Pb2660: hereditary coagulation factor fvii deficiency caused by compound heterozygous mutations

Topic: 33. Bleeding disorders (congenital and acquired) Background: Congenital factor (F) VII deficiency is a rare coagulation factor deficiency with an estimated incidence of 1 per 500,000 individuals. Patients with severe FVII deficiency present a broad range of clinical presentations. 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, daughter and elder brother’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, and c.722C> A in Exon 8,causing heterozygous p.Thr241Asn. Sanger sequencing confirmed that the proband’s mother, 61-year-old, had Exon1 heterozygous deletion frameshift mutation c.27_28del in the F7 gene, his daughter, 6 years old, heterozygous c.722C> A missense mutation in Exon 8, and his brother, 40-year-old, had the same two mutations in F7 gene. Summary/Conclusion: The compound heterozygous mutations in the F7 gene might be the molecular pathology of hereditary coagulation factor VII deficiency for the proband. Keywords: Coagulation factors, Gene mutation