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

OBJECTIVE: To investigate the genotypes of mutations of an inherited coagulation factor VII(F VII) deficiency pedigree. METHODS: The diagnosis was validated by coagulant parameters. F VII gene mutations were analysed in the proband and her family members by DNA direct sequencing. The PCR fragments were cleaved by the Msp I restriction enzyme to confirm the mutations detected by sequencing was performed in this study. 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 brother and all her three offsprings had heterozygous mutations. CONCLUSION: Double heterozygous mutations coding the same amino acid were found in a pedigree with hereditary coagulation factor VII deficiency.