Is Factor X Deficiency?
Factor X deficiency, also called Stuart-Prower factor deficiency,
is a condition caused by not having enough of the protein known as factor X in
your blood. Factor X plays a role in blood clotting, also called coagulation,
which helps you to stop bleeding. Known as coagulation factors, several crucial
proteins, including factor X, are involved in helping the blood to clot. If you
are missing one or do not have enough, there is a greater chance that you will
continue bleeding once you start.
The disorder may be passed down in families through genes (inherited
factor X deficiency) but can also be caused by certain medications or another
medical condition (acquired factor X deficiency). Inherited factor X deficiency
cannot be cured. Treatment may involve getting transfusions to add clotting
factors to your blood. To treat acquired factor X deficiency, your doctor will
adjust or change your medication or address your underlying condition.
The outlook is generally good, but sometimes severe bleeding can
Are the Symptoms of Factor X Deficiency?
Factor X deficiency can be mild or severe, depending on how much
of the protein your blood contains.
Symptoms of mild factor X deficiency may include:
- bruising easily
- bleeding from the mouth
- excessive bleeding during or after trauma or
More severe cases of the disorder often involve spontaneous
episodes of both internal and external bleeding. Symptoms may include:
- joint bleeding
- muscle bleeding
- gastrointestinal bleeding
- hematomas (masses of clotted blood that form
when a blood vessel breaks)
Very serious symptoms that are possible include:
- spontaneous bleeding in the brain
- bleeding into the spinal cord
Women with the deficiency may experience heavy bleeding during
menstruation (periods). Factor X-deficient women who become pregnant are at
high risk for miscarriage during the first trimester and severe bleeding during
and after delivery.
Factor X Deficiency and Newborns
Babies born with inherited factor X deficiency may have symptoms
such as excess bleeding at the site of the umbilical stump. Boys may bleed for
longer than normal following circumcision. Some babies are born with a vitamin
K deficiency, which may cause similar symptoms. This can usually be treated
with a single vitamin K shot.
Are the Causes of Factor X Deficiency?
Factor X deficiency is generally classified by what causes it.
Inherited Factor X Deficiency
Inherited factor X deficiency is very rare. An inherited disorder
is passed down from parents to children through genes. This type of factor X
deficiency occurs when one of the genes is defective. The risk of parents
giving it to their child is the same for both male and female children. The
inherited type is estimated to occur in about one of every 500,000 people.
Acquired Factor X Deficiency
Acquired factor X deficiency is more common. You can get acquired
factor X deficiency from a deficiency in vitamin K. Your body needs vitamin K
to produce coagulation factors. Certain medications that inhibit clotting in
the blood and blood vessels, such as warfarin or Coumadin, can also cause
acquired factor X deficiency. These medications are called anticoagulants.
Other illnesses that may result in acquired factor X deficiency
include severe liver disease and amyloidosis. Amyloidosis is a disorder in
which abnormal protein buildup causes poor function in your tissues and organs.
The cause of amyloidosis is unknown.
Is Factor X Deficiency Diagnosed?
Factor X deficiency is diagnosed through a blood test called a
factor X assay. The test measures the activity of factor X in your blood. Tell
your doctor if you are taking any medications or have any other diseases or
conditions before taking this test.
Your doctor may order other tests that are not specific to factor
X but measure the time it takes for your blood to clot. These include:
- prothrombin time
(PT) test, which determines how long it takes plasma (the liquid part of
blood) to clot. It measures the response of some of the coagulation factors,
including factor X.
thromboplastin time, which also determines clotting time but measures the
response of the other coagulation factors not covered by a PT test. The two
tests are often done together.
- thrombin time,
which evaluates how long it takes for two specific coagulation factors (thrombin
and fibrinogen) to interact and form a clot.
These tests are used to determine if your bleeding is caused by
problems with clotting. They are often used in combination to monitor patients
taking blood-thinning medications such as warfarin.
Is Factor X Deficiency Treated?
Managing and treating inherited factor X deficiency involves
blood infusions of plasma or a concentrate of clotting factors.
In October 2015, the U.S.
Food and Drug Administration approved a factor X concentrate called
Coagadex. This drug is specifically meant to treat people who have inherited
factor X deficiency. It is the first coagulation factor replacement therapy
available, and it increases the limited treatment options that are available
for people with this condition.
If you have acquired factor X deficiency, your doctor will design
your treatment plan around the underlying condition that is causing the factor
Some conditions that cause factor X deficiency, such as a vitamin
K deficiency, can be treated with vitamin supplements. Other conditions, such
as amyloidosis, have no cure. The goal of your treatment is to manage your
Can Be Expected Over Time?
If the condition is caused by another disease, the outlook for
acquired factor X deficiency will depend on treatment for that particular
disease. People with amyloidosis may need surgery to take out their spleen.
In some cases, sudden or severe bleeding can occur despite
treatment. Women who wish to become pregnant should be aware of the risks of
miscarriage and severe bleeding during delivery and after the baby is born.