1
|
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.
Collapse
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
| |
Collapse
|
2
|
Branchini A, Morfini M, Lunghi B, Belvini D, Radossi P, Bury L, Serino ML, Giordano P, Cultrera D, Molinari AC, Napolitano M, Bigagli E, Castaman G, Pinotti M, Bernardi F. F9 missense mutations impairing factor IX activation are associated with pleiotropic plasma phenotypes. J Thromb Haemost 2022; 20:69-81. [PMID: 34626083 PMCID: PMC9298354 DOI: 10.1111/jth.15552] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/06/2021] [Accepted: 10/06/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Circulating dysfunctional factor IX (FIX) might modulate distribution of infused FIX in hemophilia B (HB) patients. Recurrent substitutions at FIX activation sites (R191-R226, >300 patients) are associated with variable FIX activity and antigen (FIXag) levels. OBJECTIVES To investigate the (1) expression of a complete panel of missense mutations at FIX activation sites and (2) contribution of F9 genotypes on the FIX pharmacokinetics (PK). METHODS We checked FIX activity and antigen and activity assays in plasma and after recombinant expression of FIX variants and performed an analysis of infused FIX PK parameters in patients (n = 30), mostly enrolled in the F9 Genotype and PK HB Italian Study (GePKHIS; EudraCT ID2017-003902-42). RESULTS The variable FIXag amounts and good relation between biosynthesis and activity of multiple R191 variants results in graded moderate-to-mild severity of the R191C>L>P>H substitutions. Recombinant expression may predict the absence in the HB mutation database of the benign R191Q/W/K and R226K substitutions. Equivalent changes at R191/R226 produced higher FIXag levels for R226Q/W/P substitutions, as also observed in p.R226W female carrier plasma. Pharmacokinetics analysis in patients suggested that infused FIX Alpha distribution and Beta elimination phases positively correlated with endogenous FIXag levels. Mean residence time was particularly prolonged (79.4 h, 95% confidence interval 44.3-114.5) in patients (n = 7) with the R191/R226 substitutions, which in regression analysis were independent predictors (β coefficient 0.699, P = .004) of Beta half-life, potentially prolonged by the increasing over time ratio between endogenous and infused FIX. CONCLUSIONS FIX activity and antigen levels and specific features of the dysfunctional R191/R226 variants may exert pleiotropic effects both on HB patients' phenotypes and substitutive treatment.
Collapse
Affiliation(s)
- Alessio Branchini
- Department of Life Sciences and Biotechnology and LTTA CentreUniversity of FerraraFerraraItaly
| | | | - Barbara Lunghi
- Department of Life Sciences and Biotechnology and LTTA CentreUniversity of FerraraFerraraItaly
| | - Donata Belvini
- Transfusion ServiceHaemophilia Centre and HaematologyCastelfranco Veneto HospitalCastelfranco VenetoItaly
| | - Paolo Radossi
- Oncohematology‐Oncologic Institute of VenetoCastelfranco Veneto HospitalCastelfranco VenetoItaly
| | - Loredana Bury
- Department of Medicine and SurgeryUniversity of PerugiaPerugiaItaly
| | - Maria Luisa Serino
- Haemostasis and Thrombosis CentreUniversity Hospital of FerraraFerraraItaly
| | - Paola Giordano
- Paediatric SectionDepartment of Biomedicine and Human OncologyA. Moro” UniversityBariItaly
| | - Dorina Cultrera
- Haemophilia Regional Reference CenterVittorio Emanuele” University HospitalCataniaItaly
| | | | - Mariasanta Napolitano
- Haematology UnitThrombosis and Haemostasis Reference Regional Center and PROMISE DepartmentUniversity of PalermoPalermoItaly
| | - Elisabetta Bigagli
- Department of Neuroscience, PsychologyDrug Research and Child Health (NEUROFARBA)Section of Pharmacology and ToxicologyUniversity of FlorenceFlorenceItaly
| | - Giancarlo Castaman
- Department of Oncology, Center for Bleeding DisordersCareggi University HospitalFirenzeItaly
| | - Mirko Pinotti
- Department of Life Sciences and Biotechnology and LTTA CentreUniversity of FerraraFerraraItaly
| | - Francesco Bernardi
- Department of Life Sciences and Biotechnology and LTTA CentreUniversity of FerraraFerraraItaly
| |
Collapse
|
3
|
El-Kamah GY, Mosaad RM, Taher MB, Amr KS. Defining the molecular pathology and consequent phenotypes in Egyptian HB patients. J Genet Eng Biotechnol 2021; 19:75. [PMID: 33999344 PMCID: PMC8128942 DOI: 10.1186/s43141-021-00165-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/14/2021] [Indexed: 11/18/2022]
Abstract
BACKGROUND Hemophilia B (HB) (also known as Christmas disease) is a rare X-linked recessive disorder characterized by spontaneous or prolonged hemorrhages caused by mutations in Factor 9 (F9) gene leading to deficient or defective coagulation F9. Our study aimed at identifying the causative mutations within a sample of HB Egyptian patients. The present study comprised clinical data of eleven HB patients descending from six unrelated families and a seventh family including a carrier mother with a history of deceased HB sibling. Sequencing of F9 gene was performed. RESULTS The study revealed four mutations; two missense NM_000133.3:c.676C>G, (P.Arg226Gly) and NM_000133.3:c.1305T>G, (p.Cys435Trp), and two nonsense mutations NM_000133.3:c.880C>T, (p.Arg294*) and NM_000133.3:c.1150C>T, (p.Arg384*), identified mutations spanned exons 6 and 8 of which a total of three mutations are located in hotspot exon 8 of F9 gene. CONCLUSIONS Reviewing the literature, this is the first molecular analysis of F9 gene in HB Egyptian patients. Consistent genotype/phenotypic severity correlation could be concluded, helping proper genetic counseling and prenatal decision taking.
Collapse
Affiliation(s)
- Ghada Y El-Kamah
- Clinical Genetics Department, Human Genetics and Genome Research division (HGGR), National Research Centre (NRC), Cairo, Egypt
| | - Rehab M Mosaad
- Molecular Genetics and Enzymology Department, HGGR, NRC, El Buhouth St., Dokki, Cairo, Egypt.
| | - Mohamed B Taher
- Clinical Genetics Department, Human Genetics and Genome Research division (HGGR), National Research Centre (NRC), Cairo, Egypt
| | - Khalda S Amr
- Medical Molecular Genetics, HGGR, NRC, Cairo, Egypt
| |
Collapse
|
4
|
Khan MTM, Naz A, Ahmed J, Shamsi T, Ahmed S, Ahmed N, Imran A, Farooq N, Khan MTH, Taj AS. Mutation Spectrum and Genotype-Phenotype Analyses in a Pakistani Cohort With Hemophilia B. Clin Appl Thromb Hemost 2017; 24:741-748. [PMID: 28752769 DOI: 10.1177/1076029617721011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study aimed to (1) identify F9 genetic alterations in patients with hemophilia B (HB) of Pakistani origin and (2) determine the genotype-phenotype relationships in these patients. Diagnosed cases of HB were identified through registries at designated tertiary health-care centers across the country. Consenting patients were enrolled into the study. The factor IX (FIX) coagulation activity (FIX:C) and key clinical features were recorded. Direct sequencing of F9 was carried out in all patients. All the variants identified were analyzed for functional consequences employing in silico analysis tools. Accession numbers from National Center of Biotechnology Information ClinVar database were retrieved for the novel variants. Genotype-FIX:C relationships were determined followed by FIX:C clinical phenotype assessment. A total of 52 patients with HB from 36 unrelated families were identified, which mainly comprised patients with moderate HB (n = 35; 67.3%). Among these, 35 patients from 22 unrelated families could be contacted and enrolled into the study. Missense variants were the most frequent (58.8%), followed by nonsense variants (17.6%). A missense, a short insertion, and a nonsense novel variants in exon 2, 6, and 7, respectively, were also identified. The disease manifested FIX:C heterogeneity in relation to the corresponding mutation in a significant number of cases. Clinical phenotype heterogeneity was also observed in relation to FIX:C-based severity assessment. We concluded that the registered FIX-deficient population of Pakistan mainly comprises moderate HB. F9 mutation spectrum in Pakistani patients with HB is heterogeneous. The HB population of Pakistan manifests a significant amount of genotype-FIX:C and FIX:C-clinical phenotype heterogeneities.
Collapse
Affiliation(s)
- Muhammad Tariq Masood Khan
- 1 Hematology Department, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan
| | - Arshi Naz
- 2 National Institute of Blood Diseases & Bone Marrow Transplantation, Karachi, Pakistan
| | - Jawad Ahmed
- 1 Hematology Department, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan
| | - Tahir Shamsi
- 2 National Institute of Blood Diseases & Bone Marrow Transplantation, Karachi, Pakistan
| | - Shariq Ahmed
- 2 National Institute of Blood Diseases & Bone Marrow Transplantation, Karachi, Pakistan
| | - Nisar Ahmed
- 3 Children's Hospital & the Institute of Child Health, Lahore, Pakistan
| | - Ayisha Imran
- 4 Chughtai Lab Medical Pathology Laboratory, Lahore, Pakistan
| | - Nazish Farooq
- 1 Hematology Department, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan
| | | | - Abid Sohail Taj
- 1 Hematology Department, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan
| |
Collapse
|
5
|
Cao DH, Liu XL, Mu K, Ma XW, Sun JL, Bai XZ, Lin CK, Jin CL. Identification and Genetic Analysis of a Factor IX Gene Intron 3 Mutation in a Hemophilia B Pedigree in China. Turk J Haematol 2014; 31:226-30. [PMID: 25330515 PMCID: PMC4287022 DOI: 10.4274/tjh.2013.0275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Objective: Hemophilia B is caused by coagulation defects in the factor IX gene located in Xq27.1 on the X chromosome. A wide range of mutations, showing extensive molecular heterogeneity, have been described in hemophilia B patients. Our study was aimed at genetic analysis and prenatal diagnosis of hemophilia B in order to further elucidate the pathogenesis of the hemophilia B pedigree in China. Materials and Methods: Polymerase chain reaction amplification and direct sequencing of all the coding regions was conducted in hemophilia B patients and carriers. Prenatal diagnosis of the proband was conducted at 20 weeks. Results: We identified the novel point mutation 10.389 A>G, located upstream of the intron 3 acceptor site in hemophilia B patients. The fetus of the proband’s cousin was identified as a carrier. Conclusion: Our identification of a novel mutation in the F9 gene associated with hemophilia B provides novel insight into the pathogenesis of this genetically inherited disorder and also represents the basis of prenatal diagnosis.
Collapse
Affiliation(s)
- Dong-Hua Cao
- China Medical University, Department of Medical Genetics, Shenyang, China. E-ma-il:
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Doss C GP. In silico profiling of deleterious amino acid substitutions of potential pathological importance in haemophlia A and haemophlia B. J Biomed Sci 2012; 19:30. [PMID: 22423892 PMCID: PMC3361463 DOI: 10.1186/1423-0127-19-30] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 03/16/2012] [Indexed: 01/08/2023] Open
Abstract
Background In this study, instead of current biochemical methods, the effects of deleterious amino acid substitutions in F8 and F9 gene upon protein structure and function were assayed by means of computational methods and information from the databases. Deleterious substitutions of F8 and F9 are responsible for Haemophilia A and Haemophilia B which is the most common genetic disease of coagulation disorders in blood. Yet, distinguishing deleterious variants of F8 and F9 from the massive amount of nonfunctional variants that occur within a single genome is a significant challenge. Methods We performed an in silico analysis of deleterious mutations and their protein structure changes in order to analyze the correlation between mutation and disease. Deleterious nsSNPs were categorized based on empirical based and support vector machine based methods to predict the impact on protein functions. Furthermore, we modeled mutant proteins and compared them with the native protein for analysis of protein structure stability. Results Out of 510 nsSNPs in F8, 378 nsSNPs (74%) were predicted to be 'intolerant' by SIFT, 371 nsSNPs (73%) were predicted to be 'damaging' by PolyPhen and 445 nsSNPs (87%) as 'less stable' by I-Mutant2.0. In F9, 129 nsSNPs (78%) were predicted to be intolerant by SIFT, 131 nsSNPs (79%) were predicted to be damaging by PolyPhen and 150 nsSNPs (90%) as less stable by I-Mutant2.0. Overall, we found that I-Mutant which emphasizes support vector machine based method outperformed SIFT and PolyPhen in prediction of deleterious nsSNPs in both F8 and F9. Conclusions The models built in this work would be appropriate for predicting the deleterious amino acid substitutions and their functions in gene regulation which would be useful for further genotype-phenotype researches as well as the pharmacogenetics studies. These in silico tools, despite being helpful in providing information about the nature of mutations, may also function as a first-pass filter to determine the substitutions worth pursuing for further experimental research in other coagulation disorder causing genes.
Collapse
Affiliation(s)
- George Priya Doss C
- School of Bio Sciences and Technology, VIT University, Vellore, Tamil Nadu, India.
| |
Collapse
|
7
|
Novel mutations in factor IX gene from western India with reference to their phenotypic and haplotypic attributes. J Pediatr Hematol Oncol 2009; 31:157-60. [PMID: 19262239 DOI: 10.1097/mph.0b013e31818b3759] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Hemophilia B (HB) is an X-linked recessively inherited bleeding disorder caused by heterogeneous mutations in the factor IX gene. STUDY DESIGN AND METHODS We screened for mutations in HB patients using a combination of multiplex polymerase chain reaction, conformation sensitive gel electrophoresis, and DNA sequencing. Phenotypic analysis was performed using 1 stage assay for factor IX: C activity and enzyme-linked immunosorbent assay for factor IX: Ag. Haplotype analysis was performed using the common polymorphic markers of the factor IX gene. RESULTS Seventeen novel mutations comprising of missense mutations, nonsense mutations, and small deletions were detected. Haplotype analysis indicated that some of the patients had a common haplotype background but had different molecular defects thereby suggesting that all the mutations arose de novo. Phenotypic data suggested that about one-fourth of the patients (23%) had antigen-activity discordance. Furthermore, it was observed that a majority of the molecular defects (71%) were located in exon H of the factor IX gene. The mutation screening strategy was thus modified wherein exon H was screened first followed by screening of other exons. CONCLUSIONS The present findings suggest that there is a wide phenotypic and genotypic heterogeneity in HB. Presence of more than 70% of mutations in exon H of the factor IX gene allows us to adopt a cost effective screening strategy in offering genetic diagnosis to the affected families.
Collapse
|
8
|
Jayandharan G, Shaji RV, Nair SC, Chandy M, Srivastava A. Novel missense mutations in two patients with factor XI deficiency (Val271Leu and Tyr351Ser) and one patient with combined factor XI and factor IX deficiency (Phe349Val). J Thromb Haemost 2005; 3:808-11. [PMID: 15842381 DOI: 10.1111/j.1538-7836.2005.01230.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
9
|
Enayat MS, Karimi M, Chana G, Farjadian S, Theophilus BDM, Hill FGH. Mutation Analysis in F9 Gene of 17 Families with Haemophilia B from Iran. Haemophilia 2004; 10:751-5. [PMID: 15569175 DOI: 10.1111/j.1365-2516.2004.01041.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The most common type of surgical procedure in patients with haemophilia is orthopaedic surgery on the lower limb. These procedures are of great importance for the improvement of the function and quality of life of patients with haemophilia, but in many countries resources are lacking to provide the factor concentrates needed for these operations. We have attempted to reduce the level of replacement during and after total hip or total knee replacement without jeopardizing the outcome of the procedures. The results from 30 operations in 27 patients are presented. Steady-state levels down to 0.5 IU mL(-1) did not appear to increase the amount of blood loss or cause an increased incidence of complications, compared with higher levels. In addition, we review the possibilities to reduce the amount of factor concentrate by performing a combination of orthopaedic procedures and using local haemostatic agents or antifibrinolytic agents.
Collapse
|