PB0239 - Hereditary coagulation factor FVII deficiency caused by compound heterozygous mutation

Background: Hereditary coagulation VII deficiency is a rare autosomal recessive bleeding disorder resulting from variants in the gene encoding FVII (F7), in which clinical presentation is highly variable and correlates poorly with laboratory phenotype.

Aims: To investigate the possible pathogenesis of a patient with PT extension.

Methods: The proband’s clinical manifestations, coagulation function test and PT correction test were retrospectively analyzed and the coagulation factor activities and related genes were detected or sequenced. His mother and daughter’s activity of coagulation factor and the corresponding gene mutation was also tested

Results: The proband, a 38-year-old male, was presented for repeated and persistent epistaxis, with no abnormal local nasal examination. Coagulation tests showed PT 28s, corrected PT 12s, and normal APTT. FVII: C was 3.8%. NGS with the peripheral blood found that the F7 gene had c.27_28del in Exon1, resulting in heterozygous p.Cys10ProfsTer16; Exon 8 had c.722C> A causing heterozygous p.Thr241Asn. Sanger sequencing confirmed the proband's mother, 61-year-old, Exon1 heterozygous deletion frameshift mutation c.27_28del in the F7 gene, daughter, 6 years old, heterozygous c.722C> A missense mutation in Exon 8.

Conclusion(s): The compound heterozygous mutations in the F7 gene is the molecular pathology of its hereditary coagulation factor VII deficiency.