Traits

Traits linked to AFG2A

AAA ATPase AFG2A

The Human Phenotype Ontology links 63 traits to AFG2A, 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
Inability to walk	Always
EEG abnormality	Very often (80–99%)
Epilepsy	Very often (80–99%)
Abnormal shape of brain	Often (30–79%)
Autism spectrum disorder	Often (30–79%)
Brief seizures with staring spells	Often (30–79%)
Cerebral hypomyelination	Often (30–79%)
Generalized myoclonic seizure	Often (30–79%)
Grand mal seizures	Often (30–79%)
Intellectual disability, severe	Often (30–79%)
IQ between 34 and 49	Often (30–79%)
Poor eye contact	Often (30–79%)
Severe expressive language delay	Often (30–79%)
Severe receptive language delay	Often (30–79%)
Brain degeneration	Sometimes (5–29%)
CNS hypomyelination	Sometimes (5–29%)
Decrease in size of the outer layer of the brain due to loss of brain cells	Sometimes (5–29%)
Delayed CNS myelination	Sometimes (5–29%)
EEG with frontal sharp slow waves	Sometimes (5–29%)
Generalized brain degeneration	Sometimes (5–29%)
Hypsarrhythmia	Sometimes (5–29%)
Infantile spasms	Sometimes (5–29%)
Thin corpus callosum	Sometimes (5–29%)
Underdevelopment of part of brain called corpus callosum	Sometimes (5–29%)
Limb dystonia	Rarely (1–4%)
Repetitive movements	Rarely (1–4%)
Self-injurious behavior	Rarely (1–4%)

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Very often (80–99%)
Broad eyebrow	Sometimes (5–29%)
Depressed nasal bridge	Sometimes (5–29%)
Highly arched eyebrow	Sometimes (5–29%)
Long nose	Sometimes (5–29%)
Receding chin	Sometimes (5–29%)
Small head present at birth	Sometimes (5–29%)
Underdeveloped tissue around nostril	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Very often (80–99%)
Decreased muscle tone in infant	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Low muscle tone in trunk	Sometimes (5–29%)
Low muscle tone, in neonatal onset	Sometimes (5–29%)
Scoliosis	Sometimes (5–29%)
Spasticity and rigidity of muscles	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Often (30–79%)
Acid reflux	Sometimes (5–29%)
Chronic constipation	Sometimes (5–29%)
Constipation	Sometimes (5–29%)
Gastrostomy tube feeding in infancy	Rarely (1–4%)

Abnormality of the eye

Trait	How often it is seen
Visual impairment	Always
Cerebral visual impairment	Often (30–79%)
Cross-eyed	Sometimes (5–29%)
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)
Exodeviation	Rarely (1–4%)

Growth abnormality

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

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Low platelet count	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Increased muscle tone of arm or leg	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
An opening in the wall separating the top two chambers of the heart	Rarely (1–4%)

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Always

Abnormality of the immune system

Trait	How often it is seen
Decreased immune function	Often (30–79%)

Abnormality of the integument

Trait	How often it is seen
Sacral hypertrichosis	Rarely (1–4%)

Laboratory abnormality

Trait	How often it is seen
High nonceruloplasmin-bound serum copper	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 AFG2A and how often each is seen. Find out more at hpo.jax.org.

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