Factor X deficiency ranks with factor II as one of the rarest inherited clotting disorders, with only about 50 reported cases. It is a vitamin K-dependent clotting factor in the blood. It was first discovered in a man named Stuart from the mountains of North Carolina. He was originally thought to have factor VII deficiency, but then a woman named Prower was found to have a similar clotting abnormality and the new factor X was discovered. 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.