Traits

Traits linked to GP1BA

glycoprotein Ib platelet subunit alpha

The Human Phenotype Ontology links 45 traits to GP1BA, 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
Abnormally heavy bleeding during menstruation	Always
Impaired ristocetin-induced platelet aggregation	Always
Large platelets	Always
Low platelet count	Always
Macrothrombocytopenia	Always
Neonatal alloimmune thrombocytopenia	Always
Prolonged bleeding after dental extraction	Always
Bleeding tendency	Very often (80–99%)
Decreased platelet glycoprotein Ib-IX-V	Very often (80–99%)
Giant platelets	Very often (80–99%)
Blood spots	Often (30–79%)
Bloody nose	Often (30–79%)
Cephalohematoma	Often (30–79%)
Gastrointestinal bleeding	Often (30–79%)
Petechiae	Often (30–79%)
Platelet anisocytosis	Often (30–79%)
Recurring nosebleed	Often (30–79%)
Spontaneous hematomas	Often (30–79%)
Abnormal megakaryocyte morphology	Sometimes (5–29%)
Black feces	Sometimes (5–29%)
Bleeding gums	Sometimes (5–29%)
Bleeding within the skull	Sometimes (5–29%)
Bruising susceptibility	Sometimes (5–29%)
Ecchymosis	Sometimes (5–29%)
Prolonged bleeding after surgery	Sometimes (5–29%)
Vomiting blood	Sometimes (5–29%)
Subarachnoid hemorrhage	Rarely (1–4%)
Hemolytic anemia	Not recorded
Intermittent thrombocytopenia	Not recorded
Prolonged bleeding time	Not recorded
Stomatocytosis	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Abnormality of the nervous system	Rarely (1–4%)
Cerebral palsy	Rarely (1–4%)
Epilepsy	Rarely (1–4%)
Global developmental delay	Rarely (1–4%)
Migraine	Rarely (1–4%)

Abnormality of the eye

Trait	How often it is seen
Blindness	Rarely (1–4%)
Nonarteritic anterior ischemic optic neuropathy	Not recorded

Laboratory abnormality

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

Abnormality of the cardiovascular system

Trait	How often it is seen
Increased spleen size	Not recorded

Abnormality of the digestive system

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

Abnormality of the ear

Trait	How often it is seen
Bilateral sensorineural hearing impairment	Rarely (1–4%)

Abnormality of the genitourinary system

Trait	How often it is seen
Abnormal uterus bleeding	Sometimes (5–29%)

Abnormality of the immune system

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

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 GP1BA 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