Traits

Traits linked to GPT2

glutamic--pyruvic transaminase 2

The Human Phenotype Ontology links 34 traits to GPT2, 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
Absent speech development	Always
Global developmental delay	Always
Intellectual disability	Always
Difficulty articulating speech	Very often (80–99%)
Increased reflexes	Very often (80–99%)
Abnormal gait	Often (30–79%)
Babinski sign	Often (30–79%)
Brief seizures with staring spells	Often (30–79%)
Delayed speech and language development	Often (30–79%)
Epilepsy	Often (30–79%)
Grand mal seizures	Often (30–79%)
Wide based walk	Often (30–79%)
Abnormal CNS myelination	Sometimes (5–29%)
Febrile seizure (within the age range of 3 months to 6 years)	Sometimes (5–29%)
Tremor	Sometimes (5–29%)
Underdevelopment of part of brain called corpus callosum	Sometimes (5–29%)
Encephalopathy	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Development of small head that was not present at birth	Always
Abnormally small head	Very often (80–99%)
Drooling	Very often (80–99%)
Eye folds	Often (30–79%)
High palate	Often (30–79%)
Narrow forehead	Often (30–79%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Very often (80–99%)
Spasticity and rigidity of muscles	Very often (80–99%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Severely decreased muscle tone	Often (30–79%)
Spastic paraplegia	Often (30–79%)
Flexed joint that cannot be straightened	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Ears rotated toward back of head	Often (30–79%)
Low-set ears	Often (30–79%)

Abnormality of the digestive system

Trait	How often it is seen
Nasogastric tube feeding in infancy	Often (30–79%)

Abnormality of the eye

Trait	How often it is seen
Abnormally close eyes	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Faltering weight	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 GPT2 and how often each is seen. Find out more at hpo.jax.org.

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