Factor V deficiency

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Factor V deficiency is a rare bleeding disorder. The signs and symptoms of this condition can begin at any age, although the most severe cases are apparent in childhood. Factor V deficiency commonly causes nosebleeds; easy bruising; bleeding under the skin; bleeding of the gums; and prolonged or excessive bleeding following surgery, trauma, or childbirth. Women with factor V deficiency can have heavy or prolonged menstrual bleeding (menorrhagia). Bleeding into joint spaces (hemarthrosis) can also occur, although it is rare. Severely affected individuals have an increased risk of bleeding inside the skull (intracranial hemorrhage), in the lungs (pulmonary hemorrhage), or in the gastrointestinal tract, which can be life-threatening.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Factor V deficiency is usually caused by mutations in the F5 gene, which provides instructions for making a protein called coagulation factor V. This protein plays a critical role in the coagulation system, which is a series of chemical reactions that forms blood clots in response to injury. F5 gene mutations that cause factor V deficiency prevent the production of functional coagulation factor V or severely reduce the amount of the protein in the bloodstream. People with this condition typically have less than 10 percent of normal levels of coagulation factor V in their blood; the most severely affected individuals have less than 1 percent. A reduced amount of functional coagulation factor V prevents blood from clotting normally, causing episodes of abnormal bleeding that can be severe.

Very rarely, a form of factor V deficiency is caused by abnormal antibodies that recognize coagulation factor V. Antibodies normally attach (bind) to specific foreign particles and germs, marking them for destruction, but the antibodies in this form of factor V deficiency attack a normal human protein, leading to its inactivation. These cases are called acquired factor V deficiency and usually occur in individuals who have been treated with substances that stimulate the production of anti-factor V antibodies, such as bovine thrombin used during surgical procedures. There is no known genetic cause for this form of the condition.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Factor V deficiency is inherited in an autosomal recessive pattern, which means both copies of the F5 gene in each cell have mutations. Individuals with a mutation in a single copy of the F5 gene have a reduced amount of coagulation factor V in their blood and can have mild bleeding problems, although most have no related health effects.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Factor V deficiency affects an estimated 1 in 1 million people. This condition is more common in countries such as Iran and southern India, where it occurs up to ten times more frequently than in western countries.

Understanding terms used in the source

These definitions explain medical words used above. A definition is not evidence that another condition is present, and it does not predict how a symptom will develop. Ask the clinician which terms apply to the actual examination or test result.

Abnormal bleeding

An abnormal susceptibility to bleeding, often referred to as a bleeding diathesis. A bleeding diathesis may be related to vascular, platelet and coagulation defects.

Menorrhagia

Prolonged and excessive menses at regular intervals in excess of 80 mL or lasting longer than 7 days.

Prolonged

Applied to an abnormality whose duration is extended over a longer period of time than is expected or usual (e.g., prolonged fever lasts longer than one usually sees with an infection).

Affected

This term applies to a family member who is diagnosed with the same condition as the individual who is the primary focus of investigation (the proband).

Which doctor should you see?

The suggested department for discussing Factor V deficiency is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Factor V deficiency. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.