Analysis of a Chinese pedigree affected with Hereditary coagulation factor Ⅺ deficiency due to variant of F11 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular pathogenesis of a Chinese pedigree affected with Hereditary coagulation factor Ⅺ (FⅪ) deficiency due to variants of the F11 gene.@*METHODS@#A male proband with Hereditary coagulation factor Ⅺ deficiency who was admitted to the First Affiliated Hospital of Wenzhou Medical University due to urinary calculi on November 30, 2020 and his family members (7 individuals from 3 generations in total) were selected as the study subjects. Clinical data of the proband were collected, and relevant coagulation indices of the proband and his family members were determined. Genomic DNA of peripheral blood samples was extracted for PCR amplification. All exons, flanking sequences, and 5' and 3' untranslated regions of the F11 gene of the proband were analyzed by direct sequencing. And the corresponding sites were subjected to sequencing in other family members. The conservation of amino acid variation sites was analyzed by bioinformatic software, and the effect of the variant on the protein function was analyzed. Variants were graded based on the guidelines from the American College of Medical Genetics and Genomics (ACMG).@*RESULTS@#The proband was a 36-year-old male. His activated partial thromboplastin time (APTT) was 89.2s, which was significantly prolonged. The FⅪ activity (FⅪ:C) and FⅪ antigen (FⅪ:Ag) were 2.0% and 3.5%, respectively, which were extremely reduced. Both the proband and his sister were found to harbor compound heterozygous variants of the F11 gene, including a c.689G>T (p.Cys230Phe) missense variant in exon 7 from their father and a c.1556G>A (p.Trp519*) nonsense variant in exon 13 from their mother. Conservation analysis indicated the Cys230 site to be highly conserved. The c.1556G>A (p.Trp519*) variant was known to be pathogenic, whilst the c.689G>T variant was classified as likely pathogenic (PM2+PM5+PP1+PP3+PP4) based on the ACMG guidelines.@*CONCLUSION@#The c.689G>T and c.1556G>A compound heterozygous variants of the F11 gene probably underlay the pathogenesis of FⅪ deficiency in this pedigree.

Analysis of a pedigree affected with hereditary coagulation factor XI deficiency due to compound heterozygous variants of F11 gene / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical phenotype and genetic basis for a Chinese pedigree affected with coagulation factor XI (FXI) deficiency.@*METHODS@#Activated partial thromboplastin time (APTT) and other blood coagulation factors, and activities of FXI:C and other relevant coagulation factors for a large Chinese pedigree including 6 patients from 3 generations were determined on a Stago automatic coagulometer. The FXI:Ag was determined with an ELISA method. All exons and flanking regions of the F11 gene were subjected to Sanger sequencing. ClustalX-2.1-win software was used to analyze the conservation of amino acids. Pathogenicity of the variants was predicted with online bioinformatics software including Mutation Taster and Swiss-Pdb Viewer.@*RESULTS@#The APTT of the proband was prolonged to 94.2 s. The FXI:C and FXI:Ag were decreased to 1% and 1.3%, respectively. The APTT of her father, mother, son and daughter was 42.1 s, 43.0 s, 42.5 s and 41.0 s, respectively. The FXI:C and FXI:Ag of them were almost halved compared with the normal values. The APTT, FXI:C and FXI:Ag of her husband were all normal. Genetic testing revealed that the proband has carried a heterozygous missense c.1103G>A (p.Gly350Glu) variant in exon 10 and a heterozygous missense c.1556G>A (p.Trp501stop) variant in exon 13 of the F11 gene. The father and daughter were heterozygous for the c.1103G>A variant, whilst the mother and son were heterozygous for the c.1556G>A variant. Both Gly350 and Trp501 are highly conserved among homologous species, and both variants were predicted to be "disease causing" by Mutation Taster. Protein modeling indicated there are two hydrogen bonds between Gly350 and Phe312 in the wild-type, while the p.Gly350Glu variant may add a hydrogen bond to Glu and Tyr351 and create steric resistance between the two, both may affect the structure and stability of protein.@*CONCLUSION@#The c.1103G>A and c.1556G>A compound heterozygous variants probably underlay the pathogenesis of congenital FXI deficiency in this pedigree.

Cys482Trp Missense Mutation in the Coagulation Factor XI Gene (F11) in a Korean Patient with Factor XI Deficiency

No abstract available.