Traits

Traits linked to TCP1

t-complex 1

The Human Phenotype Ontology links 35 traits to TCP1, 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
Bilateral perisylvian polymicrogyria	Always
Delayed speech and language development	Always
Focal impaired awareness seizure	Always
Grand mal seizures	Always
Intellectual disability, mild	Always
Interictal epileptiform activity	Always
Moderate global developmental delay	Always
Multifocal epileptiform discharges	Always
Nocturnal seizures	Always
Pain insensitivity	Always
Periventricular heterotopia	Always
Seizure affecting one half of brain	Always
Twitching	Always
Weakness of one side of body	Always
More grooves in brain	Very often (80–99%)
Epilepsy	Often (30–79%)
Global developmental delay	Often (30–79%)
Gray matter heterotopia	Often (30–79%)
Hyperintensity of cerebral white matter on MRI	Often (30–79%)
Intellectual disability	Often (30–79%)
Ventriculomegaly	Often (30–79%)

Abnormality of head or neck

Trait	How often it is seen
Broad opening between the eyelids	Always
Dental crowding	Always
Fullness around the eyes	Always
High palate	Always
Highly arched eyebrow	Always
Little lower jaw	Always
Smooth philtrum	Always
Upward slanting of the opening between the eyelids	Always
Abnormally small head	Often (30–79%)
Big calvaria	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Jaundice	Always

Abnormality of the eye

Trait	How often it is seen
Visual impairment	Sometimes (5–29%)

Abnormality of the immune system

Trait	How often it is seen
Cow milk allergy	Always

Growth abnormality

Trait	How often it is seen
Faltering weight	Always

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 TCP1 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