Traits

Traits linked to GP9

glycoprotein IX platelet

The Human Phenotype Ontology links 25 traits to GP9, 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
Impaired ristocetin-induced platelet aggregation	Always
Low platelet count	Always
Macrothrombocytopenia	Always
Bleeding tendency	Very often (80–99%)
Decreased platelet glycoprotein Ib-IX-V	Very often (80–99%)
Giant platelets	Very often (80–99%)
Abnormally heavy bleeding during menstruation	Often (30–79%)
Gastrointestinal bleeding	Often (30–79%)
Petechiae	Often (30–79%)
Prolonged bleeding after dental extraction	Often (30–79%)
Recurring nosebleed	Often (30–79%)
Spontaneous hematomas	Often (30–79%)
Abnormal megakaryocyte morphology	Sometimes (5–29%)
Bleeding gums	Sometimes (5–29%)
Bruising susceptibility	Sometimes (5–29%)
Prolonged bleeding after surgery	Sometimes (5–29%)
Vomiting blood	Sometimes (5–29%)
Blood spots	Not recorded
Bloody nose	Not recorded
Prolonged bleeding time	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Epilepsy	Rarely (1–4%)
Migraine	Rarely (1–4%)

Abnormality of the digestive system

Trait	How often it is seen
Partially duplicated kidney	Rarely (1–4%)

Abnormality of the immune system

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

Laboratory abnormality

Trait	How often it is seen
Bloody 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 GP9 and how often each is seen. Find out more at hpo.jax.org.

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test