What are other Names for this Condition? (Also know as/Synonyms)

• Congenital Stuart Factor Deficiency
• F10 Deficiency
• Stuart-Prower Factor Deficiency

What is Factor X Deficiency? (Definition/Background Information)

• Factor X Deficiency is a rare bleeding disorder, caused by the deficiency of coagulation factor X. The deficiency of factor X leads to prolonged and increased bleeding in affected individuals
• Factor X (F X or factor 10) is one of the 12 clotting factors that are labeled factors I to XIII (factors V and VI actually denote the same clotting factor)
• Clotting factors are proteins that help form blood clots at the site of a blood vessel injury. A blood clot stops further blood loss and allows the blood vessel to continue functioning
• There are two subtypes of Factor X Deficiency, namely:
  • Inherited Factor X Deficiency, caused by mutation(s) in the F10 gene
  • Acquired Factor X Deficiency that arises due to liver disease, systemic amyloidosis, vitamin K deficiency, or from the use of anticoagulant drugs
• The severity of the condition varies from individual to individual, and can range from an absence of symptoms to even life-threatening complications
• Factor X Deficiency can be treated with fresh frozen plasma, or prothrombin complex concentrate containing factor X
• Regular and continued management of Factor X Deficiency may lead to good outcomes. However, the prognosis may be guarded, if complications, such as severe internal bleeding, develop

Who gets Factor X Deficiency? (Age and Sex Distribution)

• Factor X Deficiency is a rare bleeding disorder occurring at a frequency of 1:1,000,000
• The manifestation of symptoms may occur at birth, during childhood, or into adulthood
• Both males and females may be affected by this disorder
• The disorder is reported to occur without any racial or ethnic bias

What are the Risk Factors for Factor X Deficiency? (Predisposing Factors)

The risk factors for Factor X Deficiency may include:

• A family history of the disorder
• Pre-existing conditions such as the following:
  • Liver disease
  • Vitamin K deficiency
  • Systemic amyloidosis
  • Use of blood thinners 

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Factor X Deficiency? (Etiology)

Inherited Factor X Deficiency is caused by mutations in the F10 gene.

• The F10 gene codes for coagulation factor 10, an enzyme (serine endopeptidase) that plays a crucial role in the common clotting pathway
• When the F10 gene is mutated, the F10 protein levels are either depleted or not functional, leading to a manifestation of the symptoms
• Factor X Deficiency is inherited in an autosomal recessive manner. In this type of inheritance, an individual must possess both copies of the causative F7 gene in the defective form in each of his/her body’s cells for the disorder to occur. An affected individual inherits a single defective copy of the gene from each parent. Typically, parents are unaffected by the disorder and are known as “carriers”

Acquired Factor X Deficiency may also be caused by the following conditions/factors:

• Liver disease, since liver is the site of factor X production
• Vitamin K deficiency: Vitamin K helps in keeping clotting factors at optimum levels in the body; vitamin K is necessary for the synthesis of factor X
• Systemic amyloidosis: It is a condition in which an excessive buildup of amyloid protein in the body’s tissues becomes toxic; these deposits absorb free factor X
• Use of blood thinners, which interfere with blood clotting

The following is the sequence of events that lead to blood clotting:

• The clotting process starts with injury to a blood vessel, which causes it to constrict. Called the vascular phase, this is the first reaction of a blood vessel to damage. Constriction of a blood vessel reduces the flow of blood to the site of injury, which minimizes blood loss
• Next, the circulating platelets clump along the site of blood vessel injury. The platelets form a foundation for a blood clot and release chemicals that stimulate clotting
• The coagulation phase then causes a blood clot to form. Clotting occurs when an enzyme, called thrombin, converts a soluble protein fibrinogen, into its insoluble form, fibrin. Fibrin proteins make up the bulk of a blood clot
• Thrombin is activated by the merging of two pathways, called the intrinsic and extrinsic pathways, into the common pathway. These are initiated by different parts of the body after blood vessel damage:
  • The intrinsic pathway begins in blood with the activation of circulating proteins
  • The extrinsic pathway begins in the blood vessel with the release of protein factors by damaged cells lining the vessel
• The extrinsic pathway is the first to activate. The intrinsic pathway then reinforces the extrinsic pathway and provides longer-lasting clotting effects

Coagulation factor X is crucial for the first step of the common pathway of clotting. Each factor in the clotting pathway is crucial to reactions that begin the clotting process, and are central to the action of these pathways. Each factor activates the next in a stepwise manner.

What are the Signs and Symptoms of Factor X Deficiency?

The signs and symptoms of Factor X Deficiency may vary from mild to severe. Typically, the lesser the amount of F10 protein present in blood, the more severe is the symptoms.

The signs and symptoms of Factor X Deficiency may include:

• Bleeding from the umbilical stump in newborns (soon after birth)
• Frequent and easy bruising
• Subcutaneous bleeding (bleeding under the skin)
• Bleeding for a long time after a cut, such as after a circumcision 
• Nosebleeds
• Bleeding from the gums
• Bleeding in the mouth, particularly following dental procedures
• Heavy bleeding after an injury
• Abnormal bleeding during or after (minor) surgery
• Heavy and prolonged menstrual bleeding in women
• Heavy bleeding during childbirth in women
• Blood in urine (in rare cases)

In addition to the above, in severe cases, the following signs and symptoms may occur:

• Bleeding in the gastrointestinal tract, causing:
  • Abdominal pain
  • Black, tarry stools
  • Weakness
  • Lightheadedness
• Bleeding in the muscles, causing:
  • Severe pain
  • Difficulty in moving the affected muscle tissue
  • Loss of sensation in the affected area
• Bleeding in the joints (hemarthrosis), which may cause the following:
  • Swelling
  • Stiffness and pain
  • Tingling sensation
  • The joint may feel warm to touch
• Bleeding in the central nervous system, including the spinal cord and brain, which may cause:
  • Headaches
  • Seizures
  • Numbness
  • Nausea and vomiting
  • Vision changes
  • Confusion

In cases with Acquired Factor X Deficiency, the signs and symptoms may include those of the pre-existing condition that caused Factor X Deficiency.

How is Factor X Deficiency Diagnosed?

The diagnosis of Factor X Deficiency is made on the basis of the following tools:

• A complete physical examination
• Assessment of signs and symptoms
• Evaluation of one’s personal and family medical history
• Blood tests to measure time taken for clot formation, which include:
  • Serum prothrombin or PT time test
  • Prolonged thrombin test
  • Partial thromboplastin time (PTT) test
  • Factor X levels and assay for factor X activity
• Liver function test
• Imaging tests to check for internal bleeding of the gastrointestinal tract or brain:
  • Ultrasound imaging of the affected region
  • Computed tomography and/or magnetic resonance imaging (MRI) of the affected region
• In addition, if Factor X Deficiency is acquired, relevant tests pertaining to pre-existing conditions may be necessary

Note:

Certain medications that one is currently taking may influence the outcome of the lab tests. Hence, it is important to inform the healthcare provider of the complete list of medications (including any herbal supplements) one is taking. This will help the healthcare provider interpret the test results more accurately and avoid unnecessary chances of a misdiagnosis.

The laboratory test results are NOT to be interpreted as results of a “stand-alone” test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. The healthcare providers will explain the meaning of the test results, based on the overall clinical scenario.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Factor X Deficiency?

The complications of Factor X Deficiency arise from the excessive bleeding that occurs internally, and they include:

• Spontaneous miscarriages in the first trimester
• Anemia from excessive bleeding
• Problems with movement owing to pain in muscles and joints
• Increased incidence of stroke
• Deep vein thrombosis
• Spontaneous and excessive bleeding

How is Factor X Deficiency Treated?

The treatment methods for Factor X Deficiency are specific to an individual. It is also based on the cause and severity of the presenting symptoms. In some cases, prophylactic treatment may be necessary, in order to prevent bleeding in the brain.

The treatment options may include:

• Frozen plasma
• Prothrombin complex concentrate rich in factor X
• Human factor X, for inherited forms of Factor X Deficiency
• In women, the following methods may be adopted to avoid excessive bleeding during menstruation
  • Use of intra-uterine contraceptive devices
  • Contraceptive pills for controlling
  • Antifibrinolytic drugs, such as aminocaproic acid
• Vitamin K supplements, for vitamin K deficiency causing acquired Factor X Deficiency
• Medications and/or surgery for liver dysfunction and consequent acquired Factor X Deficiency, based upon the individual’s specific health condition
• Medication and/or surgery for treatment of systemic amyloidosis
• Discontinuing blood-thinning medications

How is Factor X Deficiency Prevented?

At the present time, no preventive methods or guidelines are available for the prevention of inherited Factor X Deficiency disorders.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited genetic disorders such as Factor X Deficiency
• The acquired form of Factor X Deficiency can be addressed through proper treatment of the causative (pre-existing) condition 
• Avoiding blood thinners known to cause this bleeding disorder may help prevent severe bleeding symptoms

Regular medical screening at periodic intervals with tests and physical examinations are strongly recommended in individuals who have been diagnosed with Factor X Deficiency.

What is the Prognosis of Factor X Deficiency? (Outcomes/Resolutions)

The prognosis of Factor X Deficiency is determined by whether the condition is genetic or acquired, the severity of the symptoms, age of manifestation of the disorder, the overall health of an affected individual, and his/her response to treatment.

• With an early diagnosis and prompt treatment, individuals with inherited Factor X Deficiency may have good outcomes
• However, complications, such as bleeding in the gastrointestinal tract and brain, may be life-threatening
• Additionally, if Factor X Deficiency occurs secondary to a pre-existing condition (acquired), then the outcome may be determined by the severity of the underlying disorder

Additional and relevant information for Factor X Deficiency:

Factor X Deficiency was first described in the medical literature in 1957 in a male patient who was called Mr. Prower.