Traits

Traits linked to DDX3X

DEAD-box helicase 3 X-linked

The Human Phenotype Ontology links 75 traits to DDX3X, 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
Corners of eye widely separated	Very often (80–99%)
Little lower jaw	Very often (80–99%)
Short nose	Very often (80–99%)
Short opening between the eyelids	Very often (80–99%)
Abnormality of the palate	Often (30–79%)
Abnormally small head	Often (30–79%)
Broad head shape	Often (30–79%)
Cleft palate	Often (30–79%)
Full cheeks	Often (30–79%)
Short neck	Often (30–79%)
Wider-than-typical soft spot of skull	Often (30–79%)
Abnormal facial shape	Sometimes (5–29%)
Bifid uvula	Sometimes (5–29%)
Cleft of the mouth	Sometimes (5–29%)
Cleft upper lip	Sometimes (5–29%)
High palate	Sometimes (5–29%)
Sparse eyebrow	Sometimes (5–29%)
Dandy-Walker malformation	Rarely (1–4%)
Bulbous nose	Not recorded
Long face	Not recorded
Nasal tip, upturned	Not recorded
Wide nasal bridge	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Intellectual disability	Always
Abnormal corpus callosum morphology	Very often (80–99%)
Agenesis of corpus callosum	Often (30–79%)
Aggressive behavior	Often (30–79%)
Autism spectrum disorder	Often (30–79%)
Disorder of involuntary muscle movements	Often (30–79%)
More active than typical	Often (30–79%)
Underdevelopment of part of brain called corpus callosum	Often (30–79%)
Ventriculomegaly	Often (30–79%)
Wide based walk	Often (30–79%)
Absent/small cerebellum	Sometimes (5–29%)
Behavioral abnormality	Sometimes (5–29%)
Cortical dysplasia	Sometimes (5–29%)
Degeneration of cerebrum	Sometimes (5–29%)
Epilepsy	Sometimes (5–29%)
Global developmental delay	Sometimes (5–29%)
Partial agenesis of the corpus callosum	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Abnormal cardiac septum morphology	Often (30–79%)
Disease of the heart muscle	Sometimes (5–29%)
Dysplastic pulmonary valve	Sometimes (5–29%)
Narrowing of pulmonic valve	Sometimes (5–29%)
Patent ductus arteriosus	Sometimes (5–29%)
Narrowing of aorta	Rarely (1–4%)
Tetralogy of Fallot	Rarely (1–4%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Generalized decreased muscle tone	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Low muscle tone	Often (30–79%)
Double-Jointed	Sometimes (5–29%)
Narrow chest	Sometimes (5–29%)
Scoliosis	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Abnormally shaped ears	Very often (80–99%)
Hearing impairment	Often (30–79%)
Low-set ears	Sometimes (5–29%)
Thickened helices	Sometimes (5–29%)
Absent ear	Rarely (1–4%)

Abnormality of the eye

Trait	How often it is seen
Abnormality of vision	Often (30–79%)
Cross-eyed	Often (30–79%)
Visual impairment	Sometimes (5–29%)
Wide-set eyes	Not recorded

Growth abnormality

Trait	How often it is seen
Decreased body weight	Often (30–79%)
Short stature	Often (30–79%)
Growth delay as children	Sometimes (5–29%)
Prenatal growth deficiency	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Anteriorly placed anus	Often (30–79%)
Enlarged colon lacking nerve cells	Often (30–79%)
Feeding difficulties in infancy	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Curvature of digit	Sometimes (5–29%)
Short fingers or toes	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Abnormality of the larynx	Sometimes (5–29%)
Neonatal respiratory distress	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Early onset of puberty	Sometimes (5–29%)

Abnormality of the genitourinary system

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

Abnormality of the integument

Trait	How often it is seen
Abnormal skin pigmentation	Sometimes (5–29%)

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 DDX3X and how often each is seen. Find out more at hpo.jax.org.

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