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Haemophilia : the Official Journal of... Nov 2021Congenital fibrinogen disorders (CFDs) are caused by mutations in fibrinogen-encoding genes, FGA, FGB, and FGG, which lead to quantitative or qualitative abnormalities...
INTRODUCTION
Congenital fibrinogen disorders (CFDs) are caused by mutations in fibrinogen-encoding genes, FGA, FGB, and FGG, which lead to quantitative or qualitative abnormalities of fibrinogen. Although the diagnosis of CFDs is based on antigenic and functional level of fibrinogen, few genotypes are clearly correlated with phenotype.
METHODS
In this study, we investigated all of the referred patients diagnosed as CFDs in Taiwan's population between 1995 and 2020. Clinical features, laboratory data and genetic defects were analysed. Functional fibrinogen level was determined by the Clauss method. Antigenic fibrinogen was measured by an enzyme-linked immunosorbent assay. Fibrinogen genes were assessed for mutations by polymerase chain reaction and sequencing.
RESULTS
A total of 18 patients from six unrelated families with CFDs were identified. One patient from a consanguineous family was diagnosed as afibrinogenemia type 1A with a novel homozygous frameshift mutation in FGB exon 4. The other five (83.3 %) index patients were all diagnosed as dysfibrinogenemia type 3A caused by two novel and one known mutation. Six (33.3 %) patients from three families had a novel mutation in FGB exon 8. The clinical features and laboratory data were highly variable among these patients with the same mutation.
CONCLUSIONS
Three novel mutations of CFDs causing afibrinogenemia and dysfibrinogenemia were identified. The point mutation in FGB exon 8 is also a common mutation in Taiwan's population. Considerable phenotypic variability among the patients with an identical mutation was observed.
Topics: Afibrinogenemia; Fibrinogen; Homozygote; Humans; Mutation; Taiwan
PubMed: 34460979
DOI: 10.1111/hae.14399 -
Research and Practice in Thrombosis and... Aug 2021Hypodysfibrinogenemia (HD) is a heterogeneous disorder in which plasma fibrinogen antigen and function are both reduced but discordant. This report addresses the key...
Hypodysfibrinogenemia (HD) is a heterogeneous disorder in which plasma fibrinogen antigen and function are both reduced but discordant. This report addresses the key clinical question of whether genetic analysis enables clinically useful subclassification of patients with HD. We report a new case and identify a further eight previously documented cases that have the laboratory features of HD but biallelic inheritance of quantitative and qualitative fibrinogen gene variants. The cases displayed both bleeding and thrombosis and sometimes had undetectable fibrinogen activity. In all cases, the predicted effect of the coinherited variants is reduced levels of circulating fibrinogen that is all dysfunctional. We propose the term for this subtype of recessively inherited HD that is distinct from the more commonly recognized monoallelic HD caused by a single fibrinogen gene variant.
PubMed: 34458664
DOI: 10.1002/rth2.12568 -
Zhonghua Xue Ye Xue Za Zhi = Zhonghua... Jul 2021To investigate the clinical type and gene mutations, clinical manifestations, laboratory tests, diagnosis, and fibrinogen replacement therapy of congenital fibrinogen...
To investigate the clinical type and gene mutations, clinical manifestations, laboratory tests, diagnosis, and fibrinogen replacement therapy of congenital fibrinogen disorders. Clinical data of 146 patients with congenital fibrinogen disorders diagnosed from April 2000 to November 2020 were retrospectively analyzed. Among the 146 patients, 61 (41.8%) men and 85 (58.2%) women had a median age of 33.5 years at the time of consultation. 34 patients (34.7%) were found to suffer from the disease due to bleeding symptoms, 33 patients (33.7%) due to preoperative examination. 55 patients (56.1%) had at least one bleeding symptom, and 42 patients (42.9%) had no bleeding symptoms. There is a negative correlation between fibrinogen activity concentration and bleeding ISTH-BAT score (rs=-0.412, =0.001) . A total of 34 gene mutations were detected in 56 patients, of which 84.1% were missense mutations, and 16 new mutations were found. FGA Exon2 and FGG Exon8 mutations accounted for 71.4% of all mutation sites. Patients with afibrinogenemia were younger, with a median age of 2 (1-12) years, an ISTH-BAT score of 4, and patients with dysfibrinogenemia had significantly longer thrombin time (TT) , with a median of 28.5 (19.2-36.6) s. The 1 hour in vivo recovery (IVR) after fibrinogen infusion was (127.19±44.03) %, and the 24 hour IVR was (101.78±43.98) %. In addition to the obvious increase in the concentration of fibrinogen activity, the TT and the prothrombin time (PT) both decreased significantly, and the TT decreased more significantly, with an average decrease of 15.2% compared to the baseline after 24 hours of infusion. Most patients with congenital fibrinogen disorders have mild or no bleeding symptoms. Patients with afibrinogenemia have more severe symptoms. There is a negative correlation between the fibrinogen and the degree of bleeding. Genetic testing is helpful for the diagnosis of disease classification. FIB∶C/FIB∶Ag<0.7 can be used as a basis for clinical diagnosis. The TT can be used as the basis for the diagnosis of dysfibrinogenemia and the effectiveness of fibrinogen infusion.
Topics: Adult; Afibrinogenemia; Child; Child, Preschool; Female; Fibrinogen; Hemostatics; Humans; Infant; Male; Mutation; Retrospective Studies
PubMed: 34455742
DOI: 10.3760/cma.j.issn.0253-2727.2021.07.005 -
Hematology/oncology Clinics of North... Dec 2021Fibrinogen plays a fundamental role in coagulation through its support for platelet aggregation and its conversion to fibrin. Fibrin stabilizes clots and serves as a... (Review)
Review
Fibrinogen plays a fundamental role in coagulation through its support for platelet aggregation and its conversion to fibrin. Fibrin stabilizes clots and serves as a scaffold and immune effector before being broken down by the fibrinolytic system. Given its importance, abnormalities in fibrin(ogen) and fibrinolysis result in a variety of disorders with hemorrhagic and thrombotic manifestations. This review summarizes (i) the basic elements of fibrin(ogen) and its role in coagulation and the fibrinolytic system; (ii) the laboratory evaluation for fibrin(ogen) disorders, including the use of global fibrinolysis assays; and (iii) the management of congenital and acquired disorders of fibrinogen and fibrinolysis.
Topics: Blood Coagulation; Fibrin; Fibrinogen; Fibrinolysis; Hemostatics; Humans; Thrombosis
PubMed: 34404562
DOI: 10.1016/j.hoc.2021.07.011 -
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 -
International Journal of Hematology Nov 2021We identified a novel heterozygous AαE11del variant in a patient with congenital dysfibrinogenemia. This mutation is located in fibrinopeptide A (FpA). We analyzed the...
INTRODUCTION
We identified a novel heterozygous AαE11del variant in a patient with congenital dysfibrinogenemia. This mutation is located in fibrinopeptide A (FpA). We analyzed the effect of AαE11del on the catalyzation of thrombin and batroxobin and simulated the stability of the complex structure between the FpA fragment (AαG6-V20) peptide and thrombin.
MATERIALS AND METHODS
We performed fibrin polymerization and examined the kinetics of FpA release catalyzed by thrombin and batroxobin using purified plasma fibrinogen. To clarify the association between the AαE11 residue and thrombin, we calculated binding free energy using molecular dynamics simulation trajectories.
RESULTS
Increasing the thrombin concentration improved release of FpA from the patient's fibrinogen to approximately 90%, compared to the previous 50% of that of normal fibrinogen. Fibrin polymerization of variant fibrinogen also improved. In addition, greater impairment of variant FpA release from the patient's fibrinogen was observed with thrombin than with batroxobin. Moreover, the calculated binding free energy showed that the FpA fragment-thrombin complex became unstable due to the missing AαE11 residue.
CONCLUSIONS
Our findings indicate that the AαE11 residue is involved in FpA release in thrombin catalyzation more than in batroxobin catalyzation, and that the AαE11 residue stabilizes FpA fragment-thrombin complex formation.
Topics: Afibrinogenemia; Batroxobin; Blood Coagulation; Blood Coagulation Tests; DNA Mutational Analysis; Fibrin; Fibrinopeptide A; Heterozygote; Humans; Kinetics; Molecular Docking Simulation; Molecular Dynamics Simulation; Protein Binding; Protein Conformation; Protein Multimerization; Sequence Deletion; Structure-Activity Relationship; Thrombin
PubMed: 34333754
DOI: 10.1007/s12185-021-03200-z -
Transfusion and Apheresis Science :... Dec 2021Congenital fibrinogen disorders (CFDs) are caused by mutations in the FGA, FGB and FGG genes and are classified as quantitative and qualitative fibrinogen defects. This...
INTRODUCTION
Congenital fibrinogen disorders (CFDs) are caused by mutations in the FGA, FGB and FGG genes and are classified as quantitative and qualitative fibrinogen defects. This study sought to determine the genetic background of CFDs in Iran and to examine the genotype-phenotype correlation.
METHODS
Fourteen patients with a CFD diagnosis were included. Fibrinogen antigen and activity were measured by the immunoturbidimetric and Clauss methods respectively. Gene sequencing was performed following a polymerase chain reaction amplification of fibrinogen's genes. The ISTH Bleeding Assessment Tool was also evaluated for all cases.
RESULTS
Patients were diagnosed with dysfibrinogenemia (n = 10), hypodysfibrinogenemia (n = 2) and afibrinogenemia (n = 2). Seven different mutations located on FGA exon 2 (57 %), exon 4 (7%), exon 5 (7%) and FGG exon 8 (29 %) were identified. In patients with qualitative deficiencies, mutations were including p.Arg38Thr, p.Arg35His, p.Arg35Cys, p.Val145Asp, and p.Arg301Cys and were including p.Gly316GlufsX105 and p.Trp52stop in afibrinogenemic patients. In dysfibrinogenemia, two hotspot mutations, FGA Arg35 and FGG Arg301 were identified in 60 % of patients and the remaining (40 %) had p.Arg38Thr mutation. The p.Val145Asp and two hotspot mutations, p.Arg35His, p.Arg35Cys, were identified for the first time in Iran. The overall median (range) bleeding score (BS) was 4 (0-6) in all patients and it was 3.5 (0-5) in dysfibrinogenemia. Cutaneous bleeding and menorrhagia were the most common bleeding manifestations.
CONCLUSION
There was a weak genotype-phenotype correlation in CFDs and patients with dysfibrinogenemia were more symptomatic than in previous studies. Despite ethnic's differences, the prevalence of hotspot mutations in dysfibrinogenemia was similar to the other studies.
Topics: Adolescent; Adult; Afibrinogenemia; Child; Female; Humans; Iran; Male; Middle Aged; Mutation; Young Adult
PubMed: 34275736
DOI: 10.1016/j.transci.2021.103203 -
Clinica Chimica Acta; International... Oct 2021Fibrinogen activity (Ac) is widely measured, but fibrinogen antigen (Ag) is measured only in specialized laboratories, so it is difficult to discriminate congenital...
Automated screening procedure for the phenotypes of congenital fibrinogen disorders using novel parameters, |min1|c and Ac/|min1|c, obtained from clot waveform analysis using the Clauss method.
INTRODUCTION
Fibrinogen activity (Ac) is widely measured, but fibrinogen antigen (Ag) is measured only in specialized laboratories, so it is difficult to discriminate congenital fibrinogen disorders (CFDs) from acquired hypofibrinogenemia (aHypo). In this study, to screen for CFD phenotypes we adopted novel parameters, |min1|c and Ac/ |min1|c, and compared these with validated Ac, Ag, and Ac/Ag, and previously proposed Ac/dH and Ac/|min1|.
MATERIALS AND METHODS
We calibrated |min1| using a CN-6000 instrument and investigated the correlation between Ag and |min1|c for aHypo (n = 131) and CFD [18 dysfibrinogenemia (Dys), two hypodysfibrinogenemia (Hypodys) and four hypofibrinpogenemia (Hypo)]. Furthermore, we proposed a schema for screening CFD phenotypes using |min1|c and Ac/|min1|c.
RESULTS
The |min1|c correlated well with Ag in aHypo, and Ac/|min1|c was a better parameter for screening Dys and Hypodys than Ac/dH and Ac/|min1|. With the combination of |min1|c and Ac/|min1|c parameters, 15 Dys, 2 Hypodys and four Hypo were categorized in agreement with the phenotype determined using Ag and Ac/Ag; conversely three Dys were classified as one Hypodys (AαR16C) and two Hypo (BβG15C).
CONCLUSION
We demonstrated that |min1|c and Ac/|min1|c are valuable parameters for screening CFD patients and phenotypes in laboratories that do not measure Ag or perform genetic analysis.
Topics: Afibrinogenemia; Blood Coagulation Tests; Fibrinogen; Hemostatics; Humans; Phenotype
PubMed: 34273336
DOI: 10.1016/j.cca.2021.07.012 -
Seminars in Thrombosis and Hemostasis Mar 2022The congenital dysfibrinogenemias, most often associated with bleeding disorders, encompass mutations in the amino-terminal end of fibrinogen α-chain consisting of... (Review)
Review
The congenital dysfibrinogenemias, most often associated with bleeding disorders, encompass mutations in the amino-terminal end of fibrinogen α-chain consisting of Gly17-Pro18-Arg19-Val20, known as knob A, which is a critical site for fibrin polymerization. Here we review the studies reporting dysfibrinogenemia due to mutations affecting fibrinogen knob A and identified 29 papers. The number of reports on dysfibrinogenemias related to residues Gly17, Pro18, Arg19, and Val20 is 5, 4, 18, and 2, respectively. Dysfibrinogenemias related to residues Gly17, Pro18, and Val20 are exclusively associated with bleeding tendency. However, the clinical picture associated with dysfibrinogenemia related to residue Arg19 varies, with most patients suffering from bleeding tendencies, but also transitory ischemic attacks and retinal thrombosis may occur. The reason for this variation is unclear. To elaborate the genotype-phenotype associations further, we studied a Danish family with knob A-related dysfibrinogenemia caused by the Aα Arg19Gly (p.Arg19Gly) mutation using whole-exome sequencing and fibrin structure analysis. Our family is the first reported carrying the p.Arg19Gly mutation combined with one or more single nucleotide polymorphisms (SNP)s in , , and/or and increased fibrin fiber thickness and fibrin mass-to-length ratio suffering from pulmonary emboli, suggesting that compound genotypes may contribute to the thrombogenic phenotype of these patients. Our review, accordingly, focuses on significance of SNPs, compound genotypes, and fibrin structure measures affecting the genotype-phenotype associations in fibrinogen knob A mutations.
Topics: Afibrinogenemia; Fibrinogen; Genotype; Hemorrhage; Humans; Thrombosis
PubMed: 34261148
DOI: 10.1055/s-0041-1730358 -
Vnitrni Lekarstvi 2021Pembrolizumab belongs to so called immune checkpoint inhibitors. Frequent adverse event of this therapy is hypothyroidism. The authors present a case report of patient...
Pembrolizumab belongs to so called immune checkpoint inhibitors. Frequent adverse event of this therapy is hypothyroidism. The authors present a case report of patient treated with pembrolizumab for non-small cell lung carcinoma, in whom severe hypothyroidism followed quite rapidly after transient phase of subclinical hyperthyroidism - at this time point new and spontaneous onset of large subcutaneous hematomas was observed. Acquired von Willebrand syndrome, acquired hemophilia A, dysfibrinogenemia, activation of fibrinolysis and thrombocytopathy were all actively ruled out in hematological differential diagnosis. Concomittantly, laboratory markers of secondary autoimmune disease and myositis were excluded. Despite continuous pembrolizumab treatment, there were no other bleeding complications seen after intensification of endocrine substitution therapy with thyroid hormones. Causal relationship between subcutaneous hematomas and severe drug-induced hypothyroidism is established per exclusionem.
Topics: Antibodies, Monoclonal, Humanized; Carcinoma, Non-Small-Cell Lung; Humans; Hypothyroidism; Lung Neoplasms
PubMed: 34171958
DOI: No ID Found