254265. [PMID: 38196513 PMCID: PMC10775173 DOI: 10.3389/fgene.2023.1254265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 12/11/2023] [Indexed: 01/11/2024] Open
Abstract
Hemophilia, an X-linked recessive disorder, is characterized by spontaneous or trauma-induced prolonged bleeding. It is classified as hemophilia A when caused by variants in the F8 gene, and hemophilia B when caused by F9 variants. Few studies have described hemophilia variants in the Chinese population. This study aimed to investigate the clinical and genetic profiles of 193 hemophilia patients from southern China. Utilizing Sanger sequencing, multiplex ligation-dependent probe amplification, gap detection, long-range PCR, and multiplex PCR, we identified both F8 and F9 gene variants. Pregnant women with a history of hemophilia A offspring underwent amniocentesis or villus sampling for the variant detection. Variants in F8 and F9 were pinpointed in 183 patients, with 26 being novel discoveries. Notably, genetic testing was absent in the initial evaluation of 133 out of 161 patients, leading to a protracted average definitive diagnosis timeline of 2 years. Remarkably, two hemophilia A cases with anticipated severe phenotypes due to protein-truncating variants presented with only moderate or mild clinical manifestations. Among the 40 fetuses tested, 34 were males, with 17 exhibiting hemizygous variants in the F8 gene. Our results contribute to the broader understanding of F8 and F9 variant spectrum and highlight the underuse of genetic analyses in southern China.
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Affiliation(s)
- Fucheng Li
- Department of Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Liya He
- Hematology Department, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Guilan Chen
- Department of Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Yan Lu
- Department of Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Ru Li
- Department of Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Yongling Zhang
- Department of Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Xiangyi Jing
- Department of Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Rujuan Ling
- Department of Internal Medicine, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Dongzhi Li
- Department of Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Can Liao
- Department of Prenatal Diagnostic Center, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
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Morfini M, Agnelli Giacchiello J, Baldacci E, Carulli C, Castaman G, Giuffrida AC, Malcangi G, Rocino A, Siragusa S, Zanon E. Managing Relevant Clinical Conditions of Hemophilia A/B Patients. Hematol Rep 2023; 15:384-397. [PMID: 37367088 DOI: 10.3390/hematolrep15020039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/21/2023] [Accepted: 05/31/2023] [Indexed: 06/28/2023] Open
Abstract
The Medical Directors of nine Italian Hemophilia Centers reviewed and discussed the key issues concerning the replacement therapy of hemophilia patients during a one-day consensus conference held in Rome one year ago. Particular attention was paid to the replacement therapy needed for surgery using continuous infusion (CI) versus bolus injection (BI) of standard and extended half-life Factor VIII (FVIII) concentrates in severe hemophilia A patients. Among the side effects, the risk of development of neutralizing antibodies (inhibitors) and thromboembolic complications was addressed. The specific needs of mild hemophilia A patients were described, as well as the usage of bypassing agents to treat patients with high-responding inhibitors. Young hemophilia A patients may take significant advantages from primary prophylaxis three times or twice weekly, even with standard half-life (SHL) rFVIII concentrates. Patients affected by severe hemophilia B probably have a less severe clinical phenotype than severe hemophilia A patients, and in about 30% of cases may undergo weekly prophylaxis with an rFIX SHL concentrate. The prevalence of missense mutations in 55% of severe hemophilia B patients allows the synthesis of a partially changed FIX molecule that can play some hemostatic role at the level of endothelial cells or the subendothelial matrix. The flow back of infused rFIX from the extravascular to the plasma compartment allows a very long half-life of about 30 h in some hemophilia B patients. Once weekly, prophylaxis can assure a superior quality of life in a large severe or moderate hemophilia B population. According to the Italian registry of surgery, hemophilia B patients undergo joint replacement by arthroplasty less frequently than hemophilia A patients. Finally, the relationships between FVIII/IX genotypes and the pharmacokinetics of clotting factor concentrates have been investigated.
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Affiliation(s)
- Massimo Morfini
- Italian Association of Haemophilia Centers (AICE), 21121 Milan, Italy
| | - Jacopo Agnelli Giacchiello
- Hemostasis and Thrombosis Center, Azienda Ospedaliera SS Antonio e Biagio e Cesare Arrigo, 15121 Alessandria, Italy
| | - Erminia Baldacci
- Haematology, "Umberto I" Policlinico, Department of Translational and Precision Medicine, Sapienza University of Rome, 00118 Rome, Italy
| | - Christian Carulli
- Department of Orthopaedic Surgery, Orthopaedic Clinic, University of Florence, 50121 Florence, Italy
| | - Giancarlo Castaman
- Department of Oncology, Center for Bleeding Disorders and Coagulation, Careggi University Hospital, 50121 Florence, Italy
| | | | - Giuseppe Malcangi
- UOSD Centro Emofilia e Trombosi, Azienda Ospedaliero Universitaria Policlinico di Bari, 70121 Bari, Italy
| | - Angiola Rocino
- Haemophilia and Thrombosis Centre, Haematology, S.M. di Loreto Nuovo Hospital, 80121 Naples, Italy
| | - Sergio Siragusa
- Department PROMISE, University of Palermo, 90121 Palermo, Italy
| | - Ezio Zanon
- Haemophilia Centre, General Medicine, Padua University Hospital, 35121 Padua, Italy
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8
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Lunghi B, Morfini M, Martinelli N, Branchini A, Linari S, Castaman G, Bernardi F. Modulation of factor VIII pharmacokinetics by genetic components in factor VIII receptors. Haemophilia 2023; 29:479-487. [PMID: 36533781 DOI: 10.1111/hae.14722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 11/18/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Gene variation in receptors for circulating factor VIII (FVIII) is candidate to explain the large inter-patient variability of infused FVIII pharmacokinetics (PK) in haemophilia A (HA). AIM To compare in an Italian HA cohort (n = 26) the influence on FVIII PK of genetic components in four von Willebrand factor (VWF)/FVIII receptors. METHODS Genotypes of low-density lipoprotein receptor (LDLR), asialoglycoprotein receptor minor subunit (ASGR2), family 4 member M (CLEC4M), stabilin2 (STAB2) and ABO blood-group, and VWF:Ag levels were included as independent variables in linear regression analyses of two-compartment model (TCM) - standard half-life (SHL) FVIII PK parameters. RESULTS In the initial FVIII distribution phase, the STAB2 rs4981022 AA, ASGR2 rs2289645 TT and LDLR rs688 TT genotypes may contribute to increase Cmax , and prolong or shorten AlphaHL. In the elimination phase, a shorter BetaHL was associated with the CLEC4M rs868875 GG (beta-coefficient .366, p = .025) and ASGR2 rs2289645 TC (beta-coefficient .456, p = .006) genotypes, which also showed shorter mean residence time (MRT) than TT genotypes (p = .021). The alpha and beta phase effects were independent of ABO and VWF:Ag levels at baseline. The association of the LDLR rs2228671 genotypes with clearance was independent of ABO (beta-coefficient -.363, p = .035) but not of other receptors or VWF:Ag, which may point out multiple and competing interactions. CONCLUSIONS With the limitation of the small number of HA patients, these observations highlight multiple genetic components acting in distinct phases of FVIII PK and contributing to explain FVIII PK variability. This analysis provides candidates for genotype-based, individual tailoring of FVIII substitutive treatment.
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Affiliation(s)
- Barbara Lunghi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Massimo Morfini
- Italian Association of Hemophilia Centers (AICE), Naples, Italy
| | | | - Alessio Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Silvia Linari
- Center for Bleeding Disorders, Department of Oncology, Careggi University Hospital, Florence, Italy
| | - Giancarlo Castaman
- Center for Bleeding Disorders, Department of Oncology, Careggi University Hospital, Florence, Italy
| | - Francesco Bernardi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
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9
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Wang HL, Ruan DD, Wu M, Ji YY, Hu XX, Wu QY, Zhang YP, Lin B, Hu YN, Wang H, Tang Y, Fang ZT, Luo JW, Liao LS, Gao MZ. Identification and characterization of two SERPINC1 mutations causing congenital antithrombin deficiency. Thromb J 2023; 21:3. [PMID: 36624481 PMCID: PMC9830717 DOI: 10.1186/s12959-022-00443-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 12/22/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Antithrombin (AT) is the main physiological anticoagulant involved in hemostasis. Hereditary AT deficiency is a rare autosomal dominant thrombotic disease mainly caused by mutations in SERPINC1, which was usually manifested as venous thrombosis and pulmonary embolism. In this study, we analyzed the clinical characteristics and screened for mutant genes in two pedigrees with hereditary AT deficiency, and the functional effects of the pathogenic mutations were evaluated. METHODS Candidate gene variants were analyzed by next-generation sequencing to screen pathogenic mutations in probands, followed by segregation analysis in families by Sanger sequencing. Mutant and wild-type plasmids were constructed and transfected into HEK293T cells to observe protein expression and cellular localization of SERPINC1. The structure and function of the mutations were analyzed by bioinformatic analyses. RESULTS The proband of pedigree A with AT deficiency carried a heterozygous frameshift mutation c.1377delC (p.Asn460Thrfs*20) in SERPINC1 (NM000488.3), a 1377C base deletion in exon 7 resulting in a backward shift of the open reading frame, with termination after translation of 20 residues, and a different residue sequence translated after the frameshift. Bioinformatics analysis suggests that the missing amino acid sequence caused by the frameshift mutation might disrupt the disulfide bond between Cys279 and Cys462 and affect the structural function of the protein. This newly discovered variant is not currently included in the ClinVar and HGMD databases. p.Arg229* resulted in a premature stop codon in exon 4, and bioinformatics analysis suggests that the truncated protein structure lost its domain of interaction with factor IX (Ala414 site) after the deletion of nonsense mutations. However, considering the AT truncation protein resulting from the p.Arg229* variant loss a great proportion of the molecule, we speculate the variant may affect two functional domains HBS and RCL and lack of the corresponding function. The thrombophilia and decreased-AT-activity phenotypes of the two pedigrees were separated from their genetic variants. After lentiviral plasmid transfection into HEK293T cells, the expression level of AT protein decreased in the constructed c.1377delC mutant cells compared to that in the wild-type, which was not only reduced in c.685C > T mutant cells but also showed a significant band at 35 kDa, suggesting a truncated protein. Immunofluorescence localization showed no significant differences in protein localization before and after the mutation. CONCLUSIONS The p.Asn460Thrfs*20 and p.Arg229* variants of SERPINC1 were responsible for the two hereditary AT deficiency pedigrees, which led to AT deficiency by different mechanisms. The p.Asn460Thrfs*20 variant is reported for the first time.
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Affiliation(s)
- Han-lu Wang
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China
| | - Dan-dan Ruan
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China
| | - Min Wu
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China
| | - Yuan-yuan Ji
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China
| | - Xing-xing Hu
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China ,grid.415108.90000 0004 1757 9178Department of Cardiovascular Medicine, Fujian Provincial Hospital, Fuzhou, 350001 China
| | - Qiu-yan Wu
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China
| | - Yan-ping Zhang
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China
| | - Bin Lin
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China
| | - Ya-nan Hu
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China
| | - Hang Wang
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China ,grid.415108.90000 0004 1757 9178Department of Cardiovascular Surgery, Fujian Provincial Hospital, Fuzhou, 350001 China
| | - Yi Tang
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China ,grid.415108.90000 0004 1757 9178Department of Interventional Radiology, Fujian Provincial Hospital, Fuzhou, 350001 China
| | - Zhu-ting Fang
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China ,grid.415108.90000 0004 1757 9178Department of Interventional Radiology, Fujian Provincial Hospital, Fuzhou, 350001 China
| | - Jie-wei Luo
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China ,grid.415108.90000 0004 1757 9178Department of Traditional Chinese Medicine, Fujian Provincial Hospital, Fuzhou, 350001 China
| | - Li-sheng Liao
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China ,grid.415108.90000 0004 1757 9178Department of Hematology, Fujian Provincial Hospital, Fuzhou, 350001 China
| | - Mei-zhu Gao
- grid.415108.90000 0004 1757 9178Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, Fuzhou, 350001 China ,grid.415108.90000 0004 1757 9178Department of Nephrology, Fujian Provincial Hospital, Fuzhou, 350001 China
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Shen G, Gao M, Cao Q, Li W. The Molecular Basis of FIX Deficiency in Hemophilia B. Int J Mol Sci 2022; 23:2762. [PMID: 35269902 PMCID: PMC8911121 DOI: 10.3390/ijms23052762] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/23/2022] [Accepted: 02/27/2022] [Indexed: 12/15/2022] Open
Abstract
Coagulation factor IX (FIX) is a vitamin K dependent protein and its deficiency causes hemophilia B, an X-linked recessive bleeding disorder. More than 1000 mutations in the F9 gene have been identified in hemophilia B patients. Here, we systematically summarize the structural and functional characteristics of FIX and the pathogenic mechanisms of the mutations that have been identified to date. The mechanisms of FIX deficiency are diverse in these mutations. Deletions, insertions, duplications, and indels generally lead to severe hemophilia B. Those in the exon regions generate either frame shift or inframe mutations, and those in the introns usually cause aberrant splicing. Regarding point mutations, the bleeding phenotypes vary from severe to mild in hemophilia B patients. Generally speaking, point mutations in the F9 promoter region result in hemophilia B Leyden, and those in the introns cause aberrant splicing. Point mutations in the coding sequence can be missense, nonsense, or silent mutations. Nonsense mutations generate truncated FIX that usually loses function, causing severe hemophilia B. Silent mutations may lead to aberrant splicing or affect FIX translation. The mechanisms of missense mutation, however, have not been fully understood. They lead to FIX deficiency, often by affecting FIX's translation, protein folding, protein stability, posttranslational modifications, activation to FIXa, or the ability to form functional Xase complex. Understanding the molecular mechanisms of FIX deficiency will provide significant insight for patient diagnosis and treatment.
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Affiliation(s)
- Guomin Shen
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang 471023, China; (M.G.); (Q.C.)
- School of Basic Medical Science, Henan University of Science and Technology, Luoyang 471023, China
| | - Meng Gao
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang 471023, China; (M.G.); (Q.C.)
- School of Basic Medical Science, Henan University of Science and Technology, Luoyang 471023, China
| | - Qing Cao
- Henan International Joint Laboratory of Thrombosis and Hemostasis, Henan University of Science and Technology, Luoyang 471023, China; (M.G.); (Q.C.)
- School of Basic Medical Science, Henan University of Science and Technology, Luoyang 471023, China
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
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