Rare diseases · Sign or symptom
Wide mouth
Broad mouth
HP:0000154
What it means
Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective).
The width of the mouth varies with facial movement and must be assessed when the subject has a relaxed (neutral) face. This term replaces macrostomia, large mouth, and large oral aperture because these terms imply a wide and open mouth. The term should not be used to describe a patient with a lateral oral cleft.
Rare diseases that can present with this106
Very common80–99%
31- 2q23.1microduplication syndrome
- 8p inverted duplication/deletion syndrome
- Ablepharon macrostomia syndrome
- AICA-ribosiduria
- Alazami syndrome
- Autosomal recessive faciodigitogenital syndrome
- Autosomal recessive Robinow syndrome
- Baraitser-Winter cerebrofrontofacial syndrome
- Barber-Say syndrome
- Cantú syndrome
- Cerebrofaciothoracic dysplasia
- Coffin-Siris syndrome
- Craniolenticulosutural dysplasia
- Deafness-intellectual disability syndrome, Martin-Probst type
- Duplication of the pituitary gland
- Epiphyseal dysplasia-hearing loss-dysmorphism syndrome
- Frank-Ter Haar syndrome
- Fryns-Smeets-Thiry syndrome
- Hernández-Aguirre Negrete syndrome
- Lambert syndrome
- Megalencephaly-capillary malformation-polymicrogyria syndrome
- Mosaic trisomy 14 syndrome
- Nicolaides-Baraitser syndrome
- Pitt-Hopkins syndrome
- Progressive non-infectious anterior vertebral fusion
- Simpson-Golabi-Behmel syndrome
- SSR4-CDG
- Triploidy syndrome
- Williams syndrome
- X-linked intellectual disability, Cabezas type
- X-linked intellectual disability, Nascimento type
Common30–79%
37- 16q24.3microdeletion syndrome
- Angelman syndrome
- Angelman syndrome due to a point mutation
- Angelman syndrome due to maternal 15q11q13 deletion
- Angelman syndrome due to paternal uniparental disomy of chromosome 15
- Autosomal spastic paraplegia type 18
- Beckwith-Wiedemann syndrome
- Brachymorphism-onychodysplasia-dysphalangism syndrome
- Coffin-Lowry syndrome
- Craniofrontonasal dysplasia-Poland anomaly syndrome
- Craniosynostosis-anal anomalies-porokeratosis syndrome
- Developmental delay-facial dysmorphism syndrome due to MED13L deficiency
- Distal duplication 17q syndrome
- Distal monosomy 7q36 syndrome
- Fetal hydantoin syndrome
- FG syndrome type 1
- Floating-Harbor syndrome
- Fountain syndrome
- Fryns syndrome
- Hall-Riggs syndrome
- Lenz-Majewski hyperostotic dysplasia
- Macrocephaly-spastic paraplegia-dysmorphism syndrome
- Mucopolysaccharidosis type 4
- Nager syndrome
- Oculocerebrofacial syndrome, Kaufman type
- PMM2-CDG
- Recessive intellectual disability-motor dysfunction-multiple joint contractures syndrome
- Schinzel-Giedion syndrome
- Severe intellectual disability-poor language-strabismus-grimacing face-long fingers syndrome
- Severe oculo-renal-cerebellar syndrome
- Smith-Lemli-Opitz syndrome
- Spondyloepiphyseal dysplasia-brachydactyly-speech disorder syndrome
- STAG1-related intellectual disability-facial dysmorphism-gastroesophageal reflux syndrome
- Temple-Baraitser syndrome
- TMEM70-related mitochondrial encephalo-cardio-myopathy
- X-linked intellectual disability, Wilson type
- Zimmermann-Laband syndrome
Sometimes5–29%
12- 16p12.1p12.3triplication syndrome
- 16p13.11microdeletion syndrome
- 17p11.2microduplication syndrome
- 19q13.11microdeletion syndrome
- 1p21.3microdeletion syndrome
- 3-phosphoserine phosphatase deficiency, infantile/juvenile form
- 7q31microdeletion syndrome
- Acromelic frontonasal dysplasia
and 4 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Large mouth · Large oral aperture · Macrostomia
Tracking symptoms like this for someone? Eleplan keeps symptoms, diagnoses, medications and every specialist in one plan.
Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.