Traits

Traits linked to GRIN2A

glutamate ionotropic receptor NMDA type subunit 2A

The Human Phenotype Ontology links 107 traits to GRIN2A, 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
Continuous spike and waves during slow sleep	Very often (80–99%)
Delayed speech and language development	Very often (80–99%)
Difficulty finding words	Very often (80–99%)
EEG with centrotemporal focal spike waves	Very often (80–99%)
Epilepsy	Very often (80–99%)
Interictal EEG abnormality	Very often (80–99%)
Interictal epileptiform activity	Very often (80–99%)
Language impairment	Very often (80–99%)
Loss of speech	Very often (80–99%)
Speech apraxia	Very often (80–99%)
Spoken word recognition deficit	Very often (80–99%)
Attention deficit	Often (30–79%)
Atypical absence seizure	Often (30–79%)
Autism spectrum disorder	Often (30–79%)
Behavioral abnormality	Often (30–79%)
Bilateral tonic-clonic seizure with focal onset	Often (30–79%)
Bilateral tonic-clonic seizure with generalized onset	Often (30–79%)
Brief seizures with staring spells	Often (30–79%)
Cognitive impairment	Often (30–79%)
EEG with focal sharp waves	Often (30–79%)
EEG with frontal focal spike waves	Often (30–79%)
EEG with frontal focal spikes	Often (30–79%)
EEG with generalized epileptiform discharges	Often (30–79%)
EEG with multifocal slow activity	Often (30–79%)
EEG with temporal focal spikes	Often (30–79%)
Focal aware seizure	Often (30–79%)
Focal hemiclonic seizure	Often (30–79%)
Focal hemifacial clonic seizure	Often (30–79%)
Focal impaired awareness seizure	Often (30–79%)
Focal motor seizure	Often (30–79%)
Global developmental delay	Often (30–79%)
Grand mal seizures	Often (30–79%)
Intellectual disability	Often (30–79%)
Intellectual disability, severe	Often (30–79%)
Loss of developmental milestones	Often (30–79%)
Pauses in breathing while sleeping	Often (30–79%)
Profound global developmental delay	Often (30–79%)
Seizure affecting one half of brain	Often (30–79%)
Social and occupational deterioration	Often (30–79%)
Specific learning disability	Often (30–79%)
Speech articulation difficulties	Often (30–79%)
Abnormal myelination	Sometimes (5–29%)
Abnormal prosody	Sometimes (5–29%)
Abnormally low-pitched voice	Sometimes (5–29%)
Aggressive behavior	Sometimes (5–29%)
Anxiety	Sometimes (5–29%)
Can't control feelings	Sometimes (5–29%)
Clumsiness	Sometimes (5–29%)
Decreased reflex response	Sometimes (5–29%)
Depression	Sometimes (5–29%)
Difficulty articulating speech	Sometimes (5–29%)
Difficulty sleeping	Sometimes (5–29%)
Diffuse cerebral atrophy	Sometimes (5–29%)
Dysesthesia	Sometimes (5–29%)
Dystonia	Sometimes (5–29%)
EEG with generalized polyspikes	Sometimes (5–29%)
Epileptic spasm	Sometimes (5–29%)
Febrile seizure (within the age range of 3 months to 6 years)	Sometimes (5–29%)
Focal clonic seizure	Sometimes (5–29%)
Focal myoclonic seizure	Sometimes (5–29%)
Generalized clonic seizure	Sometimes (5–29%)
Generalized tonic seizure	Sometimes (5–29%)
High stepping	Sometimes (5–29%)
Hyperactive movements	Sometimes (5–29%)
Impulsivity	Sometimes (5–29%)
Inability to coordinate movements when walking	Sometimes (5–29%)
Inability to speak	Sometimes (5–29%)
Incomprehensible speech	Sometimes (5–29%)
Intellectual disability, borderline	Sometimes (5–29%)
IQ between 34 and 49	Sometimes (5–29%)
Jerking	Sometimes (5–29%)
Memory impairment	Sometimes (5–29%)
Migraine	Sometimes (5–29%)
More active than typical	Sometimes (5–29%)
Myoclonic absence seizure	Sometimes (5–29%)
Nocturnal seizures	Sometimes (5–29%)
Non-convulsive status epilepticus without coma	Sometimes (5–29%)
Pins and needles feeling	Sometimes (5–29%)
Progressive degeneration of movement	Sometimes (5–29%)
Psychotic mentation	Sometimes (5–29%)
Short attention span	Sometimes (5–29%)
Slurred speech	Sometimes (5–29%)
Stereotypical hand wringing	Sometimes (5–29%)
Sudden loss of muscle tone	Sometimes (5–29%)
Typical absence seizure	Sometimes (5–29%)
Underdevelopment of part of brain called corpus callosum	Sometimes (5–29%)
EEG with irregular generalized spike and wave complexes	Rarely (1–4%)
Epileptic encephalopathy	Rarely (1–4%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Decreased muscle tone in infant	Often (30–79%)
Low muscle tone	Often (30–79%)
Poor head control	Often (30–79%)
Difficulty in standing	Sometimes (5–29%)
Frequent falls	Sometimes (5–29%)
Low muscle tone in trunk	Sometimes (5–29%)
Spasticity and rigidity of muscles	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Drooling	Often (30–79%)
Small head present at birth	Often (30–79%)
Abnormal facial shape	Sometimes (5–29%)
Development of small head that was not present at birth	Sometimes (5–29%)
Short nose	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Short stature	Often (30–79%)
Small for gestational age	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
High-arched foot	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Abnormal involuntary eye movements	Sometimes (5–29%)

Abnormality of the immune system

Trait	How often it is seen
Autoimmune antibody positivity	Rarely (1–4%)

Abnormality of the respiratory system

Trait	How often it is seen
Laryngospasm	Often (30–79%)

Abnormality of the voice

Trait	How often it is seen
Nasal speech	Sometimes (5–29%)

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 GRIN2A and how often each is seen. Find out more at hpo.jax.org.

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