Congenital Factor V Deficiency from Compound Heterozygous Mutations with a Novel Variant C.2426del (p.pro809hisfs2) in the F5 Gene: A Case Report

INTRODUCTION:Congenital factor V deficiency (FVD) is a rare bleeding disorder characterized by low or undetectable plasma factor V (FV) levels leading to mild to severe bleeding symptoms. Currently, more than 100 mutations have been reported in F5. We herein report a patient with FVD from mutations in the F5 gene.PATIENT CONCERNS:A 52-year-old man with prolonged prothrombin time and activated partial thromboplastin time corrected by mixing test on preoperative screening. His past medical or family history was not remarkable.DIAGNOSIS:Factor assays revealed a markedly reduced FV activity at 7%. Other factors were not decreased. DNA sequencing analysis to detect F5 gene mutations showed the patient was compound heterozygous for c.286G>C (p.Asp96His) and c.2426del (p.Pro809Hisfs*2). Asp96His was previously described missense mutation and Pro809Hisfs*2 was a novel deleterious mutation.INTERVENTIONS:Fresh-frozen plasma was administered to supplement FV before surgery.OUTCOMES:Subsequent factor assays revealed temporarily increased FV activity at 33%.CONCLUSION:As was the case in our patient, genotype-phenotype correlations are poor in FVD, and molecular genetic test is necessary to confirm the diagnosis.