Screening Factor VIII Inhibitor In Patients With Hemophilia A And Detecting New Mutations In Factor VIII

Objective: (1) In order to test factor VIII (FVIII) inhibitor in patients with severe hemophilia A (HA) and preliminary study the genetic mutation in patients with inhibitor. (2) To explore new mutation in exon12, exon14 and exon16 mutations in severe hemophilia A (HA) patients. Methods: (1) Totally 58 patients with HA (FVIII:C<1 %) were enrolled.FVIII:C activity was measured by one-stage coagulation assay. FVIII inhibitor was screened by using APTT method and determined by using Bethesda method. Resulting from previous Bethesda assays, the FVIII gene (F8) was sequenced to identify causative mutations in exon12, exon14 and exon16.(2) Totally 68 patients with HA (FVIII: C<1 %) were enrolled.The factor VIII gene (F8) was sequenced to identify new mutations in exon12, exon14 and exon16.Results: (1) FVIII inhibitor was detected in 4 patients from totally 58 patients (6.9%).Genetic mutation in exon12, exon14 and exon16 was not detected in these 4 patients.(2) Of the 68 patients with HA (FVIII: C<1 %), the detection results are as follows.①10 were detected point mutations in exon14 and exon16.1 was nonsense mutation S1095stop (TCG→TAG).1 was D1241G mutation (GAC→GAG).1 was C692Y (TGC→TAC).1 was V1492I mutation (GTT→ATT).1 was G1490G mutation (GGC→GGA).4 were S1269S mutations (TCA→TCC). 1 was nonsense mutation W1835stop (TGG→TGA).②3 were detected insertion in exon14 and exon16.1 was located in FVIII gene 4381 single nucleic acid A insertion. 1 was located in FVIII gene 2453 single nucleic acid A insertion. 1 was located in FVIII gene 5471 single nucleic acid A insertion.③2 were detected deletion in exon14.1 was located in FVIII gene 4241 single nucleic acid C deletion. 1 was located in FVIII gene 2187 single nucleic acid G deletion.Conclusions: (1) FVIII inhibitor was lower than reported in the literature abroad. It is significance that causes of inhibitor needs to further investigate.(2) FVIII gene exsist additional mutations in exon12, exon14 and exon16. Point mutation including:S1095stop(TCGTAG),C692Y(TGC→TAC),V1492I(GTT→ATT),G1490G(GGC→GGA),S1269S(TCA→TCC).Insertion including:located in FVIII gene 4381,gene 2453 and gene 5471. Deletion including:located in FVIII gene4241 and gene 2187.