Traits

Traits linked to F8

coagulation factor VIII

The Human Phenotype Ontology links 60 traits to F8, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Blood clot in cerebral vein	Always
Blood clot in portal vein	Always
Increased factor VIII activity	Always
Left ventricular thrombus	Always
Recurrent deep vein blood clot	Always
Bleeding tendency	Very often (80–99%)
Bruising susceptibility	Very often (80–99%)
Prolonged partial thromboplastin time	Very often (80–99%)
Reduced factor VIII activity	Very often (80–99%)
Abnormally heavy bleeding during menstruation	Often (30–79%)
Bleeding below the skin	Often (30–79%)
Bleeding gums	Often (30–79%)
Bleeding post-delivery	Often (30–79%)
Bleeding with minor or no trauma	Often (30–79%)
Bleeding within a joint	Often (30–79%)
Blood clot in a deep vein	Often (30–79%)
Bloody nose	Often (30–79%)
Excessive bleeding after minor trauma	Often (30–79%)
Oral cavity bleeding	Often (30–79%)
Prolonged bleeding after dental extraction	Often (30–79%)
Prolonged bleeding after surgery	Often (30–79%)
Prolonged bleeding following procedure	Often (30–79%)
Black feces	Sometimes (5–29%)
Bleeding within the skull	Sometimes (5–29%)
Cephalohematoma	Sometimes (5–29%)
Epidural hemorrhage	Sometimes (5–29%)
Gastrointestinal bleeding	Sometimes (5–29%)
Low number of red blood cells or hemoglobin	Sometimes (5–29%)
Prolonged bleeding following circumcision	Sometimes (5–29%)
Prolonged prothrombin time	Sometimes (5–29%)
Reduced von Willebrand factor activity	Sometimes (5–29%)
Subdural hemorrhage	Sometimes (5–29%)
Vomiting blood	Sometimes (5–29%)
Blood spots	Rarely (1–4%)
Intraventricular hemorrhage	Rarely (1–4%)
Petechiae	Rarely (1–4%)
Spontaneous hematomas	Rarely (1–4%)
Muscle hemorrhage	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Intramuscular hematoma	Often (30–79%)
Cartilage destruction	Sometimes (5–29%)
Disease of the joints	Sometimes (5–29%)
Limb contractures	Sometimes (5–29%)
Limitation of joint mobility	Sometimes (5–29%)
Progressive joint destruction	Sometimes (5–29%)
Synovitis	Sometimes (5–29%)
Degenerative joint disease	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Increased spleen size	Always
Portal hypertension	Always
Splenic infarction	Always
Stroke	Always
Blood clot in artery of lung	Often (30–79%)

Laboratory abnormality

Trait	How often it is seen
Joint swelling	Often (30–79%)
Blood in urine	Sometimes (5–29%)
Bloody urine	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Epilepsy	Always
Headache	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Hip contracture	Rarely (1–4%)

Abnormality of the digestive system

Trait	How often it is seen
Liver failure	Always

Abnormality of the integument

Trait	How often it is seen
Poor wound healing	Often (30–79%)

Constitutional symptom

Trait	How often it is seen
Joint pain	Often (30–79%)

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to F8 and how often each is seen. Find out more at hpo.jax.org.

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