Disease Education Information
What is Hemophilia?
Hemophilia is a family of genetic diseases that result in a deficiency of a protein that is required for normal blood clotting—clotting factor VIII in hemophilia A or clotting factor IX in hemophilia B. Because the level of factor VIII or IX in the blood usually stays the same throughout life, hemophilia is a lifelong disease. It is an X-linked genetic disorder.
However, approximately one-third of all cases of hemophilia A develop as a result of a spontaneous genetic mutation where there is no prior family history.
Patients with hemophilia must be careful to avoid injuring themselves, since any injury may result in excessive bleeding. Bleeding can be life threatening if it occurs in the central nervous system, gastrointestinal system, neck or throat, or if it is associated with severe trauma.
There are different degrees of severity of hemophilia, depending on the amount of clotting factor in the blood. People with mild hemophilia usually have problems with bleeding only after surgery, dental procedures, and trauma, while people with severe hemophilia may experience spontaneous joint and muscle bleeding, typically beginning at a very young age, and prolonged bleeding after injuries, traumas, and surgery. People with moderate hemophilia may have occasional or frequent bleeding, depending on their clotting factor level.
While there is no cure for hemophilia, it can be treated using infusions to replace the missing clotting factor in the blood. Factor replacement therapies can be derived from human plasma, but since the 1990s, genetically engineered treatments have been available using recombinant DNA technology. New approaches, such as gene therapy, are also being developed.
Who Gets Hemophilia and How?
Approximately 400,000 people in the world are affected by hemophilia A and hemophilia B, according to the World Foundation of Hemophilia. Hemophilia A is found almost exclusively in males, occurring in about one in every 5,000-10,000 males, while hemophilia B occurs in about one in 25,000-30,000 males.
It is less common for females to have hemophilia. A woman may be seriously affected if her father has the disease and her mother is a carrier of the gene, although sometimes bleeding can occur even when a woman is just a carrier of the disease (ie, when she carries one copy of the abnormal FVIII or FIX gene and one normal gene). However, approximately one-third of all cases of hemophilia A develop as a result of a spontaneous genetic mutation, where there is no prior family history.
What Are the Symptoms of Hemophilia?
The signs and symptoms of hemophilia A and hemophilia B are similar and can include the following:
- Prolonged bleeding following an injury or surgery
- Spontaneous bleeding (ie, bleeding that occurs without an apparent cause)
- Bruising, which is very common in children with hemophilia
- Pain and swelling resulting from bleeding into joints and muscles
- Blood in the urine or stool
- Heavy bleeding following circumcision
- Unexplained nosebleeds
- Bleeding into the brain, symptoms of which include long-lasting, painful headaches, repeated vomiting, sudden weakness or clumsiness of the arms or legs or problems walking, and convulsions or seizures
How Is Hemophilia Diagnosed?
Hemophilias A and B are diagnosed by blood tests that measure the level of coagulation activity for factors VIII (for hemophilia A) and IX (for hemophilia B).
Can Hemophilia Be Treated?
Treatment can be administered at the time of a bleed, in anticipation of an activity that might prompt bleeding (eg, sports), or on a regular basis (prophylaxis) to prevent bleeding.
Hemophilia treatment requires a team approach, involving a group of health care professionals who are experts in treating bleeding disorders, including hematologists, nurse specialists, physical therapists, social workers, and other medical professionals, such as dentists and orthopedic surgeons.
While there is no cure for hemophilia yet, several treatment options are available to patients, which involve infusing the missing clotting factor product directly into the vein. With proper treatment, bleeding stops when enough clotting factor reaches the bleeding site. It is critical to administer treatment as quickly as possible to prevent long-term damage.
Gene therapy is a novel approach to treatment. One type of gene therapy, called gene transfer, involves giving an individual with hemophilia a functional FVIII or FIX gene by an IV infusion. This approach to treatment, which holds the promise of eliminating the need for regular intravenous infusions of factor VIII of IX protein, may improve the patient experience.
Pfizer is currently collaborating with key research partners on other forms of gene therapy for hemophilia B, and other gene therapy research is underway at the company's Rare Disease Consortium.
Better treatment has improved the prognosis and increased the lifespans of patients with hemophilia. However, it is still important that they discuss how to maintain a healthy lifestyle with a health care professional. Some patients may fear exercise, thinking that it may cause bleeding, when, in reality, it can strengthen muscles to help protect against spontaneous bleeds and joint damage. The severity of a patient’s hemophilia must be considered when choosing any activity. With knowledge, healthy choices, and proper treatment, more people with hemophilia are playing an active role in managing their disease.
Work must still be accomplished in the developing world, where a large portion of patients with hemophilia are either not diagnosed or don’t have access to clotting factor treatment. Pfizer is working with the World Federation of Hemophilia (WFH) to improve the availability of medical care in the developing world through the WFH’s Twinning Program. Sponsored solely by Pfizer, this program pairs a hemophilia treatment center or patient advocacy organization in a developing country with a corresponding treatment center or patient organization in a developed one.