Relevance of Thrombophilic Risk Factors on Clinical Phenotype in Patients with Haemophilia A.

Introduction: By assuming the hypothesis, that a high coinheritance of genetic haemostatic abnormalities influences the clinical phenotype in patients with coagulation disorders, we analysed the bleeding tendency in adult patients with haemophilia A.

Patients: A total of 49 patients with haemophilia A (severe:20 patients, moderate:12 patients, mild:17 patients; median age:44 years, range:22–78 years) and 80 sex-matched healthy subjects (median age:26 years, range:16–58 years) were studied in our haemophilia treatment center. Two of this patients have an inhibitor against factor VIII. 10 of 49 patients receive the factor VIII replacement therapy on demand. In addition to factor VIII activity, FV G1691A mutation and the FII G20210A variant were investigated.

Results: In our study the prevalence of FV G1691A was significantly higher among patients 6/49 (severe:5, moderate:1) than among control subjects 2/80 [12% vs 2.5%; p=0.03 OR 4.9]. We found no differences in the FII G20210A variant in 2/49 patient (moderate:1, mild:1) as compared to 2/80 among controls [4% vs 2.5%; p=0.62 OR 1.63 ]. In none of our patients both defects together were identified.

Within the last year the onset of bleeding was not different in thrombophilic haemophilia patients (n=8) 64 bleeding episodes/year compared with non-carriers (n=41) 284 bleeding episodes/year [8 vs 7 bleeding episodes/year/patient; p=0.72; OR 1.15].

Conclusion: The FV G1691A was found significantly more frequent in the thrombophilic haemophiliacs than in the general population. In our smal study group we could not demonstrate a relevant influence of the FV G1691A and FII G20210A on bleeding tendency. Further studies are needed to confirm whether FV G1691A and FII G20210A plays a role on the influence of bleeding tendency in haemophilia A patients.