Can we compare haemophilia carriers with clotting factor deficiency to male patients with mild haemophilia?

Abstract Introduction Certain haemophilia carriers demonstrate an increased bleeding tendency, mainly related to clotting factor deficiency. No study has so far formally compared the bleeding phenotype of women and girls with mild FVIII or FIX deficiency and associated management with that of male patients affected by mild haemophilia A and B. Material and methods We retrospectively evaluated 44 women and girls with mild FVIII or FIX deficiency (FVIII or FIX 0.05‐0.5 IU/mL) and 77 male patients with mild haemophilia A or B and compared them with respect to clotting factor level, age at and trigger for diagnosis, as well as treatment modalities. Results After excluding gender‐related haemorrhagic symptoms, haemophilia carriers with plasma factor levels in the mild haemophilia range and male patients affected by mild haemophilia present a comparable haemorrhagic profile, mainly characterized by mucocutaneous and postinjury bleeding. Haemophilia carriers with clotting factor deficiency, however, distinguish themselves in terms of later age at diagnosis, higher mean factor levels and trigger for diagnosis. Conclusions Women and girls with mild FVIII or FIX deficiency should be considered as mild haemophilia patients and have access to care and management inspired from male haemophilia patients while integrating differences and specificities. Larger international studies comparing the clinical presentation and treatment modalities of mild clotting FVIII and FIX deficiencies in both haemophilia males and females should be encouraged.