Association between bleeding tendency and health-related quality of life in carriers of moderate and severe haemophilia.
Carriers of severe and moderate haemophilia A and B are expected to have approximately 50% of the normal level of factors VIII and IX. However, due to X chromosome inactivation in early embryonic life, factor levels can vary considerably. This can lead to increased bleeding tendency, which may in turn impact on health-related quality of life (HRQOL).