In factor X disorder, bleeding ranges from mild to severe. Severity ranges on the level of factor X clotting activity. Women may have severe menstrual bleeding and postpartum hemorrhage. The incidence ranges from 1 out of 500,000 to 1 out of 1,000,000 people. Newborns may present with prolonged bleeding after circumcision.
Some cases are due to reduced or absent synthesis of the molecule.
In other cases, the number of molecules is normal, but they don't work properly. Several genetic variations of factor X deficiency of varying severity have been described. Even more uncommon than the congenital form of factor X deficiency is the acquired form. It has occasionally developed in patients with liver disease, vitamin K deficiency, amyloidosis, myeloma, leprosy, mycoplasma infections, various tumors and exposure to the fungicide methylbromide. Factor X levels have been shown to increase during pregnancy, but aggressive replacement therapy is needed for women in pregnancy for women with a severe deficiency and a history of early and recurrent miscarriage.