[An inherited coagulation factor VII deficiency pedigree caused by homozygous mutation of His348Gln].

OBJECTIVE

To investigate the gene mutation and the molecular pathogenesis of an inherited coagulation factor VII (F VII) deficiency pedigree with consanguineous marriage.

METHODS

The diagnosis was validated by coagulant parameter assay on the prothrombin time (PT), activated partial thromboplastin time, fibrinogen and coagulation factor activity. F VII gene mutations were analyzed in the proband and other family members by direct DNA sequencing of the PCR products of all exons, exon-intron boundaries and 5'and 3' untranslated sequences. The mutations were confirmed by reverse sequencing.

RESULTS

The values of PT and F VII activity in the proband were significantly abnormal, they were 30.9 s and 3% respectively. The PT of her daughter, father and mother was slightly extended to 21.2 s, 16.3 s and 16.1 s respectively, and the F VII activity was reduced to 22%, 25% and 35% respectively. The coagulant parameters of her younger brother were within normal range. Homozygous T-->G transition at position 11482 in exon 8 was identified in the proband resulting in His348Gln, and heterozygosity for His348Gln was confirmed in her daughter and her parents, and the normal wild-type was observed in her younger brother.

CONCLUSION

Homozygous missense mutation of His348Gln was found in a pedigree of hereditary F VII deficiency. The mutation was inherited from her heterozygote parents.