Traits

Traits linked to ITPA

inosine triphosphatase

The Human Phenotype Ontology links 18 traits to ITPA, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the nervous system

Trait	How often it is seen
Epilepsy	Always
Global developmental delay	Always
Brain degeneration	Not recorded
Degeneration of cerebrum	Not recorded
Delayed CNS myelination	Not recorded
Encephalopathy	Not recorded
High pitched voice	Not recorded
Irritability	Not recorded
Limb tremor	Not recorded
Repeated seizures without recovery between them	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Elevated erythrocyte inosine triphosphate concentration	Always
Reduced erythrocyte inosine triphosphatase activity	Always

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Disease of the heart muscle	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Very often (80–99%)

Abnormality of the eye

Trait	How often it is seen
Clouding of the lens of the eye	Often (30–79%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Severely decreased muscle tone	Not recorded

Growth abnormality

Trait	How often it is seen
Prenatal growth deficiency	Not recorded

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

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