Rare diseases · Sign or symptom
Micrognathia
Little lower jaw
HP:0000347
What it means
Developmental hypoplasia of the mandible.
Mandibular hypoplasia, also known as micrognathia, is a term that describes an abnormally small lower jaw.
Rare diseases that can present with this475
Very common80–99%
79- 15q overgrowth syndrome
- 49,XXXYY syndrome
- 49,XYYYY syndrome
- 6q terminal deletion syndrome
- 8p11.2deletion syndrome
- Achondrogenesis
- Achondrogenesis type 1A
- Achondrogenesis type 1B
- Acrocraniofacial dysostosis
- Acrofacial dysostosis, Palagonia type
- Amish lethal microcephaly
- Arginine vasopressin resistance-intracranial calcification-short stature-facial dysmorphism syndrome
- Atypical Werner syndrome
- Autosomal dominant myopia-midfacial retrusion-sensorineural hearing loss-rhizomelic dysplasia syndrome
- Autosomal dominant popliteal pterygium syndrome
- Autosomal semi-dominant severe lipodystrophic laminopathy
- Axial mesodermal dysplasia spectrum
- Baraitser-Winter cerebrofrontofacial syndrome
- Beemer-Ertbruggen syndrome
- Blepharophimosis-intellectual disability syndrome, SBBYS type
- Blomstrand lethal chondrodysplasia
- Bowen-Conradi syndrome
- Brachydactyly-mesomelia-intellectual disability-heart defects syndrome
- Brachydactyly-preaxial hallux varus syndrome
- Campomelic dysplasia
- Camptodactyly-joint contractures-facial skeletal defects syndrome
- Cardiocranial syndrome, Pfeiffer type
- Carey-Fineman-Ziter syndrome
- Cerebrocostomandibular syndrome
- Charlie M syndrome
- Chondroectodermal dysplasia with night blindness
- Cleft lip/palate-intestinal malrotation-cardiopathy syndrome
- Cleidocranial dysplasia
- Cloverleaf skull-multiple congenital anomalies syndrome
- COFS syndrome
- Cohen syndrome
- Cole-Carpenter syndrome
- Congenital cataracts-facial dysmorphism-neuropathy syndrome
- Cornelia de Lange syndrome
- Crane-Heise syndrome
- Craniodigital-intellectual disability syndrome
- Craniometadiaphyseal dysplasia, wormian bone type
- Craniosynostosis-Dandy-Walker malformation-hydrocephalus syndrome
- Craniosynostosis, Herrmann-Opitz type
- C syndrome
- Cutaneous mastocytosis-deafness-microtia syndrome
- Desmosterolosis
- Distal deletion 1q syndrome
- Distal deletion 3p syndrome
- Distal duplication 15q syndrome
- Distal duplication 18q syndrome
- Distal duplication 6p syndrome
- Distal monosomy 7q36 syndrome
- Dysmorphism-cleft palate-loose skin syndrome
- Ear-patella-short stature syndrome
- Endocardial fibroelastosis
- Femoral-facial syndrome
- Fetal akinesia deformation sequence
- Fetal minoxidil syndrome
- Fetal trimethadione syndrome
- FGFR2-related bent bone dysplasia
- Fibulo-ulnar hypoplasia-renal anomalies syndrome
- Flat face-microstomia-ear anomaly syndrome
- Frontometaphyseal dysplasia
- Fryns-Smeets-Thiry syndrome
- Fryns syndrome
- GAPO syndrome
- Genitopalatocardiac syndrome
- German syndrome
- Grant syndrome
- Growth delay-hydrocephaly-lung hypoplasia syndrome
- Hajdu-Cheney syndrome
- Hamel cerebro-palato-cardiac syndrome
- Hutchinson-Gilford progeria syndrome
- Hydrolethalus
- Hypoglossia-hypodactyly syndrome
- Hypogonadotropic hypogonadism-severe microcephaly-sensorineural hearing loss-dysmorphism syndrome
- ICF syndrome
- Infantile spasms-broad thumbs syndrome
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: Decreased projection of lower jaw · Decreased projection of mandible · Decreased size of lower jaw · Decreased size of mandible · Deficiency of lower jaw · Hypoplasia of lower jaw · Hypoplasia of mandible · Hypoplastic mandible
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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.