Rare diseases · Sign or symptom
Malar flattening
Zygomatic flattening
HP:0000272
What it means
Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation.
The malar process is the most medial and superior portion of the bony midface, articulating with the maxilla and temporal and sphenoid bones, contiguous with the lateral boundary of the nasal bridge. The term malar hypoplasia is no longer preferred because surface examination cannot distinguish hypoplasia from hypotrophy. {xref="https://orcid.org/0000-0001-5889-4463"}
Rare diseases that can present with this115
Very common80–99%
49- 47,XYY syndrome
- Abruzzo-Erickson syndrome
- Acrofacial dysostosis, Rodríguez type
- Alport syndrome-intellectual disability-midface hypoplasia-elliptocytosis syndrome
- Autosomal dominant otospondylomegaepiphyseal dysplasia
- Autosomal recessive cutis laxa type 2, classic type
- Blomstrand lethal chondrodysplasia
- Cataract-intellectual disability-hypogonadism syndrome
- Char syndrome
- CK syndrome
- Cooper-Jabs syndrome
- Craniometadiaphyseal dysplasia, wormian bone type
- Craniosynostosis-hydrocephalus-Arnold-Chiari malformation type I-radioulnar synostosis syndrome
- Cutis gyrata-acanthosis nigricans-craniosynostosis syndrome
- Deafness-intellectual disability syndrome, Martin-Probst type
- Dysmorphism-pectus carinatum-joint laxity syndrome
- Familial osteodysplasia, Anderson type
- Flat face-microstomia-ear anomaly syndrome
- Gabriele-de Vries syndrome
- Hamel cerebro-palato-cardiac syndrome
- Kleefstra syndrome
- Lambert syndrome
- Larsen syndrome
- Lateral meningocele syndrome
- Mandibulofacial dysostosis-microcephaly syndrome
- Marshall syndrome
- Microbrachycephaly-ptosis-cleft lip syndrome
- Microcephalic osteodysplastic dysplasia, Saul-Wilson type
- Microcephaly-brachydactyly-kyphoscoliosis syndrome
- Monosomy 9p syndrome
- Night blindness-skeletal anomalies-dysmorphism syndrome
- Non-eruption of teeth-maxillary hypoplasia-genu valgum syndrome
- Otopalatodigital syndrome type 2
- PDE4D haploinsufficiency syndrome
- PEHO syndrome
- Pfeiffer syndrome type 2
- Pierre-Robin sequence-Manzke dysostosis-clinodactyly of the index finger syndrome
- Postaxial acrofacial dysostosis
- Progressive spondyloepimetaphyseal dysplasia-short stature-short fourth metatarsals-intellectual disability syndrome
- Pseudodiastrophic dysplasia
- Ring chromosome 7 syndrome
- Roberts syndrome
- Schneckenbecken dysplasia
- Stickler syndrome
- Treacher-Collins syndrome
- Trisomy 12p syndrome
- Trisomy 13 syndrome
- Van den Ende-Gupta syndrome
- Wiedemann-Rautenstrauch syndrome
Common30–79%
31- 13q12.3microdeletion syndrome
- 14q22q23microdeletion syndrome
- 16p12.1p12.3triplication syndrome
- 17q21.31microduplication syndrome
- 20p12.3microdeletion syndrome
- 22q11.2deletion syndrome
- 2q23.1microdeletion syndrome
- 6q25.2q25.3microdeletion syndrome
- Acrofacial dysostosis, Palagonia type
- Alazami syndrome
- Alpha-thalassemia-intellectual disability syndrome linked to chromosome 16
- Aneurysm-osteoarthritis syndrome
- Autosomal dominant omodysplasia
- Autosomal recessive Stickler syndrome
- Bloom syndrome
- Brachymorphism-onychodysplasia-dysphalangism syndrome
- Craniosynostosis-anal anomalies-porokeratosis syndrome
- Craniosynostosis, Herrmann-Opitz type
- Crouzon syndrome-acanthosis nigricans syndrome
- Dislocation of the hip-dysmorphism syndrome
- Distal deletion 6p syndrome
- FG syndrome type 1
- Hallermann-Streiff syndrome
- Hereditary sensory and autonomic neuropathy type 5
- Hydrocephalus-costovertebral dysplasia-Sprengel anomaly syndrome
- Isolated ectopia lentis
- Loeys-Dietz syndrome
- Macrocephaly-intellectual disability-left ventricular non compaction syndrome
- Marfanoid habitus-autosomal recessive intellectual disability syndrome
- Microcephalic osteodysplastic primordial dwarfism types I and III
- Muenke 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 size of malar bone · Depressed malar region · Flat cheekbone · Hypotrophic malar bone · Malar hypoplasia · Underdevelopment of malar bone
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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.