What Is Factor IX?

Factor IX is a molecule that plays a role in the blood clotting system. When a person loses blood from a cut, the body sets a special system in action. This involves different molecules signaling to each other, telling other substances to block up the source of bleeding and prevent further blood loss. People without efficient Factor IX cannot produce normal clots, and so can suffer from uncontrolled bleeding.

Blood clotting happens because many different molecules and cells work together to coagulate, or clot, the free-flowing blood at the affected site. Many of the molecules that act in this system are known as blood clotting factors, and Factor IX is just one of them. This is an enzyme, which means that it helps reactions to take place, and also helps substances to become modified into other substances.

The origin of Factor IX is in the cells of the liver. Here the molecule is produced in an early form and other molecules and enzymes, such as Vitamin K, act on it to alter it into a form suitable to circulate in blood. After the liver sends the Factor IX out into the blood, the molecule has a half-life of about one day, which means that half of new Factor IXs degrade within 24 hours.

Only when a person begins to bleed does the blood clotting process begin. Signals from the body activate other factors in the system, which in turn activate Factor IX. The exact molecules that turn the factor on are activated Factor VII and Factor XI. When these molecules work on Factor IX to tell it to begin its own work in the process, the result is that Factor IX then turns on the activity of another factor called Factor X.

All of these factors are essential to normal blood clotting, and the absence of one factor means that the body does not properly stop bleeding. The gene that codes for this particular factor is on the X chromosome, which helps to dictate gender. Women have two X chromosomes, and men have one X and one Y.

When a mutated form of the gene is present on a chromosome, it can cause a condition called Hemophilia B. Usually, one normal gene can make up for a mutated gene, which is the reason why men suffer from the disease and women usually do not. Treatment for the disorder requires that the person take artificial preparation of the factor, in order to replace the missing substance and prevent risks from uncontrolled bleeding.