4. Factor XI deficiency.
Factor XI is another one of the 13 clotting factors or proteins within the blood, that can become mutated. Like a mutation or deficiency of Factor VIII and Factor IX can be passed on from parents to children, so can a mutation or deficiency of Factor XI. A deficiency of Factor XI is referred to as hemophilia C. It is an extremely rare form of hemophilia, and it is a mild form of this bleeding disorder.
Again, mothers who pass on the mutated gene to their children usually do not present symptoms of the condition, while fathers who pass on the mutated gene may exhibit symptoms; additionally, male children who inherit a Factor XI mutation are more likely to experience symptoms of hemophilia C than female children.
Typically, severe bleeding will only occur after trauma, not spontaneously, as is the case with hemophilia A and B.