Traits

Traits linked to SMG8

SMG8 nonsense mediated mRNA decay factor

The Human Phenotype Ontology links 35 traits to SMG8, 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
Abnormally small head	Often (30–79%)
Bulbous nose	Sometimes (5–29%)
Failure of development of between one and six teeth	Sometimes (5–29%)
Frontal bossing	Sometimes (5–29%)
Full lips	Sometimes (5–29%)
Little lower jaw	Sometimes (5–29%)
Long philtrum	Sometimes (5–29%)
Narrow philtrum	Sometimes (5–29%)
Prominent nose	Sometimes (5–29%)
Smooth philtrum	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Hole in heart wall separating two lower heart chambers	Often (30–79%)
An opening in the wall separating the top two chambers of the heart	Sometimes (5–29%)
Coronary sinus enlargement	Sometimes (5–29%)
Patent foramen ovale	Sometimes (5–29%)
Persistent left superior vena cava	Sometimes (5–29%)
Pulmonary artery sling	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Global developmental delay	Always
Abnormal cerebral white matter morphology	Often (30–79%)
Toe walking	Often (30–79%)
Brain degeneration	Sometimes (5–29%)
Cavum septum pellucidum	Sometimes (5–29%)
Self-mutilation	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Hearing impairment	Often (30–79%)
Ears rotated toward back of head	Sometimes (5–29%)
Large ears	Sometimes (5–29%)
Low-set ears	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Clouding of the lens of the eye	Often (30–79%)
Astigmatism	Sometimes (5–29%)
Cross-eyed	Sometimes (5–29%)
Optic disc pallor	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Dry skin	Sometimes (5–29%)
Patchy darkened skin	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Hypospadias	Often (30–79%)

Abnormality of the immune system

Trait	How often it is seen
Eczema	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Short stature	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 SMG8 and how often each is seen. Find out more at hpo.jax.org.

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