Traits

Traits linked to FRMPD4

FERM and PDZ domain containing 4

The Human Phenotype Ontology links 29 traits to FRMPD4, 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
Delayed motor skills	Always
Delayed speech and language development	Always
Global developmental delay	Always
Intellectual disability	Always
Absent speech development	Often (30–79%)
Aggressive behavior	Often (30–79%)
Ataxia	Often (30–79%)
Autism spectrum disorder	Often (30–79%)
Delayed ability to walk	Often (30–79%)
Epilepsy	Often (30–79%)
Increased reflexes	Often (30–79%)
More active than typical	Often (30–79%)
Tremor	Often (30–79%)
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%)
Poor eye contact	Sometimes (5–29%)
Underdevelopment of part of brain called corpus callosum	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Cleft nasal tip	Sometimes (5–29%)
High forehead	Sometimes (5–29%)
High palate	Sometimes (5–29%)
Receding chin	Sometimes (5–29%)
Triangular head shape	Sometimes (5–29%)
Wide nasal bridge	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Cross-eyed	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)
Optic atrophy	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Abnormally shaped ears	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Frontal upsweep of hair	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Involuntary muscle stiffness, contraction, or spasm	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 FRMPD4 and how often each is seen. Find out more at hpo.jax.org.

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