Factor 5 Deficiency: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Factor 5 Deficiency?
A hematologist, a doctor who treats blood disorders, is the specialist who usually cares for people with factor 5 deficiency. Your regular doctor can help spot the problem and send you to one. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is factor 5 deficiency?
Factor 5 deficiency, also called factor V deficiency, is a rare bleeding disorder. It is passed down through families. It affects the ability of the blood to clot.
Blood needs special proteins, called clotting factors, to form clots and stop bleeding. In this condition, the body lacks factor V, so blood does not clot properly. Other names are Owren disease and parahemophilia. It is similar to hemophilia, except bleeding into joints is less common. It affects an estimated 1 in 1 million people.
Symptoms
Symptoms can begin at any age. The most severe cases are clear in childhood. Common signs include:
- Nosebleeds.
- Easy bruising.
- Bleeding under the skin.
- Bleeding of the gums.
- Heavy or long menstrual periods.
- Heavy bleeding after surgery, an injury, or childbirth.
- Bleeding from the umbilical stump, the part of the umbilical cord left on a newborn.
Bleeding into the joints can happen, but it is rare. People who are severely affected have a higher risk of bleeding inside the skull, in the lungs, or in the digestive tract. This kind of bleeding can be life-threatening.
Causes and who gets it
Factor 5 deficiency is usually caused by changes in the F5 gene. This gene gives the body instructions for making factor V. People with this condition typically have less than 10 percent of the normal amount of factor V in their blood.
The usual form is inherited in an autosomal recessive pattern. This means both copies of the F5 gene in each cell have changes. A person with a change in only one copy has less factor V and can have mild bleeding problems. Most such people have no related health effects. A family history of a bleeding disorder is a risk factor.
Rarely, the body makes antibodies, which are proteins that normally fight germs, that attack factor V. This acquired form can follow childbirth, surgery, or treatment with a certain type of fibrin glue. It can also occur with autoimmune diseases and certain cancers. Sometimes the cause is unknown. The condition is more common in countries such as Iran and southern India.
How doctors diagnose it
Doctors start with a physical exam and your health history. Blood tests can then check for a bleeding disorder. Tests that detect factor V deficiency include:
- A factor V assay, a test that measures how much factor V is in the blood.
- Blood clotting tests, including partial thromboplastin time (PTT) and prothrombin time (PT).
- A bleeding time test.
Treatment
During a bleeding episode or after surgery, people are given fresh blood plasma or fresh frozen plasma by infusion. Plasma is the liquid part of blood. These treatments correct the deficiency for a short time.
Treatment for bleeding disorders depends on the cause. It may include medicines and transfusions of blood, platelets, or clotting factor. The outlook is good with diagnosis and proper treatment.
When to see a doctor
Call 911 or go to the emergency room if you have bleeding that will not stop, vomiting or coughing up blood, a head or spine injury, confusion, or fainting. Severe bleeding could occur with this condition.
Talk with a doctor about nosebleeds, easy bruising, or heavy periods that worry you, especially if bleeding disorders run in your family.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A doctor in this kind of practice can review your bleeding symptoms and family history. They can order first blood tests and help coordinate care with a hematologist.
Common questions
Is factor 5 deficiency inherited?
Yes, the usual form is inherited. It follows an autosomal recessive pattern, which means both copies of the F5 gene in each cell have changes. A rare acquired form can develop later, when antibodies attack factor V.
How common is factor 5 deficiency?
It is rare. It affects an estimated 1 in 1 million people. It is more common in countries such as Iran and southern India.
Can factor 5 deficiency be prevented?
No, there is no known way to prevent this disorder.
What is the outlook for factor 5 deficiency?
The outlook is good with diagnosis and proper treatment. Severe bleeding could still occur, so know the warning signs and get care when you need it.
Sources
- MedlinePlus Genetics - Factor V deficiency
- MedlinePlus - Factor V deficiency
- MedlinePlus - Bleeding Disorders
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
