[Genetic analysis and clinical features of a pedigree affected with hereditary coagulation factor Ⅶ deficiency caused by compound heterozygotic mutations].

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 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.

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