1.Application value of thromboelastography in assessing coagulation function in children with severe hemophilia A after emicizumab therapy: a single-center study.
Dong PENG ; Ying WANG ; Gui-Chi ZHOU ; Qian LI ; Mei-Zhu LUO ; Li-Ping LUO ; Ya-Xian KUANG ; Xiao-Ying FU
Chinese Journal of Contemporary Pediatrics 2025;27(3):293-299
OBJECTIVES:
To investigate the application value of thromboelastography (TEG) in assessing coagulation function in children with severe hemophilia A (HA) after emicizumab (EMI) therapy.
METHODS:
A retrospective analysis was performed on the activated partial thromboplastin time (APTT) and TEG testing results of 17 children with severe HA before and after EMI treatment at Shenzhen Children's Hospital from January 2023 to July 2024. Correlation analysis was conducted between coagulation factor VIII (FVIII) equivalent activity and reaction time (R value) measured by TEG.
RESULTS:
After EMI treatment, the mean bleeding rate for children with severe HA was 1.6 events per year, with 15 children (88%) without spontaneous bleeding or joint bleeding. The children with severe HA showed a significant reduction in APTT after EMI treatment (P<0.05), with a significantly shorter APTT than the normal control group (P<0.05). There was no correlation between APTT and FVIII equivalent activity after treatment (P>0.05). After EMI treatment, TEG parameters, including R value, kinetic time, alpha angle (α), maximum amplitude, clot strength, and coagulation index, shifted from a hypocoagulable state before treatment to a nearly normal state after treatment (P<0.05). The R value demonstrated a strong negative correlation with FVIII equivalent activity (r=-0.758, P<0.05).
CONCLUSIONS
The bleeding condition of children with severe HA can be effectively controlled after EMI treatment. Routine APTT testing cannot reflect true coagulation function, whereas TEG testing is clinically valuable in assessing the coagulation function of children with severe HA undergoing EMI treatment.
Humans
;
Thrombelastography
;
Hemophilia A/physiopathology*
;
Male
;
Child
;
Antibodies, Bispecific/therapeutic use*
;
Antibodies, Monoclonal, Humanized/therapeutic use*
;
Blood Coagulation/drug effects*
;
Child, Preschool
;
Retrospective Studies
;
Female
;
Partial Thromboplastin Time
;
Adolescent
;
Infant
2.Molecular Pathogenic Mechanism Study of Two Cases of Inherited Dysfibrinogenemia.
Min WANG ; Tian-Ping CHEN ; Ao-Shuang JIANG ; Cheng-Lin ZHU ; Nan WEI ; Li-Juan ZHU ; Li-Jun QU ; Hong-Jun LIU
Journal of Experimental Hematology 2025;33(1):187-192
OBJECTIVE:
To analyze two families with inherited dysfibrinogenemia, and explore the molecular pathogenic mechanisms.
METHODS:
The coagulation indexes of the probands and their family members were detected. The FGA, FGB, and FGG exons and their flanking sequences were amplified by PCR, and the mutation sites were identified by sequencing. SIFT, PolyPhen2, LRT, ReVe, MutationTaster, phyloP, and phastCons bioinformatics software were used to predict the functional impact of the mutation sites. Protein structure and amino acid conservation analysis of the variant were conducted using PyMOL and Clustal X software.
RESULTS:
The thrombin time (TT) of the proband in family 1 was prolonged to 37.00 s, and Fg∶C decreased to 0.52 g/L. The TT of the proband in family 2 was 20.30 s, and Fg∶C was 1.00 g/L, which was lower than the normal range. Genetic analysis revealed that the proband in family 1 had a heterozygous mutation c.80T>C in FGA, resulting in the substitution of phenylalanine 27 with serine (Phe27Ser). The proband in family 2 had a heterozygous mutation c.1007T>A in FGG, resulting in the substitution of methionine 336 with lysine (Met336Lys). Bioinformatics software prediction analysis indicated that both mutations were deleterious variants. PyMOL mutation models revealed that the Aα chain mutation (Phe27Ser) in family 1 and γ chain mutation (Met336Lys) in family 2 resulted in alterations in spatial structure and reduced protein stability. Clustal X results showed that both Aα Phe27 and γMet336 were highly conserved across homologous species.
CONCLUSION
Heterozygous mutations of FGA gene c.80T>C and FGG gene c.1007T>A are both pathogenic variants, causing inherited dysfibrinogenemia.
Female
;
Humans
;
Male
;
Afibrinogenemia/genetics*
;
Fibrinogen/genetics*
;
Heterozygote
;
Mutation
;
Pedigree
3.Family Study and Blood Transfusion of a Patient with Hereditary Coagulation Factor XI Deficiency.
Ya-Xin HAN ; Ying REN ; Rong ZHAO ; Ai-Chun QU ; Zhi-Gang YANG
Journal of Experimental Hematology 2025;33(4):1161-1167
OBJECTIVE:
To investigate a family with hereditary coagulation factor XI (FXI) deficiency, identify its possible genetic etiology, analyze the bleeding risk of the proband, and provide a blood transfusion regimen.
METHODS:
The blood samples from the family members were collected, and the coagulation parameters of the proband and her family members were detected. Whole-exome sequencing was performed on the blood samples of the proband to identify gene variants, and validate the variants in the family using Sanger sequencing. Bioinformatics softwares were used to analyze the conservation of amino acid variant sites and the impact of the variations on protein function. The pathogenicity of the variant sites was analyzed according to the genetic variation classification criteria and guidelines of the American College of Medical Genetics and Genomics (ACMG). Thromboelastography (TEG) was used to assess the coagulation function of the family members and evaluate the transfusion regimen and its efficacy in the proband.
RESULTS:
The activated partial thromboplastin time (APTT) of the proband was significantly prolonged to 96.7 seconds, and FXI activity (FXI: C) and FXI antigen (FXI: Ag) decreased to 1.3% and 1%, respectively, both of which were extremely reduced. The FXI: C of the proband's father was also significantly lower than the normal value. The TEG results showed that the coagulation function of the proband was reduced, while the coagulation function of other family members was normal. The F11 gene of the proband exhibited compound heterozygous variants of c.738G>A (p.Trp246 *) and c.1288G>A (p.Ala430Thr). The proband's father carried a heterozygous missense variant of c.1288G>A (p.Ala430Thr), while her mother, her eldest daughter, and her youngest daughter carried a heterozygous nonsense variant of c.738G>A (p.Trp246 *). According to the ACMG genetic variation classification criteria and guidelines, c.738G>A (p.Trp246 *) is classified as a pathogenic variant (PVS1+PS3-Moderate+PP4), and c.1288G>A (p.Ala430Thr) is classified as a possible pathogenic variant (PS3-Moderate+PM1+PM3_Srong+PP4). p.Trp246 and p.Ala430 are highly conserved across different species. Swiss PdbViewer software analysis showed that p.Ala430Thr variant caused a change in the number of hydrogen bonds in FXI protein, affecting protein function. The following transfusion regimen was determined through TEG evaluation in vitro: 600 ml of fresh frozen plasma (FFP) was administered 24 hours before surgery to prevent bleeding. And there was no significant bleeding during or after the surgery.
CONCLUSION
The heterozygous nonsense variant ofc.738G>A (p.Trp246 *) and the heterozygous missense variant of c.1288G>A (p.Ala430Thr) in the F11 gene are the pathogenic factors of this hereditary FXI deficiency family.
Humans
;
Factor XI Deficiency/therapy*
;
Factor XI/genetics*
;
Blood Transfusion
;
Pedigree
;
Female
;
Male
;
Mutation
;
Thrombelastography
;
Partial Thromboplastin Time
;
Blood Coagulation
;
Adult
4.RNA Sequencing Reveals Molecular Alternations of Splenocytes Associated with Anti-FⅧ Immune Response in Hemophilia A Murine Model.
Chen-Chen WANG ; Ya-Li WANG ; Yuan-Hua CAI ; Qiao-Yun ZHENG ; Zhen-Xing LIN ; Ying-Yu CHEN
Journal of Experimental Hematology 2025;33(5):1476-1485
OBJECTIVE:
To investigate the molecular alterations of splenocytes associated with anti-factor Ⅷ (FⅧ) immune response and the underlying mechanisms based on hemophilia A (HA) murine model via RNA sequencing (RNA-seq) technology.
METHODS:
Severe HA mice were immunized with recombinant human factor Ⅷ (rhF8) weekly for 4 weeks to establish an FⅧ inhibitor model. High quality raw data were obtained by using bulk RNA-seq and CASAVA base identification technology, and the differentially expressed genes (DEGs) were identified. The DEGs were statistically classified by gene ontology (GO) annotation to obtain information on the major signaling pathways and biological processes involved in anti-FⅧ immune response in HA mouse splenocytes. The cell clusters, genes, and signaling pathway datasets were comprehensively analyzed by GO, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and single cell RNA-seq (ScRNA-seq) analysis, respectively. Flow cytometry analysis was used to verify the changes in T follicular helper cells (Tfh) and regulatory T cells (Treg).
RESULTS:
A total of 3731 DEGs was identified, including 2275 genes with up-regulated expression and 1456 genes with down-regulated expression. The DEGs were enriched in helper T cell differentiation, cytokine receptor, T cell receptor signaling pathway, ferroptosis, etc. Uniform Manifold Approximation and Project (UMAP) downscaling and visualization analysis yielded a total number of 11 T/NK cell subsets, visualizing the overall expression distribution of C-X-C chemokine-specific receptor gene cxcr5 among these T/NK cell subsets. Higher expression of cxcr5 was found in activated Tfh from FⅧ inhibitor mice, in comparison to the control group. The visualization using Upset plot R language showed a close interaction between Tfh and Treg. Moreover, the increased frequencies of Tfh and the decreased frequencies of Treg in inhibitor mouse splenocytes were further verified by flow cytometry analysis.
CONCLUSION
Multiple immune cell subsets, signaling pathways, and characteristic genes may be involved in the process of anti-FⅧ immune response in HA mouse splenocytes. The molecules involved in the regulation of Tfh/Treg may play key roles, which provide potential biological targets and therapeutic strategies for HA patients with inhibitors in the future.
Animals
;
Hemophilia A/genetics*
;
Mice
;
Sequence Analysis, RNA
;
Disease Models, Animal
;
Spleen/cytology*
;
T-Lymphocytes, Regulatory/immunology*
;
Humans
;
Signal Transduction
;
Factor VIII/immunology*
;
T-Lymphocytes, Helper-Inducer/immunology*
5.Acquired hemophilia A secondary to cholangiocarcinoma: A case report and literature review.
Xiaoting HAN ; Lei FU ; Liang LI ; Jianjun BIAN ; Mei ZHAO ; Guobin BI
Journal of Central South University(Medical Sciences) 2025;50(2):275-280
Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder. Its occurrence secondary to hepatobiliary malignancies is even rarer, and without timely diagnosis and treatment, the mortality rate is extremely high. There is a need to raise awareness of this disease. This report describes a case of a 70-year-old female patient diagnosed with AHA 2 months after surgery for cholangiocarcinoma, admitted to the Second Affiliated Hospital of Bengbu Medical College in October 2022. The patient presented with subcutaneous hematoma in both lower limbs. Coagulation function tests showed a markedly prolonged activated partial thromboplastin time (APTT) of 74.5 seconds, with no correction in the APTT mixing test. Coagulation factor assays revealed a severely reduced coagulation factor VIII activity (FVIII:C) of 0.3%, and an inhibitor titer of 25.6 BU/mL was detected. After ruling out other potential causes, the patient was diagnosed with cholangiocarcinoma-associated AHA. With chemotherapy to control the primary tumor, alongside hemostatic and immunosuppressive therapy for inhibitor eradication, AHA was brought under control. The patient had no further coagulation abnormalities or bleeding, enabling timely and full-course chemotherapy for cholangiocarcinoma and significantly improving survival and quality of life. Therefore, in patients with malignancies who present with spontaneous bleeding or unusual bleeding following surgery, trauma, or invasive procedures, clinicians should be alert to the possibility of secondary AHA. Timely diagnosis and treatment can significantly improve prognosis.
Humans
;
Cholangiocarcinoma/surgery*
;
Female
;
Hemophilia A/drug therapy*
;
Aged
;
Bile Duct Neoplasms/surgery*
;
Factor VIII
6.Clinical characteristics and genotypes of patients with Congenital fibrinogen disorders.
Haijian WANG ; Shuang ZHENG ; Xiaomin YU ; Kaiwen WU ; Misheng ZHAO
Chinese Journal of Medical Genetics 2025;42(3):264-273
OBJECTIVE:
To explore the clinical features and genetic mutation sites of 28 patients with Congenital fibrinogen disorders (CFDs).
METHODS:
A total of 28 unrelated CFDs patients admitted to Wenzhou People's Hospital from June 2018 to April 2023 were enrolled into this research. A total of 2.7 mL of peripheral blood was collected from each patient for coagulation function tests, which included thrombin time (TT), fibrinogen activity (Fg:C), fibrinogen antigen (Fg:Ag), and gene detection. The Sanger sequencing method was employed to verify variations in the fibrinogen (Fg) protein-coding gene across 28 patients. Bioinformatics analyses, including harmfulness analysis, conservation analysis across different species, and spatial simulation predictions of variant proteins, were conducted byPolyPhen-2, PROVEAN, SnapGene, and Pymol softwares on the variant sites of these patients. Pathogenicity ratings for the detected variant sites were performed in accordance with the Standards and Guidelines for the Interpretation of Sequence variants by the American College of Medical Genetics and Genomics (ACMG) (hereafter referred to as the ACMG Guidelines). This study received approval from the Ethics Committee of Wenzhou People's Hospital (Approval No. KY-2023-269), and informed consent was obtained from all participants before enrollment.
RESULTS:
The clinical and genetic characteristics of 28 patients with CFDs in this study were as follows.
CLINICAL DATA:
Among the 28 patients, 2 cases were diagnosed with type I CFDs, while 26 cases were diagnosed with type II CFDs. And 50.0% (14/28) of the patients exhibited no clinical manifestations, while 28.6% (8/28) presented with bleeding manifestations, and 7.1% (2/28) exhibited thrombus manifestations, 3.6% (1/28) experienced both bleeding and thrombosis. Among female patients, 13.0% (3/23) exhibited a history of habitual abortion. All patients demonstrated TT and a significant decrease in Fg:C. Sanger sequencing revealed a total of 10 types of heterozygous variations in the FGA, FGB, and FGG genes across 28 patients, distributed among 9 loci. The variation at the γ c.902G>A/c.901C>T accounted for the highest proportion (35.7%, 10/28), followed by the Bβ c.569 A>G (28.6%, 8/28). Biological informatics analysis: the Aα c.180+1G>T mutation was predicted to be highly deleterious. And the Aα c.104G>A, Bβ c.425T>G, Bβ c.586C>T, and γ c.902G>A/c.901C>T variations were also predicted to be harmful. Conservation analysis indicates that the 9 variant sites were highly conserved among homo sapiens, musculus, ovis aries, scrofa, and rattus. Spatial conformation analysis revealed that some variations lead to an increase or decrease in the number of hydrogen bonds. ACMG guideline rating analysis: Among the ten variations in the Fg protein-coding genes FGA, FGB, and FGG identified in 28 patients, 9 variations (Aα c.104G>A, Aα c.180+1G>T, Bβ c.425T>G, Bβ c.569A>G, Bβ c.586C>T, Bβ c.643G>A, γ c.901C>T, γ c.902G>A, γ c.1001A>C) were classified as pathogenic, while one variation (γ c.908C>G) was classified as likely pathogenic.
CONCLUSION
In this study, the majority of CFDs patients are diagnosed with type II CFDs, with 50% presenting clinical symptoms predominantly manifesting as bleeding, thrombosis, and recurrent miscarriage. The mutation hotspots are mainly located in exon 2 of FGA, exon 4 of FGB, and exon 8 of FGG.
Humans
;
Female
;
Male
;
Afibrinogenemia/congenital*
;
Fibrinogen/metabolism*
;
Mutation
;
Genotype
;
Adult
;
Child
;
Adolescent
;
Child, Preschool
;
Infant
7.Analysis of a Chinese pedigree with Hereditary coagulation factor Ⅻ deficiency due to compound heterozygous variants of Ⅻ gene.
Haixiao XIE ; Huanhuan WANG ; Meina LIU ; Huinan XIA ; Yuan CHEN ; Kaiqi JIA ; Lihong YANG ; Mingshan WANG
Chinese Journal of Medical Genetics 2025;42(3):282-285
OBJECTIVE:
To analyze a Chinese pedigree with Hereditary coagulation factor Ⅻ (FⅫ) deficiency duo to variants of F12 gene and explore its molecular pathogenesis.
METHODS:
A patient who underwent laparoscopic cystectomy at the Department of Gynecology of the First Affiliated Hospital of Wenzhou Medical University in June 2012 was selected as the study subject. Coagulation factor indexes of the proband and her family members (5 individuals from three generations) were determined. All exons, flanking sequences, 5' and 3' untranslated regions of the F12 gene of the proband and her family members were analyzed by direct sequencing. Three bioinformatics software was used to analyze the conservation, pathogenicity and protein model of the variant. This study was approved by the Medical Ethics Committee of the Hospital (Ethics No. 2012-17).
RESULTS:
The activated partial thromboplastin time (APTT), FⅫ activity (FⅫ:C) and FⅫ antigen (FⅫ:Ag) of the proband was 180.0 s, 1.0% and 2.1%, respectively. DNA sequencing revealed that she has harbored compound heterozygous variants of the F12 gene, namely c.712_713insT (p.Cys238Leufs *73) in exon 8 and c.1561G>A (p.Glu521Lys) in exon 13. Her mother and younger son were heterozygous for the p.Cys238Leufs*73 variant, while her older son was heterozygous for the p.Glu521Lys variant. Bioinformatic analysis suggested that Cys238 is highly conserved and p.Cys238Leufs*73 is a pathogenic variant, which eventually resulted in a truncated protein.
CONCLUSION
The c.712_713insT and c.1561G>A compound heterozygous variants of the F12 gene probably underlay the decreased FⅫ level in this pedigree, among which c.712_713insT (NM_000505) was unreported previously.
Adult
;
Female
;
Humans
;
Male
;
Middle Aged
;
Base Sequence
;
China
;
Factor XII/genetics*
;
Heterozygote
;
Mutation
;
Pedigree
;
Factor XII Deficiency/genetics*
;
East Asian People
8.Genetic analysis of a Chinese pedigree affected with Hereditary coagulation factor XI deficiency due to homozygous p.Thr299Ser variants of F11 gene.
Conglian WU ; Yiyin CHEN ; Yancheng JIANG ; Zixuan CHEN ; Mengcha TIAN ; Zhishan ZHANG
Chinese Journal of Medical Genetics 2025;42(8):905-910
OBJECTIVE:
To explore the phenotypic and genotypic characteristics of a Chinese pedigree affected with Hereditary coagulation factor XI (FXI) deficiency.
METHODS:
A female patient with FXI deficiency and her family members (five individuals from three generations) who presented at Quanzhou First Hospital Affiliated to Fujian Medical University on September 19, 2024 due to diarrhea and fever were selected as study subjects. A retrospective study was conducted to collect the patients' clinical data. Peripheral venous blood samples were collected from the patient and her family members. Genomic DNA was extracted, followed by sequencing of all exons and flanking sequences of the F11 gene. Candidate variants were validated by Sanger sequencing of the family members, and their pathogenicity was classified according to the guidelines of the American College of Medical Genetics and Genomics (ACMG). This study was approved by the Medical Ethics Committee of Quanzhou First Hospital [Approval No.: Quanyi Lun (2024) K281].
RESULTS:
The patient exhibited significantly prolonged activated partial thromboplastin time (APTT) of 80.9 seconds, while FXI activity (FXI:C) and FXI antigen (FXI:Ag) levels were extremely low (2% and 3%, respectively). Genetic analysis revealed that the proband harbored homozygous c.896C>G (p.Thr299Ser) missense variant in exon 9 of the F11 gene, for which her son was heterozygous. The variant was located in a highly conserved domain. Although Mutation Taster predicted it as a polymorphism, SIFT, PolyPhen-2, and LRT analyses suggested it to be likely pathogenic. Protein modeling indicated that the p.Thr299Ser variant may alter the hydrogen bonds between amino acids, thereby affecting the structure and function of the FXI protein. According to the ACMG guidelines, c.896C>G was rated as a likely pathogenic variant (PM1+PM2_Supporting+PP1_Strong+PP3+PP4).
CONCLUSION
The c.896C>G (p.Thr299Ser) missense variant of the F11 gene probably underlay the FXI deficiency in this pedigree. Above finding has enriched the mutational spectrum of the F11 gene and provided a basis for genetic counseling and prenatal diagnosis for this family.
Adult
;
Female
;
Humans
;
Male
;
Middle Aged
;
China/ethnology*
;
Factor XI/chemistry*
;
Factor XI Deficiency/genetics*
;
Homozygote
;
Pedigree
;
Retrospective Studies
;
East Asian People/genetics*
9.Genetic analysis of a family with inheritary coagulation factor Ⅹ deficiency due to compound heterozygous variants p.Phe71Ser and p.Val424Phe.
Shuangnyu LIN ; Bile CHEN ; Zuoting XIE ; Lihong YANG ; Mingshan WANG ; Yanhui JIN
Chinese Journal of Medical Genetics 2025;42(10):1272-1277
OBJECTIVE:
To analyze the phenotype and genotype of a family with hereditary coagulation factor Ⅹ (FⅩ) deficiency and preliminarily explore its molecular pathogenesis.
METHODS:
A hereditary FⅩ deficiency pedigree presented at the First Affiliated Hospital of Wenzhou Medical University on August 13, 2024 was selected as the study subject. Coagulation parameters of the proband and her family members (7 individuals from 3 generations) were measured using a one-stage clotting assay. All of the 8 exons and flanking sequences of the F10 gene were amplified by PCR and directly sequenced. Bioinformatics software was used to analyze the functional impact and pathogenicity of the variant proteins, as well as the spatial conformational changes and evolutionary conservation of the mutation sites. This study has been approved by the Medical Ethics Committee of the First Affiliated Hospital of Wenzhou Medical University (Ethics No.: KY2022-R193).
RESULTS:
The proband exhibited significantly abnormal prothrombin time (PT, 33.3 s), activated partial thromboplastin time (APTT, 47.7 s), and FⅩ activity (FⅩ:C, 3%), while other coagulation parameters remained normal. The plasma thromboplastin generation test (PTGT) demonstrated that the proband and her children had lower thromboplastin generation levels compared with the healthy control group, and the proband's thromboplastin generation capacity was more severely impaired. Genetic analysis revealed that the proband, her daughter, and grandson have all harbored a heterozygous missense variant c.212T>C (p.Phe71Ser) in exon 2 of the F10 gene, which was located in the β-sheet core region of the Gla domain. The variant has altered surrounding hydrogen bonds and disrupted calcium-binding sites. Additionally, the proband, her son, and granddaughter have all carried a heterozygous missense variant c.1270G>T (p.Val424Phe) in exon 8, which increased the side-chain volume, leading to steric hindrance in the catalytic domain and impaired coagulation function. Bioinformatics analysis confirmed that both p.Phe71Ser and p.Val424Phe were pathogenic variants, with Phe71 and Val424 being highly conserved residues.
CONCLUSION
The reduced FⅩ levels in this hereditary FⅩ-deficient family may be attributed to the heterozygous missense variants c.212T>C (p.Phe71Ser) in the exon 2 and c.1270G>T (p.Val424Phe) in the exon 8 of the F10 gene.
Humans
;
Female
;
Male
;
Pedigree
;
Adult
;
Heterozygote
;
Mutation
;
Middle Aged
;
Factor X/genetics*
;
Exons
;
Factor X Deficiency/genetics*
10.Molecular pathogenesis of a novel p.Cys467Tyr missense variant underlying Hereditary factor Ⅻ deficiency.
Langyi QIN ; Yanhui JIN ; Yaosheng XIE ; Fengjiao WANG ; Lihong YANG ; Haixiao XIE ; Mingshan WANG ; Meina LIU
Chinese Journal of Medical Genetics 2025;42(12):1424-1430
OBJECTIVE:
To investigate the molecular mechanism for a family with Hereditary coagulation factor Ⅻ (FⅫ) deficiency.
METHODS:
The proband, a 63-year-old female, was admitted to the First Affiliated Hospital of Wenzhou Medical University in August 2024 for lumbar disc herniation. Coagulation tests, including prothrombin time (PT), activated partial thromboplastin time (APTT), and FⅫ activity (FⅫ:C), were carried out for the proband and her family members (9 individuals from three generations) using a one-stage clotting assay. The level of FⅫ antigen (FⅫ:Ag) was determined with an Enzyme-linked immunosorbent assay (ELISA). Sanger sequencing was conducted to identify potential variants in the F12 gene. Multiple in silico tools were used to predict the conservation, hydrophobicity, and structural impact of the identified variants. Recombinant expression plasmids were constructed and transiently transfected into HEK293T cells. The recombinant FⅫ protein was analyzed using Western blotting (WB) and ELISA. This study was approved by the Ethics Committee of the First Affiliated Hospital of Wenzhou Medical University (Ethics No.: KY2022-R193).
RESULTS:
The proband showed a markedly prolonged APTT (160.3 s) and significantly decreased FⅫ:C (2%) and FⅫ:Ag (5%) levels. Analysis of the F12 gene sequence revealed a 46C/T genotype in the promoter region, a heterozygous c.1457G>A (p.Cys467Tyr) missense variant in exon 12, and a heterozygous c.1561G>A (p.Glu502Lys) missense variant in exon 13. Bioinformatic analysis showed that the p.Cys467 is highly conserved across various species, and the p.Cys467Tyr variant may affect local structural stability of the FⅫ protein. The p.Cys467Tyr variant had no effect on the transcription of the F12 gene. However, the variant has significantly decreased the FⅫ:Ag levels and FⅫ protein expression in the cell culture supernatant compared to the wild-type expression vector, while in the cell lysate, it is higher than the wild-type expression vector. In other words, the p.Cys467Tyr variant has probably caused a secretion defect of FⅫ protein.
CONCLUSION
The 46C/T genotype, the heterozygous p.Cys467Tyr missense variant, and the heterozygous p.Glu502Lys missense variant are associated with reduced plasma FⅫ levels in this pedigree. The p.Cys467Tyr variant, which was unreported previously, did not affect the synthesis of FⅫ but may have resulted in a secretion defect.
Humans
;
Female
;
Middle Aged
;
Mutation, Missense
;
Pedigree
;
HEK293 Cells
;
Male
;
Factor XII/genetics*
;
Adult
;
Factor XII Deficiency/genetics*

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