What Is Hemophilia? Understanding the Disease

Knowing what causes hemophilia and how it may impact patients and caregivers is the first step in getting effective treatment. By definition, most cases of hemophilia are caused by an inherited genetic mutation that prevents the body from producing enough of a specific clotting factor needed to stop bleeding.

Sometimes hemophilia occurs spontaneously, meaning it is not passed down from parent to child. When this happens, hemophilia is classified as an autoimmune disorder where the body mistakenly attacks clotting factors.

What Causes Hemophilia: The “Hemophilia Gene”

Most cases of hemophilia are genetic or inherited (passed down from parent to child). The “hemophilia gene” or genetic mutation responsible for clotting factor deficiencies is found on the X chromosome, making hemophilia an X-linked disorder. Males, who have just one X chromosome, are much more likely to inherit hemophilia than females, who have two X chromosomes.

As an X-linked disorder, hemophilia is only inherited if all X chromosomes have the genetic mutation. For a male, who only has one X chromosome, the chance of inheriting hemophilia is 50% if his mother has the defective gene. For a female to inherit hemophilia, she must receive the hemophilia gene from her mother and her father must also have the disease.

A female with the hemophilia genetic mutation is called a carrier. While a carrier does not have hemophilia, her male children will have a 50% chance of inheriting hemophilia and her female children will have a 50% chance of becoming carriers themselves.

Blood Clotting Factors

Blood clotting factors are proteins that stop bleeding. After a blood vessel is damaged, the body releases chemical signals to aid in forming a clot using clotting factors to control and eventually stop bleeding.

Hemophilia is known as a clotting or bleeding disorder because the blood of affected individuals lacks sufficient amounts of one of the clotting factors needed to stop bleeding. The level of a clotting factor deficiency determines how severe a patient’s symptoms are and what treatment regimen is needed. Those with a relatively mild clotting factor deficiency may only need treatment when undergoing dental or surgical procedures. Those whose blood lacks higher levels of clotting factor may need regular infusions and other treatment to prevent severe hemophilia complications.

Types of Hemophilia

There are two types of inherited hemophilia (hemophilia passed down from parent to child): hemophilia A and hemophilia B. Hemophilia type is determined by which blood clotting factor a person is missing or is deficient in. Hemophilia A patients lack clotting factor VIII and hemophilia B patients lack clotting factor IX.

Hemophilia A

The most common type of hemophilia is hemophilia A, in which a patient lacks clotting factor VIII. Hemophilia A occurs in approximately 1 in 5,000 live births and affects mostly males. Roughly 20,000 people within the United States have hemophilia A.

Hemophilia B

Hemophilia B occurs when levels of clotting factor IX are absent or deficient. Much rarer than hemophilia A, hemophilia B occurs in about 1 in 30,000 live male births and is about one fifth as common as hemophilia A.

Hemophilia C

Hemophilia C is another bleeding disorder caused by missing or low levels of factor XI. This form of hemophilia is usually mild and often affects individuals of Jewish Ashkenazi descent. While hemophilia C is more prevalent than hemophilia A and B, the severe form of hemophilia C is much more rare (affecting roughly 1 in 100,000 people within the United States). Hemophilia C occurs in both sexes.

Hemophilia Treatment Options

Hemophilia treatment depends upon the type and severity of the disease. Individuals with mild hemophilia may only need treatment before a surgical or dental procedure. Those who have severe hemophilia may require routine infusions.

For individuals with missing or low levels of a particular clotting factor, treatment entails replacing the factor intravenously as needed to stop a bleeding episode in progress and routine factor infusions to prevent bleeding episodes from occurring.

Hemophilia treatment plans can be therapeutic to treat current symptoms or prophylactic to keep symptoms from developing.

Therapeutic Hemophilia Treatments

A therapeutic or “on-demand” hemophilia treatment addresses current or existing symptoms, such as uncontrolled bleeding episodes.

Prophylactic Hemophilia Treatments

Routine clotting replacement treatments are often recommended for individuals with moderate to severe symptoms to prevent bleeding episodes. Replacement treatments are performed either at hemophilia treatment centers or at home using self-infusion.

Other Hemophilia Treatment Options

Additional hemophilia treatment options may help manage hemophilia symptoms and prevent bleeding episodes, including:

  • Hormone drugs to stimulate clotting factor production
  • Antifibrinolytics to keep already-formed clots from breaking down
  • Topical treatments to promote clotting
  • Physical therapy for joints damaged by internal bleeding

Patients who manage their hemophilia proactively by maintaining a healthy lifestyle and obtaining preventive treatments have a better long-term prognosis than those who don’t. To learn more about which hemophilia treatment options are right for you, including self-infusion and home infusion, visit our Hemophilia Treatment page or contact us to speak with a patient support specialist.