Traits

Traits linked to F9

coagulation factor IX

The Human Phenotype Ontology links 16 traits to F9, 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 a deep vein	Always
Increased factor IX activity	Always
Reduced factor IX activity	Always
Bleeding within a joint	Very often (80–99%)
Bruising susceptibility	Very often (80–99%)
Excessive bleeding after minor trauma	Very often (80–99%)
Black feces	Sometimes (5–29%)
Bloody nose	Sometimes (5–29%)
Petechiae	Sometimes (5–29%)
Vomiting blood	Sometimes (5–29%)
Gastrointestinal bleeding	Not recorded
Hypercoagulability	Not recorded
Prolonged partial thromboplastin time	Not recorded
Prolonged whole-blood clotting time	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Degenerative joint disease	Not recorded

Laboratory abnormality

Trait	How often it is seen
Blood in urine	Sometimes (5–29%)

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 F9 and how often each is seen. Find out more at hpo.jax.org.

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