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.

Clinical phenotype and gene mutation analysis of 12 patients with hereditary protein C deficiency in different families / 中华血液学杂志

Objective: To investigate the molecular pathogenesis and clinical features of unrelated 12 patients with inherited coagulation protein C (PC) deficiency in Chinese population. Methods: The PC activity (PC:A) and PC antigen (PC:Ag) were detected by chromogenic substrate and enzyme linked immunosorbent assay, respectively. The nine exons and flanking sequences of the protein C (PROC) gene were amplified by polymerase chain reaction with direct sequencing, and the suspected mutations were validated by reverse sequencing (clone sequencing for deletion mutations) . Results: The PC:A of the 12 probands decreased significantly, ranging from 18% to 55%, and the PC:Ag of the 10 probands decreased significantly. Eleven mutations were found, out of which four mutations [c.383G>A (p.Gly128Asp) , c.997G>A (p.Ala291Thr) , c.1318C>T (p.Arg398Cys) , and c.532G>C (p.Leu278Pro) ] were discovered for the first time. Six mutations were in the serine protease domain, four mutations were located in epidermal growth factor (EGF) -like domains, and one mutation was located in activation peptide. There were two deletion mutations (p.Met364Trp fsX15 and p.Lys192del) , and the rest were missense mutations. Mutations p.Phe181Val and p.Arg189Trp were identified in three unrelated families. All mutations may be inherited, and consanguineous marriages were reported in two families. Among the probands, nine cases had venous thrombosis, two cases had poor pregnancy manifestations, and one case had purpura. Conclusion: Patients with PC deficiency caused by PROC gene defects are prone to venous thrombosis, especially when there are other thrombotic factors present at the same time.

Analysis of a hereditary protein C deficient consanguineous pedigree caused by Phe139Val homozygous mutation / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze genetic mutation and explore its molecular pathogenesis for an hereditary protein C (PC) deficient consanguineous pedigree.</p><p><b>METHODS</b>The pedigree included three generations and contained eight members. PC activity (PC:A), PC antigen (PC:Ag) and other coagulant parameters were detected for all family members. Protein C gene (PROC) include all the exons and intron exon boundaries were amplified by PCR for the proband, then analyzed by direct sequencing. Mutation sites were detected for the other family members.</p><p><b>RESULTS</b>The PC:A and PC:Ag in the proband plasma were 20% (normal range 70% -140%) and 13.2% (normal range 70%-130%). A homozygous missense mutation g.6128T>G in exon 7 resulting in Phe139Val was identified in the proband. The PC:A and PC:Ag in her younger brother were 31% and 18.90%, Phe139Val homozygous was also found. The left family members were heterozygous for Phe139Val.</p><p><b>CONCLUSION</b>Phe139Val homozygous missense mutation in exon 7 of PROC caused serious hereditary protein C deficiency. We speculated that homozygous mutation might be resulted from this consanguineous marriage.</p>

Analysis of a consanguineous pedigree featuring hereditary coagulation factor Ⅴ deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To screen potential mutation and explore the underlying mechanism for a consanguineous pedigree featuring hereditary coagulation factor Ⅴ (FⅤ) deficiency.</p><p><b>METHODS</b>Clinical diagnosis was validated by coagulant parameter assays of prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), FⅤ procoagulant activity (FⅤ:C) and FⅤ antigen (FⅤ:Ag). Potential mutations of the F5 gene in the proband and his family members were analyzed by direct DNA sequencing of PCR products of all exons, exon-intron boundaries and 3', 5' untranslated regions. Suspected mutation was confirmed by reverse sequencing.</p><p><b>RESULTS</b>The PT and APTT in the proband were significantly prolonged, which measured 23.5 s (reference range 11.8-14.8 s) and 50.5 s (reference range 27.0-41.0 s), respectively. FⅤ activity and FⅤ antigen of the proband were significantly reduced to 8% and <1%, respectively. PT and APTT in the younger sister of the proband were also significantly prolonged (24.1 s and 62.4 s, respectively). Her FⅤ activity and FⅤ antigen were also significantly decreased (7% and <1%, respectively). PT and APTT of other family members were within the normal range. The homozygous missence mutation causing T→C transition at position 29170 in exon 5 of F5 gene has resulted in a Phe190Ser substitution in the proband. His younger sister was also homozygous for Phe190Ser. Heterozygosity for Phe190Ser was confirmed in his elder brother, elder sister, two daughters and niece, and their FⅤ activity were slightly decreased (57%, 73%, 72%, 66% and 75%, respectively). A normal wild type was observed in two younger brothers of the proband, and their FⅤ activity and FⅤ antigen were in the normal range.</p><p><b>CONCLUSION</b>Homozygous missence mutation of Phe190Ser has been found in above family featuring hereditary FⅤ deficiency. The homozygous missence mutation was inherited from the parents by consanguineous marriage. Phe190Ser probably underlies may underlie the pathogenesis of hereditary FⅤ deficiency in this pedigree.</p>

Gene analysis in four inherited coagulation FⅫ deficiency pedigree / 中华血液学杂志

<p><b>OBJECTIVE</b>To identify the genotype and pathogenesis in four Chinese pedigrees with Factor Ⅻ deficiency.</p><p><b>METHODS</b>Activated partial thromboplastin time (APTT), FⅫ procoagulant activity (FⅫ∶C), FⅫ antigen（FⅫ∶Ag）and other coagulant parameters were detected. The FⅫ deficiency Pedigree members,all exons,boundary introns including the splice junctions of the FⅫ gene were amplified with Polymerase chain reaction (PCR). Expression plasmids were constructed by mutagenesis based on the wild-type and transfected into COS7 cells. FⅫ∶C and FⅫ∶Ag of the expression levels were tested in the supernatant and cell lysate.</p><p><b>RESULTS</b>The four probands presented prolonged APTT with all the values of FⅫ∶C and FⅫ∶Ag were low to 2% and 1%, respectively. There were common 46C/T polymorphism in the promoter regions of FⅫ gene in four pedigrees. Proband A was heterozygous for two mutations, g.5741-5742delCA (His101Gln) and g.7142insertC (Lys346Gln). Proband B was a heterozygous deletion mutation g.6800-6808del9bp. The results of the transfection revealed that FⅫ∶Ag in cell lysates and conditioned media protein FⅫ6800-6808del9bp were 85.6% and 51.9%. The FⅫ∶C in the conditioned media was 56.4%. Proband C was a heterozygous mutation g.8699G>A(Gly542Ser). Proband D was a homozygous mutation 8699G>A, whose parents with consanguineous marriage.</p><p><b>CONCLUSION</b>Four mutations, g.5741-5742delCA, g.7142insertC, g.6800-6808del9bp and g.8699G>A with 46C/T polymorphism in the promoter regions of FⅫ gene, were identified in the four Factor Ⅻ deficiency pedigrees. The two mutations g.5741-5742delCA and g.6800-6808del9bp were first found in China. FⅫ 6800-6808del9bp expressed in vitro suggested that almost normal proteinum synthesis but defect proteinum secretion.</p>

Analysis of an hereditary protein C deficiency pedigree with compound heterozygous gene mutations / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze genetic mutations and explore its molecular pathogenesis for an hereditary protein C (PC) deficiency pedigree.</p><p><b>METHODS</b>The pedigree has included 15 individuals from 4 generations. Plasma levels of PC activity (PC:A), PC antigen (PC:Ag) and other coagulant parameters were determined for members of the family. The 9 exons and intron-exon boundaries of protein C gene (PROC) of the proband were amplified with PCR and analyzed with direct sequencing. Detected mutations were confirmed with reverse sequencing. Corresponding PCR fragments from the family members were also directly sequenced.</p><p><b>RESULTS</b>Plasma PC:A and PC:Ag for the proband was 26% and 18.60%, respectively, both being lower than normal references. Seven members from the pedigree also had lower PC:A, six had lower PC:Ag. A compound heterozygous missense mutation, including a T to G transition at position 6128 of exon 7, which results in Phe139Val, and a G to C transition at position 8478 in exon 9, which results in Asp255His, were identified in the proband. The paternal grandma, father and two aunts were heterozygous for g.6128 T to G, whilst the mother, the second uncle, sister and son were heterozygous for g.8478 G to C. There were lower PC:A in family members with g.8478 G to C.</p><p><b>CONCLUSION</b>The proband had inherited two independent mutations of the PROC gene including g.6128 T to G in exon 7 and g.8478 G to C in exon 9 from her father and mother, respectively. The resulting compound heterozygous mutation has caused a serious hereditary protein C deficiency.</p>

Molecular genetics and clinical features of nine patients with inherited coagulation factor VII deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate potential mutations and clinical features of 9 unrelated patients with inherited coagulation factor VII (FVII) deficiency.</p><p><b>METHODS</b>Clinical diagnosis was validated by assaying of coagulation parameters including prothrombin time, activated partial thromboplastin time, FVII activity and specific antigens. All exons, exon-intron boundaries, and 5' and 3' untranslated regions of F7 genes were amplified with PCR. Potential mutations were detected by direct sequencing of purified PCR products. Suspected mutations were confirmed by sequencing of the opposite strand.</p><p><b>RESULTS</b>All probands have featured prolonged prothrombin time, with FVII activity ranging between 2.0% to 6.0%. The titers of FVII antigen were significantly reduced in 7 probands. Eight mutations, including 6 missense mutations, 1 deletion and 1 insertion, were identified, among which 3 (Gln100Leu, Ser269Pro and g.11520_11521insT) were not described previously. Six mutations have located in the protease domain. All mutations were inherited, and consanguineous marriages were reported in 5 families. Mutations g.27_28delCT, Cys329Gly, Arg304Trp and His348Gln have been identified in unrelated families. There was a lack of correlation between the mutations and their clinical features. Two individuals with homozygous His348Gln mutations and 1 individual with homozygous Arg304Trp mutation were only mildly affected or asymptomatic. Two patients, who have respectively carried homozygous and heterozygous deletions of g.27_28delCT, were moderately affected and asymptomatic. In 4 patients carrying double heterozygous mutations, 1 (Ser269Pro and Cys329Gly) was asymptomatic, 2 (Arg304Trp and Cys329Gly, Arg277Cys and g.11520_11521insT, respectively) had a mild bleeding tendency, whilst 1 (Gln100Leu and His348Gln) has a moderate bleeding diathesis.</p><p><b>CONCLUSION</b>There seem to be hotspots of F7 gene mutations in ethnic Han Chinese populations. And there is a lack of correlation between particular types of mutations and clinical phenotypes.</p>

Gene analysis of a combined inherited factor VII and factor X deficiency pedigree / 中华血液学杂志

<p><b>OBJECTIVE</b>To perform gene analysis and family survey of a patient with combined inherited FVII and FX deficiency, and to identify the gene mutation of this patient.</p><p><b>METHODS</b>The phenotype diagnosis was validated by coagulant parameter assay on prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, FVII and FX activity (FVII:C, FX:C) and FVII and FX antigen (FVII:Ag, FX:Ag). FVII and FX gene mutations were analyzed in the proband and other family members by DNA direct sequencing of all exons, exon-intron boundaries and 5', 3' untranslated sequences. One hundred and six health examination participants were selected as control.</p><p><b>RESULTS</b>The values of PT and APTT of the proband showed significantly prolonged, which were 84.5s and 63.4s, respectively. The levels of FVII:C, FVII:Ag, FX:C and FX:Ag were 6%, 7%, 4% and 30%, respectively. The PT of his father, mother and sister was prolonged slightly while both APTT and FVII:Ag were in the normal range. Two homozygous mutations, g.11267C→T in exon 8 of FVII gene resulting in the substitution of Arg277Cys and g.28139G→T in exon 8 of FX gene leading to the substitution of Val384Phe, were identified in the proband. The proband's parents and sister were heterozygous for Arg277Cys and Val384Phe mutations.</p><p><b>CONCLUSION</b>Homozygous mutation Arg277Cys in FVII gene and Val384Phe in FX gene were the molecular mechanism causing combined inherited FVII and FX deficiency. The Val384Phe substitution was a novel mutation, which may affect the synthesis or secretion of FX protein.</p>

An inherited coagulation factor VII deficiency pedigree caused by homozygous mutation of His348Gln / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the gene mutation and the molecular pathogenesis of an inherited coagulation factor VII (F VII) deficiency pedigree with consanguineous marriage.</p><p><b>METHODS</b>The diagnosis was validated by coagulant parameter assay on the prothrombin time (PT), activated partial thromboplastin time, fibrinogen and coagulation factor activity. F VII gene mutations were analyzed in the proband and other family members by direct DNA sequencing of the PCR products of all exons, exon-intron boundaries and 5'and 3' untranslated sequences. The mutations were confirmed by reverse sequencing.</p><p><b>RESULTS</b>The values of PT and F VII activity in the proband were significantly abnormal, they were 30.9 s and 3% respectively. The PT of her daughter, father and mother was slightly extended to 21.2 s, 16.3 s and 16.1 s respectively, and the F VII activity was reduced to 22%, 25% and 35% respectively. The coagulant parameters of her younger brother were within normal range. Homozygous T-->G transition at position 11482 in exon 8 was identified in the proband resulting in His348Gln, and heterozygosity for His348Gln was confirmed in her daughter and her parents, and the normal wild-type was observed in her younger brother.</p><p><b>CONCLUSION</b>Homozygous missense mutation of His348Gln was found in a pedigree of hereditary F VII deficiency. The mutation was inherited from her heterozygote parents.</p>

Analysis of an hereditary coagulation factor XII deficiency in a consanguineous pedigree / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze genetic mutation and explore its molecular pathogenesis for an hereditary coagulation factor XII(F XII) deficiency in a pedigree featuring consanguineous marriage.</p><p><b>METHODS</b>Activated partial thromboplastin time (APTT), F XII procoagulant activity (F XII:C), F XII antigen (F XII:Ag) and other coagulant parameters were assayed. For the proband and his family members, exons 1-4, introns including the splice junctions of the F XII gene were amplified with polymerase chain reaction (PCR). The PCR product was purified and sequenced. The mutations were confirmed by sequencing the complimentary strand.</p><p><b>RESULTS</b>The proband has featured prolonged APTT at 157.5 s (reference range, 27.0-41.0 s). The APTT of his son has increased slightly at 48.3 s. The remaining members of the family were in normal range. F XII activity and F XII antigen of the proband were significantly decreased (<1%). The F XII activity of his wife, daughter, son and mother was also dropped to about 51%, 21%, 21% and 50%, respectively, and so was the F XII antigen (42%, 32%, 37% and 48%, respectively). Homozygous missense mutation of G→A transition at position 8699 in exon 14 resulting in Gly542Ser was identified in the proband. His mother, son and daughter were heterozygous for Gly542Ser. In the promoter regions of F XII gene, the genotype of the proband and the other members was 46T/T.</p><p><b>CONCLUSION</b>Homozygous missense mutation Gly542Ser was found in a pedigree of hereditary F XII deficiency. The homozygous missense mutation might have resulted from his parents by consanguineous marriage. Gly542Ser and 46T/T have contributed to the pathogenesis of the hereditary factor XII deficiency pedigree.</p>

Identification of compound heterozygous mutations in the ITGA2B gene in a Chinese patient with Glanzmann thrombasthenia / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Glanzmann thrombasthenia (GT) is an autosomal recessive bleeding disorder characterized by the tendency to hemorrhage and the inability of platelets to aggregate in response to agonists. GT is caused by a defect of the platelet glycoprotein IIb/IIIa complex. The objective of this study was to describe the clinical features and the genetic cause of GT in a 6-year-old girl from south China.</p><p><b>METHODS</b>A three-generation family was studied. The proband patient aged 6 years and her parents undertook examinations of platelet counts, blood film, bleeding time, platelet aggregation, and flow cytometry. All coding exons of the ITGA2B and ITGB3 genes were amplified by polymerase chain reaction (PCR), and direct sequencing was performed for mutational screening on the patient and normal controls consisted of 52 healthy blood donors. Reverse transcription PCR was conducted to test for exon skipping.</p><p><b>RESULTS</b>The proposita patient showed dispersing platelets, prolonged bleeding time, and severely reduced platelet aggregation in response to the physiological agonists adenosine diphosphate (ADP), epinephrine, collagen, and ristocetin. Flow cytometric measurements showed that the contents of alphaIIb and beta3 were significantly decreased. Sequencing results demonstrated two different types of heterozygous mutations existed in the alphaIIb gene (c.2930delG and IVS15-1delG). The compound mutations were also confirmed in the patient's mother and father separately.</p><p><b>CONCLUSIONS</b>The alphaIIbbeta3 deficiency of the proband was caused by two compound ITGA2B mutations, which were first reported in Chinese GT patients. The IVS15-1delG was first confirmed to cause an exon skipping.</p>