Effects of the factor V G1691A mutation and the factor II G20210A variant on the clinical expression of severe hemophilia A in children – results of a multicenter study

The present multicenter cohort study of 107 pediatric PUPs was performed to determine whether the concomitant inheritance of the factor (F) V G1691A or the F II G20210A mutation influences the clinical expression of severe hemophilia A (HA). Carriers of the FV and FII mutations had a significantly lower annual bleeding frequency (ABF) than non-carriers (p=0.012). Joint damage (Pettersson score) was significantly less severe in patients with thrombophilia (p=0.022). A protective effect of thrombophilic risk factors was shown for ABF (OR [CIs]: 0.7[0.5–0.9]; p=0.02) and the severity of the hemophilic arthropathy (OR [CIs]: 0.06[0.01–0.3]; p=0.0009).