Traits

Traits linked to FGF12

fibroblast growth factor 12

The Human Phenotype Ontology links 68 traits to FGF12, 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
Degeneration of cerebellum	Always
Epileptic encephalopathy	Always
IQ less than 20	Always
Limb ataxia	Always
Loss of developmental milestones	Always
Multifocal epileptiform discharges	Always
Tonic seizure	Always
Encephalopathy	Very often (80–99%)
Abnormality of coordination	Often (30–79%)
Absent speech development	Often (30–79%)
Agitation	Often (30–79%)
Ataxia	Often (30–79%)
Decreased reflex response	Often (30–79%)
Delayed speech and language development	Often (30–79%)
EEG with multifocal slow activity	Often (30–79%)
Epilepsy	Often (30–79%)
Global developmental delay	Often (30–79%)
Grand mal seizures	Often (30–79%)
Hypsarrhythmia	Often (30–79%)
Intellectual disability	Often (30–79%)
Repeated seizures without recovery between them	Often (30–79%)
Seizure affecting one half of brain	Often (30–79%)
Abnormal corpus callosum morphology	Sometimes (5–29%)
Abnormal gait	Sometimes (5–29%)
Abnormal myelination	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%)
Diminished deep tendon reflex	Sometimes (5–29%)
Disorder of involuntary muscle movements	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%)
EEG abnormality	Not recorded
Inability to walk	Not recorded
Poor speech	Not recorded

Abnormality of the eye

Trait	How often it is seen
Cerebral visual impairment	Often (30–79%)
Optic disc pallor	Often (30–79%)
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 the musculoskeletal system

Trait	How often it is seen
Generalized decreased muscle tone	Often (30–79%)
Low muscle tone	Often (30–79%)
Low muscle tone in trunk	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Sometimes (5–29%)
Poor head control	Sometimes (5–29%)
Rigidity	Sometimes (5–29%)

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	Sometimes (5–29%)
Downward slanting of the opening between the eyelids	Sometimes (5–29%)
Failure of development of between one and six teeth	Sometimes (5–29%)
High forehead	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Always
Acid reflux	Sometimes (5–29%)
Chronic constipation	Not recorded

Growth abnormality

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

Abnormality of limbs

Trait	How often it is seen
Increased muscle tone of arm or leg	Rarely (1–4%)

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 cardiovascular system

Trait	How often it is seen
Narrowing of blood vessels in back of eye	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 FGF12 and how often each is seen. Find out more at hpo.jax.org.

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