- Choanal atresia (HP:0000453): 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. Evidence: PCS. Frequency: 7/7. Onset: Congenital onset (HP:0003577). (PMID:20826270)
- Autosomal recessive inheritance (HP:0000007): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:20826270)
- High palate (HP:0000218): Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective). Evidence: TAS. (OMIM:613611)
- Pericardial effusion (HP:0001698): Accumulation of fluid within the pericardium. Evidence: TAS. (OMIM:613611)
- Lymphedema (HP:0001004): Localized fluid retention and tissue swelling caused by a compromised lymphatic system. Evidence: PCS. Frequency: 5/7. Onset: Childhood onset (HP:0011463). (PMID:20826270)
These phenotypes are associated with the disease lymphedema-posterior choanal atresia syndrome (OMIM:613611).