Gene analysis of a combined inherited factor VII and factor X deficiency pedigree / 中华血液学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To perform gene analysis and family survey of a patient with combined inherited FVII and FX deficiency, and to identify the gene mutation of this patient.</p><p><b>METHODS</b>The phenotype diagnosis was validated by coagulant parameter assay on prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, FVII and FX activity (FVII:C, FX:C) and FVII and FX antigen (FVII:Ag, FX:Ag). FVII and FX gene mutations were analyzed in the proband and other family members by DNA direct sequencing of all exons, exon-intron boundaries and 5', 3' untranslated sequences. One hundred and six health examination participants were selected as control.</p><p><b>RESULTS</b>The values of PT and APTT of the proband showed significantly prolonged, which were 84.5s and 63.4s, respectively. The levels of FVII:C, FVII:Ag, FX:C and FX:Ag were 6%, 7%, 4% and 30%, respectively. The PT of his father, mother and sister was prolonged slightly while both APTT and FVII:Ag were in the normal range. Two homozygous mutations, g.11267C→T in exon 8 of FVII gene resulting in the substitution of Arg277Cys and g.28139G→T in exon 8 of FX gene leading to the substitution of Val384Phe, were identified in the proband. The proband's parents and sister were heterozygous for Arg277Cys and Val384Phe mutations.</p><p><b>CONCLUSION</b>Homozygous mutation Arg277Cys in FVII gene and Val384Phe in FX gene were the molecular mechanism causing combined inherited FVII and FX deficiency. The Val384Phe substitution was a novel mutation, which may affect the synthesis or secretion of FX protein.</p>