What is hemophilia?
A clotting disorder that occurs mostly in males. The disorder makes bleeding hard to control. is a bleeding Bleeding
In hemophilia, a collection of blood in an area, such as a muscle or joint. disorder that prevents blood from clotting Clotting
The process of forming into a clot or clots. properly. There are 13 proteins in blood called clotting (coagulation) factors Clotting (coagulation) factors
Substances in the blood that work together with platelets to form a fibrin clot in an injured blood vessel and stop bleeding. Clotting factors are named using Roman numerals (Factor I  to Factor XIII ). that work together in a series of steps to form blood clots Clot
The thickened mass of blood and cells your body forms to stop the bleeding at the place where you have been injured. . People with hemophilia are missing one of these clotting factors, so they may need special treatment to make their blood clot.
What are inhibitors?
A substance made by the body that attacks factor so it cannot work as well. For example, a Factor VIII (8) inhibitor would keep Factor VIII from working with other factors and platelets to stop bleeding. are a complication of hemophilia. People with severe hemophilia A Hemophilia A
A bleeding disorder caused by lack of Factor VIII (8). It is sometimes called classic or standard hemophilia. or B Hemophilia B
A bleeding disorder caused by lack of Factor IX (9). are usually treated by replacing the missing factor VIII (8) Factor VIII (8)
One of the 13 clotting-factor proteins that helps form blood clots. or factor IX (9) Factor IX (9)
One of the 13 clotting-factor proteins that helps form blood clots. through infusion Infusion
The injection of medicine directly into a vein using a needle and syringe. . For some people, however, this treatment does not work. Their bodies react as though the treatment is an invader and their immune system Immune system
A mechanism within the body used to protect itself from harmful substances. develops antibodies Antibodies
Cells of the immune system that fight and destroy viruses and bacteria that can cause infection. —inhibitors—that attack and neutralize Neutralize
To counteract the effect of something so that it is not capable of producing change. the factor VIII or IX. The neutralized factor Factor
A protein in the blood that helps form blood clots. is not able to stop the bleeding.