Congenital Factor V Deficiency from Compound Heterozygous Mutations with a Novel Variant c.5403del (p.Lys1801AsnfsTer11) in the F5 Gene: A Case Report

thromboplastin time (aPTT), which are corrected in the mixing test and confirmed by reduced FV activity.In this report, we describe a patient with hereditary FVD and compound heterozygous variants, including a novel pathogenic variant. CASE REPORTA 50-year-old male was referred to the hematology clinic because of prolonged PT and aPTT during a preoperative examination.He had a right parotid mass that needed excision.The patient had no medical or family history of bleeding.Prolonged PT (30.8 s; reference range, 10.8-14.0)and aPTT (51.8 s; reference range, 21.0-34.0)were corrected in the mixing test, and reduced FV activity (6%) was confirmed.Factor II and VII-XII assays showed no specific findings.Considering the discrepancy between the patient's clinical symptoms and FV activity, as well as the presence of two children in his family tree, genetic studies and counseling were conducted.