Functional study of abnormal fibrinogen caused by Arg275His mutation in fibrinogen γ chain / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the function of abnormal fibrinogen in two inherited dysfibrinogenemia pedigrees.</p><p><b>METHODS</b>Routine coagulation tests were conducted in the probands and related family members. The antigen and activity levels of fibrinogen were detected by immunoturbidimetry assay and clauss assay, respectively. All the exons and exon-intron boundaries of the three fibrinogen genes and antithrombin gene（AT3）were analyzed by PCR amplification and direct sequencing. Routine thrombelastography (TEG) test and functional fibrinogen TEG test were both used to make a comprehensive evaluation of coagulation status and functional fibrinogen level in patients. The molecular weights of the three peptides from fibrinogen were measured by Western blot. The function of abnormal fibrinogen was assessed by fibrinogen dynamic polymerization and fibrinolysis velocity.</p><p><b>RESULTS</b>The coagulation routine tests were normal in two probands except for prolonged thrombin time (TT) and reptilase time (RT), as well as reduced activity levels of 0.5 g/L and 0.6 g/L fibrinogen, respectively. The antigen levels of fibrinogen were 2.32 g/L and 2.66 g/L in two probands, which were in the normal reference range. The genotype analysis showed that Arg275His in fibrinogen γ chain (γ Arg275His) existed in both probands and patients in these two pedigrees. Meanwhile, proband B's grandfather and aunt also carried heterozygote g.5876T>C (Ser116Pro) mutation in AT3. The results of routine TEG test demonstrated that the α values of proband B and his father were close to and lower than the lower limit of reference range, respectively, while the MA values were normal in both of them. However, functional fibrinogen TEG test revealed obviously reduced MA value. All the probands and patients demonstrated prolonged lag-off time and reduced peak value in fibrinogen dynamic polymerization tests. Meanwhile, most of fibrin formed from the patients' plasma could not be dissolved completely by plasminogen (PLG) and urokinase-typeplasminogenactivator (u-PA) at a certain time.</p><p><b>CONCLUSION</b>We first reported cases of inherited dysgibrinogenemia associated with inherited AT deficiency. γArg275His mutation caused the abnormal fibrinogen in terms of fibrin mono polymerization and possibly in fibrinolysis. Combined use of routine TEG test and functional fibrinogen TEG test with comprehensive analyses of the parameters in both tests could better evaluate the level of functional fibrinogen and predict the risk of hemorrhage and thrombosis in patients with inherited dysfibrinogenemia.</p>

Genotype and function analyses of four inherited dysfibrinogenemia pedigree caused by Arg16 amino acid substitution in fibrinogen Aα chain / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the phenotype, genotype and function in four Chinese pedigrees with inherited dysfibrinogenemia.</p><p><b>METHODS</b>Routing tests including activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), reptilase time (RT), the activities of antithrombin (AT), protein C (PC) and protein S (PS) were detected in four pedigrees. The activity and antigen of plasma fibrinogen were analyzed by Clauss and immunoturbidimetry methods, respectively. The molecular weight of fibrinogen of four probands was assessed by Western blot. The function of abnormal fibrinogen was evaluated by fibrinogen clottability, fibrinogen dynamic polymerization and fibrinolysis velocity, respectively. The sequences of all the exons and exon-intron boundaries of the three fibrinogen genes were amplified by PCR and analyzed by direct sequencing.</p><p><b>RESULTS</b>Four probands had prolonged TT and RT, reduced plasma fibrinogen activity levels and normal antigen levels. The assays of Western blot showed no abnormal molecular weight of fibrinogen. Function tests revealed reduced fibrinogen clottability, delayed and decreased fibrinogen dynamic polymerization and reduced fibrinolysis velocity. Aα chain Arg16His and Arg16Cys mutations were identified in the four probands, respectively.</p><p><b>CONCLUSION</b>The four probands with dysfibrinogenemia were caused by the mutations of Aα chain Arg16His or Arg16Cys. Mutation of the fibrinogen induced dysfunction of plasma fibrinogen.</p>

Phenotype and genotype analysis of two Chinese pedigrees with type 3 von Willebrand diseases / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze the phenotype and genotype of two Chinese pedigrees with von Willebrand diseases, and to investigate the molecular pathogenesis.</p><p><b>METHODS</b>Bleeding time (BT), activated partial thromboplastin time (APTT), ristocetin-induced platelet aggregation (RIPA), von Willebrand factor-ristocetin cofactor (vWF:Rco), von Willebrand factor antigen (vWF:Ag), von Willebrand factor activity (vWF:A), von Willebrand factor collagen binding assay (vWF:CB) and multimer analysis were used for phenotype diagnosis. DNA was extracted. All of the 52 exons and exon-intron bounda ries of the VWF gene were amplified with polymerase chain reaction(PCR) and analyzed by direct sequencing.</p><p><b>RESULTS</b>APTT and BT were prolonged. Plasma RIPA, vWF:Rco, vWF:Ag, vWF:A and vWF:CB was significantly decreased. No VWF multimer can be found by plasma VWF multimer analysis. Homozygous insertional mutation g.82888_82889insCATG in exon 17 was found in proband A. Compound heterozygous mutations g.94865 G to A (Trp856stop) in exon 20 and g.110698_110699delinsG in exon 28 were found in proband B.</p><p><b>CONCLUSION</b>Homozygous insertional mutation g.82888_82889insCATG and compound heterozygous mutations g.94865G to A(Trp856X) and g.110698_110699delinsG probably have respectively induced type 3 von Willebrand diseases in the two probands.</p>

Analysis of phenotype and genotype in three Chinese pedigrees with inherited dysfibrinogenemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the phenotype and genotype in three Chinese pedigrees with inherited dysfibrinogenemia.</p><p><b>METHODS</b>Laboratory tests including activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), reptilase time (RT), and the activities of antithrombin (AT:C), protein C (PC:C) and protein S(PS:C) were detected in three pedigrees. The activity and antigen of plasma fibrinogen (Fg) were analyzed by Clauss and immunoturbidimetry methods, respectively. The Fg of three probands was assessed by Western blot and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The sequences of all the exons and exon-intron boundaries of the three Fg genes FGA, GFB and FGG were amplified by PCR and analyzed by direct sequencing.</p><p><b>RESULTS</b>Three probands had normal APTT, PT, PC:C, PS:C and AT:C, but prolonged TT and RT. The activity levels of the 3 probands's plasma Fg were reduced, but antigen levels were normal. Western blot and SDS-PAGE showed no abnormal molecular weight of Fg. The 3 heterozygous mutations of γ Arg275His, Aα Pro18Leu and Aα Arg16Cys were identified in the 3 probands, respectively.</p><p><b>CONCLUSION</b>The three probands with dysfibrinogenemia were caused by the mutations of γ Arg275His, Aα Pro18Leu and Aα Arg16Cys, respectively. Both Aα Pro18Leu and Aα Arg16Cys were first reported in Chinese population.</p>

Two novel mutations in one pedigree with hereditary Factor VII deficiency / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the mutations of coagulation factor VII (FVII) gene in one pedigree with hereditary FVII deficiency, and to investigate the molecular mechanisms of FVII deficiency.</p><p><b>METHODS</b>FVII gene mutations were analysed in the pedigree by direct DNA sequencing. The mutated DNA fragments were cloned into pMD19-T simple TA vector, and sequenced to confirm their distribution on chromosome. The plasma activity of FVII of the probands and their family members was detected with coagulation assay. The antigen of FVII were identified with ELISA.</p><p><b>RESULTS</b>Three gene mutations were detected in the pedigree: A/G to C at 15386 resulting in Arg353Pro/Gln353Pro, A to T at 15274 resulting in Lys316Stop, all three mutations were heterozygotes. Three kinds of polymorphisms were identified in his father: A to G transition at position 15386 resulting in Arg353Gln, heterozygotic deletion of 2050 - 2059 cctatatcct in promoter and G to A mutation in intron 1a, the same polymorphisms were found in his grandfather. The three polymorphisms were located in the same chromosome of his father.</p><p><b>CONCLUSION</b>Two mutations were found in the pedigree with hereditary FVII deficiency. One is nonsense mutation (Lys316Stop), the other is missense one (Gln353Pro). Gln353Pro and Lys316Stop might be the molecular mechanisms of FVII deficiency. The two novel mutations were reported for the first time in the literature.</p>

Molecular mechanisms of recurrent venous thrombosis in two pedigrees with type I antithrombin deficiency / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the clinical phenotype, genotype and molecular mechanism of recurrent venous thrombosis in two Chinese pedigrees with type I antithrombin (AT) deficiency.</p><p><b>METHODS</b>The routine coagulation screening tests were detected, thrombin generation tests was performed to evaluate the hypercoagulation. Anticardiolipin antibody (ACA) and lupus anticoagulant (LA) were detected with enzyme-linked immunosorbent assay (ELISA) and diluted viper venom time assay (DVVT), respectively. The activities of protein C, protein S and AT (PC:A, PS:A, AT:A) were tested with chromogenic substrate assay or clotting method. The antigen of AT (AT:Ag) was performed with immunoturbidimetry methods. Western blot was used to analyze the molecular weight (MW) and the plasma levels of AT:Ag. All 7 exons and the flanking sequences were amplified by PCR. The mutation of AT gene and thrombophilia associated gene polymorphisms were analyzed by direct DNA sequencing. The expression plasmid of Ala404Asp mutant was constructed with site-directed mutagenesis method based on the wild-type (WT) AT cDNA contained in pcDNA 3.1 vector, and transiently expression of AT WT and the Ala404Asp mutant was performed using HEK293T cells. Cultured supernatant and cell lysates were collected and measured for AT:Ag by ELISA and Western blot.</p><p><b>RESULTS</b>The results of routine coagulation tests in two probands were normal, thrombin generation tests indicated that proband 1 presented hypercoagulable state with 2.8 and 1.5 times higher of the endogenous thrombin potential (ETP) and peak height compared with that of normal, respectively. The levels of PC:A, PS:A, ACA and LA were normal. AT:A in proband 1 and proband 2 were 45% and 32%, and AT:Ag were almost half of the normal (121 mg/L and 158 mg/L), respectively. The results of Western blot showed that both probands' plasma levels of AT:Ag were lower than the normal pooled plasma and MW was normal. Two heterozygous mutations of g.3291C→T(Thr98Ile), g.13863C > A(Ala404Asp) were identified in the probands, respectively. No proband had venous thrombosis associated gene polymorphisms. Expression in vitro showed that AT:Ag in culture media and lysates of Ala404Asp are 4.8% and 60.6% of that of WT, respectively.</p><p><b>CONCLUSION</b>Thr98Ile and Ala404Asp mutation of AT gene significantly correlate with recurrent venous thrombosis in the two probands, respectively. Ala404Asp has not been described before. The mutant Ala404Asp protein can not be expressed due to impaired secretion and increased intracellular degradation, resulting in type I AT deficiency.</p>

Phenotype and genotype analysis of three Chinese pedigrees with von Willebrand disease / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze phenotype and genotype of three Chinese pedigrees with von Willebrand disease (vWD), and explore the molecular mechanism.</p><p><b>METHODS</b>Bleeding time (BT), activated partial thromboplastin time (APTT), ristocetin-induced platelet aggregation (RIPA), von Willebrand factor (vWF): ristocetin cofactor (RCof) (vWF:RCof), vWF antigen (vWF:Ag), vWF activity (vWF:A) test, vWF collagen binding assay (vWF:CB), vWF and Factor VIII (FVIII) binding assay (vWF:FVIII:B) and multimer analysis were used for phenotype diagnosis. Genomic DNA was extracted from the peripheral blood (PB). All the 52 exons and flanking sequences of the probands' vWF gene were amplified by PCR and analyzed by direct sequencing.</p><p><b>RESULTS</b>APTT were prolonged in all three probands, while BT were normal excepting for proband 3. Plasma RIPA, vWF:RCo, vWF:Ag, vWF:A and vWF:CB were decreased in different extents. In multimer analysis, proband 3 lost the large and intermediate molecular weight multimers, while proband 1 and 2 were normal. Gene analysis in the three probands revealed three heterozygous missense mutations of 144067 G→A (R2287Q) in exon 39, 110374G→A (R1374H) and 110770C→T (S1506L) in exon 28 and heterozygous polymorphism 110667G→A (D1472H) in exon 28, respectively.</p><p><b>CONCLUSION</b>The three heterozygous mutations (R2287Q, R1374H and S1506L) and an heterozygous polymorphism (D1472H) are genetic defects of the hereditary vWD of the three pedigrees respectively. R2287Q is a novel mutation reported for the first time in the literature.</p>

Two new mutations of AT gene in type I inherited antithrombin deficiency / 中华血液学杂志

<p><b>OBJECTIVE</b>To identify the clinical phenotype and gene mutation in two kindreds with type I inherited antithrombin (AT) deficiency.</p><p><b>METHODS</b>The coagulation and anticoagulation testing and thrombophilia screening were used for phenotypic diagnosis and immunonephelometry and chromogenic assay for plasma level of AT antigen (AT:Ag) and AT activity (AT:A), respectively. All of the seven exons and intron-exon boundaries and untranslation regions of AT gene were amplified by PCR, and the PCR products analysis was by direct sequencing. The corresponding gene sites of the two family members and healthy individuals were detected according to the gene mutation sites.</p><p><b>RESULTS</b>The plasma levels of AT:Ag of proband 1 and proband 2 were 126 mg/L and 117 mg/L, and AT:A was 49% and 48%, respectively. Heterozygotic deletion of 3239-3240delCT in proband 1 and nonsense mutation 3206A-->T (K70Stop) in proband 2 were rchaacterized in exon 2 of AT gene. And some of their family members were also detected with the heterozygotic gene mutation.</p><p><b>CONCLUSION</b>Type I inherited antithrombin deficiency of the two probands were caused by AT gene mutation 3239-3240delCT and 3206A-->T (K70Stop).</p>

Analysis of phenotype and genotype in four Chinese pedigrees with inherited coagulation factor V deficiency / 中华血液学杂志

<p><b>OBJECTIVE</b>To identify the phenotype and genotype in four Chinese pedigrees with inherited coagulation factor V (FV) deficiency.</p><p><b>METHODS</b>The tests of activated partial thromboplastin time (APTT), prothrombin time (PT), FV activity (FV:C) and FV antigen (FV:Ag) were used for phenotype diagnosis. All the exons and exon-intron boundaries of F5 gene were amplified by PCR and analyzed by direct sequencing.</p><p><b>RESULTS</b>The APTT and PT in each of the four probands were obviously prolonged, and both activity and antigen of FV in the four probands were extremely lower compared with that of normal mixed plasma. Sequencing of F5 gene in proband 1 identified a heterozygous mutation, G16088C (Asp68His), and four polymorphisms, T35788C (Met385Thr), A47295G (His1299Arg), A58668G (Met1736Val) and A74083G (Asp2194Gly), which were located in the same chromosome; proband 2 was homozygous for two mutations, C46253T (Arg952Cys) and C46724T(Gln1109stop); the F5 gene of proband 3 showed a homozygous missense mutation, C67793G(Pro2006Ala); and proband 4 was homozygous for one missense mutation, C74022T (Arg2174Cys).</p><p><b>CONCLUSION</b>Five mutations (Asp68His, Arg952Cys, Gln1109stop, Pro2006Ala and Arg2174Cys) and four polymorphisms (Met385Thr, His1299Arg, Met1736Val and Asp2194Gly) may lead to type I inherited FV deficiency for these four probands, respectively. Gln1109stop, Pro2006Ala and Arg2174Cys haven't been identified before.</p>

The application of thrombin generation tests to warfarin anticoagulation monitoring / 中华血液学杂志

<p><b>OBJECTIVES</b>To explore the thrombin generation capacity in patients on warfarin therapy with different prothrombin time international normalized ratio (PT-INR), the capacity in relation to bleeding, and the application of thrombin generation tests to warfarin therapy monitoring.</p><p><b>METHODS</b>Seventy eight blood samples were taken from patients on warfarin therapy for more than 3 months owing to valve replacement or atrial fibrillation. The patients' case history and PT-INR were collected and thrombin generation tests were performed in all samples.</p><p><b>RESULTS</b>Patients were ranked into three groups according to different PT-INR. There were 23 patients in group I with PT-INR from 1.51 to 2.00, 39 patients in group II with PT-INR from 2.01 to 3.00, and 16 patients in group III with PT-INR from 3.01 to 4.26. There were significant differences between each two of the three groups in lag time, peak, and ttpeak (time to peak) (P <0.01). There was a significant difference between group I and group II in endogenous thrombin potential (ETP) (P = 0.0001), but not between group II and group III (P= 0.06). Five patients developed bleeding and their ETP was less than 15% of normal control.</p><p><b>CONCLUSION</b>In patients on warfarin therapy, when the PT-INR was more than 3.0, increasing the dose of warfarin doesn' t decrease the thrombin generation, but increase bleeding risk. PT-INR combined with ETP may better reflect patient's coagulation status, therefore be of more significance in preventing bleeding.</p>

Studies on inherited coagulation factor VII deficiency and tissue factor abnormality in a pedigree / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of clinical haemorrhage in an inherited coagulation factor VII (FVII) deficiency and tissue factor abnormality pedigree.</p><p><b>METHODS</b>All exons, exon-intron boundaries and the 3', 5' untranslated sequences of FVII and tissue factor (TF) genes were amplified by PCR and sequenced directly. Any mutation identified by direct sequencing was confirmed by reverse sequencing. FVII cDNA of the proband was synthesized with random primers and amplified by nest PCR.</p><p><b>RESULTS</b>55C-->T heterozygous mutation located in promoter of FVII gene was identified in the proband. The heterozygous mutation was derived from his mother. Tracing the other pedigree members found that his sister had the same heterozygous mutation and the others had wild-type FVII genes. A 9363 C-->T (Arg131Trp) heterozygous polymorphism in TF gene, which was 2.63% frequency of T allele polymorphism, was found in all of the pedigree members.</p><p><b>CONCLUSION</b>It was the first report that the -55C-->T heterozygous mutation in FVII gene and the Arg131Trp heterozygous polymorphism in TF gene explained the clinical symptom of the proband.</p>