INTRODUCTION: Congenital hypofibrinogenemia (CH) and congenital dysfibrinogenemia (CD) are rare coagulation disorders caused by quantitative or qualitative defects in the fibrinogen gene. The aim of this study was to characterize the genetic background and the clinical manifestations of congenital fibrinogen disorders in the patients from Slovakia registered at the National Haemophilia Centre. MATERIALS AND METHODS: Results of genetic analysis of the fibrinogen genes FGA, FGB and FGG using polymerase chain reaction followed by direct sequencing were evaluated in 36 patients. RESULTS: Molecular-genetic analysis revealed six novel variants - FGA c.923_968dup p.(Gly324Lysfs*44) and FGG c.1105C>T p.(His369Tyr) were identified in CD patients. In CH patients, in the FGG gene c.8G>A p.(Trp3*), c.823G>T p.(Glu275*) and c.323C>A p.(Ala108Asp) variants were detected. In the FGB gene c.1427C>T p.(Ser476Leu) was identified. CONCLUSION: This study is a positive contribution towards expanding knowledge about genetic variants in patients with congenital fibrinogen disorders.

• Klíčová slova
• FGA, FGB, FGG, dysfibrinogenemia, hypofibrinogenemia,
• Publikační typ
• časopisecké články MeSH

Abnormal coagulation properties indicative of a dysfibrinogen were found in the plasma of a 72-year-old male with multiple myeloma (IgGkappa, stage IIIA). The patient had high paraprotein concentration (85.75 g/l) and prolonged thrombin time (76.8 s), activated partial thromboplastin time (39.5 s), prothrombin time (23.5 s) and reptilase time (72.0 s). The fibrinogen level was increased. The fibrin polymerization induced by both thrombin and reptilase was impaired. Scanning electron microscopy revealed abnormal clot morphology. After six months of treatment, the paraprotein level decreased (19.48 g/l) and coagulation normalized as well as fibrin polymerization and fibrin clot morphology. It was found that the paraprotein interacts with the gamma-chain of fibrinogen. Acquired dysfibrinogenemia associated with multiple myeloma was diagnosed in the 72-year-old patient.

• MeSH
• afibrinogenemie etiologie   terapie   MeSH
• fibrin chemie   MeSH
• fibrinogen metabolismus   MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• mnohočetný myelom komplikace   MeSH
• paraproteiny analýza   metabolismus   MeSH
• peptidové fragmenty metabolismus   MeSH
• senioři MeSH
• vyšetření krevní srážlivosti MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fibrin MeSH
• fibrinogen gamma (151-411) MeSH Prohlížeč
• fibrinogen MeSH
• paraproteiny MeSH
• peptidové fragmenty MeSH

Fibrinogen—a 340-kDa glycoprotein—plays a crucial role in blood coagulation, platelet aggregation, wound healing, and other physiological processes. A mutation in fibrinogen may lead to congenital dysfibrinogenemia,a rare disease characterized by the functional deficiency of fibrinogen. About 580 cases of abnormal fibrinogens have been reported worldwide; thereof 335 cases in the fibrinogen Aa chain[1]. To our knowledge, only five cases of abnormal fibrinogens with two mutations [2–6] and one case of two different mutations in the same family [7] have been described earlier. A 52-year-old female was examined for bleeding. Routine hemostasis screening resulted in a diagnosis of dysfibrinogenemia. Functional testing revealed prolonged fibrin polymerization, prolonged lysis of the clot, abnormal fibrin morphology,and fibrinopeptides release. Genetic analysis showed two heterozygous nonsense mutations—previously described mutation AaGly13Glu and a novel mutation Aa Ser314Cys. The mutation Aa Gly13-Glu was found in her brother and niece, but there was no evidence in either of the mutation Aa Ser314Cys. While mutation Aa Gly13Glu is responsible for abnormal fibrinopeptide release and prolonged thrombin time, the novel mutation Aa Ser314Cys seems to affect fibrin morphology and fibrinolysis.

• MeSH
• afibrinogenemie krev   komplikace   genetika   MeSH
• bodová mutace * MeSH
• dítě MeSH
• dospělí MeSH
• elektroforéza sérových bílkovin MeSH
• fibrin ultrastruktura   MeSH
• fibrinogeny abnormální genetika   izolace a purifikace   MeSH
• fibrinopeptid A metabolismus   MeSH
• hemoragické poruchy etiologie   MeSH
• heterozygot MeSH
• lidé středního věku MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• nesmyslný kodon * MeSH
• posttranslační úpravy proteinů MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• fibrin MeSH
• Fibrinogen Sumperk II MeSH Prohlížeč
• fibrinogeny abnormální MeSH
• fibrinopeptid A MeSH
• nesmyslný kodon * MeSH

A 2-year-old asymptomatic boy and his relatives were investigated for a suspected fibrinogen mutation after coagulation tests revealed a decreased functional fibrinogen level (family A). Eight-year-old and 1-year-old asymptomatic brothers were investigated for a suspected fibrinogen mutation after coagulation tests revealed a decreased functional fibrinogen level and prolonged thrombin time (family B). To identify whether genetic mutations were responsible for these dysfibrinogens, DNA extracted from the blood was analyzed. Fibrin polymerization and fibrinolysis were measured by a turbidimetric method at 450 nm. DNA analysis was performed by the Sanger method. Mass spectroscopy was performed on a Biflex IV mass spectrometer. DNA sequencing showed the heterozygous point mutation Aα Arg16His in the fibrinogen of family A and the heterozygous point mutation Aα Arg16Cys in the fibrinogen of family B. Kinetics of fibrinopeptide release, fibrinolysis, and fibrin polymerization were impaired in the carriers of the mutations in both families. Mass spectroscopy showed the presence of mutant fibrinogen chains in circulation. Scanning electron microscopy revealed thicker fibrin fibers, differing significantly from the normal control in both cases. Two cases of asymptomatic dysfibrinogenemias, found by routine coagulation testing, were genetically identified as new cases of fibrinogen variants Aα Arg16His and Aα Arg16Cys.

• MeSH
• afibrinogenemie vrozené   diagnóza   genetika   MeSH
• bodová mutace * MeSH
• dítě MeSH
• fibrin metabolismus   MeSH
• fibrinogen genetika   MeSH
• heterozygot MeSH
• kojenec MeSH
• lidé MeSH
• mutační analýza DNA metody   MeSH
• sourozenci MeSH
• trombinový čas MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fibrin MeSH
• fibrinogen MeSH

Congenital dysfibrinogenemia is a rare disease characterised by inherited abnormality in the fibrinogen molecule, resulting in functional defects. Two patients, a 26-year-old woman and a 61-year-old man, both with history of thrombotic events, had abnormal coagulation test results. DNA sequencing showed the heterozygous gamma Y363N mutation (Fibrinogen Praha III) and the heterozygous Aalpha N106D mutation (Fibrinogen Plzen), respectively. Fibrin polymerisation, after addition of either thrombin or reptilase, showed remarkably delayed polymerisation in both cases. Fibrinolysis experiments showed slower tPA initiated lysis of clots. SDS-PAGE did not show any difference between normal and Praha III and Plzen fibrinogens. Both mutations had a significant effect on platelet aggregation. In the presence of either ADP or TRAP, both mutations caused the decrease of platelet aggregation. SEM revealed abnormal clot morphology, with a large number of free ends and narrower fibres of both fibrin Praha III and Plzen. Praha III mutation was situated in the polymerisation pocket "a". The replacement of the bulky aromatic side chain of tyrosine by the polar uncharged small side chain of asparagine may lead to a conformational change, possibly altering the conformation of the polymerisation pocket. The Plzen mutation is situated in the coiled-coil connector and this replacement of polar uncharged asparagine residue by polar acidic aspartate changes the alpha-helical conformation of the coiled-coil connector; and may destabilise hydrogen bonds in its neighborhood. Although both mutations are situated in different regions of the molecule, both mutations have a very similar effect on fibrinogen functions and both are connected with thromboses.

• MeSH
• agregace trombocytů MeSH
• dospělí MeSH
• fibrin chemie   MeSH
• fibrinogen genetika   MeSH
• fibrinogeny abnormální genetika   MeSH
• hemokoagulace MeSH
• lidé středního věku MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• mutace MeSH
• plicní embolie genetika   MeSH
• poruchy koagulačních proteinů komplikace   vrozené   diagnóza   genetika   MeSH
• trombóza komplikace   diagnóza   genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fibrin MeSH
• fibrinogen MeSH
• fibrinogeny abnormální MeSH

INTRODUCTION: Various dysfibrinogenemias have been described worldwide. This paper describes two new cases of dysfibrinogenemia identified in the Czech Republic. MATERIALS AND METHODS: The proposita of fibrinogen Nový Jicín, a 12-year-old girl, presented with hemorrhagic complications, low Clauss fibrinogen level (0.3 g/l) and prolonged both thrombin (70.8 s) and reptilase (>180 s) time. Her mother and sister both presented with normal coagulation tests, normal fibrinogen level and reported no history of bleeding. The carriers of the fibrinogen Praha II were a 31-year-old man and his 11-year-old daughter. They both presented with low fibrinogen Clauss level (0.88 g/l) and prolonged thrombin and reptilase time. To identify the genetic mutation responsible for these dysfibrinogens, genomic DNA extracted from the blood was analyzed. The presence of the mutant chains in the circulation was determined by MALDI-TOF mass spectroscopy. Scanning electron micrographs of the patients' fibrin clots were obtained. RESULTS: The kinetics of fibrinopeptide release and fibrin polymerization were impaired for both fibrinogen Nový Jicín and Praha II. DNA sequencing showed heterogeneous fibrinogen Aalpha R16C mutation in the fibrinogen Nový Jicín case and heterogeneous fibrinogen Aalpha R16H in the fibrinogen Praha II case. The mutant chains were found to be expressed to the circulation by MALDI-TOF mass spectroscopy. Scanning electron micrographs of the patient's fibrin clot were found to be abnormal. CONCLUSIONS: The case of dysfibrinogenemia Aalpha R16C-fibrinogen Nový Jicín and the case of dysfibrinogenemia Aalpha R16H were found by routine coagulation testing and were genetically identified.

• MeSH
• afibrinogenemie genetika   MeSH
• dítě MeSH
• dospělí MeSH
• fibrin metabolismus   MeSH
• fibrinogeny abnormální genetika   MeSH
• kinetika MeSH
• krvácení MeSH
• lidé MeSH
• missense mutace * MeSH
• mutační analýza DNA MeSH
• vyšetření krevní srážlivosti MeSH
• zdraví rodiny MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• fibrin MeSH
• fibrinogen Novy Jicin MeSH Prohlížeč
• fibrinogen Praha II MeSH Prohlížeč
• fibrinogeny abnormální MeSH

INTRODUCTION: Congenital dysfibrinogenemia and hypofibrinogenemia are rare diseases characterized by inherited abnormality in the fibrinogen molecule, resulting in functional defects (dysfibrinogenemia) or low fibrinogen plasma levels (hypofibrinogenemia). MATERIALS AND METHODS: We have described two abnormal fibrinogens - fibrinogen Hranice (γ Phe204Val) and Praha IV (γ Ser313Gly). The carrier of the Hranice mutation was a 40-year-old female with low fibrinogen levels. The carrier of the Praha IV mutation was a 42-year-old man with a history of idiopathic thrombosis, low functional fibrinogen levels, and a prolonged thrombin time. RESULTS: Fibrin polymerization kinetics measurement was normal in both cases (after the addition of either thrombin or reptilase), as well as was fibrinolysis. Scanning electron microscopy and confocal microscopy revealed significantly wider fibers in both cases, when compared with fibers prepared from healthy control samples. Although both cases are situated in the γ-nodule, they manifested differently. While the γ Ser313Gly mutation manifested as dysfibrinogenemia with a thrombotic background, the γ Phe204Val mutation manifested as hypofibrinogenemia without clinical symptoms. The mutation sites of both fibrinogens are in highly conserved regions of the fibrinogen γ chains. γ Ser313 is situated in a class 16:18 β hairpin and is involved in hydrogen bonding with γ Asp320. γ Phe204 is situated in an inverse γ turn and may be involved in π-π interactions. CONCLUSIONS: Both mutations cause conformational changes in fibrinogen, which lead either to impaired fibrinogen assembly (fibrinogen Hranice) or abnormal fibrinogen function (fibrinogen Praha IV).

• Klíčová slova
• Abnormal fibrinogens, Coagulation, Fibrinogen, Hereditary coagulation disorders, Thrombosis,
• MeSH
• afibrinogenemie krev   vrozené   genetika   metabolismus   MeSH
• bodová mutace * MeSH
• dospělí MeSH
• fibrin genetika   metabolismus   ultrastruktura   MeSH
• fibrinogen genetika   metabolismus   ultrastruktura   MeSH
• fibrinogeny abnormální genetika   metabolismus   ultrastruktura   MeSH
• fibrinolýza MeSH
• lidé MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fibrin MeSH
• fibrinogen MeSH
• fibrinogeny abnormální MeSH
• fibrinopeptides gamma MeSH Prohlížeč

• MeSH
• chronické selhání ledvin krev   komplikace   terapie   MeSH
• dialýza ledvin * MeSH
• dospělí MeSH
• fibrinogen analýza   MeSH
• koagulopatie etiologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• trombinový čas MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• fibrinogen MeSH

Fibrinogen, an abundant plasma glycoprotein, is involved in the final stage of blood coagulation. Decreased fibrinogen levels, which may be caused by mutations, are manifested mainly in bleeding and thrombotic disorders. Clinically relevant mutations of fibrinogen are listed in the Human Fibrinogen Database. For the αC-connector (amino acids Aα240-410, nascent chain numbering), we have extended this database, with detailed descriptions of the clinical manifestations among members of reported families. This includes the specification of bleeding and thrombotic events and results of coagulation assays. Where available, the impact of a mutation on clotting and fibrinolysis is reported. The collected data show that the Human Fibrinogen Database reports considerably fewer missense and synonymous mutations than the general COSMIC and dbSNP databases. Homozygous nonsense or frameshift mutations in the αC-connector are responsible for most clinically relevant symptoms, while heterozygous mutations are often asymptomatic. Symptomatic subjects suffer from bleeding and, less frequently, from thrombotic events. Miscarriages within the first trimester and prolonged wound healing were reported in a few subjects. All mutations inducing thrombotic phenotypes are located at the identical positions within the consensus sequence of the tandem repeats.

• Klíčová slova
• Human Fibrinogen Database, afibrinogenemia, dysfibrinogenemia, fibrinogen, hypodysfibrinogenemia, hypofibrinogenemia, mutations, αC-connector,
• MeSH
• fibrinogen genetika   MeSH
• hemokoagulace genetika   MeSH
• krvácení genetika   MeSH
• lidé MeSH
• mutace genetika   MeSH
• trombóza genetika   MeSH
• vyšetření krevní srážlivosti metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• fibrinogen MeSH

Congenital fibrinogen disorders are caused by mutations in genes coding for fibrinogen and may lead to various clinical phenotypes. Here, we present a functional and structural analysis of 4 novel variants located in the FGB gene coding for fibrinogen Bβ chain-heterozygous missense BβY416C and BβA68S, homozygous nonsense BβY345*, and heterozygous nonsense BβW403* mutations. The cases were identified by coagulation screening tests and further investigated by various methods. Fibrin polymerization had abnormal development with decreased maximal absorbance in all patients. Plasmin-induced fibrin degradation revealed different lytic phases of BβY416C and BβW403* than those of the control. Fibrinopeptide cleavage measured by reverse phase high pressure liquid chromatography of BβA68S showed impaired release of fibrinopeptide B. Morphological properties, studied through scanning electron microscopy, differed significantly in the fiber thickness of BβY416C, BβA68S, and BβW403*, and in the fiber density of BβY416C and BβW403*. Finally, homology modeling of BβA68S showed that mutation caused negligible alternations in the protein structure. In conclusion, all mutations altered the correct fibrinogen function or structure that led to congenital fibrinogen disorders.

• Klíčová slova
• FGB, afibrinogenemia, congenital fibrinogen disorder, dysfibrinogenemia, functional assays, homology modeling, hypofibrinogenemia, scanning electron microscopy,
• MeSH
• afibrinogenemie krev   diagnóza   genetika   MeSH
• fenotyp * MeSH
• fibrinogen chemie   genetika   metabolismus   MeSH
• genetická predispozice k nemoci * MeSH
• genetické asociační studie MeSH
• hemokoagulace MeSH
• konformace proteinů MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• molekulární modely MeSH
• mutace * MeSH
• mutační analýza DNA MeSH
• novorozenec MeSH
• senioři MeSH
• vyšetření krevní srážlivosti MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Názvy látek
• FGB protein, human MeSH Prohlížeč
• fibrinogen MeSH