-
Zhonghua Yi Xue Yi Chuan Xue Za Zhi =... Nov 2023To explore the coagulation deficit and genetic basis for a Chinese pedigree affected with Congenital dysfibrinogenemia (CD).
OBJECTIVE
To explore the coagulation deficit and genetic basis for a Chinese pedigree affected with Congenital dysfibrinogenemia (CD).
METHODS
Peripheral venous blood samples of the proband and her family members (including 4 individuals from three generations) were subjected to routine blood test and assays of liver and kidney functions and viral hepatitis to exclude related diseases. Clauss method and DFg-PT method were used to determine the fibrinogen activity (Fg:C), and an immunoturbidimetric assay was used to determine the level of fibrinogen antigen (Fg:Ag). All of the exons (22 in total) and their flanking sequences of the FGA, FGB and FGG genes were amplified by PCR and directly sequenced. Variants in the coding regions of the three genes and transcriptional splicing sites were screened by using Mutation Surveyor software.
RESULTS
The Clauss method showed that Fg:C was significantly reduced in the proband and her father, whilst her mother and son were normal. With the DFg-PT method, the proband, her parents and son were all within the normal range. The Fg:C/Fg:Ag ratio of the proband and her father was lower than 0.7, whilst her mother and son were above 0.7. No significant change in the prothrombin time, activated partial thromboplastin clotting time and thrombin time was noted. Two genetic variants were detected, which included a homozygous missense variant in the FGA gene [c.991A>G (p.Thr331Ala)], which was predicted to be benign, and a heterozygous missense variant of the γ chain of the FGG gene [c.1211C>G (p.Ser404Phe)], which is located in a conserved region and unreported in the CLINVAR/HGMD/EXAC/1000G databases and literature.
CONCLUSION
This pedigree has conformed to the autosomal dominant inheritance of CD. The c.1211C>T (p.Ser404Phe) missense variant of the γ chain of the FGG gene probably underlay the pathogenesis of CD in this pedigree. The variant was unreported previously and named as "Fibrinogen Harbin II Ser404Phe".
Topics: Female; Humans; Afibrinogenemia; East Asian People; Fibrinogen; Mothers; Mutation; Pedigree
PubMed: 37906135
DOI: 10.3760/cma.j.cn511374-20220112-00027 -
Zhongguo Shi Yan Xue Ye Xue Za Zhi Oct 2023To investigate a family with congenital dysfibrinogenemia, and analyze the risk of hemorrhage and thrombosis and blood transfusion strategies.
OBJECTIVE
To investigate a family with congenital dysfibrinogenemia, and analyze the risk of hemorrhage and thrombosis and blood transfusion strategies.
METHODS
Prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT) of the proband and her family members were detected by automatic coagulometer, fibrinogen (Fg) activity and antigen were detected by Clauss method and PT algorithm respectively. Meanwhile, thromboelastometry was analyzed for proband and her family members. Then, peripheral blood samples of the proband and her family members were collected, and all exons of and and their flanks were amplified by PCR and sequenced to search for gene mutations.
RESULTS
The proband had normal APTT and PT, slightly prolonged TT, reduced level of Fg activity (Clauss method). The Fg of the proband's aunt, son and daughter all decreased to varying degrees. The results of thromboelastogram indicated that Fg function of the proband and her family members (except her son) was basically normal. Gene analysis showed that there were 6233 G/A (p.AαArg35His) heterozygous mutations in exon 2 of gene in the proband, her children and aunt. In addition, 2 polymorphic loci were found in the family, they were gene g.9308A/G (p.AαThr331Ala) and gene g.12628G/A (p.BβArg478Iys) polymorphism, respectively. The proband was injected with 10 units of cryoprecipitate 2 hours before delivery to prevent bleeding, and no obvious bleeding occurred during and after delivery.
CONCLUSION
Heterozygous mutation of 6233G/A (p.AαArg35His) of gene is the biogenetic basis of the disease in this family with congenital dysfibrinogenemia.
Topics: Humans; Child; Female; Fibrinogen; Pedigree; Afibrinogenemia; Mutation; Blood Transfusion
PubMed: 37846702
DOI: 10.19746/j.cnki.issn.1009-2137.2023.05.034 -
Research and Practice in Thrombosis and... Jul 2023Variants of fibrinogen sequences that bind to thrombin's catalytic sites are mostly associated with bleeding phenotypes, while variants with fibrinogen...
BACKGROUND
Variants of fibrinogen sequences that bind to thrombin's catalytic sites are mostly associated with bleeding phenotypes, while variants with fibrinogen nonsubstrate-thrombin-binding sites are commonly believed to cause thrombosis. AαGlu39 and BβAla68 play important roles in fibrin(ogen)-thrombin-nonsubstrate binding. The BβAla68Thr variant has been described in several unrelated families with apparent thrombotic phenotypes.
OBJECTIVES
Homozygous AαGlu39Lys variant (fibrinogen BOE II) was identified in a boy with dysfibrinogenemia who had multiple cerebral hemorrhages. A series of analyses were performed to assess the variant's functions and elucidate underlying bleeding mechanisms.
METHODS
Abnormal fibrinogen was purified from plasma and subjected to Western blot, fibrinogen and fibrin monomer polymerization, clottability, fibrinopeptides release, activated factor (F)XIII (FXIIIa) cross-linking, fibrinolysis, and scanning electron microscopy analyses.
RESULTS
Fibrinogen BOE II weakened the binding capacity of thrombin to fibrinogen and delayed the formation of fibrin clots. The release of fibrinopeptides, polymerization of fibrinogen catalyzed by thrombin, and cross-linking of FXIIIa of fibrinogen BOE II were impaired. In contrast, batroxobin-catalyzed fibrinogen polymerization and desA/desAB fibrin monomer polymerization did not differ from those in normal controls. Fibrin clots formed by fibrinogen BOE II were composed of thicker fibrin fibers and showed a faster fibrinolysis rate.
CONCLUSION
Defective fibrin(ogen)-thrombin-nonsubstrate binding is not necessarily associated with thrombotic disorders. When the hypercoagulable state created by increased circulating free thrombin is insufficient to compensate for defective hemostasis caused by slowly formed but rapidly lysed clots, the primary concern of thrombin-binding deficiency dysfibrinogenemia appears to be hemorrhage rather than thrombosis.
PubMed: 37601017
DOI: 10.1016/j.rpth.2023.102145 -
British Journal of Haematology Nov 2023Congenital fibrinogen disorders or CFDs are heterogenous, both in clinical manifestation and array of culprit molecular lesions. Correlations between phenotype and... (Review)
Review
Congenital fibrinogen disorders or CFDs are heterogenous, both in clinical manifestation and array of culprit molecular lesions. Correlations between phenotype and genotype remain poorly defined. This review examines the genetic landscape discovered to date for this rare condition. The question of a possible oligogenic model of inheritance influencing phenotypic heterogeneity is raised, with discussion of the benefits and challenges of sequencing technology used to enhance discovery in this space. Considerable work lies ahead in order to achieve diagnostic and prognostic precision and subsequently provide targeted management to this complex cohort of patients.
PubMed: 37583269
DOI: 10.1111/bjh.19039 -
Hamostaseologie Dec 2023Our study aimed to analyze the phenotype and genotype of a pedigree with inherited dysfibrinogenemia, and preliminarily elucidate the probable pathogenesis.
OBJECTIVE
Our study aimed to analyze the phenotype and genotype of a pedigree with inherited dysfibrinogenemia, and preliminarily elucidate the probable pathogenesis.
METHODS
The one-stage clotting method was used to test the fibrinogen activity (FIB:C), whereas immunoturbidimetry was performed to quantify the fibrinogen antigen (FIB:Ag). Furthermore, DNA sequence analysis was conducted to confirm the site of mutation. Conservation analysis and protein model analysis were performed using online bioinformatics software.
RESULTS
The FIB:C and FIB:Ag of the proband were 1.28 and 2.20 g/L, respectively. Gene analysis revealed a heterozygous c.293C > A (p.BβAla68Asp) mutation in . Bioinformatics and modeling analysis suggested that the missense mutation could potentially have a deleterious effect on fibrinogen.
CONCLUSION
The BβAla68Asp mutation in exon 2 of may account for the reduced FIB:C levels observed in the pedigree. To our knowledge, this point mutation is the first report in the world.
Topics: Humans; Fibrinogen; Afibrinogenemia; Genotype; Mutation, Missense; Mutation; Hemostatics; Pedigree
PubMed: 37516116
DOI: 10.1055/a-2116-8957 -
Hamostaseologie Dec 2023Inherited dysfibrinogenemia is a qualitative defect of fibrinogen caused by various mutations among three fibrinogen genes. Dysfibrinogenemia can be associated with...
INTRODUCTION
Inherited dysfibrinogenemia is a qualitative defect of fibrinogen caused by various mutations among three fibrinogen genes. Dysfibrinogenemia can be associated with an increased risk of thrombosis, bleeding, or both. Here, we report a 36-year-old female with dysfibrinogenemia who experienced two successful pregnancies under thromboprophylaxis after cerebral venous sinus thrombosis (CVST).
PATIENTS AND METHODS
In addition to plasmatic coagulation tests, fibrinogen genes , , and were screened using direct genomic DNA sequencing. The structural-functional implications of the detected mutation were analyzed in silico.
RESULTS
Inherited dysfibrinogenemia was diagnosed in an index patient after CVST in a risk situation. Anticoagulation with warfarin was stopped after 12 months when the first pregnancy was planned. Pregnancy and spontaneous delivery (2020) was uncomplicated. A second pregnancy was interrupted because of acute cytomegalovirus infection and the third pregnancy was successful in 2022. Pregnancies were accompanied by thromboprophylaxis with enoxaparin 40 mg once daily until 6 weeks postpartum. Substitution of fibrinogen has not become necessary in the index patient so far. Genetic analysis revealed a novel missense mutation (p. Arg510Cys) in the gene ("fibrinogen Bonn") in the index patient, as well as an asymptomatic sister, and their father who experienced recurrent pulmonary embolism. Surface exposure of wild-type Arg510 suggested the mutated Cys510 to form nonnative disulfide bonds with surface-exposed reactive cysteines from other plasma proteins like albumin leading to formation of aggregates and impaired fibrinolysis.
CONCLUSIONS
Fibrinogen Bonn might be associated with an increased risk of thrombosis, possibly due to impaired polymerization.
Topics: Pregnancy; Female; Humans; Adult; Fibrinogen; Anticoagulants; Venous Thromboembolism; Afibrinogenemia; Venous Thrombosis; Mutation; Thrombosis; Hemostatics
PubMed: 37442158
DOI: 10.1055/a-2094-7191 -
Blood Coagulation & Fibrinolysis : An... Jul 2023Inherited dysfibrinogenemias are molecular disorders of fibrinogen that affect fibrin polymerization. The majority of cases are asymptomatic, but a significant...
Inherited dysfibrinogenemias are molecular disorders of fibrinogen that affect fibrin polymerization. The majority of cases are asymptomatic, but a significant proportion suffer from increased bleeding or thrombosis. We present two unrelated cases of dysfibrinogenemia, both of whom showed a characteristic discrepancy between fibrinogen activity and the immunologic fibrinogen. In one patient, the dysfibrinogenemia was confirmed by molecular analysis; in the other case, the diagnosis was presumptive based upon laboratory studies. Both patients underwent elective surgery. Both received a highly purified fibrinogen concentrate preoperatively and demonstrated a suboptimal laboratory response to the infusion. Three methods for determining fibrinogen concentration (Clauss fibrinogen, prothrombin-derived fibrinogen, and the viscoelastic functional fibrinogen) were utilized in the case of one patient, and these techniques showed discrepant results with the classic Clauss method giving the lowest concentration. Neither patient experienced excessive bleeding during surgery. Although these discrepancies have been previously described in untreated patients, their manifestation after infusion of purified fibrinogen is less well appreciated.
Topics: Humans; Fibrinogen; Afibrinogenemia; Thrombosis; Hemorrhage; Hemostatics
PubMed: 37395199
DOI: 10.1097/MBC.0000000000001237 -
Journal of Thrombosis and Haemostasis :... Aug 2023Women with hereditary fibrinogen disorders (HFDs) seem to be at an increased risk of adverse obstetrical outcomes, but epidemiologic data are limited.
BACKGROUND
Women with hereditary fibrinogen disorders (HFDs) seem to be at an increased risk of adverse obstetrical outcomes, but epidemiologic data are limited.
OBJECTIVES
We aimed to determine the prevalence of pregnancy complications; the modalities and management of delivery; and the postpartum events in women with hypofibrinogenemia, dysfibrinogenemia, and hypodysfibrinogenemia.
METHODS
We conducted a retrospective and prospective multicentric international study.
RESULTS
A total of 425 pregnancies were investigated from 159 women (49, 95, and 15 cases of hypofibrinogenemia, dysfibrinogenemia, and hypodysfibrinogenemia, respectively). Overall, only 55 (12.9%) pregnancies resulted in an early miscarriage, 3 (0.7%) resulted in a late miscarriage, and 4 (0.9%) resulted in an intrauterine fetal death. The prevalence of live birth was similar among the types of HFDs (P = .31). Obstetrical complications were observed in 54 (17.3%) live birth pregnancies, including vaginal bleeding (14, 4.4%), retroplacental hematoma (13, 4.1%), and thrombosis (4, 1.3%). Most deliveries were spontaneous (218, 74.1%) with a vaginal noninstrumental delivery (195, 63.3%). A neuraxial anesthesia was performed in 116 (40.4%) pregnancies, whereas general or no anesthesia was performed in 71 (16.6%) and 129 (44.9%) pregnancies, respectively. A fibrinogen infusion was administered in 28 (8.9%) deliveries. Postpartum hemorrhages were observed in 62 (19.9%) pregnancies. Postpartum venous thrombotic events occurred in 5 (1.6%) pregnancies. Women with hypofibrinogenemia were at an increased risk of bleeding during the pregnancy (P = .04).
CONCLUSION
Compared with European epidemiologic data, we did not observe a greater frequency of miscarriage, while retroplacental hematoma, postpartum hemorrhage, and thrombosis were more frequent. Delivery was often performed without locoregional anesthesia. Our findings highlight the urgent need for guidance on the management of pregnancy in HFDs.
Topics: Female; Humans; Pregnancy; Abortion, Spontaneous; Afibrinogenemia; Fibrinogen; Gastrointestinal Hemorrhage; Hematoma; Hemostatics; Postpartum Hemorrhage; Prospective Studies; Retrospective Studies; Thrombosis
PubMed: 37172732
DOI: 10.1016/j.jtha.2023.04.035 -
Scars, Burns & Healing 2023Surgical burn excision (along with skin grafting) carries the risk of blood loss. The use of enzymatic debridement agents such as Nexobrid® has gained increased...
INTRODUCTION
Surgical burn excision (along with skin grafting) carries the risk of blood loss. The use of enzymatic debridement agents such as Nexobrid® has gained increased popularity as an alternative to surgical debridement in the management of burns with its reported benefits of selective burn debridement, minimising blood loss and potentially reducing the need for skin grafting. However, there is limited evidence regarding its effects on bleeding. Currently, the manufacturer declares there is no evidence for increased risk of localised bleeding and its systemic effects upon coagulation are less clear.
METHODS
We present two clinical cases demonstrating the possible effects of Nexobrid® on coagulation and bleeding at the debridement site. Comparisons are drawn with the manufacturers' guidance as well as evaluating the current recommendations of its use.
DISCUSSION
Nexobrid® is a novel therapy and there are few adverse effects reported in the literature. The basis of its appeal is the reduced blood loss at the debridement site and the selectivity it possesses in preserving healthy dermis. However, our cases have demonstrated that haemorrhage can occur and that those using Nexobrid® should be mindful of the potential bleeding risk from varicosities within the burn wound. We have also illustrated that Nexobrid® can be used in patients with pre-existing clotting disorders without requiring the use of blood products. However, we emphasise the importance of haematological support for its safe administration.
LAY SUMMARY
Nexobrid®, a debriding agent that contains enzymes, has been developed as an alternative to surgery which for most surgeons is the traditional method of removing dead tissue following a burn injury. The active agent is bromelain and this is derived from the stems of pineapples. This novel treatment is increasingly being used in the management of middle to deep skin thickness burns and it seems to have a number of benefits such as reducing blood loss, reducing the need for skin grafting as well as being able to treat burns in certain areas of the body that would be technically challenging to remove in the standard fashion. It simply targets the dead tissue leaving viable remnants of the skin that would hopefully allow healing to occur without the need for surgical intervention. Being a relatively new concept, current evidence regarding the safety and value of Nexobrid® continues to develop. In 2020, an agreement guideline outlining best practice with the use of Nexobrid® was published. In this statement, it was advised that caution should be taken when using Nexobrid® in patients who have blood clotting disturbances as this could increase the likelihood of bleeding. However, they did not mention that excessive bleeding can potentially occur with this treatment.We present two clinical cases demonstrating the possible effects of Nexobrid® on the clotting system and bleeding at the application site. Comparisons are drawn with the manufacturers' guidance as well as assessing the current recommendations of its use. We illustrate that Nexobrid® can be safely used in patients with pre-existing clotting disturbances if the correct procedures are performed. We also highlight the potential complication of excessive bleeding if Nexobrid® is used in patients who have co-existing enlarged surface veins along with their burn injury. We feel the guidance should be updated to reflect these findings.
PubMed: 37124159
DOI: 10.1177/20595131231168333 -
Journal of Thrombosis and Haemostasis :... Jun 2023Fibrinogen is a soluble, multisubunit, and multidomain dimeric protein, which, upon its proteolytic cleavage by thrombin, is converted to insoluble fibrin, initiating...
BACKGROUND
Fibrinogen is a soluble, multisubunit, and multidomain dimeric protein, which, upon its proteolytic cleavage by thrombin, is converted to insoluble fibrin, initiating polymerization that substantially contributes to clot growth. Fibrinogen contains numerous, transiently accessible "cryptic" epitopes for hemostatic and immunologic proteins, suggesting that fibrinogen exhibits conformational flexibility, which may play functional roles in its temporal and spatial interactions. Hitherto, there have been limited integrative approaches characterizing the solution structure and internal flexibility of fibrinogen.
METHODS
Here, utilizing a multipronged, biophysical approach involving 2 solution-based techniques, temperature-dependent hydrogen-deuterium exchange mass spectrometry and small angle X-ray scattering, corroborated by negative stain electron microscopy, we present a holistic, conformationally dynamic model of human fibrinogen in solution.
RESULTS
Our data reveal 4 major and distinct conformations of fibrinogen accommodated by a high degree of internal protein flexibility along its central scaffold. We propose that the fibrinogen structure in the solution consists of a complex, conformational landscape with multiple local minima. This is further supported by the location of numerous point mutations that are linked to dysfibrinogenemia and posttranslational modifications, residing near the identified fibrinogen flexions.
CONCLUSION
This work provides a molecular basis for the structural "dynamism" of fibrinogen that is expected to influence the broad swath of its functionally diverse macromolecular interactions and fine-tune the structural and mechanical properties of blood clots.
Topics: Humans; Fibrin Fibrinogen Degradation Products; Fibrin; Fibrinogen; Thrombosis; Molecular Conformation
PubMed: 36746319
DOI: 10.1016/j.jtha.2023.01.034