Human Phenotype Ontology 
Grandparent Node:
expandAbnormality of the nose (HP:0000366)help
Parent Node:
expandAbnormality of the choanae (HP:0000415)help
..Starting node
..expandChoanal atresia (HP:0000453)help
Term ID: 453
Name: Choanal atresia
Synonym: Blockage of the rear opening of the nasal cavity
Definition: 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.
Comments:
Reference: HP:0000453
Genes and Diseases: SELECT DISTINCT 'HP:0000453' AS Input, t2.acc as HPO_ID, t2.name as HPO_term, g.Distance, t1.Entrez_gene AS Gene, t1.Entrez_gene_id AS Gene_id_entrez, t1.HGNC_ID, t1.DiseaseId, t1.DiseaseName, t1.Frequency, t1.Onset #, t1.ConceptID, Source, t1.Typical_association , h.Variants AS HGMD_variants, c.variants AS ClinVar_variants FROM hpo202212.graph_path AS g, hpo202212.term AS t, hpo202212.term AS t2 LEFT JOIN hpo202212.hpo_phenotype_to_genes as t1 ON (t1.HPO = t2.acc) LEFT JOIN gb_exome.clinvar_variation_latest_sum AS c ON ( c.Gene = t1.Entrez_Gene) LEFT JOIN gb_exome.hgmd_allmumt_sum_latest AS h ON (h.gene = t1.Entrez_Gene ) WHERE (t.acc ='HP:0000453' AND g.term1_id = t.id AND g.distance <=20 AND t2.id = g.term2_id) order by g.distance, gene, DiseaseName;