| This section of our Web site sponsored by:  |
HEMOPHILIA.ORG
> BLEEDING DISORDERS INFO CENTER > TYPES >
FACTOR X DEFICIENCY
Factor X Deficiency
(Stuart Prower Factor)
What Is It?
Factor X deficiency ranks similarly to factor II as one of the rarest inherited
clotting disorders, with only about 50 reported cases. Factor X 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. People with factor activity that is less than 1% of
normal are susceptible to severe bleeding. Those with 10% or more are only
mildly effected.
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 pregnant women or women with a severe
deficiency and a history of early and recurrent miscarriage.
Inheritance Pattern
This is an extremely rare inherited disorder. It is not sex-linked as is
hemophilia. It affects both males and females with equal frequency. It is
autosomal recessive, which means that if the clotting defect is inherited
from a parent, the child will be a genetic carrier of the condition, but
may or may not have symptoms.
Even more rarely, factor X deficiency may also be acquired, as described
above.
Symptoms and Diagnosis
As mentioned, severity of bleeding complications depend on the level of
factor X clotting activity. Symptoms include:
• nose bleeds
• the loss of blood into joints
• muscle bleeding
• mucous membrane bleeding
• frequent bruising
• gastrointestinal bleeding
• excessive menstrual bleeding
Muscle and intracranial bleeding may be severe. Women with factor X deficiency
may have problems controlling menstrual bleeding and are susceptible to
first-trimester miscarriage.
Diagnostic signs and tests include:
• prolonged prothrombin time
• prolonged partial thromboplastin time
• factor X assay
Treatments
Bleeding episodes are usually managed by infusion of fresh frozen plasma,
factor X concentrates or Prothrombin complex concentrates (PCCs). The half-life
of factor X is 24 to 40 hours.Factor levels of 10% to 40% are considered
the minimum to prevent bleeding.
Complications
Severe bleeding or hemorrhage can occur. Loss of blood may be life threatening.
Disclaimer
The information contained on the NHF web site is provided for your general
information only. NHF does not give medical advice or engage in the practice
of medicine. NHF under no circumstances recommends particular treatment
for specific individuals and in all cases recommends that you consult your
physician or local treatment center before pursuing any course of treatment.
All information and content on this web site
are protected by copyright. All rights are reserved. Users are prohibited
from modifying, copying, distributing, transmitting, displaying, publishing,
selling, licensing, creating derivative works, or using any information
available on or through the site for commercial or public purposes.