Traits

Traits linked to FOXG1

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The Human Phenotype Ontology links 101 traits to FOXG1, 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
Delayed ability to sit	Always
Delayed ability to walk	Always
Delayed speech and language development	Always
Global developmental delay	Always
Intellectual disability, severe	Always
Poor social interactions	Always
Seizure affecting one half of brain	Always
Simplified gyral pattern	Always
Underdeveloped frontal lobe	Always
Encephalopathy	Very often (80–99%)
Epilepsy	Very often (80–99%)
Loss of developmental milestones	Very often (80–99%)
Repetitive movements	Very often (80–99%)
Underdevelopment of part of brain called corpus callosum	Very often (80–99%)
Abnormality of coordination	Often (30–79%)
Agenesis of corpus callosum	Often (30–79%)
Decreased reflex response	Often (30–79%)
Difficulty sleeping	Often (30–79%)
EEG abnormality	Often (30–79%)
EEG with multifocal slow activity	Often (30–79%)
Inappropriate crying	Often (30–79%)
Intellectual disability	Often (30–79%)
Irritability	Often (30–79%)
Teeth grinding	Often (30–79%)
Abnormal corpus callosum morphology	Sometimes (5–29%)
Abnormal gait	Sometimes (5–29%)
Abnormal myelination	Sometimes (5–29%)
Ataxia	Sometimes (5–29%)
Attention deficit	Sometimes (5–29%)
Autism	Sometimes (5–29%)
Behavioral abnormality	Sometimes (5–29%)
Brain degeneration	Sometimes (5–29%)
Degeneration of cerebrum	Sometimes (5–29%)
Delayed CNS myelination	Sometimes (5–29%)
Diminished deep tendon reflex	Sometimes (5–29%)
Disorder of involuntary muscle movements	Sometimes (5–29%)
Fewer and broader ridges in brain	Sometimes (5–29%)
Hypsarrhythmia	Sometimes (5–29%)
Impulsivity	Sometimes (5–29%)
Involuntary movements	Sometimes (5–29%)
Jerking	Sometimes (5–29%)
Mental deterioration	Sometimes (5–29%)
Tremor	Sometimes (5–29%)
Unsteady walk	Sometimes (5–29%)
Repeated seizures without recovery between them	Rarely (1–4%)
Apraxia	Not recorded
Chorea	Not recorded
Dystonia	Not recorded
Involuntary writhing movements in fingers, hands, toes, and feet	Not recorded
Motor delay	Not recorded
Poor eye contact	Not recorded
Tongue thrusting	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Progressively abnormally small cranium	Always
Abnormally small head	Very often (80–99%)
Bulbous nose	Very often (80–99%)
Depressed nasal bridge	Very often (80–99%)
Drooping lower lip	Very often (80–99%)
Eye folds	Very often (80–99%)
Tented mouth	Very often (80–99%)
Abnormally large tongue	Often (30–79%)
Big lower jaw	Often (30–79%)
Downward slanting of the opening between the eyelids	Often (30–79%)
Excessive salivation	Often (30–79%)
Fullness of eyelids	Often (30–79%)
Narrow opening between the eyelids	Often (30–79%)
Prominent metopic ridge	Often (30–79%)
Short nose	Often (30–79%)
Smooth philtrum	Often (30–79%)
Failure of development of between one and six teeth	Sometimes (5–29%)
High forehead	Sometimes (5–29%)
Drooling	Not recorded
Midface retrusion	Not recorded
Thin red part of the upper lip	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Generalized decreased muscle tone	Always
Low muscle tone	Always
Hunched back	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Scoliosis	Often (30–79%)
Poor head control	Sometimes (5–29%)
Rigidity	Sometimes (5–29%)
Low muscle tone, in neonatal onset	Not recorded

Abnormality of the eye

Trait	How often it is seen
Drooping upper eyelid	Sometimes (5–29%)
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)
Abnormal involuntary eye movements	Rarely (1–4%)
Abnormality of vision	Rarely (1–4%)
Optic atrophy	Rarely (1–4%)
Retina degeneration	Rarely (1–4%)

Abnormality of limbs

Trait	How often it is seen
Increased muscle tone of arm or leg	Rarely (1–4%)
Club feet	Not recorded
Dropped arches	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Acid reflux	Very often (80–99%)
Feeding difficulties	Very often (80–99%)
Constipation	Not recorded

Growth abnormality

Trait	How often it is seen
Growth delay	Very often (80–99%)
Faltering weight	Often (30–79%)
Short stature	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Abnormal antihelix morphology	Very often (80–99%)
Prominent ear	Very often (80–99%)

Abnormality of prenatal development or birth

Trait	How often it is seen
Less than 10 fetal movements in 12 hours	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Aspiration	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 FOXG1 and how often each is seen. Find out more at hpo.jax.org.

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