Factor V Research Articles

A Systematic Review and Meta-Analysis of the Association between the FV H1299R Variant and the Risk of Recurrent Pregnancy Loss.

This study evaluated the association between the H1299R factor V (FV) variant (rs1800595) and recurrent pregnancy loss (RPL). Pubmed (MEDLINE) and Embase (OVID) bibliographic databases were searched from the inception to 31 May 2022 to identify suitable articles according to PRISMA and MOOSE guidelines. We included observational studies, case-control studies, cross-sectional studies, and cohort studies reporting a numerical and well-distinguished Het or Hom status of the H1299R variant obtained through PCR or other biochemical techniques and comparing RPL patients with a healthy control group. The review protocol was registered at PROSPERO (CRD42022330077). Two authors independently screened studies, extracted data, and carried out the risk of bias assessment using the Newcastle Ottawa scale (NOS). A meta-analysis was performed with RevMan software Version 5.4 using an odds ratio (OR) with an M-H, random effect, and 95% CI. We included 13 clinical studies for a total of 1669 RPL patients and 1466 healthy women as a control group. H1299R variant was slightly associated with RPL albeit without significance (OR 1.18, 95% CI: 0.78-1.80, p = 0.44). Subgroup analyses considering H1299R in heterozygosity (OR 1.13, 95% CI: 0.76-1.67, p = 0.56) and in homozygosity (OR: 2.11, 95% CI: 0.74-6.01, p = 0.16) revealed a similar trend. Lastly, we evaluated the association between H1299R and RPL based on the number of previous miscarriages (≥2 or ≥3). This comprehensive systematic review and meta-analysis sheds light on the specific influence of the H1299R variant in the F5 gene on RPL, constituting valid support for medical care during pregnancy and genetic counseling.

Preimplantation genetic testing (PGT) for hemophilia A: Experience from one center

ObjectiveHemophilia A (HA) is an X-linked recessive bleeding disease caused by a deficiency or dysfunction of blood coagulation factor VIII (FVIII). Available treatment to replenish the missing factor may not reach a good outcome for all patients because of potential complications that include the development of inhibitor antibodies directed against factor VIII. Therefore, the prevention of transmitting pathogenic mutations to the next generation is the best solution for this disease. Preimplantation genetic testing for a monogenic disorder (PGT-M) has become a standard method to prevent the transmission of monogenic heritable disease. The gold standard of the molecular technique used for PGT-M nowadays is the co-amplification of the polymorphic microsatellite linkage markers that use microsatellite DNA technique that overcomes the limitation of other methods. The important issue of this technique is the definition of markers that are specific for each allele on different loci. Each gene locus needs a characteristic design to allow accurate diagnosis that can be applied on PGT-M due to the limited quantity of DNA available. Here we present our study of four specific self-designed linked polymorphic markers applied on screening the embryos before implantation for hemophilia A families in Vietnam. Material and methodsIn this study, we investigated the feasibility of application and diagnostic value of 4 STR loci (FXS1108, DXS9897, F8int22, DXS9901) in the intragenic or neighbouring regions of the F8 gene. 35 hemophilia A families were recruited for STR analysis to define at least two characteristic heterologous markers for each family and 12 cases of pre-implantation genetic testing (PGT-M) for carrier mothers were performed. ResultAll 4 of these loci (FXS1108, DXS9897, F8int22, DXS9901) were found practical and useful for preimplantation genetic testing (PGT-M). All 12 cases of PGT-M using the method had informative STR results and correct diagnosis was achieved. 9 out of the 12 mothers (75%) were implanted with 1–2 thawed embryos after the biopsy resulting in the birth of 5 healthy babies (55%). ConclusionWe conclude that specific 4 STR markers for rapid pre-implantation genetic testing of hemophilia A can be successfully applied with high confidence and accuracy in clinical settings. The results of the study provide solid evidence confirming that the microsatellite DNA technique is a highly reliable method, suitable for hemophilia A families wishing to determine carrier status or having healthy babies.

Рідкісні порушення згортання крові

The problem of impaired hemostasis remains relevant even today. Rare bleeding disorders that cause life-threatening bleeding in patient are often overlooked by clinicians. Rare blood coagulation disorders are a genetically determined group of coagulopathies caused by a deficiency of blood plasma proteins involved in hemostasis, as well as a deficiency of fibrinogen, prothrombin, blood coagulation factor V (FV), blood coagulation factors V and VIII (FV+FVIII), blood coagulation factor VII (FVII), blood coagulation factor X (FX), blood coagulation factor XI (FXI), blood coagulation factor XII (FXII), blood coagulation factor XIII (FXIII), which are clinically are manifested by bleeding. The amount of the factor determines not only the nature of bleeding, but also their severity and prognosis for the disease. In such patients, the general hemostatic balance is important, since the level of each blood coagulation factor and the general control of hemostasis, which can determine the risk of bleeding, remain important. Purpose - to draw the attention of doctors of various specialties to the problem of clinical manifestations of rare hereditary disorders of blood coagulation, which can be accompanied by bleeding that poses a threat to the health and life of patient. Clinical case. A clinical case is presented that illustrates the course of a rare blood coagulation disorder in children from one family, where a comprehensive diagnostic search was conducted by doctors of various specialties to establish a final diagnosis. Conclusions. Rare blood coagulation disorders are a pathology that is not often found in the population, but clinical symptoms can have negative consequences for a person's health and life. Children with various manifestations of hemorrhagic syndrome need a thorough diagnostic examination in specialized laboratories. Physicians of related specialties should look for a possible rare deficiency of the coagulation factor in early and late complications in the postoperative period or after medical manipulations. It is necessary to remember the hereditary genesis of this pathology and examine all family members. The research was carried out in accordance with the principles of the Helsinki Declaration. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Laparoscopic hepatectomy for hepatocellular carcinoma in a patient with congenital factor V deficiency: a case report

BackgroundFactor V (FV) deficiency is an extremely rare disease, with an incidence of 1 in 1 million. The bleeding symptoms are mild, and the prognosis is good; however, the safety of surgical treatment is unclear, because there are few available reports. Herein, we report a case of hepatocellular carcinoma with congenital FV deficiency in a patient who safely underwent laparoscopic hepatectomy.Case presentationA 79-year-old man, diagnosed with hepatocellular carcinoma of liver segment 5, with type C cirrhosis and sustained virological response visited our hospital. He had congenital FV deficiency, and blood tests showed coagulation deficiencies with an FV activity of < 2.6%, prothrombin time activity of 11%, and activated partial thromboplastin time of 100.3 s. Surgery and radiofrequency ablation were considered for treatment. Since the tumor was in contact with the Glissonean pedicle 5 + 6, surgery was judged to be superior from the viewpoint of safety and curability. After discussing the safety of the surgery with a hematologist, it was determined that the operation could be performed safely by transfusing sufficient fresh frozen plasma (FFP). Laparoscopic hepatic segment 5 + 6 subsegmental resection was performed with FFP transfusion, fluid restriction, airway pressure control, and central venous pressure reduction to control the bleeding. Bleeding was minimized during the transection of the liver parenchyma and no bleeding tendency was observed. The operative time was 445 min, and the amount of intraoperative bleeding was 171 mL. No complications, such as postoperative bleeding, were observed, and the patient was discharged on the eighth postoperative day.ConclusionsLiver surgery can be performed safely in FV-deficient patients with strict coagulation capacity monitoring and appropriate transfusion of FFP. Preoperative evaluation of cardiac function to determine tolerance to high doses of FFP and ingenuity of surgery and intraoperative management to minimize blood loss are important.

Primary Graft Dysfunction: Factor V's Value for Its Early Diagnosis

Primary graft dysfunction is a common postoperative complication, lacking consensus regarding diagnostic criteria. Olthoff criteria are the most used, based on blood parameters in the first 7 postoperative days. This lack of consensus and late diagnosis evidence the need of early parameters. This study proposes factor V (FV) as a marker in the first 3 postoperative days for primary graft dysfunction. Within a 500-patient database, 27 patients with graft loss in the first 90 days were chosen and compared with a group of 54 patients composed of the immediately preceding and following transplant to each case. Through receiver operating characteristic curves, FV and maximum glutamic pyruvic transaminase (GPT) predictive value on the first 3 postoperative days were assessed. The best threshold value was selected according to the Youden index. FV was significantly higher in the control group, with second postoperative day as the highest discriminative one (area under the curve=0.893). In addition, a cutoff point of FV 37.50 exhibited a specificity of 92% and sensibility of 69% in predicting allograft failure in the first 3 months. GPT showed a lower validity with area under the curve=0.77, and a GPT of 1539 presented a specificity of 82% and sensibility of 67%. Combining FV < 37.5 and GPT > 1539, a specificity of 98% and sensibility of 55% was reached. FV could postulate as an early marker of primary graft dysfunction because of its high specificity despite having a lower sensibility. With de association of FV and GPT the maximum specificity for predicting graft loss in the first 3 months was reached, becoming a promising parameter for further analysis.

Universal DNAzyme walkers-triggered CRISPR-Cas12a/Cas13a bioassay for the synchronous detection of two exosomal proteins and its application in intelligent diagnosis of cancer

Exosomal proteins are considered to be promising indicators of cancer. Herein, a novel DNAzyme walkers-triggered CRISPR-Cas12a/Cas13a strategy was proposed for the synchronous determination of exosomal proteins: serum amyloid A-1 protein (SAA1) and coagulation factor V (FV). In this design, the paired antibodies were used to recognize targets, thereby ensuring the specificity. DNAzyme walkers were employed to convert the contents of SAA1 and FV into activators (P1 and P2), and one target can produce abundant activators, thus achieving an initial amplification of signal. Furthermore, the P1 and P2 can activate CRISPR-Cas12a/Cas13a system, which in turn trans-cleaves the reporters, enabling a second amplification and generating two fluorescent signals. The assay is highly sensitive (limits of detection as low as 30.00 pg/mL for SAA1 and 200.00 pg/mL for FV), highly specific and ideally accurate. More importantly, it is universal and can be used to detect both non-membrane and membrane proteins in exosome. Besides, the method can be successfully applied to detect SAA1 and FV in plasma exosomes to differentiate between lung cancer patients and healthy individuals. To explore the application of the developed method in tumor diagnosis, a deep learning model based on the expressions of SAA1 and FV was developed. The accuracy of this model can achieve 86.96%, which proves that it has a promising practical application capacity. Thus, this study does not only provide a new tool for the detection of exosomal proteins and cancer diagnosis, but also propose a new strategy to detect non-nucleic acid analytes for CRISPR-Cas system.

A Clot Waveform Analysis of Thrombin Time Using a Small Amount of Thrombin Is Useful for Evaluating the Clotting Activity of Plasma Independent of the Presence of Emicizumab.

Objective: Although emicizumab is a bispecific, monoclonal antibody that has led to a significant improvement of treatment for hemophilia A patients with inhibitors, the routine monitoring of patients treated with emicizumab is difficult. Thrombin time (TT) reflects thrombin burst, which mainly depends on activation of factor V (FV) and FVIII. Methods: We, therefore, developed a method for evaluating clotting activity independent of the presence of emicizumab. Normal plasma (NP) or FVIII-deficient plasma (FVIIIDP) with and without emicizumab was measured using clot waveform analysis (CWA)-activated partial thromboplastin time (APTT) and TT. Results: Emicizumab caused clot formation in FVIIIDP using the CWA-APTT; however, the coagulation peaks of plasma with and without emicizumab measured by the CWA-TT did not differ to a statistically significant extent. Regarding the mixing tests with NP and FVIIIDP, CWA-APTT showed large differences between each mixing test in plasma with and without emicizumab, whereas the CWA-TT showed similar patterns in mixing plasma with and without emicizumab. Regarding the standard curve of FVIII activity, the CWA-APTT showed an FVIII-concentration-dependent increase; however, the values with each concentration of FVIII differed between samples with and without emicizumab, whereas CWA-TT showed FVIII-concentration-dependent fluctuations independent of the presence of emicizumab, and the values with each concentration of FVIII were similar in samples with and without emicizumab. Conclusions: As CWA-TT using a small amount of thrombin (0.5 IU/mL) can reflect thrombin burst and be useful for evaluating FVIII activity, independent of the presence of emicizumab, it is useful for monitoring clotting activity in patients with an anti-FVIII inhibitor treated with emicizumab.

Compound heterozygosity for novel von Willebrand factor genetic variants associated with von Willebrand disease in two Chinese patients.

Von Willebrand factor (VWF) encodes a secreted glycoprotein involved in primary hemostasis. Genetic mutations in this gene leading to either quantitation or qualitative defects of VWF, result in von Willebrand disease (VWD), an inherited bleeding disorder. In this study, two families with VWD were recruited and submitted to a series of clinical and genetic examinations. prothrombin time, activated partial thromboplastin time, thrombin time, factor VIII coagulant activity (FVIII:C), VWF antigen (VWF:Ag), VWF ristocetin cofactor (VWF:RCo) tests were measured in peripheral blood. F8, F9, and VWF genes were sequenced using next-generation sequencing, and Sanger sequencing was used as a validation method. Both families had a child suffered spontaneous bleeding. Patient 1 showed normal VWF:Ag, severely decreased FVIII:C and VWF:RCo. Patient 2 showed severely decreased FVIII:C, VWF:Ag, and VWF:RCo. Compound heterozygous mutations of VWF gene were identified in both patients. Patient 1 had a novel deletion variant c.1910_1932del (p.Gly637AlafsTer5) and a missense variant c.605G>A (p.Arg202Gln). Patient 2 had a novel missense variant c.4817T>A (p.Met1606Lys) and a novel missense variant c.5983C>T (p.Pro1995Ser). We described clinical and molecular features of VWD caused by compound heterozygous mutations in two Chinese patients. Our results expand the variation spectrum of the VWF gene and deepen the understanding of the relationship between the genotype and clinical characteristics of VWD.

Accessibility and visibility of genetic testing for haemophilia across Europe: Where do we stand?

Haemophilia is characterized by bleeding complications resulting from clotting factor VIII (FVIII) or IX (FIX) deficiency. Identifying the causal pathogenic genetic variant denotes a vital aspect of haemophilia management. This study evaluated the accessibility and performances of genetic testing for haemophilia across Europe. The types of genetic analyses, techniques used, turn-around time (TAT) and costs were collected and analysed, as were data updating and quality control. Reported data were retrieved from open access resources, including international databases, Google, laboratory websites, PubMed and government organizations. Overall, 51 genetic laboratories across 15 European countries providing recently updated molecular haemophilia testing were identified. Gene sequencing for small variants of both F8 and F9 genes was provided in most surveyed laboratories. Almost two-thirds of them offer analysis for inversions using a polymerase chain reaction (PCR) method and detection of copy number variation (CNV) using multiplex ligation-dependent probe amplification (MLPA). Cost and TAT were found to vary considerably. In total, 74% of laboratories exhibited a last modified date or change history. The same percentage of laboratories was in possession of an ISO 15189 standard accreditation, whereas only few of them recently performed external quality assessment schemes (EQA) for haemophilia. Despite several initiatives to improve access to genetic testing for haemophilia, such access must still be improved. Our study similarly revealed the large heterogeneity of the variants tested, techniques employed, TAT, cost and quality among the surveyed laboratories.

INVESTIGATION OF INHERITANCE BY MOLECULAR DIAGNOSIS IN A FAMILY WITH NO FAMILY HISTORY OF HEMOPHILIA A: CASE REPORT

Hemophilia A (HA) is classified according to residual circulating FVIII (FVIII:C). Patients with FVIII:C 5%-40% are classified as mild HA; patients with FVIII:C 1%-5% are considered moderate; and patients with FVIII:C <1% are classified as severe HA. Patients with severe HA have two common mutations: Inversions of introns 1 and 22 of the F8 gene. The aim of this study is to report the case of a patient diagnosed with HA without any family history of the disease and treated in Fundação Hemominas in 2022. Male patient, NB, presented an extensive hematoma on the back after 24 hours of delivery. A blood count was performed, which reveals a hemoglobin value of 5 g/dL (reference value approximately 16 g/dL). Patient is admitted to the ICU where a blood transfusion and coagulometric tests are performed, indicating HA. The patient is referred to the pediatric hematology unit of Fundação Hemominas. Coagulation tests confirmed the diagnosis of severe HA. The patient was referred for molecular diagnosis of the disease. In addition, three members of the patient's family agreed to participate in the molecular diagnosis. The family members answered two questionnaires: 1) bleeding assessment score - ISTH (BAT-ISTH); and 2) arthralgia assessment. Peripheral blood was drawn from all participants in a citrate tube, and samples were processed for genomic DNA extraction. Genotyping of the intron 22 inversion mutation was performed by inverse PCR. The patient was positive for intron-22 inversion, confirming the diagnosis of severe hemophilia A. The patient's mother (34 years old), with a bleeding score of 3, without joint pain, was diagnosed with the same inversion and received genetic counseling when the report was handed over. The patient's aunt (30 years old), with a bleeding score of 0, without joint pain, had a negative result for intron inversion 22. The patient's grandmother, 59 years old, with a bleeding score of 1, who presented right knee pain, also had a negative result. Evaluation of the patient's three-generation pedigree suggests that the patient inherited the de novo mutation from his mother. In conclusion, molecular diagnosis of patients and their families is considered important for correct classification of disease severity and for the development of family studies with regard to genetic counseling of patients and women with mutated F8 genes. Additionally, molecular diagnosis is important to verify the de novo mutation rate in the population of patients with HA. We thank all participants, Fapemig, Hemominas, and the CGSH of the Ministry of Health.

Regulation of factor V by the anticoagulant protease activated protein C: Influence of the B-domain and TFPIα

Activated protein C (APC) is an important anticoagulant protein that regulates thrombin generation through inactivation of factor V (FV) and activated factor V (FVa). The rate of APC inactivation of FV is slower compared to FVa, although proteolysis occurs at the same sites (Arg306, Arg506, and Arg679). The molecular basis for FV resistance to APC is unknown. Further, there is no information about how FV-short, a physiologically relevant isoform of FV with a shortened B-domain, is regulated by APC. Here, we identify the molecular determinants which differentially regulate APC recognition of FV versus FVa and uncover how FV-short can be protected from this anticoagulant pathway. Using recombinant FV derivatives and B-domain fragments, we show that the conserved basic region (BR; 963-1008) within the central portion of the B-domain plays a major role in limiting APC cleavage at Arg506. Derivatives of FV lacking the BR, including FV-short, were subject to rapid cleavage at Arg506 and were inactivated like FVa. The addition of a FV-BR fragment reversed this effect and delayed APC inactivation. We also found that anticoagulant glycoprotein TFPIα, which has a C-terminal BR homologous to FV-BR, protects FV-short from APC inactivation by delaying cleavage at Arg506. We conclude that the FV-BR plays a major role in protecting FV from APC inactivation. Using a similar mechanistic strategy, TFPIα also shields FV-short from APC. These findings clarify the resistance of FV to APC, advance our understanding of FV/FVa regulation, and establish a mechanistic framework for manipulating this reaction to alter coagulation.

Спектр мутаций гена F9 у российских больных гемофилией В

Гемофилия В - Х-сцепленное рецессивное заболевание, связанное с нарушением свертываемости крови, вызванное мутациями в гене фактора свертывания IX (F9). В гене описаны как точковые изменения последовательности, так и крупные структурные перестройки. Целью данного исследования было определение спектра мутаций гена F9 у российских больных гемофилией B. Проведено исследование 59 неродственных семей с направительным диагнозом «гемофилия B» методами секвенирования по Сэнгеру, массового параллельного секвенирования и количественного MLPA анализа. Мутации обнаружены в 86,4% случаев. Наибольшую долю среди выявленных патогенных вариантов составляют миссенс-мутации - 62,7%, на долю нонсенс-мутаций приходится 19,6%, крупных делеций, включающих один или несколько экзонов - 3,9%, мутаций со сдвигом рамки считывания - 5,9%, мутаций сайта сплайсинга - 2%, мутаций промотора - 5,9%, что в целом соответствует литературным данным. Четырнадцать выявленных нуклеотидных вариантов ранее не были описаны. Большинство из них являются миссенс-мутациями. Таким образом, было проведено изучение спектра мутаций у российских больных гемофилией B. Определение типа мутации, ее локализации в гене и белке позволит предсказать характер течения заболевания и подобрать оптимальное лечение. Hemophilia B is an X-linked recessive disease associated with blood clotting disorder caused by mutations in the coagulation factor IX (F9) gene. Both point sequence changes and large structural rearrangements were described in the gene. The aim of this study was to determine the spectrum of mutations in the F9 gene in Russian patients with hemophilia B. A study of 59 unrelated families with a referral diagnosis of “hemophilia B” was conducted using Sanger sequencing, mass parallel sequencing, and quantitative MLPA analysis. Mutations were detected in 86.4% of cases. The prevalent among the identified pathogenic variants were missense mutations - 62.7%; nonsense mutations account for 19.6%, large deletions involving one or more exons - 3.9%, mutations with a reading frame shift - 5.9%, splice site mutations - 2%, mutations in the promoter- 5.9%, which generally corresponds to the literature data. Fourteen identified nucleotide variants have not been previously described. Most of them were missense mutations. Thus, we studied the spectrum of mutations in Russian patients with hemophilia B. Determining the type of mutation and its localization in the gene and protein will allow to predict the course of the disease and to choose the optimal treatment.

Factor IX inhibitors in haemophilia B: A report of National Haemophilia Registry in China.

The development of inhibitors against factor FIX (FIX) is the most serious complication of FIX replacement therapy in haemophilia B (HB) patients. Currently, only few cohorts of HB inhibitor patients have been reported worldwide. This Chinese nationwide study of HB inhibitor patients explored their risk factors for FIX inhibitor development and experience on their management. We retrospectively analysed patient characteristics, F9 genotypes, treatment strategies and outcomes of HB inhibitor patients registered to the Chinese National Registry and Patient Organization Registry. Forty-four unique HB inhibitor patients were identified in 4485 unique HB patients registered by year 2021 to the two Registries. Inhibitor diagnosis were usually delayed and the low prevalence (.98%) may suggest some inhibitor patients were not identified. Their median age at inhibitor diagnosis was 7.5 (IQR, 3.0-14.8) years. Most patients (95.5%) had high-titre inhibitors. Allergic/Anaphylactic reactions occurred in 59.1% patients. Large deletions and nonsense mutations were the most common F9 mutation types in our FIX inhibitor patients. Patients with large F9 gene deletions were more likely to develop inhibitors (p =.0002), while those with missense mutations had a low risk (p <.0001). Thirteen (29.5%) patients received immune tolerance induction (ITI) therapy using low-dose prothrombin complex concentrate regimens. Twelve completed ITI with three (25.0%) achieving success. Nephrotic syndrome developed in two (16.7%) patients during ITI. This study reports the largest Chinese cohort of HB inhibitor patients. Large deletions were most significantly associated with inhibitor development. Low-dose ITI might be feasible for FIX inhibitor eradication.

Identification of Diagnostic Genes and Effective Drugs Associated with Osteoporosis Treatment by Single-Cell RNA-Seq Analysis and Network Pharmacology.

Background Osteoporosis is a common bone metabolic disease with increased bone fragility and fracture rate. Effective diagnosis and treatment of osteoporosis still need to be explored due to the increasing incidence of disease. Methods Single-cell RNA-seq was acquired from GSE147287 dataset. Osteoporosis-related genes were obtained from chEMBL. Cell subpopulations were identified and characterized by scRNA-seq, t-SNE, clusterProfiler, and other computational methods. “limma” R packages were used to identify all differentially expressed genes. A diagnosis model was build using rms R packages. Key drugs were determined by proteins-proteins interaction and molecular docking. Results Firstly, 15,577 cells were obtained, and 12 cell subpopulations were identified by clustering, among which 6 cell subpopulations belong to CD45+ BM-MSCs and the other subpopulations were CD45-BM-MSCs. CD45- BM-MSCs_6 and CD45+ BM-MSCs_5 were consider as key subpopulations. Furthermore, we found 7 genes were correlated with above two subpopulations, and F9 gene had highest AUC. Finally, five compounds were identified, among which DB03742 bound well to F9 protein. Conclusions This work discovered that 7 genes were correlated with CD45-BM-MSCs_6 and CD45+ BM-MSCs_5 subpopulations in osteoporosis, among which F9 gene had better research value. Moreover, compound DB03742 was a potential inhibitor of F9 protein.

Skewed X-Chromosome Inactivation and Parental Gonadal Mosaicism Are Implicated in X-Linked Recessive Female Hemophilia Patients.

Background: Hemophilia A (HA) and B (HB) are X-linked recessive disorders that mainly affect males born from a mother carrier. Females are rarely affected but a number of mechanisms have been suggested in symptomatic females, such as skewed X-chromosome inactivation (XCI), chromosomal rearrangements, and hermaphrodites. Different methodologies are required to elucidate the underlying causes of such diseases in female patients. Methods: Three families with female hemophilia patients, including two HA and one HB, were enrolled for genetic analyses. Cytogenetics, molecular examinations on F8 and F9 genes, XCI assay, and linkage analysis were performed. Results: All three female patients are demonstrated to be heterozygous for an F8, or F9 mutation: one patient is inherited from her unaffected mother and the other two are sporadic cases. All three patients exhibit skewed XCI. The inherited patient is found to be unmethylated in the maternal X chromosome, which increases the potential for the expression of the mutant allele. The two sporadic cases are hypomethylated or unmethylated in the paternal X chromosome, suggesting that paternal gonadal mosaicism may exist in these families. Conclusions: In addition to screening for coagulation function, different genetic analyses are mandatory to explore the nature of mechanisms responsible for the X-linked recessive disorders in female patients as shown in this study. Our results confirm that skewed XCI is responsible for hemophilia in heterozygous female patients. Likewise, our results implicate that parental gonadal mosaicism, followed by skewed XCI, contributes to hemophilia in “sporadic” female patients.

Results of genetic analysis of 11 341 participants enrolled in the My Life, Our Future hemophilia genotyping initiative in the United States

BackgroundHemophilia A (HA) and hemophilia B (HB) are rare inherited bleeding disorders. Although causative genetic variants are clinically relevant, in 2012 only 20% of US patients had been genotyped. ObjectivesMy Life, Our Future (MLOF) was a multisector cross‐sectional US initiative to improve our understanding of hemophilia through widespread genotyping. MethodsSubjects and potential genetic carriers were enrolled at US hemophilia treatment centers (HTCs). Bloodworks performed genotyping and returned results to providers. Clinical data were abstracted from the American Thrombosis and Hemostasis Network dataset. Community education was provided by the National Hemophilia Foundation. ResultsFrom 2013 to 2017, 107 HTCs enrolled 11 341 subjects (68.8% male, 31.2% female) for testing for HA (n = 8976), HB (n = 2358), HA/HB (n = 3), and hemophilia not otherwise specified (n = 4). Variants were detected in most male patients (98.2%% HA, 98.1% HB). 1914 unique variants were found (1482 F8, 431 F9); 744 were novel (610 F8, 134 F9). Inhibitor data were available for 6986 subjects (5583 HA; 1403 HB). In severe HA, genotypes with the highest inhibitor rates were large deletions (77/80), complex intron 22 inversions (9/17), and no variant found (7/14). In severe HB, the highest rates were large deletions (24/42). Inhibitors were reported in 27.3% of Black versus 16.2% of White patients. ConclusionsThe findings of MLOF are reported, the largest hemophilia genotyping project performed to date. The results support the need for comprehensive genetic approaches in hemophilia. This effort has contributed significantly towards better understanding variation in the F8 and F9 genes in hemophilia and risks of inhibitor formation.

Congenital factor V deficiency in Taiwan: identification of a novel variant p.Tyr1813 ∗ and two variants specific to East Asians.

Congenital coagulation factor V deficiency (FVD) is a rare, autosomal recessive bleeding disorder. We characterized the clinical presentations, laboratory features, and genetic alterations of Taiwanese patients with FVD. From 1983 to 2010, five women, one man, and one boy diagnosed with FVD were enrolled in this study. The factor V coagulant activity was determined using a one-stage prothrombin time-based test. The factor V antigen level was measured in an ELISA. Sanger sequencing was performed for genetic analyses of F5 , the gene responsible for the disease. One novel and de novo F5 genetic variant, p.Tyr1813 ∗ , was identified. Based on the presence of a premature termination codon with a resultant truncated factor V-protein lacking an intact light chain fragment, the variant is pathogenic. In addition, we identified seven variants previously found to cause FVD. Among them, p.Gly420Cys and p.Asp96His were repeatedly detected in five and four patients, respectively. Both variants are found to be specific to the East Asian populations. Various FVD-associated bleeding manifestations were observed, predominantly mucocutaneous bleeding and hypermenorrhea. All patients exhibited very low factor V coagulant activity (<1-2.5 IU/dl, reference range: 60-133 IU/dl). The factor V antigen level was less than 2% in six patients (reference range: 75-157%). The novel F5 genetic variant p.Tyr1813 ∗ and two distinct, East Asians-specific, recurrent variants p.Gly420Cys and p.Asp96His were identified among seven index patients with FVD in Taiwan. Our clinical and laboratory findings support the reported features of FVD.

Mutations of TFPI-binding exosites on factor VII cause bleeding phenotypes in factor VII deficiency

AbstractTissue factor (TF) pathway inhibitor (TFPI) is a Kunitz-type anticoagulation protein that inhibits activated factor VII (FVIIa)/TF complex. Incidentally, many different F7 gene variants, including TFPI-binding exosite mutations, have been reported in patients with congenital FVII deficiency and clinical bleeding variabilities. Here, TFPI-binding exosites (R147 and K192) on FVII zymogen were selectively disrupted to understand their roles in the pathogenesis of bleeding phenotypes. Expression of recombinant FVII variants (R147A, K192A, and R147A/K192A) demonstrated markedly reduced secretion of FVII owing to intracellular retention in the endoplasmic reticulum, as demonstrated by upregulation of the unfolded protein response genes in all FVII variants. FVII variants showed a similar FVII activation pattern and FVIIa amidolytic activity than FVII wild-type (WT). In contrast to FVII activation, R147A and K192A showed a 90% reduction in FX activation relative to WT, whereas the R147A/K192A variant demonstrated a 99% decrease in FX activation. The clotting time was markedly prolonged with R147A and K192A than WT, and no FVII coagulant activity was detected in R147A/K192A. In addition, the thrombin generation assay revealed a significant prolongation of lag time in all FVII variants. Our study explains how mutations of TFPI-binding exosites of FVII can lead to bleeding phenotypes in individuals carrying these aberrancies.

Molecular and functional characterization of teleost-specific Interleukin-17N in yellow catfish (Pelteobagrus fulvidraco)

In mammals, six interleukin-17 (IL-17) genes, as potent pro-inflammatory cytokines, all accelerate the inflammatory responses. In teleosts, seven IL-17 genes have been found in various species, but little is known about the function of teleost-specific IL-17N. In this study, teleost IL-17N and IL-17A/F2 genes all had six conserved cysteine residues forming three intrachain disulfide bridges, the length of three exons of teleost IL-17N gene was similar to that of teleost IL-17A/F2 gene, and the neighbor-joining (NJ) phylogenetic tree showed that teleost IL-17N was clustered with vertebrate IL-17A/F, implying that teleost IL-17N gene may be a paralog of teleost IL-17A/F gene. Pelteobagrus fulvidraco (Pf) IL-17N gene was highly expressed in the blood, brain and kidney of healthy yellow catfish. Pf_IL-17N transcript and protein were notably up-regulated in the spleen, head kidney, gill and kidney detected after Edwardsiella ictaluri infection. Lipopolysaccharides (LPS), polyinosinic-polycytidylic acid (Poly I:C) and peptidoglycan (PGN) also remarkably induced the expression of Pf_IL-17N in the isolated peripheral blood leucocytes (PBLs) of yellow catfish. These results reveal that Pf_IL-17N may play important roles in preventing the invasion of pathogens. Furthermore, the recombinant (r) Pf_IL-17N protein could significantly induce the mRNA expressions of inflammatory cytokines, chemokines and antimicrobial peptide genes in yellow catfish in vivo and in vitro, and it also notably promoted the phagocytosis of myeloid cells in the PBLs and the chemotaxis of the PBLs and gill leucocytes (GLs) in yellow catfish. Besides, though the rPf_IL-17N protein could induce and aggravate inflammation infiltration in the kidney of yellow catfish, it did not effectively and notably increase the survival rate of yellow catfish after E. ictaluri infection. Furthermore, the rPf_IL-17N protein could induce the mRNA expressions of nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signal pathways related genes, and the inhibitor of NF-κB and MAPK signal pathways could restrain the rPf_IL-17N protein-induced inflammatory response. This study provides crucial evidence that the Pf_IL-17N may mediate inflammatory response to eliminate invasive pathogens.

Molecular heterogeneity of factor XI deficiency in Tunisia.

Factor XI (FXI) deficiency is a rare inherited bleeding disorder that is highly prevalent in Ashkenazi Jewish ancestry but sporadically observed in most ethnic groups. It is heterogeneous both in clinical presentation and in genetic causality. Although a large spectrum of mutations associated with this disorder has been reported in several populations, genetic data of FXI deficiency in Tunisia are poorly described. The purpose of this study was to determine the molecular basis of FXI deficiency among Tunisian patients. Fourteen index cases from nine unrelated families with FXI deficiency, referred to Hemophilia Treatment Center of Aziza Othmana Hospital, were included in this study. The patients' F11 genes were amplified by PCR and subjected to direct DNA sequencing analysis. Sequencing analysis of F11 genes identified three distinct mutations; the Jewish type II nonsense mutation E117X, one previously reported missense mutation E602Q and one novel missense mutation V271M, which led to the disruption of the third apple domain structure of FXI. Furthermore, seven polymorphisms previously described, were also detected: C321F, c. 294A>G, -138 A>C, p.D125D, p.T249T, p.G379G, p.D551D. This report represents the first genetic study analyzing the molecular characteristics of factor XI deficiency within Tunisian population. Identification of the Jewish type II mutation in two families, as well as one missense previously reported mutation and one novel mutation confirmed the genetic heterogeneity of this disorder. Screening a large number of Tunisian factor XI deficient would reveal the spectrum mutations causing factor XI deficiency in Tunisia.