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Blood Advances Mar 2024Congenital fibrinogen deficiency (CFD) is a rare bleeding disorder caused by mutations in FGA, FGB, and FGG. We sought to comprehensively characterize patients with CFD...
Congenital fibrinogen deficiency (CFD) is a rare bleeding disorder caused by mutations in FGA, FGB, and FGG. We sought to comprehensively characterize patients with CFD using PRO-RBDD (Prospective Rare Bleeding Disorders Database). Clinical phenotypes, laboratory, and genetic features were investigated using retrospective data from the PRO-RBDD. Patients were classified from asymptomatic to grade 3 based on their bleeding severity. In addition, FGA, FGB, and FGG were sequenced to find causative variants. A total of 166 CFD cases from 16 countries were included, of whom 123 (30 afibrinogenemia, 33 hypofibrinogenemia, 55 dysfibrinogenemia, and 5 hypodysfibrinogenemia) were well characterized. Considering the previously established factor activity and antigen level thresholds, bleeding severity was correctly identified in 58% of the cases. The rates of thrombotic events among afibrinogenemic and hypofibrinogenemic patients were relatively similar (11% and 10%, respectively) and surprisingly higher than in dysfibrinogenemic cases. The rate of spontaneous abortions among 68 pregnancies was 31%, including 86% in dysfibrinogenemic women and 14% with hypofibrinogenemia. Eighty-six patients received treatment (69 on-demand and/or 17 on prophylaxis), with fibrinogen concentrates being the most frequently used product. Genetic analysis was available for 91 cases and 41 distinct variants were identified. Hotspot variants (FGG, p.Arg301Cys/His and FGA, p.Arg35Cys/His) were present in 51% of dysfibrinogenemia. Obstetric complications were commonly observed in dysfibrinogenemia. This large multicenter study provided a comprehensive insight into the clinical, laboratory, and genetic history of patients with CFDs. We conclude that bleeding severity grades were in agreement with the established factor activity threshold in nearly half of the cases with quantitative defects.
Topics: Humans; Female; Fibrinogen; Afibrinogenemia; Prospective Studies; Retrospective Studies; Hemorrhage; Hemostatics
PubMed: 38286442
DOI: 10.1182/bloodadvances.2023012186 -
Diagnostics (Basel, Switzerland) Nov 2021Congenital fibrinogen disorders are rare pathologies of the hemostasis, comprising quantitative (afibrinogenemia, hypofibrinogenemia) and qualitative (dysfibrinogenemia... (Review)
Review
Congenital Afibrinogenemia and Hypofibrinogenemia: Laboratory and Genetic Testing in Rare Bleeding Disorders with Life-Threatening Clinical Manifestations and Challenging Management.
Congenital fibrinogen disorders are rare pathologies of the hemostasis, comprising quantitative (afibrinogenemia, hypofibrinogenemia) and qualitative (dysfibrinogenemia and hypodysfibrinogenemia) disorders. The clinical phenotype is highly heterogeneous, being associated with bleeding, thrombosis, or absence of symptoms. Afibrinogenemia and hypofibrinogenemia are the consequence of mutations in the homozygous, heterozygous, or compound heterozygous state in one of three genes encoding the fibrinogen chains, which can affect the synthesis, assembly, intracellular processing, stability, or secretion of fibrinogen. In addition to standard coagulation tests depending on the formation of fibrin, diagnostics also includes global coagulation assays, which are effective in monitoring the management of replacement therapy. Genetic testing is a key point for confirming the clinical diagnosis. The identification of the precise genetic mutations of congenital fibrinogen disorders is of value to permit early testing of other at risk persons and better understand the correlation between clinical phenotype and genotype. Management of patients with afibrinogenemia is particularly challenging since there are no data from evidence-based medicine studies. Fibrinogen concentrate is used to treat bleeding, whereas for the treatment of thrombotic complications, administered low-molecular-weight heparin is most often. This review deals with updated information about afibrinogenemia and hypofibrinogenemia, contributing to the early diagnosis and effective treatment of these disorders.
PubMed: 34829490
DOI: 10.3390/diagnostics11112140 -
Journal of Thrombosis and Thrombolysis Feb 2020Congenital dysfibrinogenemia is characterized with undetectable or low fibrinogen level by Clauss assay complicated by bleeding and/or thrombosis. These may lead to a...
Congenital dysfibrinogenemia is characterized with undetectable or low fibrinogen level by Clauss assay complicated by bleeding and/or thrombosis. These may lead to a diagnostic problem to some clinicians unfamiliar with this disease. We reported a case of congenital dysfibrinogenemia manifested as hemorrhage, repeated thrombosis, low fibrinogen levels through Clauss assay and but normal levels of fibrinogen through PT-derived tests. In conclusion, to patients with thrombosis complicated by decreased fibrinogen level, clinicians and laboratory physicians should be alert to the possibility of congenital dysfibrinogenemia.
Topics: Adult; Afibrinogenemia; Blood Coagulation Tests; Fibrinogens, Abnormal; Humans; Male; Thrombosis
PubMed: 31542854
DOI: 10.1007/s11239-019-01958-y -
Clinical Laboratory Apr 2021Fibrinogen plays an important role in hemostasis. The normal concentration of fibrinogen in blood plasma is between 1.8 - 4.2 g/L. Decreased fibrinogen levels are...
BACKGROUND
Fibrinogen plays an important role in hemostasis. The normal concentration of fibrinogen in blood plasma is between 1.8 - 4.2 g/L. Decreased fibrinogen levels are observed in congenital afibrinogenemia, hypofibrinogenemia, dysfibrinogenemia, disseminated intravascular coagulation, fibrinolytic therapy, some more severe hepatic parenchymal disorders, and increased blood loss. Elevated fibrinogen levels occur in inflammatory diseases and neoplastic diseases, in pregnancy, and postoperative conditions. Functional fibrinogen measurement is also one of the basic coagulation screening tests. The fibrinogen antigen assay is used to distinguish between qualitative and quantitative fibrinogen disorders.
METHODS
The aim of the study was the use of fibrinogen determination methods in differential diagnosis of hypofibrinogenemia and dysfibrinogenemia, statistical evaluation and determine the relationship of fibrinogen Clauss assay, prothrombin time (PT) derived fibrinogen assay, and fibrinogen antigen in the group of 60 patients with congenital fibrinogen disorders (n = 40 dysfibrinogenemia; n = 20 hypofibrinogenemia).
RESULTS
The results measured by the PT-derived fibrinogen assay were approximately four times higher compared to the fibrinogen Clauss assay in the group of patients with dysfibrinogenemia. In patients with hypofibrinogenemia, there is a correlation (r = 0.9016) between the fibrinogen Clauss assay and PT-derived fibrinogen assay with a statistical significance of p < 0.0001. Using a linear or quadratic interpolation function, we were able to determine the fibrinogen Clauss assay and the fibrinogen antigen assay before analysis.
CONCLUSIONS
The higher level of the PT-derived fibrinogen assay compared to the fibrinogen Clauss assay in the group of patients with dysfibrinogenemia may pose a greater risk to asymptomatic patients who require diagnosis and treatment in case of bleeding. The fibrinogen value using the PT-derived fibrinogen assay could erroneously give a normal level. The use of the interpolation function is important to estimate the value of fibrinogen activity and antigen before the analysis itself by the Clauss assay or analysis by the fibrinogen antigen assay.
Topics: Afibrinogenemia; Blood Coagulation Tests; Diagnosis, Differential; Female; Fibrinogen; Humans; Pregnancy; Prothrombin Time
PubMed: 33865248
DOI: 10.7754/Clin.Lab.2020.200820 -
Seminars in Thrombosis and Hemostasis Nov 2022Fibrinogen is a complex protein that plays a key role in the blood clotting process. It is a hexamer composed of two copies of three distinct chains: Aα, Bβ, and γ...
Fibrinogen is a complex protein that plays a key role in the blood clotting process. It is a hexamer composed of two copies of three distinct chains: Aα, Bβ, and γ encoded by three genes, , and clustered on the long arm of chromosome 4. Congenital fibrinogen disorders (CFDs) are divided into qualitative deficiencies (dysfibrinogenemia, hypodysfibrinogenemia) in which the mutant fibrinogen molecule is present in the circulation and quantitative deficiencies (afibrinogenemia, hypofibrinogenemia) with no mutant molecule present in the bloodstream. Phenotypic manifestations are variable, patients may be asymptomatic, or suffer from bleeding or thrombosis. Causative mutations can occur in any of the three fibrinogen genes and can affect one or both alleles. Given the large number of studies reporting on novel causative mutations for CFDs since the review on the same topic published in 2016, we performed an extensive search of the literature and list here 120 additional mutations described in both quantitative and qualitative disorders. The visualization of causative single nucleotide variations placed on the coding sequences of , and eveals important structure function insight for several domains of the fibrinogen molecule.
Topics: Humans; Fibrinogen; Afibrinogenemia; Mutation; Hemorrhage; Exons; Hemostatics
PubMed: 35073585
DOI: 10.1055/s-0041-1742170 -
Hematology/oncology Clinics of North... Dec 2021In patients presenting with a suspect hereditary bleeding disorder a detailed bleeding history is first obtained. Testing proceeds in a tiered manner with platelet... (Review)
Review
In patients presenting with a suspect hereditary bleeding disorder a detailed bleeding history is first obtained. Testing proceeds in a tiered manner with platelet count, platelet morphology, platelet histogram, PFA-100, fibrinogen, prothrombin time, and activated partial thromboplastin time. More detailed testing includes von Willebrand factor, individual clotting factor assays, and platelet function testing. Next, testing for a dysfibrinogenemia, FXIII, or a fibrinolytic defect is considered. Hemostatic abnormality is not demonstrated in a fraction of patients. An approach to management in these patients, such as desmopressin or antifibrinolytic therapy, may be required and empiric use of blood component therapy is discouraged.
Topics: Blood Coagulation Disorders; Blood Coagulation Tests; Hemostatic Disorders; Humans; Laboratories; Platelet Function Tests
PubMed: 34391602
DOI: 10.1016/j.hoc.2021.07.002 -
Thrombosis and Haemostasis Nov 2018Numerous mutations in , or lead to congenital fibrinogen disorders (CFDs), but their epidemiology is not well characterized. The aim of this study was to evaluate...
BACKGROUND
Numerous mutations in , or lead to congenital fibrinogen disorders (CFDs), but their epidemiology is not well characterized. The aim of this study was to evaluate the molecular epidemiology of CFD and to develop a genotyping strategy.
METHODS
Genetic data from 266 unrelated CFD patients genotyped at our laboratory and from a CFD open access database ( = 1,142) were evaluated. We developed a step-wise screening strategy for the molecular diagnosis of CFD and prospectively tested this strategy on 32 consecutive CFD probands.
RESULTS
We identified 345 mutated alleles overall, among 187 heterozygous, 63 homozygous and 16 compound heterozygous individuals. Afibrinogenemia was almost always caused by null mutations (98.6%), mainly in (85%). Hypofibrinogenemia was mainly caused by missense mutations of or (54.2%). Dysfibrinogenemia was almost always caused by heterozygous missense mutations (99.3%) in and . Hotspot mutations were prevalent among quantitative (33.1%) and qualitative fibrinogen disorders (71.1%). The mutational cluster at our laboratory was similar with that reported in the CFD open access database. The proposed step-wise genetic screening strategy proved efficient in both the development and validation samples for CFD: the screening of exons 2, 4, 5 and exon 8 and search for the 11 kb deletion of led to the identification of approximately 80% of mutated alleles, including 15 new mutations.
CONCLUSION
The described molecular epidemiology of CFD is complex. The proposed step-wise genetic screening strategy may provide an efficient way to identify causative mutations analysing a minimal number of exons.
Topics: Adolescent; Adult; Afibrinogenemia; Alleles; Child; Child, Preschool; DNA Mutational Analysis; Female; Fibrinogen; Genetic Testing; Genotype; Hemostasis; Humans; Male; Molecular Epidemiology; Mutation; Prospective Studies; Switzerland; Young Adult
PubMed: 30332696
DOI: 10.1055/s-0038-1673685 -
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 -
Frontiers in Pediatrics 2020Pediatric Acute Liver Failure (PALF) is a rapidly progressive clinical syndrome encountered in the pediatric ICU which may rapidly progress to multi-organ dysfunction,... (Review)
Review
Pediatric Acute Liver Failure (PALF) is a rapidly progressive clinical syndrome encountered in the pediatric ICU which may rapidly progress to multi-organ dysfunction, and on occasion to life threatening cerebral edema and hemorrhage. Pediatric Acute Liver Failure is defined as severe acute hepatic dysfunction accompanied by encephalopathy and liver-based coagulopathy defined as prolongation of International Normalized Ratio (INR) >1.5. However, coagulopathy in PALF is complex and warrants a deeper understanding of the hemostatic balance in acute liver failure. Although an INR value of >1.5 is accepted as the evidence of coagulopathy and has historically been viewed as a prognostic factor of PALF, it may not accurately reflect the bleeding risk in PALF since it only measures procoagulant factors. Paradoxically, despite the prolongation of INR, bleeding risk is lower than expected (around 5%). This is due to "rebalanced hemostasis" due to concurrent changes in procoagulant, anticoagulant and fibrinolytic systems. Since the liver is involved in both procoagulant (Factors II, V, IX, XI, and fibrinogen) and anticoagulant (Protein C, Protein S, and antithrombin) protein synthesis, PALF results in "rebalanced hemostasis" or even may shift toward a hypercoagulable state. In addition to rebalanced coagulation there is altered platelet production due to decreased thrombopoietin production by liver, increased von Willebrand factor from low grade endothelial cell activation, and hyperfibrinolysis and dysfibrinogenemia from altered synthetic liver dysfunction. All these alterations contribute to the multifactorial nature of coagulopathy in PALF. Over exuberant use of prophylactic blood products in patients with PALF may contribute to morbidities such as fluid overload, transfusion-associated lung injury, and increased thrombosis risk. It is essential to use caution when using INR values for plasma and factor administration. In this review we will summarize the complexity of coagulation in PALF, explore "rebalanced hemostasis," and discuss the limitations of current coagulation tests. We will also review strategies to accurately diagnose the coagulopathy of PALF and targeted therapies.
PubMed: 33425821
DOI: 10.3389/fped.2020.618119 -
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