Phenotype and genotype analyses of two pedigrees with inherited fibrinogen deficiency / 中华血液学杂志

Objective: To analyze the phenotype and genotype of two pedigrees with inherited fibrinogen (Fg) deficiency caused by two heterozygous mutations. We also preliminarily probed the molecular pathogenesis. Methods: The prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and plasma fibrinogen activity (Fg∶C) of all family members (nine people across three generations and three people across two generations) were measured by the clotting method. Fibrinogen antigen (Fg:Ag) was measured by immunoturbidimetry. Direct DNA sequencing was performed to analyze all exons, flanking sequences, and mutated sites of FGA, FGB, and FGG for all members. Thrombin-catalyzed fibrinogen polymerization was performed. ClustalX 2.1 software was used to analyze the conservatism of the mutated sites. MutationTaster, PolyPhen-2, PROVEAN, SIFT, and LRT online bioinformatics software were applied to predict pathogenicity. Swiss PDB Viewer 4.0.1 was used to analyze the changes in protein spatial structure and molecular forces before and after mutation. Results: The Fg∶C of two probands decreased (1.28 g/L and 0.98 g/L, respectively). The Fg∶Ag of proband 1 was in the normal range of 2.20 g/L, while it was decreased to 1.01 g/L in proband 2. Through genetic analysis, we identified a heterozygous missense mutation (c.293C>A; p.BβAla98Asp) in exon 2 of proband 1 and a heterozygous nonsense mutation (c.1418C>G; p.BβSer473*) in exon 8 of proband 2. The conservatism analysis revealed that Ala98 and Ser473 presented different conservative states among homologous species. Online bioinformatics software predicted that p.BβAla98Asp and p.BβSer473* were pathogenic. Protein models demonstrated that the p.BβAla98Asp mutation influenced hydrogen bonds between amino acids, and the p.BβSer473* mutation resulted in protein truncation. Conclusion: The dysfibrinogenemia of proband 1 and the hypofibrinogenemia of proband 2 appeared to be related to the p.BβAla98Asp heterozygous missense mutation and the p.BβSer473* heterozygous nonsense mutation, respectively. This is the first ever report of these mutations.

Genetic analysis of two Chinese pedigrees affected with Hereditary hypofibrinemia due to missense variants / 中华医学遗传学杂志

OBJECTIVE@#To retrospectively analyze the clinical phenotypes and genetic variants in two Chinese pedigrees affected with Hereditary hypofibrinemia (IFD) and explore their molecular pathogenesis.@*METHODS@#Two probands and their pedigree members were admitted to the First Affiliated Hospital of Wenzhou Medical University on March 30, 2021 and May 27, 2021, respectively. Clinical phenotypes of the probands were collected, and blood clotting indexes of the probands and their pedigree members were determined. Variants of the FGA, FGB and FGG genes were analyzed by Sanger sequencing, and candidate variants were verified by sequence comparison. Bioinformatic software was used to analyze the conservation of the amino acids and pathogenicity of the proteins. Alteration in protein structure and intermolecular force before and after the variant was analyzed by simulating the protein model.@*RESULTS@#Proband 1, a 18-year-old male, had significantly low plasma fibrinogen activity (Fg:C) and plasma fibrinogen antigen (Fg:Ag), respectively at 0.80 g/L and 1.00 g/L. Proband 2, a 43-year-old male, had slightly low Fg:C and Fg:Ag at 1.35 g/L and 1.30 g/L, respectively. The Fg:C and Fg:Ag of proband 1's father, proband 2's father and son were also below the normal level. Genetic testing showed that proband 1 had harbored a heterozygous missense variant of c.688T>G (p.Phe230Val) in exon 7 of the FGG gene, which was inherited from his father. Proband 2, his father and son all had harbored a heterozygous variant of c.2516A>C (p.Asn839Thr) in exon 6 of the FGA gene. Homology analysis showed that the Phe230 and Asn839 residues were highly conserved among homologous species. Bioinformatic analysis predicted that both p.Phe230Val and p.Asn839Thr were pathogenic variants.@*CONCLUSION@#Analysis of protein simulation model showed that the p.Asn839Thr variant has changed the hydrogen bo`nd between the amino acids, thus affecting the stability of the protein structure. The heterozygous missense variants of p.Phe230Val and p.Asn839Thr probably underlay the IFD in the two pedigrees.

Genetic analysis of a Chinese pedigree affected with Congenital dysfibrinogenemia due to variant of FGG gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the coagulation deficit and genetic basis for a Chinese pedigree affected with Congenital dysfibrinogenemia (CD).@*METHODS@#Peripheral venous blood samples of the proband and her family members (including 4 individuals from three generations) were subjected to routine blood test and assays of liver and kidney functions and viral hepatitis to exclude related diseases. Clauss method and DFg-PT method were used to determine the fibrinogen activity (Fg:C), and an immunoturbidimetric assay was used to determine the level of fibrinogen antigen (Fg:Ag). All of the exons (22 in total) and their flanking sequences of the FGA, FGB and FGG genes were amplified by PCR and directly sequenced. Variants in the coding regions of the three genes and transcriptional splicing sites were screened by using Mutation SurveyorTM software.@*RESULTS@#The Clauss method showed that Fg:C was significantly reduced in the proband and her father, whilst her mother and son were normal. With the DFg-PT method, the proband, her parents and son were all within the normal range. The Fg:C/Fg:Ag ratio of the proband and her father was lower than 0.7, whilst her mother and son were above 0.7. No significant change in the prothrombin time, activated partial thromboplastin clotting time and thrombin time was noted. Two genetic variants were detected, which included a homozygous missense variant in the FGA gene [c.991A>G (p.Thr331Ala)], which was predicted to be benign, and a heterozygous missense variant of the γ chain of the FGG gene [c.1211C>G (p.Ser404Phe)], which is located in a conserved region and unreported in the CLINVAR/HGMD/EXAC/1000G databases and literature.@*CONCLUSION@#This pedigree has conformed to the autosomal dominant inheritance of CD. The c.1211C>T (p.Ser404Phe) missense variant of the γ chain of the FGG gene probably underlay the pathogenesis of CD in this pedigree. The variant was unreported previously and named as "Fibrinogen Harbin II Ser404Phe".

A Family with Congenital Dysfibrinogenemia and Blood Transfusion / 中国实验血液学杂志

OBJECTIVE@#To investigate a family with congenital dysfibrinogenemia, and analyze the risk of hemorrhage and thrombosis and blood transfusion strategies.@*METHODS@#Prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT) of the proband and her family members were detected by automatic coagulometer, fibrinogen (Fg) activity and antigen were detected by Clauss method and PT algorithm respectively. Meanwhile, thromboelastometry was analyzed for proband and her family members. Then, peripheral blood samples of the proband and her family members were collected, and all exons of FGA, FGB and FGG and their flanks were amplified by PCR and sequenced to search for gene mutations.@*RESULTS@#The proband had normal APTT and PT, slightly prolonged TT, reduced level of Fg activity (Clauss method). The Fg of the proband's aunt, son and daughter all decreased to varying degrees. The results of thromboelastogram indicated that Fg function of the proband and her family members (except her son) was basically normal. Gene analysis showed that there were 6233 G/A (p.AαArg35His) heterozygous mutations in exon 2 of FGA gene in the proband, her children and aunt. In addition, 2 polymorphic loci were found in the family, they were FGA gene g.9308A/G (p.AαThr331Ala) and FGB gene g.12628G/A (p.BβArg478Iys) polymorphism, respectively. The proband was injected with 10 units of cryoprecipitate 2 hours before delivery to prevent bleeding, and no obvious bleeding occurred during and after delivery.@*CONCLUSION@#Heterozygous mutation of 6233G/A (p.AαArg35His) of FGA gene is the biogenetic basis of the disease in this family with congenital dysfibrinogenemia.

Effects of the ITGA2B Nonsense Mutation (c.2659C > T, p.Q887X) on Platelet Function in a Mouse Model of Glanzmann's Thrombasthenia Generated with CRISPR/Cas9 Technology / 中国实验血液学杂志

OBJECTIVE@#To construct a mouse model of Glanzmann's thrombasthenia (GT) with ITGA2B c.2659 C>T (p.Q887X) nonsense mutation by CRISPR/Cas9 technology, and then further explore the expression and function of glycoprotein αIIbβ3 on the surface of platelet membrane.@*METHODS@#The donor oligonucleotide and gRNA vector were designed and synthesized according to the ITGA2B gene sequence. The gRNA and Cas9 mRNA were injected into fertilized eggs with donor oligonucleotide and then sent back to the oviduct of surrogate mouse. Positive F0 mice were confirmed by PCR genotyping and sequence analysis after birth. The F1 generation of heterozygous GT mice were obtained by PCR and sequencing from F0 bred with WT mice, and then homozygous GT mice and WT mice were obtained by mating with each other. The phenotype of the model was then further verified by detecting tail hemorrhage time, saphenous vein bleeding time, platelet aggregation, expression and function of αIIbβ3 on the surface of platelet.@*RESULTS@#The bleeding time of GT mice was significantly longer than that of WT mice (P<0.01). Induced by collagen, thrombin, and adenosine diphosphate (ADP), platelet aggregation in GT mice was significantly inhibited (P<0.01, P<0.01, P<0.05). Flow cytometry analysis showed that the expression of αIIbβ3 on the platelet surface of GT mice decreased significantly compared with WT mice (P<0.01), and binding amounts of activated platelets to fibrinogen were significantly reduced after thrombin stimulation (P<0.01). The spreading area of platelet on fibrinogen in GT mice was significantly smaller than that in WT mice (P<0.05).@*CONCLUSION@#A GT mouse model with ITGA2B c.2659 C>T (p.Q887X) nonsense mutation has been established successfully by CRISPR/Cas9 technology. The aggregation function of platelet in this model is defective, which is consistent with GT performance.

Congenital Fibrinogen Deficiency Caused by Novel FGG Gene Mutation / 中国实验血液学杂志

OBJECTIVE@#To detect and analyze coagulation related indexes and genotypes of a patient with congenital fibrinogen deficiency and his family members, and to investigate the possible molecular pathogenesis.@*METHODS@#Four peripheral blood samples (proband and 3 family members) were collected and the prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (Fg), D-Dimer and eight coagulation factor indicators were detected. All exons and flanking sequences of the FGA, FGB, and FGG genes encoding the three peptide chains of fibrinogen were sequenced and analyzed by bioinformatics.@*RESULTS@#Among the eight coagulation factors of the proband and the elder sister, F Ⅴ and F Ⅷ were slightly higher, TT was significantly prolonged, and Fg was significantly reduced. Sequencing results showed that c.901C>T heterozygous mutation existed in the FGG gene. Bioinformatics analysis showed that the mutation changed the original protein structure and reduced the number of hydrogen bonds.@*CONCLUSION@#The fibrinogen gamma chain c.901C>T heterozygous mutation is the main cause of congenital fibrinogen deficiency in this family. This mutation is reported for the first time at home and abroad.

A case of inherited afibrinogenemia caused by an IVS7-12A>G splice mutation of FGG gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree affected with inherited afibrinogenemia.@*METHODS@#For the proband and his family members, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), Fibrin(ogen) degradation products (FDPs), D-dimer (D-D), plasminogen activity (PLG:A) and the TT mixed experiment with protamine sulfate were determined with a STAGO-R automatic coagulation analyzer. The activity and antigen of fibrinogen (Fg) in plasma were measured with the Clauss method and immunonephelometry method, respectively. All exons and flanking regions of the fibrinogen genes (FGA, FGB and FGG) were amplified by PCR and directly sequenced. Human Splicing Finder software was used to predict and score the change of splicing site caused by the mutation.@*RESULTS@#The proband showed normal FDPs and D-D but significantly prolonged TT, PT and APTT. The activity and antigen of fibrinogen in plasma were significantly decreased (G (g.4147A>G) mutations of the FGG gene, for which his parents and young sister were heterozygous. As predicted by Human Splicing Finder and Mutation Taster software, the variant may generate a new splicing site which can extend the sequence of exon 7 by 11 bp, with alteration of the coding sequence. PROVEAN suggested the variant to be deleterious.@*CONCLUSION@#The afibrinogenemia of the proband may be attributed to the FGG IVS7-12A>G variant, which was unreported previously.

beta fibrinogen gene G-455A polymorphism in Asian subjects with coronary heart disease: a meta analysis

Background: There are many studies about the association of b fibrinogen gene G-455A polymorphism and the risk of coronary heart disease [CHD]. However, the results of these studies are inconsistent

Objective: This study aimed to investigate the association of b fibrinogen gene G-455A polymorphism with the risk of CHD using meta analysis. This study was limited to the Asian population

Methods: Published studies from PubMed, Embase, and CNKI databases [up to December 20th, 2015] were searched for eligible publications. The following information was extracted from each study: [1] name of first author; [2] year of publication; [3] country of origin; [4] sample size of cases and controls, and [5] size of each allele. The combined odds ratios [ORs] and 95% confidence intervals [95% CIs] for the association between b fibrinogen gene G-455A polymorphism and the risk of CHD were assessed using random or fixed effect model. A comprehensive meta analysis [CMA] 2.0 was used to analyze the data

Results: Nineteen studies [4011 cases/3673 controls] regarding the association of b fibrinogen gene G-455A polymorphism and the risk of CHD were included in this meta analysis. The results indicated that b fibrinogen gene G-455A polymorphism was associated with increased [A vs. G: OR 95% CI= 1.42 [1.19-1.70], p<0.001; AA vs. GG +GA: OR 95% CI= 1.60 [1.13-2.26], p= 0.008; GA vs. GG + AA: OR 95% CI = 1.30 [1.07-1.58], p= 0.008] and decreased the risk of CHD [G vs. A: OR 95% CI= 0.70 [0.59-0.84], p <0.001; GG vs. GA +AA: OR 95% CI= 0.68 [0.55-0.84], p< 0.001]

Conclusions: In the Asian population, the b fibrinogen gene G-455A polymorphism was associated with the risk of CHD

Análise da variabilidade imunológica e da expressão dos genes FREPs entre as espécies Biomphalaria glabrata e B. straminea com diferentes perfis de suscetibilidade ao parasito Schistosoma mansoni / Analysis of immune variability and expression of FREPS genes between the species Biomphalaria glabrata and B. straminea with different susceptibility profiles to infection to by Schistosoma mansoni

Algumas espécies do gênero Biomphalaria se apresentam como potenciais hospedeiras ao parasito Schistosoma mansoni, estando a suscetibilidade a este parasito, neste gênero, ligada ao sistema interno de defesa de cada espécie de Biomphalaria. Um dos componentes importantes no sistema imune de invertebrados é a enzima fenoloxidase, que ainda apresenta muitos aspectos desconhecidos no sistema de defesa do gênero Biomphalaria. Foi relatado também que os genes de proteínas relacionadas ao fibrinogênio (FREPs) possuem importância na resposta imune de Biomphalaria glabrata, entre esses, as subfamílias dos FREPs 3 e 4 são diferencialmente expressas em linhagens susceptíveis e resistentes frente a infecção com trematódeos. No entanto os trabalhos existentes em sua maioria estudam a espécie Biomphalaria glabrata, excluindo a espécie Biomphalaria straminea, amplamente distribuída no Brasil e principal responsável pela disseminação da esquistossomose. Tendo em vista a falta de conhecimento sobre a resposta imune destes moluscos hospedeiros, principalmente em relação à expressão de genes imune relevantes e ao tipo de resposta, o presente trabalho se propôs a estudar a variação do número de hemócitos, da produção de fenoloxidase e da expressão dos genes dos FREP 3 e FREP 4 envolvidos com a ligação a antígenos de trematódeos, nas espécies Biomphalaria glabrata, Biomphalaria straminea pós-infecção com S. mansoni, bem como em caramujos pré-expostos a antígenos de S. mansoni...

Hemophilia a and congenital Hypofibrinogenemia: A rare association in same family.

Hemophilia A is the commonest inherited coagulation defect in human beings, whereas congenital hypofibrinogenemia is a much rarer disease. Occurrence of these two inherited diseases in the same family has not been reported so far. Younger sibling of a known case of Hemophilia A presented with recurrent, spontaneously occurring echymotic spots having prolonged PT, APTT, TT and very low absolute fibrinogen level with normal factor VIII level ultimately diagnosed as a case of congenital hypofibrinogenemia.

A doença arterial coronariana sob o prisma da genética molecular / A genetic view of the coronary artery disease

A biologia molecular evolui de forma vertiginosa e atualmente é tida como ferramenta indispensável na compreensão de doenças complexas e multifatoriais como a doença arterial coronariana. Tal abordagem gera uma nova forma de avaliação de doenças conhecidas e propicia a criação de novas técnicas, novos métodos diagnósticos e possíveis abordagens terapêuticas, interferindo diariamente no desfecho clínico final do paciente. O número de publicações em genética cardiovascular aumentou cinco vezes nos últimos 20 anos e a descoberta de novos polimorfismos e mutações bem como marcadores de inflamação, coagulação e genes relacionados ao metabolismo lipídico contribuem para se conhecer cada vez mais os aspectos intrínsecos envolvidos na aterosclerose. Este artigo irá abordar os principais avanços nessa área, identificando os polimorfismos mais comuns e sua relevância clínica segundo grandes ensaios e meta-análises,bem como fazer um breve racional acerca do desenho atual dos ensaios clínicos em biologia molecular