[Genetic analysis of a pedigree with hereditary coagulation factor Ⅶ deficiency].

OBJECTIVE

To identify potential mutations in a family affected with inherited factor Ⅶ (FⅦ) deficiency.

METHODS

Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, FⅦ activity (FⅦ:C) and other coagulant parameters of the proband and 15 family members were measured. Potential mutations were screened in the pedigree by polymerase chain reaction and direct DNA sequencing.

RESULTS

The PT of the proband and his younger brother was significantly prolonged to 39.0 s and 30.1 s, respectively. FⅦ:C of the proband and his younger brother was obviously reduced to 2% and 3%, respectively. FⅦ:C of his grandmother, maternal grandmother, aunt, father, mother, maternal uncle and maternal aunt was all below the normal range (80%-108%), which measured 68%, 54%, 71%, 73%, 62%, 72% and 59%, respectively. The other coagulant parameters were in the normal range. Two heterozygous mutations, g.11349G>A and g.11482T>G, both reside in exon 8 of the F7 gene, have resulted in p.Arg304Gln and p.His348Gln substitutions, were identified in the proband. The same mutations were also found in the proband's younger brother. Four maternal members in this family (grandmother, mother, maternal uncle and maternal aunt of the proband) were heterozygous for the p.Arg304Gln mutation, while three paternal members (grandmother, aunt and father of the proband) were heterozygous for the p.His348Gln mutation.

CONCLUSION

The proband had inherited two independent mutations of the F7 gene including g.11349G>A and g.11482T>G from his mother and father, respectively. The compound heterozygous mutation probably explains the low FⅦ concentrations in this pedigree.