Traits

Traits linked to PRRX1

paired related homeobox 1

The Human Phenotype Ontology links 31 traits to PRRX1, 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 tongue	Always
Absence of lower jaw bones	Always
Cleft palate	Always
Downward slanting of the opening between the eyelids	Always
Narrow mouth	Always
Wide nose	Always
Decreased nasal size	Very often (80–99%)
Missing nostrils	Very often (80–99%)
Sparse or absent eyebrows	Very often (80–99%)
Failure of development of tongue	Not recorded
Little lower jaw	Not recorded

Abnormality of the ear

Trait	How often it is seen
Low-set ears	Always
Synotia	Always
Ears rotated toward back of head	Very often (80–99%)
Narrow internal auditory canal	Very often (80–99%)
Conductive deafness	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Breathing difficulties	Always
Floppy windpipe	Always
Hypoplasia of the epiglottis	Always
Laryngeal hypoplasia	Always
Poorly developed lungs	Always

Abnormality of the nervous system

Trait	How often it is seen
Abnormal cranial nerve morphology	Very often (80–99%)
Absent/small cerebellum	Very often (80–99%)
Agenesis of corpus callosum	Very often (80–99%)
Holoprosencephaly	Very often (80–99%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Secundum atrial septal defect	Always
All organs on wrong side of body	Very often (80–99%)

Abnormality of the eye

Trait	How often it is seen
Abnormality of the eye	Very often (80–99%)
Cyclops eye	Very often (80–99%)

Abnormality of prenatal development or birth

Trait	How often it is seen
High levels of amniotic fluid	Always

Abnormality of the genitourinary system

Trait	How often it is seen
Underdeveloped penis	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 PRRX1 and how often each is seen. Find out more at hpo.jax.org.

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