3. Factor IX deficiency.
As mentioned above, there are supposed to be a total of 13 clotting factors, or proteins, within the blood. These factors work together with platelets to form a clot over the sigh of a wound, and this clot slows down and eventually stops bleeding. A mutation in any of these clotting factors can lead to hemophilia. The blood clotting factor, Factor VIII, isn’t the only factor that can become mutated; so can Factor IX.
A mutation of Factor IX is referred to as hemophilia B, or Christmas disease. Like hemophilia A, hemophilia B is inherited; a parent who carries a mutated Factor IX gene can pass it onto their children.
Fathers who pass it ono their children may exhibit symptoms of the bleeding disorder, while mothers who pass it on usually don’t exhibit symptoms. Furthermore, male children are more likely to develop symptoms of hemophilia B.