Trait

Absence of lower jaw bones

Clinical name: Mandibular aplasia

Absence of the mandible.

HPO HP:0009939

Also called: Failure of development of lower jaw, Missing lower jaw, Absence of lower jaw, Absence of lower jaw bone, Absence of mandible, Absent mandible, Agenesis of the mandible, Aplasia of the lower jaw bone, Failure of development of mandible
Body system: Abnormality of head or neck Abnormality of the musculoskeletal system

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13 genes linked to Absence of lower jaw bones

Changes in these genes cause rare conditions in which Absence of lower jaw bones is seen. Most people with this trait have none of those conditions, and a gene on this list says nothing about anyone's own genome.

Gene	How often it is seen	Conditions
PRRX1paired related homeobox 1	Always	In 2 conditions
CDC45cell division cycle 45	Very often (80–99%)	In 1 condition
CDC6cell division cycle 6	Very often (80–99%)	In 1 condition
CDT1chromatin licensing and DNA replication factor 1	Very often (80–99%)	In 1 condition
GMNNgeminin DNA replication inhibitor	Very often (80–99%)	In 1 condition
ORC1origin recognition complex subunit 1	Very often (80–99%)	In 1 condition
ORC4origin recognition complex subunit 4	Very often (80–99%)	In 1 condition
ORC6origin recognition complex subunit 6	Very often (80–99%)	In 1 condition
OTX2orthodenticle homeobox 2	Very often (80–99%)	In 1 condition
COX7Bcytochrome c oxidase subunit 7B	Often (30–79%)	In 1 condition
FAM20CFAM20C golgi associated secretory pathway kinase	Often (30–79%)	In 1 condition
HCCSholocytochrome c synthase	Often (30–79%)	In 1 condition
NDUFB11NADH:ubiquinone oxidoreductase subunit B11	Often (30–79%)	In 1 condition

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.

Broader traits

Aplasia/Hypoplasia of the mandible

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the trait, its names, its definition and the genes linked to it. Find out more at hpo.jax.org.
Data release 2026.10.16-c6eea6bf.

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