Posted by Leanne Kodsmann on
Factor IX is one of the proteins that play a role in coagulation. Produced in the liver and activated by Factor XIa or Factor VIIa, depending on whether the coagulation cascade is following the contact activation pathway or the tissue factor pathway, it then catalyzes the next reaction in the cascade continuing down the path toward clot formation. Factor IX deficiency results in Hemophilia B, a clotting disorder that prevents the blood from clotting appropriately.
What is Factor IX and what does it do?
Factor IX, also referred to as Christmas Factor and sometimes called Coagulation Factor IX or F9, is a serine protease that is produced as an inactive enzyme precursor called a zymogen, and plays a role in blood coagulation. Factor IX is a Vitamin K-Dependent protein, meaning that Vitamin K is necessary for the body to generate functionally active Factor IX. It is produced in the liver and circulates in the bloodstream in its inactive zymogen form until the coagulation cascade is triggered.
When this happens, Factor IX is cleaved at the reactive peptide bond, resulting in both a heavy chain and a light chain that can then form a complex with Factor VIII, calcium ions, and membrane phospholipids. This complex will catalyze the next step in the chain of chemical reactions that ultimately leads to the formation of a blood clot.
What is Factor IX deficiency and how is it involved in disease?
Factor IX deficiency results in the condition known as Hemophilia B. Hemophilia B is also called Christmas Disease, after a young boy with the last name Christmas who was found to have a Factor IX deficiency in the early 1950s. This deficiency was discovered to be the root cause for his hemophilia.
Hemophilia B is a clotting disorder that results from the genetic deficiency of Factor IX. While this condition can be inherited genetically, roughly 33% of Hemophilia B is caused by spontaneous mutation and is not directly passed from a parent to a child.
Hemophilia B is an X-linked recessive disorder, so if a son inherits a hemophilia-carrying X chromosome from his mother he will present with hemophilia B. A daughter would need to inherit a hemophilia-carrying X chromosome from both her mother and her father, and because of this, hemophilia B is less likely to occur in female children. A daughter who inherits only one hemophilia-carrying X chromosome will not have this disorder, but she will be a carrier and can pass this gene on to her children.
Individuals with Hemophilia B bleed for a longer time than those without a bleeding or clotting condition. Under normal circumstances, when some form of tissue trauma occurs, Factor IX is activated and then activates Factor X in turn, continuing the series of chemical reactions that eventually result in the formation of a blood clot. Without Factor IX, the coagulation cascade is interrupted and this results in continued bleeding, as the body is unable to form a proper clot as it normally would.
With more than 100 mutations of the Factor IX gene discovered so far, some mutations cause no symptoms. Many, however, lead to significant bleeding disorders like Hemophilia B. Some uncommon mutations of Factor IX can result in increased clotting (the opposite of Hemophilia B), and can contribute to diseases like deep vein thrombosis (DVT).
Supporting Factor IX Research
Innovative Research, Inc. has a wide range of Factor IX products available from many species, including purified proteins, polyclonal and monoclonal antibodies, and ELISA Kits.
Not only that, but we offer a line of Factor IX Mouse Knockout products. These are collected from mice with targeted disruption of F9, with male hemizygotes displaying a severe Hemophilia B phenotype. We have Mouse Factor IX Knockout (genetically deficient) plasma available, as well as whole organs, lyophilized organs, and tissue lysates. We also offer the live knockout mouse model.