Traits

Traits linked to NFIX

nuclear factor I X

The Human Phenotype Ontology links 196 traits to NFIX, 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
Anterior position of the premaxilla	Always
Big calvaria	Always
High forehead	Always
Abnormal facial shape	Very often (80–99%)
Abnormally small head	Very often (80–99%)
Downward slanting of the opening between the eyelids	Very often (80–99%)
Long face	Very often (80–99%)
Midface retrusion	Very often (80–99%)
Narrow face	Very often (80–99%)
Nasal tip, upturned	Very often (80–99%)
Prominent forehead	Very often (80–99%)
Receding chin	Very often (80–99%)
Big lower jaw	Often (30–79%)
Broad forehead	Often (30–79%)
Corners of eye widely separated	Often (30–79%)
Decreased size of tooth	Often (30–79%)
Depressed nasal bridge	Often (30–79%)
Drooling	Often (30–79%)
Drooping lower lip	Often (30–79%)
Early eruption of teeth	Often (30–79%)
Extra bones within cranial sutures	Often (30–79%)
Eye folds	Often (30–79%)
Frontal bossing	Often (30–79%)
Full lips	Often (30–79%)
Gum enlargement	Often (30–79%)
High palate	Often (30–79%)
Highly arched eyebrow	Often (30–79%)
Irregular teeth	Often (30–79%)
Little lower jaw	Often (30–79%)
Long, narrow head	Often (30–79%)
Low hairline at back of neck	Often (30–79%)
Narrow mouth	Often (30–79%)
Open mouth	Often (30–79%)
Outward turned lips	Often (30–79%)
Oval face	Often (30–79%)
Prominent back of the head	Often (30–79%)
Prominent nose	Often (30–79%)
Protruding tongue	Often (30–79%)
Recurrent colds	Often (30–79%)
Short nose	Often (30–79%)
Short philtrum	Often (30–79%)
Small retruded chin	Often (30–79%)
Triangular face	Often (30–79%)
Asymmetry of the posterior head	Sometimes (5–29%)
Blockage of the rear opening of the nasal cavity	Sometimes (5–29%)
Cleft palate	Sometimes (5–29%)
Deformity of the skull	Sometimes (5–29%)
Facial asymmetry	Sometimes (5–29%)
Narrowing of the rear opening of the nasal cavity	Sometimes (5–29%)
Pointed chin	Sometimes (5–29%)
Scaphocephaly	Sometimes (5–29%)
Sloping forehead	Sometimes (5–29%)
Underdeveloped tissue around nostril	Sometimes (5–29%)
Upward slanting of the opening between the eyelids	Sometimes (5–29%)
Decreased depth of eye sockets	Not recorded
Monobrow	Not recorded
Retraction of the tongue	Not recorded
Short mandibular rami	Not recorded
Thick eyebrow	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Anxiety	Always
Delayed speech and language development	Always
Global developmental delay	Always
Intellectual disability	Always
IQ between 34 and 49	Always
Absent septum pellucidum	Often (30–79%)
Absent speech development	Often (30–79%)
Autism spectrum disorder	Often (30–79%)
Brisk reflexes	Often (30–79%)
Delayed ability to walk	Often (30–79%)
Fewer and broader ridges in brain	Often (30–79%)
Motor delay	Often (30–79%)
Obstructive sleep apnea	Often (30–79%)
Too much cerebrospinal fluid in the brain	Often (30–79%)
Underdevelopment of part of brain called corpus callosum	Often (30–79%)
Ventriculomegaly	Often (30–79%)
Cervical cord compression	Sometimes (5–29%)
Degeneration of cerebrum	Sometimes (5–29%)
Epilepsy	Sometimes (5–29%)
Episodic ataxia	Sometimes (5–29%)
Febrile seizure (within the age range of 3 months to 6 years)	Sometimes (5–29%)
Intellectual disability, mild	Sometimes (5–29%)
Intellectual disability, severe	Sometimes (5–29%)
Irritability	Sometimes (5–29%)
Lateral ventricle dilatation	Sometimes (5–29%)
Migraine	Sometimes (5–29%)
More active than typical	Sometimes (5–29%)
Self-injurious behavior	Sometimes (5–29%)
Small brainstem	Sometimes (5–29%)
Small cerebellum	Sometimes (5–29%)
Agenesis of corpus callosum	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Advanced bone age	Very often (80–99%)
Double-Jointed	Very often (80–99%)
Low muscle tone	Very often (80–99%)
Slender long bone	Very often (80–99%)
Abnormal formation of the hip	Often (30–79%)
Atlantoaxial dislocation	Often (30–79%)
Decreased hip abduction	Often (30–79%)
Funnel chest	Often (30–79%)
Hunched back	Often (30–79%)
Increased susceptibility to fractures	Often (30–79%)
Kyphoscoliosis	Often (30–79%)
Low muscle tone in trunk	Often (30–79%)
Low muscle tone, in neonatal onset	Often (30–79%)
Low solidness and mass of the bones	Often (30–79%)
Scoliosis	Often (30–79%)
Thoracic kyphosis	Often (30–79%)
Thoracic scoliosis	Often (30–79%)
Osteoporosis	Sometimes (5–29%)
Recurrent fractures	Sometimes (5–29%)
Spasticity and rigidity of muscles	Sometimes (5–29%)
Hypoplasia of the odontoid process	Not recorded
Large sternal ossification centers	Not recorded
Short sternum	Not recorded

Abnormality of the eye

Trait	How often it is seen
Bulging eye	Always
Blue outer white part of eyeball	Very often (80–99%)
Astigmatism	Often (30–79%)
Close sighted	Often (30–79%)
Cross-eyed	Often (30–79%)
Farsightedness	Often (30–79%)
Optic nerve hypoplasia	Often (30–79%)
Severe near sightedness	Often (30–79%)
Wide-set eyes	Often (30–79%)
Deeply set eye	Sometimes (5–29%)
Glaucoma	Sometimes (5–29%)
Horizontal nystagmus	Sometimes (5–29%)
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)
Lazy eye	Sometimes (5–29%)
Optic atrophy	Sometimes (5–29%)
Optic disc hypoplasia	Sometimes (5–29%)
Optic disc pallor	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Bowing of the long bones	Very often (80–99%)
Bunion	Often (30–79%)
Coxa valga	Often (30–79%)
Coxa vara	Often (30–79%)
Curvature of little finger	Often (30–79%)
Long fingers	Often (30–79%)
Prominent fingertip pads	Often (30–79%)
Slender finger	Often (30–79%)
Curvature of digit	Sometimes (5–29%)
High-arched foot	Sometimes (5–29%)
Hip dislocation	Sometimes (5–29%)
Partial hip dislocation	Sometimes (5–29%)
Bullet-shaped middle phalanges of the hand	Not recorded
Short outermost finger bone	Not recorded
Wide outermost end of long bone	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Cutis marmorata	Often (30–79%)
Dysplastic aortic valve	Often (30–79%)
Abnormal cardiovascular system morphology	Sometimes (5–29%)
An opening in the wall separating the top two chambers of the heart	Sometimes (5–29%)
Extra heart beat	Sometimes (5–29%)
Hole in heart wall separating two lower heart chambers	Sometimes (5–29%)
Increased blood pressure in blood vessels of lungs	Sometimes (5–29%)
Patent ductus arteriosus	Sometimes (5–29%)
High blood pressure	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Often (30–79%)
Feeding difficulties in infancy	Often (30–79%)
Acid reflux	Sometimes (5–29%)
Anteriorly placed anus	Sometimes (5–29%)
Constipation	Sometimes (5–29%)
Episodic vomiting	Sometimes (5–29%)
Pyloric stenosis	Sometimes (5–29%)
Umbilical hernia	Sometimes (5–29%)
Omphalocele	Not recorded

Abnormality of the ear

Trait	How often it is seen
Bilateral conductive hearing impairment	Often (30–79%)
Cholesteatoma	Often (30–79%)
Conductive deafness	Often (30–79%)
Hearing impairment	Often (30–79%)
Low-set ears	Often (30–79%)
Overfolded ears	Often (30–79%)
Ears rotated toward back of head	Sometimes (5–29%)
Small ears	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Decreased body weight	Always
General overgrowth	Always
Faltering weight	Very often (80–99%)
Prenatal growth deficiency	Very often (80–99%)
Growth delay	Often (30–79%)
Short stature	Often (30–79%)
Tall stature	Often (30–79%)

Abnormality of the integument

Trait	How often it is seen
Excessive hair growth	Very often (80–99%)
Thin skin	Very often (80–99%)
Beauty mark	Often (30–79%)
Brittle hair	Often (30–79%)
Excessive hairiness over body	Often (30–79%)
Sparse hair	Often (30–79%)

Abnormality of the respiratory system

Trait	How often it is seen
Obstructive lung disease	Very often (80–99%)
Noisy breathing	Often (30–79%)
Softening of voice box tissue	Often (30–79%)
Apnea	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Bilateral cryptorchidism	Often (30–79%)
Undescended testes	Often (30–79%)
Unilateral cryptorchidism	Sometimes (5–29%)

Abnormality of the immune system

Trait	How often it is seen
Aspiration pneumonia	Often (30–79%)
Recurrent aspiration pneumonia	Often (30–79%)

Abnormality of blood and blood-forming tissues

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

Abnormality of the breast

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

Abnormality of the endocrine system

Trait	How often it is seen
Early onset of puberty	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 NFIX and how often each is seen. Find out more at hpo.jax.org.

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