Inherited coagulation factor VII deficiency caused by double heterozygotic mutations Arg304Gln and Arg304Trp

objetive: To investigate the genotypes of mutations of an inherited coagulation factor Ⅶ (FⅦ) deficiency pedigree. Methods: The diagnosis was validated by coagulant parameters. FⅦ gene mutations were analysed in the proband and her family members by DNA direct sequencing. The PCR fragments were cleaved by the MspI restriction enzyme to confirm the mutations detected by sequencing. Results: Double heterozygous mutations at the same coding site of amino acid were detected in propositus of the pedigree: a C to T mutation at position 11348 resulting in Arg304Trp substitution combined with a G to A mutation at position 11349 resulting in Arg304Gln substitution. Her farther had a G to A mutation at position 11349 and her mother had a C to T mutation at position 11348, respectively. Both were heterozygous mutations. One of her brothers had normal genotype, the other one and all her three offsprings had heterozygous mutations. Conclutions: double heterozygous mutations coding the same amino acid were found in a pedigree with hereditary coagulation factor Ⅶ deficiency.