Women and Girls with Hemophilia
Who is a Hemophilia carrier?
A Hemophilia carrier is a female who has inherited an X chromosome having a Hemophilia gene variant. This can come from her father or mother. All female children of a father with Hemophilia will be Hemophilia carriers. Females born to Hemophilia carrier mother have a 50% chance to be a Hemophilia carrier. Rarely, this can be a new genetic change in the carrier female. In a Hemophilia carrier, one X chromosome has unaffected clotting factor gene, and one X chromosome is affected with the Hemophilia gene. It is rare for a female to inherit affected X chromosome from her father and mother. If so, both her X chromosomes will then be affected. For every male with Hemophilia, there are 1.6 female Hemophilia carriers.
How is the clotting factor level affected in Hemophilia carriers?
The X chromosomes in females go through a process of random inactivation. In medical terms, this is called “lyonization.” In a Hemophilia carrier, if the unaffected X chromosome is mostly inactivated, the affected X chromosome will be the predominant one. This can cause her to have low factor levels. If the affected X chromosome is mostly inactivated, she will have normal clotting factor levels. One-third of Hemophilia carriers have factor levels <40%, as seen in Hemophilia males.
New terminologies for Hemophilia carriers
Recent international recommendations for Hemophilia carriers recommend giving the diagnosis of severe, moderate, or mild Hemophilia, if they have factor levels <1%, 1-5% or 5-40% respectively. Females with clotting factor levels >40% and with a Hemophilia gene will be called as Hemophilia carriers. Of these, females with bleeding symptoms may be called “symptomatic carriers”, and those without increased bleeding are called “asymptomatic carriers”.
Can Hemophilia carriers have bleeding symptoms?
Hemophilia carriers can have increased bleeding. In Hemophilia carriers with low clotting factor levels (<40%), increased bleeding is seen as in Hemophilia males. Bleeding has also been seen in 1 in 4 Hemophilia carriers without low factor (level>40%). Factor levels do not correlate well with bleeding symptoms in Hemophilia carriers. Their bleeding symptoms include excessive bleeding from mucous membranes in nose and mouth, heavy menstrual bleeding, bleeding after dental work, surgery, or childbirth, and less often joint bleeds. The most common bleeding in Hemophilia carriers is reproductive tract bleeding. This includes heavy menstrual bleeding, bleeding into ovarian cysts, bleeding during and after delivery. Hemophilia carriers who are pregnant should receive care during their pregnancy, delivery, and the postpartum period from a team of healthcare specialists. This team should provide proper care for not only the newborn who may have Hemophilia, but also the carrier mother to prevent and treat her excessive bleeding.
Hemophilia carriers are often underdiagnosed and undertreated
The awareness that Hemophilia carriers can have bleeding is lacking amongst individuals and healthcare providers. Because of this, Hemophilia carriers may not have clotting factor levels checked, and their bleeding may not be properly managed. Hemophilia males are often treated in established Hemophilia Treatment Centers. However, female Hemophilia carriers may not receive similar treatment. This can cause many complications in Hemophilia carriers including anemia, low blood pressure due to excessive bleeding, hospital admissions, blood transfusions, surgery, pregnancy, and delivery complications.