Hemophilia A
Hemophilia A

What is hemophilia A?

Hemophilia A, also called classic hemophilia or factor VIII deficiency, is a genetic (or inherited) blood clotting disorder that occurs when clotting factor VIII is either absent or not present in sufficient amounts. There is no cure for hemophilia A, but there are a number of treatment options.1

A column chart with a white filled bar inside of a red circle.

Hemophilia A is the most common type of hemophilia

Gender male icon inside of a red circle.

Occurs in 1 in 5,000 male births

What are the signs and symptoms of hemophilia A?

People with hemophilia may experience excessive bleeding or bruising in the joints, muscles, or soft tissue. Additional symptoms can include2:

  • Pain, swelling, or tightness in joints
  • Bleeding of the mouth and gums and bleeding after losing a tooth
  • Bleeding after circumcision or after receiving a shot
  • Bleeding in the head of an infant after a difficult delivery
  • Blood in the urine or stool
  • Frequent and hard-to-stop nosebleeds

What causes hemophilia A?

Hemophilia A is caused by a mutation of a gene on the X chromosome that results in a deficiency of factor VIII. It is often inherited and is most common in male patients. However, in about 30% of hemophilia A cases, there is no family history of the disorder and it is the result of a spontaneous gene mutation.1,2

A pie chart depicting in red 30% of hemophilia A cases have no family history.

30% of cases have no family history

Because hemophilia is an X-linked recessive disorder, it can only be passed from a mother to her child via the X chromosome.1 A female who has one of the affected gene mutations is known as a 'carrier.'2

In rare instances, females may also develop hemophilia if both of their X chromosomes have the mutation or one is affected and the other is missing or inactive.2

How is hemophilia A diagnosed?

If a doctor suspects a patient may have hemophilia A, they will likely use blood tests (such as a complete blood test, coagulation tests, and measurement of factor levels) to help make a diagnosis. If blood clot formation is not within the normal range, then a clotting factor activity test is performed to confirm the diagnosis of hemophilia A or another blood clotting factor deficiency.1

“When I was diagnosed, my fears disappeared. I knew there was support out there for me.” — Cathy, hemophilia A patient

Once the diagnosis of hemophilia A is made, genetic testing can help predict a patient's risk of developing inhibitors to factor treatment. Analysis of the specific gene mutation can also help identify female carriers of hemophilia A in a given family. Genetic information like this can aid in the diagnosis of hemophilia A prior to birth and after delivery.1

What are the three severity levels of hemophilia A?

The three levels of severity of hemophilia A (mild, moderate, and severe) are related to the amount of clotting factor that is either missing or deficient.3

When considering the levels of severity, keep in mind that individual bleeding patterns vary. For example, some people with moderate hemophilia can bleed just as much as those with severe hemophilia.4

Severe hemophilia A is the most common form of the disease, with 60% of hemophilia A patients having less than 1% working factor VIII.3

hemophilia A

A pie chart depicting in light blue tile 25% of hemophilia A cases are mild.

25% of people with hemophilia A

hemophilia A

A pie chart depicting in blue tile 15% of hemophilia A cases are moderate.

15% of people with hemophilia A

hemophilia A

A pie chart depicting in dark blue tile 60% of hemophilia A cases are severe.

60% of people with hemophilia A

What is acquired hemophilia A?

While most people with hemophilia A are born with it, some people do develop it later in life. This is called acquired hemophilia A. In this case, the body produces antibodies that attack clotting factor VIII in the blood and prevent it from working.5

Treatment for hemophilia A

Options are available for this factor VIII deficiency.

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  1. Hemophilia A. National Organization for Rare Disorders website. Accessed February 9, 2021. https://rarediseases.org/rare-diseases/hemophilia-a/
  2. What is hemophilia? Centers for Disease Control and Prevention. Accessed February 9, 2021. https://www.cdc.gov/ncbddd/hemophilia/facts.html
  3. Hemophilia A. National Hemophilia Foundation. Accessed February 9, 2021. https://www.hemophilia.org/Bleeding-Disorders/Types-of-Bleeding-Disorders/Hemophilia-A
  4. Severity levels. The hemophilia, von Willebrand disease & platelet disorders handbook. Accessed February 9, 2021. https://www.hog.org/handbook/article/1/3/severity-levels
  5. Paul Giangrande; World Federation of Hemophilia. Acquired hemophilia. Published 2005. Revised 2012. Accessed February 9, 2021. http://www1.wfh.org/publication/files/pdf-1186.pdf