Phenotypic and genetic analysis of a pedigree affected with hereditary FⅤ deficiency due to a novel deletional variant of F5 gene / 中华医学遗传学杂志

Objective@#To analyze the phenotype and F5 gene variant in a pedigree affected with hereditary coagulation factor Ⅴ (FⅤ) deficiency.@*Methods@#All of the exons, flanking sequences, and 5′ and 3′ untranslated regions of the F5 gene were subjected to PCR and direct sequencing. Suspected variant sites were confirmed by clone sequencing. Influence of the variants was predicted by using software including ClustalX and Mutation Taster.@*Results@#The prothrombin time (PT) and activated partial thromboplastin time (APTT) of the proband were prolonged to 20.3 s and 59.2 s, respectively, while FⅤ activity (FⅤ∶C) and FⅤ antigen (FⅤ∶Ag) were reduced by 13% and 17%, respectively. The FⅤ∶C and FⅤ∶Ag of his father, sister and daughter were decreased to 35%, 37%, 29% and 42%, 46%, 35%, respectively. The proband was found to carry a heterozygous c. 2851delT variant in exon 13 of the F5 gene, which caused a frameshift and resulted in a truncated protein (p.Ser923LeufsX8). In addition, a heterozygous c. 1538G>A (p.Arg485Lys) variant was found in exon 10. The father, sister and daughter of the proband all carried the p. Ser923LeufsX8 variant, while his mother and son carried the heterozygous p. Arg485Lys polymorphism. His younger brother and wife were of the wild type. Bioinformatic analysis showed that p. Ser923 was highly conserved across various species. Mutation Taster scored 1.00 for the p. Ser923LeufsX8 variant, and the result has predicted a corresponding disease.@*Conclusion@#A heterozygous deletional mutation c. 2851delT in exon 13 of the F5 gene and a heterozygous c. 1538G>A polymorphism harbored by the proband may be associated with the decreased FⅤ level in this pedigree.

Genetic analysis and clinical features of a pedigree affected with hereditary coagulation factor Ⅶ deficiency caused by compound heterozygotic mutations / 中华医学遗传学杂志

Objective@#To detect potential mutations of the coagulation factor Ⅶ (F7) gene in a pedigree affected with hereditary FⅦ deficiency and explore its molecular pathogenesis.@*Methods@#The FⅦ antigen (FⅦ∶Ag) was analyzed by an enzyme-linked immunosorbent assay (ELISA) method. Prothrombin time (PT), FⅦ activity (FⅦ∶C) and other coagulant parameters were quantified with an one-stage clotting assay. The F7 gene was amplified by PCR and sequenced. Mutational sites were confirmed by reverse sequencing. Impact of amino acid substitution was assessed using SIFT and PolyPhen-2 software. Structure of the mutant protein was analyzed using Swiss-pdb Viewer software based on the three-dimensional structure in the Protein Data Bank.@*Results@#The propositus had prolonged PT (36.3 s), with FⅦ∶C and FⅦ∶Ag significantly reduced to 2% and 44%, respectively. Her father, mother, younger sister and daughter had slightly prolonged PT and reduced FⅦ∶C (86%-120%). The FⅦ∶Ag of her father and younger sister were also reduced. DNA sequencing revealed that the propositus has carried compound heterozygous mutations (Lys341Glu and IVS6-1G>A) of the F7 gene. Her father and younger sister were heterozygous for the IVS6-1G>A mutation, while her mother and daughter were heterozygous for the Lys341Glu mutation. Bioinformatics analysis indicated that Lys341Glu mutation may affect the stability and function of the FⅦ protein.@*Conclusion@#The Lys341Glu and IVS6-1G>A mutations probably underlie the reduced activity of FⅦ in this pedigree.

Identification of compound heterozygous mutations of F11 gene in a pedigree affected with heriditary coagulation factor XI deficiency / 中华医学遗传学杂志

OBJECTIVE@#To identify potential mutations of F11 gene in a pedigree affected with hereditary coagulation factor XI (FXI) deficiency and explore its molecular pathogenesis.@*METHODS@#Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), coagulation factor VIII activity (FVIIIC), coagulation factor IX activity (FIXC), coagulation factor XI activity (FXIC), coagulation factor XII activity (FXIIC) and lupus anticoagulation (LA) of the proband and eight family members were determined. FXI antigen (FXIAg) was determined by enzyme-linked immunosorbent assay (ELISA). For the proband, potential mutations in the exons, flanking introns and 5'-, 3'-untranslated regions of the F11 gene were screened by direct DNA sequencing. The results were confirmed by reverse sequencing. Suspected mutations were detected in other family members. ClustalX-2.1-win and four online bioinformatic tools (PolyPhen-2, PROVEAN, SIFT, and Mutation Taster) were used to study the conservation and possible impact of the mutations. The structure of the mutational sites was processed with Swiss-PdbViewer.@*RESULTS@#The propositus had prolonged APTT (69.6 s), whose FXIC and FXIAg were reduced to 6.0% and 10.7%, respectively. Her mother, elder sister, one younger sister, little brother, daughter and son showed slightly prolonged APTT and moderate FXIC and FXIAg levels. Gene sequencing revealed that the propositus carried a heterozygous nonsense mutation c.738G>A (p.Trp228stop) in exon 7 and a heterozygous mutation c.1556G>C (p.Trp501Ser) in exon 13. Her mother, elder sister and daughter were heterozygous for the p.Trp228stop mutation, while one younger sister and little brother and son were heterozygous for p.Trp501Ser. Her husband and the youngest sister were of the wild type. Phylogenetic analysis suggested that Trp501 was highly conserved among all homologous species. The p.Trp501Ser was predicted to be "probably damaging","deleterious", "affect protein function" and "disease causing" corresponding to PolyPhen-2, PROVEAN, SIFT and Mutation Taster. Model analysis demonstrated that the non-polar Trp501 has two benzene rings, forming a hydrogen bond with Gln512 in the wild type. Once substituted by Ser501, the side chain may form another hydrogen bond with the benzene of His396. This may affect the normal space conformation and stability of FXI protein.@*CONCLUSION@#The compound heterozygous mutations of the F11 gene probably accounted for the low FXI concentration in this pedigree.

Genetic analysis and clinical features of a pedigree affected with hereditary coagulation factor Ⅶ deficiency caused by compound heterozygotic mutations / 中华医学遗传学杂志

OBJECTIVE@#To detect potential mutations of the coagulation factor Ⅶ (F7) gene in a pedigree affected with hereditary FⅦ deficiency and explore its molecular pathogenesis.@*METHODS@#The FⅦ antigen (FⅦ:Ag) was analyzed by an enzyme-linked immunosorbent assay (ELISA) method. Prothrombin time (PT), FⅦ activity (FⅦ:C) and other coagulant parameters were quantified with an one-stage clotting assay. The F7 gene was amplified by PCR and sequenced. Mutational sites were confirmed by reverse sequencing. Impact of amino acid substitution was assessed using SIFT and PolyPhen-2 software. Structure of the mutant protein was analyzed using Swiss-pdb Viewer software based on the three-dimensional structure in the Protein Data Bank.@*RESULTS@#The propositus had prolonged PT (36.3 s), with FⅦ:C and FⅦ:Ag significantly reduced to 2% and 44%, respectively. Her father, mother, younger sister and daughter had slightly prolonged PT and reduced FⅦ:C (86%-120%). The FⅦ:Ag of her father and younger sister were also reduced. DNA sequencing revealed that the propositus has carried compound heterozygous mutations (Lys341Glu and IVS6-1G>A) of the F7 gene. Her father and younger sister were heterozygous for the IVS6-1G>A mutation, while her mother and daughter were heterozygous for the Lys341Glu mutation. Bioinformatics analysis indicated that Lys341Glu mutation may affect the stability and function of the FⅦ protein.@*CONCLUSION@#The Lys341Glu and IVS6-1G>A mutations probably underlie the reduced activity of FⅦ in this pedigree.

Phenotypic and genetic analysis of a pedigree affected with hereditary FV deficiency due to a novel deletional variant of F5 gene / 中华医学遗传学杂志

OBJECTIVE@#To analyze the phenotype and F5 gene variant in a pedigree affected with hereditary coagulation factor V (FV) deficiency.@*METHODS@#All of the exons, flanking sequences, and 5' and 3' untranslated regions of the F5 gene were subjected to PCR and direct sequencing. Suspected variant sites were confirmed by clone sequencing. Influence of the variants was predicted by using software including ClustalX and Mutation Taster.@*RESULTS@#The prothrombin time (PT) and activated partial thromboplastin time (APTT) of the proband were prolonged to 20.3 s and 59.2 s, respectively, while FV activity (FV:C) and FV antigen (FV:Ag) were reduced by 13% and 17%, respectively. The FV:C and FV:Ag of his father, sister and daughter were decreased to 35%, 37%, 29% and 42%, 46%, 35%, respectively. The proband was found to carry a heterozygous c.2851delT variant in exon 13 of the F5 gene, which caused a frameshift and resulted in a truncated protein (p.Ser923LeufsX8). In addition, a heterozygous c.1538G to A (p.Arg485Lys) variant was found in exon 10. The father, sister and daughter of the proband all carried the p.Ser923LeufsX8 variant, while his mother and son carried the heterozygous p.Arg485Lys polymorphism. His younger brother and wife were of the wild type. Bioinformatic analysis showed that p.Ser923 was highly conserved across various species. Mutation Taster scored 1.00 for the p.Ser923LeufsX8 variant, and the result has predicted a corresponding disease.@*CONCLUSION@#A heterozygous deletional mutation c.2851delT in exon 13 of the F5 gene and a heterozygous c.1538G to A polymorphism harbored by the proband may be associated with the decreased FV level in this pedigree.

Phenotypic and mutational analysis of a pedigree affected with hereditary coagulation factor Ⅴ deficiency / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To explore the molecular pathogenesis for a pedigree affected with coagulation factor Ⅴ (FⅤ) deficiency.</p><p><b>METHODS</b>Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), coagulation factor Ⅱ activity (FⅡ: C), FⅤ activity (FⅤ: C), coagulation factor Ⅶ activity (FⅦ: C), and coagulation factor Ⅹ activity (FⅩ: C) were determined with a STAGO automatic coagulometer. FⅤ antigen (FⅤ: Ag) was detected with enzyme linked immunosorbent assay (ELISA). All exons and their flanking regions, and 5' and 3' untranslated regions of the F5 gene were analyzed by direct sequencing. Suspected mutation was verified by reverse sequencing as well as testing of family members. ClustalX software was used to analyze the conservative property of the mutation sites. PROVEAN and MutationTaster online software was used to predict the effect of the mutation on the protein function. Swiss-pdbViewer was used to analyze the protein model and interaction of amino acids.</p><p><b>RESULTS</b>The PT and APTT of the proband were slightly prolonged to 15.2 s and 41.8 s, respectively. And the FⅤ: C and FⅤ: Ag measured 55% and 62%, respectively. The FⅤ: C and FⅤ: Ag of his father and son were decreased to various extent (60%, 65% and 31%, 40%, respectively). A c.911G>A heterozygous mutation (Gly276Glu) was detected in exon 6 of the proband, for which her father and son were heterozygotes. The same mutation was not found in her mother, brother and husband. Conservation analysis showed that the Gly276 is highly conserved across various species. By bioinformatic analysis, the PROVEAN (scored -6.214) indicated Gly276Glu was harmful, and MutationTaster (scored 0.976) suggested that it is pathogenic. Model analysis suggested there are two hydrogen bonds between Gly276 and Ile298 in the wild type protein. When Gly276 was replaced by Glu276, the original hydrogen bond did not change, but the side chain of Glu was extended, which added steric hindrance with the surrounding amino acids, which resulted in decreased protein stability.</p><p><b>CONCLUSION</b>The heterozygous c.911G>A (Gly276Glu) mutation of the F5 gene probably underlies the decreased level of FⅤin the proband.</p>