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Marguerite Neermanarbez - One of the best experts on this subject based on the ideXlab platform.
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heterogeneity of congenital Afibrinogenemia from epidemiology to clinical consequences and management
Blood Reviews, 2021Co-Authors: Alessandro Casini, Marguerite Neermanarbez, Philippe De MoerlooseAbstract:Fibrinogen is a complex protein playing a major role in coagulation. Congenital Afibrinogenemia, characterized by the complete absence of fibrinogen, is associated with major hemostatic defects. Even though the clinical course is unpredictable and can be completely different among patients, severe bleeding is the prominent symptom. Patients are also at increased risk of thrombosis and sometimes suffer from spontaneous spleen rupture, bone cysts and defective wound healing. Due to the relative rarity of Afibrinogenemia, there are no evidence-based strategies for helping physicians in care of these patients. Fibrinogen supplementation is the keystone to prevent or treat bleeding events. In addition, fibrinogen, a pleiotropic protein with numerous physiological roles in immunity, angiogenesis and tissue repair, is involved in many diseases. Indeed, depletion of fibrinogen in animal models of infections, tumors and neurological diseases has an effect on the clinical course. The consequences for patients with Afibrinogenemia still need to be investigated.
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Afibrinogenemia caused by a novel homozygous missense mutation fgb p cys241tyr in a male patient with recurrent intracranial bleeding case report and review of literature
Haemophilia, 2021Co-Authors: Joanna Zdziarska, Marguerite Neermanarbez, Ewa Wypasek, Teresa Iwaniec, Rui Vilar, Anetta UndasAbstract:Introduction Congenital Afibrinogenemia is a severe bleeding disorder, sometimes manifesting as thrombosis and/or pregnancy complications. Intracranial haemorrhage (ICH) constitutes the major cause of death in this disease. Methods We present the case of a male patient with congenital Afibrinogenemia, who presented with recurrent intracranial hemorrhages, despite prophylactic fibrinogen substitution. We also review the literature for the risk of intracranial hemorrhages in Afibrinogenemia. Result Molecular analysis revealed a novel homozygous missense mutation in FGB exon 5, p.Cys241 Tyr, that was named "Fibrinogen Krakow V". Discussion and conclusion Intracranial hemorrhage is a severe manifestation of Afibrinogenemia, also in children. The clinical presentation of Afibrinogenemia is variable. Fibrinogen substitution carries a risk of thrombotic complications.
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a novel frameshift mutation in the fga gene c 196 delt leading to congenital Afibrinogenemia
Journal of Pediatric Hematology Oncology, 2020Co-Authors: Sultan Aydin Koker, Marguerite Neermanarbez, Alper Koker, Gokcen Oz Tuncer, Yilmaz Akbas, Tugce Tural Kara, Yasemin CobanAbstract:Background Congenital Afibrinogenemia is characterized by the absence of fibrinogen. Congenital fibrinogen disorders result from several mutations in FGA, FGB, or FGG. Their epidemiology is not well known. Observation The present study reports on 2 children with congenital Afibrinogenemia. The first child, a male who is now 9 years old, was diagnosed with Afibrinogenemia after spontaneous intracranial bleeding at the age of 3 years. The second child is a 2-year-old female cousin of the first patient, who was diagnosed with Afibrinogenemia after coagulation tests were carried out due to frequent epistaxis and mucocutaneous bleeding. At follow-up, blood samples of the patients and their parents were sent to the Department of Genetic Medicine and Development, University Medical Center, Switzerland, for polymerase chain reaction analysis. In both patients, the novel homozygous frameshift mutation in the FGA exon 3: c.196 delT was detected. The parents of the patients were both heterozygous for the same mutation. Conclusions Congenital Afibrinogenemia is a rare coagulation disease. The molecular epidemiology of congenital fibrinogen disorders is complex, and the identification of new mutations will help shed light on this complex molecular structure. Therefore, a genetic analysis that includes more centers is needed.
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targeted mutation of zebrafish fga models human congenital Afibrinogenemia
Blood, 2014Co-Authors: Richard J Fish, Corinne Di Sanza, Marguerite NeermanarbezAbstract:Mutations in the human fibrinogen genes can lead to the absence of circulating fibrinogen and cause congenital Afibrinogenemia. This rare bleeding disorder is associated with a variable phenotype, which may be influenced by environment and genotype. Here, we present a zebrafish model of Afibrinogenemia. We introduced targeted mutations into the zebrafish fga gene using zinc finger nuclease technology. Animals carrying 3 distinct frameshift mutations in fga were raised and bred to produce homozygous mutants. Using a panel of anti-zebrafish fibrinogen antibodies, fibrinogen was undetectable in plasma preparations from homozygous mutant fish. We observed hemorrhaging in fga mutants and reduced survival compared with control animals. This model will now serve in the search for Afibrinogenemia modifying genes or agents and, to our knowledge, is the first transmissible zebrafish model of a defined human bleeding disorder.
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congenital fibrinogen disorders an update
Seminars in Thrombosis and Hemostasis, 2013Co-Authors: Philippe De Moerloose, Alessandro Casini, Marguerite NeermanarbezAbstract:Hereditary fibrinogen abnormalities comprise two classes of plasma fibrinogen defects: Type I, Afibrinogenemia or hypofibrinogenemia, which has absent or low plasma fibrinogen antigen levels (quantitative fibrinogen deficiencies), and Type II, dysfibrinogenemia or hypodysfibrinogenemia, which shows normal or reduced antigen levels associated with disproportionately low functional activity (qualitative fibrinogen deficiencies). In Afibrinogenemia and hypofibrinogenemia, most mutations of the FGA, FGB, or FGG fibrinogen encoding genes are null mutations. In some cases, missense or late truncating nonsense mutations allow synthesis of the corresponding fibrinogen chain but intracellular fibrinogen assembly and/or secretion are impaired. Afibrinogenemia is associated with mild-to-severe bleeding, whereas hypofibrinogenemia is most often asymptomatic. Thromboembolism may occur either spontaneously or in association with fibrinogen substitution therapy. Women with Afibrinogenemia suffer from recurrent pregnancy loss but this can also occur in women with hypofibrinogenemia. Dysfibrinogenemia, caused mainly by missense mutations, is commonly associated with bleeding, thrombophilia, or both; however, most individuals are asymptomatic. Hypodysfibrinogenemia is a subcategory of this disorder. Even in specialized laboratories, the precise diagnosis of some fibrinogen disorders may be difficult. Determination of the molecular defects is important because it gives the possibility to confirm the diagnosis, to elaborate a diagnostic strategy, to distinguish in some cases that the patient is at risk of thrombosis rather than bleeding, and to enable prenatal diagnosis. However, genotype–phenotype correlations are not easy to establish. Replacement therapy is effective in treating bleeding episodes, but because the pharmacokinetics of fibrinogen after replacement therapy is highly variable among patients, it is important to adjust the treatment individually.
Philippe De Moerloose - One of the best experts on this subject based on the ideXlab platform.
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heterogeneity of congenital Afibrinogenemia from epidemiology to clinical consequences and management
Blood Reviews, 2021Co-Authors: Alessandro Casini, Marguerite Neermanarbez, Philippe De MoerlooseAbstract:Fibrinogen is a complex protein playing a major role in coagulation. Congenital Afibrinogenemia, characterized by the complete absence of fibrinogen, is associated with major hemostatic defects. Even though the clinical course is unpredictable and can be completely different among patients, severe bleeding is the prominent symptom. Patients are also at increased risk of thrombosis and sometimes suffer from spontaneous spleen rupture, bone cysts and defective wound healing. Due to the relative rarity of Afibrinogenemia, there are no evidence-based strategies for helping physicians in care of these patients. Fibrinogen supplementation is the keystone to prevent or treat bleeding events. In addition, fibrinogen, a pleiotropic protein with numerous physiological roles in immunity, angiogenesis and tissue repair, is involved in many diseases. Indeed, depletion of fibrinogen in animal models of infections, tumors and neurological diseases has an effect on the clinical course. The consequences for patients with Afibrinogenemia still need to be investigated.
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congenital Afibrinogenemia identification and characterization of two novel homozygous fibrinogen aα and bβ chain mutations in two tunisian families
Thrombosis Research, 2016Co-Authors: Yessine Amri, Nour El Houda Toumi, Sondess Hadj Fredj, Philippe De MoerlooseAbstract:Abstract Introduction Inherited abnormalities of fibrinogen (FG) are rare coagulation disorders divided into two types: quantitative abnormalities (Afibrinogenemia and hypofibrinogenemia) or qualitative abnormalities (dysfibrinogenemia and hypo-dysfibrinogenemia) of circulating fibrinogen. In particular, congenital Afibrinogenemia is inherited as an autosomal recessive mode and is usually determined by homozygous or compound heterozygous mutations affecting any of the three fibrinogen genes (FGA, FGB and FGG), resulting in the complete absence or extremely reduced amount of fibrinogen. The aim of the present study was to characterize the fibrinogen abnormalities in two Tunisian families. Methods Coagulation studies were performed on the patients and family members. All the exons and the flanking intron regions of fibrinogen genes were screened by direct sequencing. Results Probands had concomitant bleeding complications with infinitely prolonged standard coagulation assays. Mutational screening of the fibrinogen gene cluster of each proband, disclosed two previously undescribed homozygous point mutations. The first mutation was a major truncation (AαArg252Stop) leads to a severe premature termination codon in the exon 5 of the FGA gene. This mutation defines in vivo the importance of the αC flexible segment in the secretion of a stable fibrinogen molecule. The second afibrinogenemic mutation (BβGly295Ala) occurs in the exon 7 of the FGB gene. This missense mutation would probably lead to significant conformational change not allowing the expression of the fibrinogen protein. Conclusion Current molecular characterization of these two fibrinogen abnormalities confirms the importance of the first portion of αC-region (αC-connector) as well as the Bβ globular domain in the secretion processes.
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congenital fibrinogen disorders an update
Seminars in Thrombosis and Hemostasis, 2013Co-Authors: Philippe De Moerloose, Alessandro Casini, Marguerite NeermanarbezAbstract:Hereditary fibrinogen abnormalities comprise two classes of plasma fibrinogen defects: Type I, Afibrinogenemia or hypofibrinogenemia, which has absent or low plasma fibrinogen antigen levels (quantitative fibrinogen deficiencies), and Type II, dysfibrinogenemia or hypodysfibrinogenemia, which shows normal or reduced antigen levels associated with disproportionately low functional activity (qualitative fibrinogen deficiencies). In Afibrinogenemia and hypofibrinogenemia, most mutations of the FGA, FGB, or FGG fibrinogen encoding genes are null mutations. In some cases, missense or late truncating nonsense mutations allow synthesis of the corresponding fibrinogen chain but intracellular fibrinogen assembly and/or secretion are impaired. Afibrinogenemia is associated with mild-to-severe bleeding, whereas hypofibrinogenemia is most often asymptomatic. Thromboembolism may occur either spontaneously or in association with fibrinogen substitution therapy. Women with Afibrinogenemia suffer from recurrent pregnancy loss but this can also occur in women with hypofibrinogenemia. Dysfibrinogenemia, caused mainly by missense mutations, is commonly associated with bleeding, thrombophilia, or both; however, most individuals are asymptomatic. Hypodysfibrinogenemia is a subcategory of this disorder. Even in specialized laboratories, the precise diagnosis of some fibrinogen disorders may be difficult. Determination of the molecular defects is important because it gives the possibility to confirm the diagnosis, to elaborate a diagnostic strategy, to distinguish in some cases that the patient is at risk of thrombosis rather than bleeding, and to enable prenatal diagnosis. However, genotype–phenotype correlations are not easy to establish. Replacement therapy is effective in treating bleeding episodes, but because the pharmacokinetics of fibrinogen after replacement therapy is highly variable among patients, it is important to adjust the treatment individually.
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a novel frameshift mutation in fga c 1846 del a leading to congenital Afibrinogenemia in a consanguineous syrian family
Blood Coagulation & Fibrinolysis, 2011Co-Authors: Emmanuel Levrat, Philippe De Moerloose, Imad Aboukhamis, Jaafar Farho, Sahar Chamaa, G Reber, Alexandre Fort, Marguerite NeermanarbezAbstract:Congenital Afibrinogenemia is a rare autosomal recessive coagulation disorder characterized essentially by bleeding symptoms, but miscarriages and, paradoxically, thromboembolic events can also occur. Most reported mutations leading to congenital Afibrinogenemia are located in FGA encoding the fibrinogen A α-chain. In this study, we analysed 12 individuals from a consanguineous Syrian family with reduced or absent fibrinogen levels: those with fibrinogen levels around 1 g/l (n = 7) were found to be heterozygous for a novel frameshift mutation in FGA exon 5 (c.1846 del A) and those with undetectable fibrinogen levels (n = 5) were homozygous for the same mutation. This novel frameshift mutation is the most C-terminal causative FGA mutation identified to date in afibrinogenemic patients. The resulting aberrant Aα-chain (p.Thr616HisfsX32) is most likely synthesized, but is less efficiently assembled and/or secreted into the circulation given the phenotype of asymptomatic hypofibrinogenemia in heterozygous individuals and bleeding diathesis in homozygous individuals.
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a novel frameshift mutation in fga accounting for congenital Afibrinogenemia predicted to encode an aberrant peptide terminating 158 amino acids downstream
Blood Coagulation & Fibrinolysis, 2009Co-Authors: H Robertebadi, Philippe De Moerloose, El M Khorassani, El M Khattab, Marguerite NeermanarbezAbstract:Congenital Afibrinogenemia is a rare autosomal recessive disorder characterized by complete absence of detectable fibrinogen and bleeding symptoms. Many causative mutations have been described to date in all three fibrinogen genes, most of them in the fibrinogen A alpha-chain gene (FGA), but also in the fibrinogen B beta-chain gene (FGB) and the fibrinogen gamma-chain gene (FGG). We report here a novel frameshift mutation (p.Glu262AspfsX158) in FGA exon 5 predicted to lead to a truncated polypeptide with an exceptionally long stretch of abnormal residues identified in homozygosity in a patient with congenital Afibrinogenemia. Interestingly, five other frameshift mutations predicted to truncate at the same stop codon have already been described in FGA exon 5.
Maria Luisa Tenchini - One of the best experts on this subject based on the ideXlab platform.
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Liver histology of an afibrinogenemic patient with the Bbeta-L353R mutation showing no evidence of hepatic endoplasmic reticulum storage disease (ERSD); comparative study in COS-1 cells of the intracellular processing of the Bbeta-L353R fibrinogen vs. the
'Wiley', 2005Co-Authors: S Duga, Rosanna Asselta, E Santagostino, P. Braidotti, M. Maggioni, C. Pellegrini, G. Coggi, M. Malcovati, Maria Luisa TenchiniAbstract:BACKGROUND: Type I fibrinogen deficiencies (hypofibrinogenemia and Afibrinogenemia) are rare congenital disorders characterized by low or unmeasurable plasma fibrinogen antigen levels. Their genetic bases are represented by mutations within the three fibrinogen genes. Among the 11 reported missense mutations, a few have been characterized by expression studies and found to have an impaired fibrinogen assembly and/or secretion. Histopathological analyses were previously reported in two hypofibrinogenemic cases with discernible hepatic disease, revealing that both underlying mutations (gamma-Gly284Arg and gamma-Arg375Trp) were associated with hepatic fibrinogen endoplasmic reticulum storage disease (ERSD). OBJECTIVE: The objective of this study was to investigate the liver histology in an afibrinogenemic patient, homozygous for the Bbeta-Leu353Arg mutation, and to study the intracellular processing of the mutant protein. Patients and methods: Liver histology was evaluated by light microscopy, electron microscopy and immunocytochemistry. Intracellular processing of mutant fibrinogen was analyzed by pulse-chase labeling and immunoprecipitation experiments. Messenger RNA levels were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The histopathological characterization of the liver showed no signs of fibrinogen accumulation, a difference from the previously reported findings in two hypofibrinogenemic kindreds with ERSD. To evaluate whether the Bbeta-Leu353Arg mutation and the ERSD-associated gamma-Gly284Arg mutation affected intracellular fibrinogen trafficking differently, both mutant proteins were expressed in COS-1 cells. Bbeta-Leu353Arg led to a more severe secretion defect, but no differences that could explain phenotype-genotype correlation were found in the intracellular processing. Endoglycosidase-H analysis demonstrated a secretion block before translocation to the Golgi medial stacks. Real-time RT-PCR studies showed normal levels of the Bbeta mRNA in the patient's liver. CONCLUSIONS: The results confirm that Bbeta-Leu353Arg is associated with impaired fibrinogen secretion, but not with hepatic ERSD
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congenital afibrinogenaemia caused by uniparental isodisomy of chromosome 4 containing a novel 15 kb deletion involving fibrinogen aα chain gene
European Journal of Human Genetics, 2004Co-Authors: Silvia Spena, S Duga, Rosanna Asselta, Massimo Malcovati, Flora Peyvandi, C Mahasandana, Maria Luisa TenchiniAbstract:Congenital afibrinogenaemia caused by uniparental isodisomy of chromosome 4 containing a novel 15-kb deletion involving fibrinogen A α -chain gene
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congenital Afibrinogenemia intracellular retention of fibrinogen due to a novel w437g mutation in the fibrinogen bβ chain gene
Biochimica et Biophysica Acta, 2003Co-Authors: Silvia Spena, S Duga, Rosanna Asselta, Massimo Malcovati, Flora Peyvandi, Pier Mannuccio Mannucci, Maria Luisa TenchiniAbstract:Congenital Afibrinogenemia is a rare autosomal recessive coagulation disorder characterised by hemorrhagic manifestations of variable entity and by severe plasma fibrinogen deficiency. Among the 31 Afibrinogenemia-causing mutations so far reported, only 2 are missense mutations and both are located in the fibrinogen Bbeta-chain gene. Direct sequencing of the fibrinogen gene cluster in two afibrinogenemic Iranian siblings revealed a novel homozygous T>G transversion in exon 8 (nucleotide position 8025) of the fibrinogen Bbeta-chain gene. The resulting W437G missense mutation involves a highly conserved amino acid residue, located in the C-terminal globular D domain. The role of the W437G amino acid substitution on fibrinogen synthesis, folding, and secretion was assessed by in vitro expression experiments in COS-1 cells, followed by qualitative and quantitative analyses of intracellular and secreted mutant fibrinogen. Results of both pulse-chase experiments and enzyme-linked immunosorbent assays demonstrated intracellular retention of the mutant W437G fibrinogen and marked reduction of its secretion. These data, besides elucidating the pathogenetic role of the W437G mutation in Afibrinogenemia, underline the importance of the Bbeta-chain D domain in fibrinogen folding and secretion.
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congenital Afibrinogenemia first identification of splicing mutations in the fibrinogen bβ chain gene causing activation of cryptic splice sites
Blood, 2002Co-Authors: Silvia Spena, S Duga, Rosanna Asselta, Massimo Malcovati, Flora Peyvandi, Maria Luisa TenchiniAbstract:Congenital Afibrinogenemia is a rare inherited coagulopathy, characterized by very low or unmeasurable plasma levels of immunoreactive fibrinogen. So far, 25 mutations have been identified in Afibrinogenemia, 17 in the Aα, 6 in the γ, and only 2 in the Bβ fibrinogen–chain genes. Here, 2 afibrinogenemic probands, showing undetectable levels of functional fibrinogen, were screened for causative mutations at the genomic level. Sequence analysis of the 3 fibrinogen genes disclosed 2 novel homozygous mutations in introns 6 and 7 of the Bβ-chain gene (IVS6 + 13C > T and IVS7 + 1G > T), representing the first Bβ-chain gene splicing mutations described in Afibrinogenemia. The IVS6 + 13C > T mutation predicts the creation of a donor splice site in intron 6, whereas the IVS7 + 1G > T mutation causes the disappearance of the invariant GT dinucleotide of intron 7 donor splice site. To analyze the effect of these mutations, expression plasmids containing Bβ-chain minigene constructs, either wild-type or mutant, were transfected in HeLa cells. Assessed by semiquantitative analysis of reverse transcriptase–polymerase chain reaction products, the IVS7 + 1G > T mutation resulted in multiple aberrant splicings, while the IVS6 + 13C > T mutation resulted in activation of a new splice site 11 nucleotides downstream of the physiologic one. Both mutations are predicted to determine protein truncations, supporting the importance of the C-terminal domain of the Bβ chain for fibrinogen assembly and secretion.
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analysis of iranian patients allowed the identification of the first truncating mutation in the fibrinogen bbeta chain gene causing Afibrinogenemia
Haematologica, 2002Co-Authors: Rosanna Asselta, S Duga, Massimo Malcovati, Flora Peyvandi, Silvia Spena, Pier Mannuccio Mannucci, Maria Luisa TenchiniAbstract:BACKGROUND AND OBJECTIVES: Congenital Afibrinogenemia is a rare coagulation disorder whose molecular basis is still poorly characterized. Most mutations have been identified in the fibrinogen Aalpha- and gamma-chain genes, whereas only two missense mutations have been reported in the Bbeta-chain gene. The aim of this work was to widen knowledge about the mutational spectrum of this disease by analyzing the molecular bases of congenital Afibrinogenemia in three unrelated Iranian patients. DESIGN AND METHODS: All patients showed unmeasurable levels of clottable fibrinogen in plasma. Mutational screening was performed by sequencing the whole coding region, including exon-intron boundaries and part of the promoter region of the three fibrinogen genes. RESULTS: Sequencing in one patient revealed the presence of a novel nonsense mutation (3282C-->T) in exon 2 of the fibrinogen Bbeta-chain gene, causing a severe truncation of the corresponding polypeptide (R17X). In the remaining probands, two already known small deletions (4209delA and 4220delT), both located in exon 5 of the fibrinogen Aalpha-chain gene, were identified, and their effect at the protein level explored by computer-assisted analysis. INTERPRETATION AND CONCLUSIONS: The identification of the first truncating mutation in the fibrinogen Bbeta-chain gene confirms the involvement of all three fibrinogen genes in the pathogenesis of congenital Afibrinogenemia and widens the mutational spectrum of the disease. This knowledge is clinically essential in order to carry out prenatal diagnosis in families at risk.
Rosanna Asselta - One of the best experts on this subject based on the ideXlab platform.
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Congenital fibrinogen deficiency in Pakistan and identification of five novel mutations
'Wiley', 2014Co-Authors: M. Borhany, S Duga, Rosanna Asselta, M. Robusto, N. Fatima, T.s. Shamsi, F. PeyvandiAbstract:Objectives: The aim of the study is to identify the underlying mutations of Afibrinogenemia and possibly to correlate bleeding symptoms with the identified genotype. Methods: Subjects with inherited bleeding tendency in the absence of any acquired cause of hemostatic defect were included in the study. Afibrinogenemia was diagnosed after analysis of PT, APTT, and measurements of functional and antigen fibrinogen levels. Genomic DNA was extracted from whole blood by the QiAamp DNA Blood mini kit (Qiagen).Genomic DNA was PCR amplified by using sense and antisense primers designed on the basis of known sequences of the three fibrinogen genes and intergenic regions (GenBank accession numbers M64982, M64983, M10014, U36478, and AF229198). Molecular analysis was performed by DNA sequencing on both strands, by using the Big Dye Terminator Cycle Sequencing kit and an ABI-3130-XL automated DNA sequencer (Applied Biosystems). The Variant Reporter software (Applied Biosystems) was used for mutation detection. Results: A total of 21 afibrinogenemic patients (10 males and 11 females) came to our attention: their mean age was 11.54 +/- 11.2 years (range 1\u201340) and the mean bleeding score was 13.3 +/- 6.7.The most common bleeding manifestations were bruises, umbilical cord bleeding, gum bleeding, hematomas, circumcision bleeding, epistaxis, and menorrhagia. Genetic analysis was completed in nine cases, revealing a total of six different mutations: four in FGA (p.Arg 129 X, p.Cys8 X, p.Gln 200X,p. Gln162 X, the last three being novel) and two in FGB (p.Arg 47 X, p.Thr 407 Lys, both being novel). All afibrinogenemic patients resulted homozygous for the identified mutation. Conclusion: We have reported five novel mutations leading to congenital Afibrinogenemia in a cohort of 21 patients
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recurrence of the deep intronic fgg ivs6 320a t mutation causing quantitative fibrinogen deficiency in the italian population of veneto
Blood Coagulation & Fibrinolysis, 2009Co-Authors: Manuela Plate, S Duga, Giancarlo Castaman, Francesco Rodeghiero, Rosanna AsseltaAbstract:: Quantitative fibrinogen deficiency is a rare bleeding disorder characterized by abnormally low levels of fibrinogen in plasma, generally due to mutations in one of the three fibrinogen genes: FGA, FGB, and FGG, coding for A alpha, B beta, and gamma chain, respectively. Although the partial defect (hypofibrinogenemia) is due to mutations occurring in the heterozygous state, homozygosity or compound heterozygosity for the same genetic defects give rise to the more severe Afibrinogenemia. Mutations responsible for these conditions are scattered throughout the three fibrinogen genes, with only few sites representing relative mutational hot spots. In this study, we report the identification of the FGG IVS6-320A>T mutation in an Italian hypofibrinogenemic patient from Veneto (a region of North-Eastern Italy). This 'deep-intronic' mutation, which would go unnoticed by using conventional mutational screening strategies was previously reported in an afibrinogenemic family from Vicenza (a province of Veneto). The geographic clustering of patients carrying the FGG IVS6-320A>T mutation and the results of haplotype analysis suggest the existence of a common founder. This information will be useful to direct future genetic screenings in patients coming from the same geographic area.
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Recurrence of the “deep-intronic” FGG IVS6-320A>T mutation causing quantitative fibrinogen deficiency in the Italian population of Veneto
'Ovid Technologies (Wolters Kluwer Health)', 2009Co-Authors: M. Platè, S Duga, Giancarlo Castaman, Francesco Rodeghiero, Rosanna AsseltaAbstract:Quantitative fibrinogen deficiency is a rare bleeding disorder characterized by abnormally low levels of fibrinogen in plasma, generally due to mutations in one of the three fibrinogen genes: FGA, FGB, and FGG, coding for A[alpha], B[beta], and [gamma] chain, respectively. Although the partial defect (hypofibrinogenemia) is due to mutations occurring in the heterozygous state, homozygosity or compound heterozygosity for the same genetic defects give rise to the more severe Afibrinogenemia. Mutations responsible for these conditions are scattered throughout the three fibrinogen genes, with only few sites representing relative mutational hot spots. In this study, we report the identification of the FGG IVS6-320A>T mutation in an Italian hypofibrinogenemic patient from Veneto (a region of North-Eastern Italy). This \u2018deep-intronic\u2019 mutation, which would go unnoticed by using conventional mutational screening strategies was previously reported in an afibrinogenemic family from Vicenza (a province of Veneto). The geographic clustering of patients carrying the FGG IVS6-320A>T mutation and the results of haplotype analysis suggest the existence of a common founder. This information will be useful to direct future genetic screenings in patients coming from the same geographic area
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Liver histology of an afibrinogenemic patient with the Bbeta-L353R mutation showing no evidence of hepatic endoplasmic reticulum storage disease (ERSD); comparative study in COS-1 cells of the intracellular processing of the Bbeta-L353R fibrinogen vs. the
'Wiley', 2005Co-Authors: S Duga, Rosanna Asselta, E Santagostino, P. Braidotti, M. Maggioni, C. Pellegrini, G. Coggi, M. Malcovati, Maria Luisa TenchiniAbstract:BACKGROUND: Type I fibrinogen deficiencies (hypofibrinogenemia and Afibrinogenemia) are rare congenital disorders characterized by low or unmeasurable plasma fibrinogen antigen levels. Their genetic bases are represented by mutations within the three fibrinogen genes. Among the 11 reported missense mutations, a few have been characterized by expression studies and found to have an impaired fibrinogen assembly and/or secretion. Histopathological analyses were previously reported in two hypofibrinogenemic cases with discernible hepatic disease, revealing that both underlying mutations (gamma-Gly284Arg and gamma-Arg375Trp) were associated with hepatic fibrinogen endoplasmic reticulum storage disease (ERSD). OBJECTIVE: The objective of this study was to investigate the liver histology in an afibrinogenemic patient, homozygous for the Bbeta-Leu353Arg mutation, and to study the intracellular processing of the mutant protein. Patients and methods: Liver histology was evaluated by light microscopy, electron microscopy and immunocytochemistry. Intracellular processing of mutant fibrinogen was analyzed by pulse-chase labeling and immunoprecipitation experiments. Messenger RNA levels were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The histopathological characterization of the liver showed no signs of fibrinogen accumulation, a difference from the previously reported findings in two hypofibrinogenemic kindreds with ERSD. To evaluate whether the Bbeta-Leu353Arg mutation and the ERSD-associated gamma-Gly284Arg mutation affected intracellular fibrinogen trafficking differently, both mutant proteins were expressed in COS-1 cells. Bbeta-Leu353Arg led to a more severe secretion defect, but no differences that could explain phenotype-genotype correlation were found in the intracellular processing. Endoglycosidase-H analysis demonstrated a secretion block before translocation to the Golgi medial stacks. Real-time RT-PCR studies showed normal levels of the Bbeta mRNA in the patient's liver. CONCLUSIONS: The results confirm that Bbeta-Leu353Arg is associated with impaired fibrinogen secretion, but not with hepatic ERSD
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congenital afibrinogenaemia caused by uniparental isodisomy of chromosome 4 containing a novel 15 kb deletion involving fibrinogen aα chain gene
European Journal of Human Genetics, 2004Co-Authors: Silvia Spena, S Duga, Rosanna Asselta, Massimo Malcovati, Flora Peyvandi, C Mahasandana, Maria Luisa TenchiniAbstract:Congenital afibrinogenaemia caused by uniparental isodisomy of chromosome 4 containing a novel 15-kb deletion involving fibrinogen A α -chain gene
S Duga - One of the best experts on this subject based on the ideXlab platform.
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Congenital fibrinogen deficiency in Pakistan and identification of five novel mutations
'Wiley', 2014Co-Authors: M. Borhany, S Duga, Rosanna Asselta, M. Robusto, N. Fatima, T.s. Shamsi, F. PeyvandiAbstract:Objectives: The aim of the study is to identify the underlying mutations of Afibrinogenemia and possibly to correlate bleeding symptoms with the identified genotype. Methods: Subjects with inherited bleeding tendency in the absence of any acquired cause of hemostatic defect were included in the study. Afibrinogenemia was diagnosed after analysis of PT, APTT, and measurements of functional and antigen fibrinogen levels. Genomic DNA was extracted from whole blood by the QiAamp DNA Blood mini kit (Qiagen).Genomic DNA was PCR amplified by using sense and antisense primers designed on the basis of known sequences of the three fibrinogen genes and intergenic regions (GenBank accession numbers M64982, M64983, M10014, U36478, and AF229198). Molecular analysis was performed by DNA sequencing on both strands, by using the Big Dye Terminator Cycle Sequencing kit and an ABI-3130-XL automated DNA sequencer (Applied Biosystems). The Variant Reporter software (Applied Biosystems) was used for mutation detection. Results: A total of 21 afibrinogenemic patients (10 males and 11 females) came to our attention: their mean age was 11.54 +/- 11.2 years (range 1\u201340) and the mean bleeding score was 13.3 +/- 6.7.The most common bleeding manifestations were bruises, umbilical cord bleeding, gum bleeding, hematomas, circumcision bleeding, epistaxis, and menorrhagia. Genetic analysis was completed in nine cases, revealing a total of six different mutations: four in FGA (p.Arg 129 X, p.Cys8 X, p.Gln 200X,p. Gln162 X, the last three being novel) and two in FGB (p.Arg 47 X, p.Thr 407 Lys, both being novel). All afibrinogenemic patients resulted homozygous for the identified mutation. Conclusion: We have reported five novel mutations leading to congenital Afibrinogenemia in a cohort of 21 patients
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recurrence of the deep intronic fgg ivs6 320a t mutation causing quantitative fibrinogen deficiency in the italian population of veneto
Blood Coagulation & Fibrinolysis, 2009Co-Authors: Manuela Plate, S Duga, Giancarlo Castaman, Francesco Rodeghiero, Rosanna AsseltaAbstract:: Quantitative fibrinogen deficiency is a rare bleeding disorder characterized by abnormally low levels of fibrinogen in plasma, generally due to mutations in one of the three fibrinogen genes: FGA, FGB, and FGG, coding for A alpha, B beta, and gamma chain, respectively. Although the partial defect (hypofibrinogenemia) is due to mutations occurring in the heterozygous state, homozygosity or compound heterozygosity for the same genetic defects give rise to the more severe Afibrinogenemia. Mutations responsible for these conditions are scattered throughout the three fibrinogen genes, with only few sites representing relative mutational hot spots. In this study, we report the identification of the FGG IVS6-320A>T mutation in an Italian hypofibrinogenemic patient from Veneto (a region of North-Eastern Italy). This 'deep-intronic' mutation, which would go unnoticed by using conventional mutational screening strategies was previously reported in an afibrinogenemic family from Vicenza (a province of Veneto). The geographic clustering of patients carrying the FGG IVS6-320A>T mutation and the results of haplotype analysis suggest the existence of a common founder. This information will be useful to direct future genetic screenings in patients coming from the same geographic area.
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Recurrence of the “deep-intronic” FGG IVS6-320A>T mutation causing quantitative fibrinogen deficiency in the Italian population of Veneto
'Ovid Technologies (Wolters Kluwer Health)', 2009Co-Authors: M. Platè, S Duga, Giancarlo Castaman, Francesco Rodeghiero, Rosanna AsseltaAbstract:Quantitative fibrinogen deficiency is a rare bleeding disorder characterized by abnormally low levels of fibrinogen in plasma, generally due to mutations in one of the three fibrinogen genes: FGA, FGB, and FGG, coding for A[alpha], B[beta], and [gamma] chain, respectively. Although the partial defect (hypofibrinogenemia) is due to mutations occurring in the heterozygous state, homozygosity or compound heterozygosity for the same genetic defects give rise to the more severe Afibrinogenemia. Mutations responsible for these conditions are scattered throughout the three fibrinogen genes, with only few sites representing relative mutational hot spots. In this study, we report the identification of the FGG IVS6-320A>T mutation in an Italian hypofibrinogenemic patient from Veneto (a region of North-Eastern Italy). This \u2018deep-intronic\u2019 mutation, which would go unnoticed by using conventional mutational screening strategies was previously reported in an afibrinogenemic family from Vicenza (a province of Veneto). The geographic clustering of patients carrying the FGG IVS6-320A>T mutation and the results of haplotype analysis suggest the existence of a common founder. This information will be useful to direct future genetic screenings in patients coming from the same geographic area
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Liver histology of an afibrinogenemic patient with the Bbeta-L353R mutation showing no evidence of hepatic endoplasmic reticulum storage disease (ERSD); comparative study in COS-1 cells of the intracellular processing of the Bbeta-L353R fibrinogen vs. the
'Wiley', 2005Co-Authors: S Duga, Rosanna Asselta, E Santagostino, P. Braidotti, M. Maggioni, C. Pellegrini, G. Coggi, M. Malcovati, Maria Luisa TenchiniAbstract:BACKGROUND: Type I fibrinogen deficiencies (hypofibrinogenemia and Afibrinogenemia) are rare congenital disorders characterized by low or unmeasurable plasma fibrinogen antigen levels. Their genetic bases are represented by mutations within the three fibrinogen genes. Among the 11 reported missense mutations, a few have been characterized by expression studies and found to have an impaired fibrinogen assembly and/or secretion. Histopathological analyses were previously reported in two hypofibrinogenemic cases with discernible hepatic disease, revealing that both underlying mutations (gamma-Gly284Arg and gamma-Arg375Trp) were associated with hepatic fibrinogen endoplasmic reticulum storage disease (ERSD). OBJECTIVE: The objective of this study was to investigate the liver histology in an afibrinogenemic patient, homozygous for the Bbeta-Leu353Arg mutation, and to study the intracellular processing of the mutant protein. Patients and methods: Liver histology was evaluated by light microscopy, electron microscopy and immunocytochemistry. Intracellular processing of mutant fibrinogen was analyzed by pulse-chase labeling and immunoprecipitation experiments. Messenger RNA levels were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The histopathological characterization of the liver showed no signs of fibrinogen accumulation, a difference from the previously reported findings in two hypofibrinogenemic kindreds with ERSD. To evaluate whether the Bbeta-Leu353Arg mutation and the ERSD-associated gamma-Gly284Arg mutation affected intracellular fibrinogen trafficking differently, both mutant proteins were expressed in COS-1 cells. Bbeta-Leu353Arg led to a more severe secretion defect, but no differences that could explain phenotype-genotype correlation were found in the intracellular processing. Endoglycosidase-H analysis demonstrated a secretion block before translocation to the Golgi medial stacks. Real-time RT-PCR studies showed normal levels of the Bbeta mRNA in the patient's liver. CONCLUSIONS: The results confirm that Bbeta-Leu353Arg is associated with impaired fibrinogen secretion, but not with hepatic ERSD
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congenital afibrinogenaemia caused by uniparental isodisomy of chromosome 4 containing a novel 15 kb deletion involving fibrinogen aα chain gene
European Journal of Human Genetics, 2004Co-Authors: Silvia Spena, S Duga, Rosanna Asselta, Massimo Malcovati, Flora Peyvandi, C Mahasandana, Maria Luisa TenchiniAbstract:Congenital afibrinogenaemia caused by uniparental isodisomy of chromosome 4 containing a novel 15-kb deletion involving fibrinogen A α -chain gene