Analysis of A Pedigree with Hereditary Coagulation Factor Ⅻ Deficiency Caused by Compound Heterozygous Mutations / 中国实验血液学杂志

OBJECTIVE@#To analysis clinical phenotype and potential genetic cause of a family affected with hereditary coagulation factor Ⅻ deficiency.@*METHODS@#The prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), D-Dimer (D-D), coagulation factor Ⅻ activity (FⅫ:C) and coagulation factor Ⅻ antigen (FⅫ:Ag) were determined for phenotype diagnosis of the proband and his family members(3 generations and 5 people). Targeted capture and whole exome sequencing were performed in peripheral blood sample of the proband. Possible disease-causing mutations of F12 gene were obtained and further confirmed by Sanger sequencing. The corresponding mutation sites of the family members were analyzed afterwards. The online bioinformatics software AutoPVS1 and Mutation Taster was used to predict the effects of mutation sites on protein function.@*RESULTS@#The APTT of the proband was significantly prolonged, reaching 180.9s. FⅫ:C and FⅫ:Ag of the proband was significantly reduced to 0.8% and 4.17%, respectively. The results of whole exome sequencing displayed that there were compound heterozygous mutations in F12 gene of the proband, including the c.1261G＞T heterozygous nonsense mutation in exon 11 (causing p.Glu421*) and the c.251dupG heterozygous frameshift mutation in exon 4 (causing p.Trp85Metfs*53). Both mutations are loss of function mutations with very strong pathogenicity, leading to premature termination of the protein. AutoPVS1 and Mutation Taster software predicted both mutations as pathogenic mutations. The results of Sanger sequencing revealed that c.1261G＞T heterozygous mutation of the proband was inherited from his mother, for which his brother and his daughter were c.1261G＞T heterozygous carriers. Genotype-phenotype cosegregation was observed in this family.@*CONCLUSION@#The c.1261G＞T heterozygous nonsense mutation in exon 11 and the c.251dupG heterozygous frameshift mutation in exon 4 of the F12 gene probably account for coagulation factor Ⅻ deficiency in this family. This study reports two novel pathogenic F12 mutations for the first time worldwide.

Coagulation factor XII deficiency: Clinical report of 7 patients and literature review / 中国输血杂志

【Objective】 To retrospectively analyze the clinical manifestations and laboratory characteristics of 7 patients with coagulation factor Ⅻ deficiency in our hospital from February 2016 to January 2020 in order to improve the understanding of diagnosis and treatment for the diseases. 【Methods】 The clinical data of 7 patients with coagulation factor Ⅻ deficiency were analyzed, and related literatures were reviewed. 【Results】 All the 7 patients showed significantly prolonged APTT without bleeding or thrombosis. Among them, 1 had a positive family history, and 1 acquired coagulation factor Ⅻ deficiency secondary to the tumor. 【Conclusion】 It is very necessary to comprehensively screen related internal and external coagulation factors and acquired factors in patients with prolonged APTT but no bleeding, so as to avoid missed diagnosis, misdiagnosis and over treatment.

Homozygous mutation Gly542Ser in one pedigree with congenital factor Ⅻ deficiency / 中华检验医学杂志

Objective To analyze the mutations of F12 gene in one pedigree with congenital factor FⅫ(FⅫ)deficiency, and investigate the molecular mechanisms of FⅫ deficiency.Methods Pedigree investigation.In February 2015,a patient with hereditary FⅫdeficiency was admitted to the Third Clinical College of Wenzhou Medical University.Activated partial thromboplastin time(APTT), prothrombin time (PT),FⅫactivity(FⅫ:C),FⅫ antigen(FⅫ:Ag)and other coagulant parameters were tested in the proband and his family members.5′and 3′UTR, all exons and their exon-intron boundaries of F12 gene were analyzed by direct sequencing.The detected mutations were confirmed by reverse sequencing.The conserved amino acids were analyzed by ClustalX-2.1-win software, and four bioinformatics softwares (PolyPhen-2,PROVEAN,SIFT and MutationTaster)were also used to analyze the effect of mutations on protein function.Results The proband and her younger brother showed a markedly prolonged APTT which were 116.4 s and 101.3 s, while her father had slightly prolonged APTT, and other family members were normal.The FⅫ:C and FⅫ:Ag of family members were also decreased(the proband,2.0% and 1.0%;her younger brother,2.0% and 1.0%; her father,18.0% and 13.0%).The phenotype of all members was consistent with cross-reactive material(CRM)negative.Nucleotide sequencing analysis showed that the proband and her younger brother had missense mutations in the F 12 gene, including one homozygous mutation c.1681G>A(p.Gly542Ser)and a commonly reported single nucleotide polymorphism site within the promoter region of the F12 gene(46T/T).Sequencing results from the proband's parents and son demonstrated them as carriers of a heterozygous missense mutation.The proband's husband was normal and with 46C/C in the promoter region.The ClustalX-2.1-win results indicated that the Gly542 was highly conserved among the homologousspecies.The predicting outcomes of the four bioinformatics softwares were the same,the PolyPhen-2(score 1.000)and PROVEAN(score -4.975)both declared p.Gly542Ser was a harmful mutation.The SIFT(score 0.00)and the MutationTaster(score 0.999)manifested the mutation could affect the protein funtion.Conclusions c.1681G>A(p.Gly542Ser)in exon 14 and 46T/T were related with the significant decrease of the FⅫlevel of this pedigree of hereditary FⅫ deficiency.

Analysis of clinical phenotype and genotype of two hereditary coagulation factor Ⅻ deficiency / 中华检验医学杂志

Objective Two Chinese pedigrees with congenital factor Ⅻ(FⅫ)deficiency were enrolled in the present study,and studies on the clinical manifestations,family survey,biochemical examinations and gene diagnosis of these pedigrees were performed.Methods In October 2014-2015 March,two cases of hereditary FⅫ deficiency patients were included in Xinhua hospital.Activated partial thromboplastin time(APTT),FⅫ procoagulant activity(FⅫ:C),FⅫ antigen(FⅫ:Ag)and other parameters of coagulant were detected.The FⅫ deficiency pedigree members,exons 1-14,boundary introns including the splice junctions of the F12 gene were amplified with polymerase chain reaction(PCR).Direct sequencing was exerted to purified PCR product to detect the gene mutation.If the gene mutations were found,polymorphism should be ruled out by directing sequence.One hundred and three healthy persons as normal controls.Results The two probands were manifested prolonged APTT(101 s and 143 s).They showed lower FⅫ activity and FⅫ antigen(2％and 6％,0.4％and 4％,respectively).FⅡ:C,FⅦ:C,FⅧ:C,FⅨ:C,FⅩ:C and Fg are normal in the two probands.LAC is negative.Proband 1 has c.1285C>T(p.Q429 stop)mutation.His parents and son have the heterozygous mutation in the same position.Proband 2 has c.1556T>C(p.L519P)mutation.Her two sons have the heterozygous mutation in the same position.In the promoter regions of F12 gene,there were common 46C/T and 619 G/C polymorphisms in two pedigrees.Conclusion c.1285C>T(p.Q429 stop)and c.1556T>C(p.L519P)are the cause of FⅫ deficiency.

A novel homozygous mutation Leu519Arg in one pedigree with congenital factor XII deficiency / 中华检验医学杂志

To analyze the mutations of F12 genein one pedigree with congenital factor FXII (FXII) deficiency , and investigatethe molecular mechanisms of FXII deficiency . Methods Activated partial thromboplastin time(APTT),Prothrombin time(PT), FXII activity(FXII:C), FXII antigen(FXII:Ag) and other coagulant parameters were tested in the proband and his family members .5'and 3'UTR,all exons and their exon-intron boundaries of F12 gene were analyzed by direct sequencing .The detected mutations were confirmed by reverse sequencing .100 healthy persons were as normal controls .Results The proband showed a markedly prolonged APTT (106.4s), the FXII:C and FXII:Ag were 2.0% and 1.0%, respectively .Hissecond daughter and granddaughter had slightly prolonged APTT , and other family members are normal.The FXII:C and FXII:Ag of family members were also decreased ( his son, 23.0% and 21. 0%;his elder daughter , 23.0%and 23.0%;his second daughter ,24.0%and 23.0%;hisgranddaughter , 23.0%and 23.0%).The phenotype of all members is consistent with cross -reactive material negative . Nucleotide sequencing analysis showed that the proband had missense mutations in the F 12 gene, including one homozygous mutationc.1556T >G ( p.Leu519Arg) and a commonly reported single nucleotide polymorphism site within the promoter region of the F 12 gene (46T/T) .Sequencing results from the proband 'children demonstrate them as carriers of a heterozygous missense mutation .The proband 's wife is normal and with 46C/C in the promoter region .Conclusion The c.1556T>G in exon 13 is a novel mutation .This mutation affects FXIIcatalytic function , associated with a reduced level of FXII .

The correlation of antiphospholipid antibody and factor Ⅻ deficiency in patients with retinal vein occlusion / 眼科研究

Objective Antiphospholipid antibody and factor Ⅻ deficiency are among the coagulation disorders that have been implicated in many thrombembolic events. The aim of this study was to investigate the prevalence of antiphospholipid antibodies and factor Ⅻ deficiency in patients with retinal vein occlusion (RVO). Methods The investigation was a case control study. The periphery blood was collected from a cohort of 33 consecutive patients with RVO and 30 age- and gender-matched normal subjects. Anticardiolipin antibody (ACA) was detected by ELISA as binding index (BI) =A value/standard A value. The lupus anticoagulant antibody was examined by APTT test and the activity of factor Ⅻ was detected. This study was approved by The Human Research Ethics Committee of this hospital, and written informed consent was obtained from all the subjects before initiation of any study protocol. Results The total positive rate of APA in RVO group was 24. 24% (8/33), showing a insignificant difference in comparison with control group (6. 67%, 2/30) (P = 0. 085). The positive rate of anticardiolipin antibody in RVO group was 18.18% (6/33), presenting an obvious enhance in control group (P = 0. 025) . Three patients in RVO group disclosed positive response for IgG-anticardiolipin antibody, one patient for IgM-anticardiolipin antibody, two patients for both isotypes IgG and IgM anticardiolipin antibodies, and two patients revealed positive reaction for lupus anticoagulant antibody. The presence of lupus anticoagulant antibody among the patients with ≤ 50 years and ＞ 50 years was similar to that in age-matched controls (P =0. 160, P =0. 206). Factor Ⅻ deficiency was found in 14 of 33 patients(42. 42%) and in 4 of 30 controls(13. 33%) (P = 0. 013). The prevalence of factor Ⅻ deficiency among the patients with ≤50 years and ＞ 50 years was similar to that in age-matched controls (P = 0. 206, P = 0. 052) . Conclusion Our results indicate that the prevalence of ACA and factor Ⅻ deficiency in RVO patients appears to be correlated.