Traits

Traits linked to RNU12

RNA, U12 small nuclear

The Human Phenotype Ontology links 75 traits to RNU12, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of head or neck

Trait	How often it is seen
Coronal craniosynostosis	Always
Enlarged cisterna magna	Always
Holes in parietal bones	Always
Wide fontanelles	Always
Abnormal tooth enamel	Very often (80–99%)
Abnormality of dental shape	Very often (80–99%)
Abnormality of the palate	Very often (80–99%)
Absent eyebrow	Very often (80–99%)
Absent eyelashes	Very often (80–99%)
Broad head shape	Very often (80–99%)
Delayed cranial suture closure	Very often (80–99%)
Frontal bossing	Very often (80–99%)
Large posterior fontanelle	Very often (80–99%)
Wider-than-typical soft spot of skull	Very often (80–99%)
Early closure of midline skull joint	Often (30–79%)
Full lips	Often (30–79%)
Lambdoidal craniosynostosis	Often (30–79%)
Little lower jaw	Often (30–79%)
Wide mouth	Often (30–79%)
Zygomatic flattening	Often (30–79%)
Asymmetry of the posterior head	Sometimes (5–29%)
Cleft palate	Sometimes (5–29%)
Everted eyelid	Not recorded
Midface retrusion	Not recorded
Sparse eyebrow	Not recorded
Sparse eyelashes	Not recorded
Sparse scalp hair	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Delayed ability to walk	Always
Dilated fourth ventricle	Always
Head titubation	Always
Inability to coordinate movements when walking	Always
Instability or lack of coordination of central trunk muscles	Always
Intention tremor	Always
Small cerebellum	Always
Wide based walk	Always
Difficulty articulating speech	Very often (80–99%)
Abnormal gait	Often (30–79%)
Cerebellar vermis atrophy	Often (30–79%)
Degeneration of cerebellum	Often (30–79%)
Delayed motor skills	Often (30–79%)
Febrile seizure (within the age range of 3 months to 6 years)	Often (30–79%)
Global developmental delay	Often (30–79%)
Intellectual disability	Often (30–79%)
Neurodevelopmental abnormality	Often (30–79%)
Poor fine motor coordination	Often (30–79%)
Focal impaired awareness seizure	Sometimes (5–29%)
Abnormal corpus callosum morphology	Not recorded
Decrease in size of the outer layer of the brain due to loss of brain cells	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Frequent falls	Always
Generalized muscle weakness	Always
Abnormal collarbone	Very often (80–99%)
Absent collarbone	Very often (80–99%)
Delayed bone maturation	Very often (80–99%)
Low muscle tone	Very often (80–99%)
Short collarbone	Very often (80–99%)
Shorter than typical length between neck and abdomen	Very often (80–99%)
Low muscle tone in trunk	Often (30–79%)
Hunched back	Sometimes (5–29%)
Short ribs	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Absent anus	Always
Abnormal anus position	Very often (80–99%)
Rectourethral fistula	Often (30–79%)
Decreased liver function	Sometimes (5–29%)
Abnormal connection between rectum and vagina	Not recorded

Abnormality of the eye

Trait	How often it is seen
Bulging eye	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)
Drooping upper eyelid	Not recorded

Abnormality of the ear

Trait	How often it is seen
Hearing impairment	Often (30–79%)
Sensorineural hearing impairment	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Hypospadias	Always
Urogenital fistula	Very often (80–99%)

Abnormality of the integument

Trait	How often it is seen
Porokeratosis	Very often (80–99%)
Thin fingernail	Very often (80–99%)

Abnormality of limbs

Trait	How often it is seen
Fused ankle bones	Very often (80–99%)

Abnormality of the immune system

Trait	How often it is seen
Eczema	Very often (80–99%)

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 RNU12 and how often each is seen. Find out more at hpo.jax.org.

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