Types of Bleeding Disorders

Hemophilia and Bleeding Disorders Toolkit

Overview of Hemophilia: Types of Bleeding Disorders

Most bleeding disorders are inherited and affect people from all racial and ethnic groups. Although there are several different types, these are the three most common:

  • Hemophilia A (Classic Hemophilia)
    • Involves a clotting factor VIII deficiency
    • Is four times more common as Hemophilia B
    • Is responsible for 80% of total cases of hemophilia
    • 30% of cases are the result of “spontaneous mutations” meaning there is no family history
  • Hemophilia B (Christmas Disease)
    • Involves a clotting factor IX deficiency
    • Is responsible for 20% of total cases of hemophilia
    • 30% of cases are the result of “spontaneous mutations” meaning there is no family history
  • von Willebrand Disease (VWD)
    • Involves a low level of a protein called von Willebrand Factor (VWF)
    • Most common inherited bleeding disorder; 1 in 1,000 Americans have clinically relevant VWD
    • Is usually milder than Hemophilia A and B
    • More women show symptoms of VWD due to menstruation and childbirth

Clotting factor tests are blood tests used to determine hemophilia type and severity. The severity of symptoms can vary greatly, and bleeding tendency depends on the clotting factor levels in the blood. In a person without hemophilia, clotting factor levels are between 50% and 100%. A person with hemophilia will be in one of the following categories:

  • Severe: Factor level is less than 1% and frequent spontaneous bleeding episodes can occur, often into the joints. Repeated bleeds into the joints makes those in the severe category more likely to develop joint disease. Sixty percent of Hemophilia A patients are diagnosed as severe.
  • Moderate: Factor level is between 1% - 5% and bleeding tends to happen after injury or surgery; may have occasional bleeding without apparent cause (spontaneous bleeding). Fifteen percent of hemophilia A patients are diagnosed as moderate.
  • Mild: Factor level is greater than 5% but less than 50% and bleeding is generally experienced only after severe injury, trauma or surgery. The first episode may not appear until adulthood. Women with mild hemophilia can experience heavy menstrual periods and/or hemorrhage following childbirth. Twenty-five percent of Hemophilia A patients are diagnosed as mild.