Disease Summary

Hemophilia is a rare inherited (genetic) bleeding disorder in which the blood does not clot normally due to missing or low levels of proteins that are known as clotting factors. Blood clotting factors are needed to help stop bleeding after a cut or injury and to prevent spontaneous bleeding. The number of people with hemophilia in the United States is estimated to be about 20,000. Hemophilia is a lifelong disease. However, with proper treatment and self-care, most people with the disease can lead active and productive lives. The hallmark symptom of hemophilia is spontaneous bleeding. In many cases, bleeding occurs without any external trauma and can occur in any part of the body, most commonly in the knees, ankles, elbows and shoulders.

Hemophilia A

Approximately one in 5,000 live male births have hemophilia A. Approximately 80 percent of all people with hemophilia have hemophilia A. Prolonged bleeding is the hallmark sign due to a deficiency of active clotting factor VIII (8).

Hemophilia B

(Also referred to as “Christmas disease”) is caused by a deficiency of active clotting factor IX (9). It is less common than hemophilia A, occurring in one out of every 30,000 live male births.

Factor VII, X, or XIII deficiencies

Caused by a deficiency of either factor VII, X, or XIII, which are active clotting factor in the body. These deficiencies are very rare. Factor VII deficiency affects 1 in 300,000-500,000 live birth; Factor X deficiency affects 1 in 500,000 to 1 million live birth; and Factor XIII deficiency affects 1 in 5 million live birth.

Von Willebrand Disease

Caused by missing or defective von Willebrand factor (VWF), a clotting protein. VWD is the most common bleeding disorder, affecting up to 1% of the US population. It occurs equally in men and women.

Classifications of Hemophilia

Hemophilia is usually classified by the percentage of normal clotting factor (VIII or IX) in the blood, and in what situation bleeding most often occurs. There can be overlap between the following three disease classifications. The percentage of clotting factor stays about the same throughout a person’s life. Family members who have hemophilia usually have similar classifications.

  • Mild – In these cases, bleeding occurs only under severe stress, such as major injury or surgery. Normal clotting factor VIII or IX is less than five percent in the blood.
  • Moderate – In these cases, spontaneous bleeding is rare, but patients will bleed after surgery or from a fall, strain or sprain. Normal clotting factor VIII or IX is one percent to five percent in the blood.
  • Severe – In these cases, patients will exhibit spontaneous bleeding often one or more times per week without any recognizable trauma. This bleeding can occur in any part of the body, but it is usually in the joint of the wrists, fingers, feet and or spine. Normal clotting factor VIII or IX is less than one percent in the blood.