Traits

Traits linked to ODC1

ornithine decarboxylase 1

The Human Phenotype Ontology links 75 traits to ODC1, by body system: features seen in people with one of the gene's rare conditions.

ODC1

Abnormality of the nervous system

Trait	How often it is seen
Delayed ability to walk	Always
Delayed speech and language development	Always
Global developmental delay	Always
Periventricular cysts	Always
Aggressive behavior	Often (30–79%)
Attention deficit	Often (30–79%)
Hyperintensity of cerebral white matter on MRI	Often (30–79%)
Abnormal cerebellar vermis morphology	Sometimes (5–29%)
Absent speech development	Sometimes (5–29%)
Behavioral abnormality	Sometimes (5–29%)
Dilated third ventricle	Sometimes (5–29%)
Dysgenesis of the cerebellar vermis	Sometimes (5–29%)
Dysplastic corpus callosum	Sometimes (5–29%)
Epilepsy	Sometimes (5–29%)
Focal polymicrogyria	Sometimes (5–29%)
Lateral ventricle dilatation	Sometimes (5–29%)
Non-convulsive status epilepticus without coma	Sometimes (5–29%)
Poor speech	Sometimes (5–29%)
Self-injurious behavior	Sometimes (5–29%)
Thick corpus callosum	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Absent eyebrow	Always
Big calvaria	Always
High forehead	Always
High palate	Always
Sparse eyelashes	Always
Bulbous nose	Often (30–79%)
Large forehead	Often (30–79%)
Absent eyelashes	Sometimes (5–29%)
Big head present at birth	Sometimes (5–29%)
Broad forehead	Sometimes (5–29%)
Downward slanting of the opening between the eyelids	Sometimes (5–29%)
Increased nuchal translucency	Sometimes (5–29%)
Narrow opening between the eyelids	Sometimes (5–29%)
Receding chin	Sometimes (5–29%)
Skin tag in front of the ear	Sometimes (5–29%)
Sparse eyebrow	Sometimes (5–29%)
Sparse scalp hair	Sometimes (5–29%)
Thin red part of the upper lip	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Small nail	Often (30–79%)
Chicken skin	Sometimes (5–29%)
Dry skin	Sometimes (5–29%)
Hair loss	Sometimes (5–29%)
Spinal dimple	Sometimes (5–29%)
Underdeveloped toenails	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Generalized decreased muscle tone	Always
Low muscle tone, in neonatal onset	Always
Lower limb spasticity	Always
Abnormal deposits of calcium in the brain	Sometimes (5–29%)
Involuntary muscle stiffness, contraction, or spasm	Sometimes (5–29%)
Rib fusion	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties in infancy	Always
Celiac disease	Sometimes (5–29%)
Chronic constipation	Sometimes (5–29%)
Inguinal hernia	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Wide-set eyes	Always
Deeply set eye	Often (30–79%)
Drooping of both upper eyelids	Often (30–79%)
Drooping upper eyelid	Often (30–79%)

Abnormality of limbs

Trait	How often it is seen
Curvature of little finger	Sometimes (5–29%)
Tapered finger	Sometimes (5–29%)
Tapered toe	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Cupped ear	Always
Sensorineural hearing impairment	Always
Large ears	Often (30–79%)

Abnormality of prenatal development or birth

Trait	How often it is seen
High levels of amniotic fluid	Very often (80–99%)
Less than 10 fetal movements in 12 hours	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Dilation of Virchow-Robin spaces	Often (30–79%)
Vascular skin abnormality	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Bilateral cryptorchidism	Often (30–79%)
Undescended testes	Often (30–79%)

Abnormality of the immune system

Trait	How often it is seen
Asthma	Sometimes (5–29%)
Recurrent ear infections	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
High blood bilirubin levels	Always
Low blood sugar	Always

Growth abnormality

Trait	How often it is seen
Birth weight > 90th percentile	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 ODC1 and how often each is seen. Find out more at hpo.jax.org.

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