Rare diseases · Sign or symptom
Choanal atresia
Blockage of the rear opening of the nasal cavity
HP:0000453
What it means
Absence or abnormal closure of the choana (the posterior nasal aperture). Most embryologists believe that posterior choanal atresia results from a failure of rupture between the 35th and 38th day of fetal life of the partition which separates the bucconasal or buccopharyngeal membranes. The resultant choanal atresia may be unilateral or bilateral, bony or membranous, complete or incomplete. In over 90 per cent of cases the obstruction is bony, while in the remainder it is membranous. The bony type of atresia is commonly located 1-2 mm. anterior to the posterior edge of the hard palate, and the osseous septum varies in thickness from 1 to 10 mm. In the membranous form of choanal atresia the obstruction usually occurs further posteriorly. In approximately one third of cases the atresia is bilateral.
Rare diseases that can present with this61
Very common80–99%
6Common30–79%
14- Acrocraniofacial dysostosis
- Anophthalmia plus syndrome
- Antley-Bixler syndrome
- CHARGE syndrome
- Corpus callosum agenesis-intellectual disability-coloboma-micrognathia syndrome
- Crouzon syndrome-acanthosis nigricans syndrome
- Holoprosencephaly
- Hyposmia-nasal and ocular hypoplasia-hypogonadotropic hypogonadism syndrome
- Imperforate oropharynx-costovertebral anomalies syndrome
- Methimazole embryofetopathy
- Pfeiffer syndrome type 2
- Pfeiffer syndrome type 3
- Trisomy 18 syndrome
- X-linked female restricted facial dysmorphism-short stature-choanal atresia-intellectual disability
Sometimes5–29%
35- 22q11.2deletion syndrome
- Apert syndrome
- Autosomal dominant popliteal pterygium syndrome
- Bilateral perisylvian polymicrogyria
- Congenital adrenal hyperplasia due to cytochrome P450 oxidoreductase deficiency
- Cornelia de Lange syndrome
- Crouzon syndrome
- Distal 22q11.2 microdeletion syndrome
and 27 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
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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.