These authors contributed equally.
Determinants of factor VIII plasma levels in carriers of haemophilia A and in control women
Article first published online: 16 SEP 2009
© 2009 Blackwell Publishing Ltd
Volume 16, Issue 1, pages 111–117, January 2010
How to Cite
AY, C., THOM, K., ABU-HAMDEH, F., HORVATH, B., QUEHENBERGER, P., MALE, C., MANNHALTER, C. and PABINGER, I. (2010), Determinants of factor VIII plasma levels in carriers of haemophilia A and in control women. Haemophilia, 16: 111–117. doi: 10.1111/j.1365-2516.2009.02108.x
- Issue published online: 29 DEC 2009
- Article first published online: 16 SEP 2009
- Accepted after revision 18 August 2009
- factor VIII;
- haemophilia A
Summary. Factor VIII (FVIII) levels show a considerable variability in female carriers of haemophilia A. Presently, the reasons for this are poorly understood. The aim of the study was to elucidate the influence of genetic and non-genetic parameters on FVIII plasma levels in carriers (n = 42). Results were compared with age-matched healthy women without carriership of haemophilia A (n = 42). Each carrier was tested for the family-specific mutation, ABO blood group, FVIII level, von Willebrand factor (VWF) antigen and activity and C-reactive protein (CRP). FVIII levels were lower in carriers compared to non-carriers [74% (51–103) vs. 142% (109–169), P < 0.001]. No statistically significant differences were observed between the two groups with respect to VWF activity, prothrombin–time, hs-CRP, fibrinogen, body mass index (BMI), age and smoking status as well as the distribution of ABO blood groups. In non-carriers, FVIII was statistically significantly correlated with BMI, activated partial thromboplastin time (APTT), VWF antigen, hs-CRP and fibrinogen. In carriers, significant correlations between FVIII and APTT, VWF antigen and activity were found, whereas BMI, hs-CRP or fibrinogen did not correlate with FVIII. In non-carriers, the association of FVIII with ABO blood groups was statistically significant (P = 0.006), but not in carriers of haemophilia A (P = 0.234). The type of FVIII gene mutation did not influence FVIII levels. Carrier status is the major determinant of a carrier`s FVIII plasma level. Factors known to influence FVIII levels in the general population do not significantly affect FVIII activity in carriers, neither does the type of mutation influence FVIII levels.