Traits

Traits linked to DHX9

DExH-box helicase 9

The Human Phenotype Ontology links 31 traits to DHX9, 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
Global developmental delay	Always
Epilepsy	Often (30–79%)
Intellectual disability, severe	Often (30–79%)
Peripheral axonal neuropathy	Often (30–79%)
Reduced cerebral white matter volume	Often (30–79%)
Ventriculomegaly	Often (30–79%)
Ataxia	Sometimes (5–29%)
Increased reflexes	Sometimes (5–29%)
Intellectual disability, borderline	Sometimes (5–29%)
Intellectual disability, mild	Sometimes (5–29%)
IQ between 34 and 49	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Eye folds	Always
Narrow eyelid opening	Always
Receding chin	Always
Smooth philtrum	Always
Thin red part of the upper lip	Always
Upward slanting of the opening between the eyelids	Always
Wide nasal bridge	Always
Abnormal facial shape	Often (30–79%)
Abnormally small head	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Short stature	Always
Small for gestational age	Always
Faltering weight	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Acid reflux	Always
Feeding difficulties	Always

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone in trunk	Often (30–79%)
Appendicular hypotonia	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Noncompaction cardiomyopathy	Always

Abnormality of the ear

Trait	How often it is seen
Low-set ears	Always

Abnormality of the eye

Trait	How often it is seen
Wide-set eyes	Always

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 DHX9 and how often each is seen. Find out more at hpo.jax.org.

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