Phenotypes associated with the disease Treacher Collins syndrome 2 (OMIM:613717):
- Cleft palate (HP:0000175): Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate). Evidence: PCS. Frequency: 4/13. (PMID:21131976;PMID:24603435)
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 2/4. (PMID:24603435)
- Downslanted palpebral fissures (HP:0000494): The palpebral fissure inclination is more than two standard deviations below the mean. Evidence: PCS. Frequency: 9/12. (PMID:21131976;PMID:24603435)
- Preauricular pit (HP:0004467): Small indentation anterior to the insertion of the ear. Evidence: PCS. Frequency: 1/4. (PMID:24603435)
- 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: 1/5. (PMID:21131976)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: PCS. Frequency: 2/7. (PMID:21131976)
- Choanal stenosis (HP:0000452): Abnormal narrowing of the choana (the posterior nasal aperture). Evidence: PCS. Frequency: 1/5. (PMID:21131976)
- Fusion of middle ear ossicles (HP:0005473): Bony fusion of malleus, incus, and stapes. Evidence: PCS. Frequency: 1/4. (PMID:24603435)
- Malar flattening (HP:0000272): Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation. Evidence: PCS. Frequency: 3/4. (PMID:24603435)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 1/7. (PMID:21131976)
- Hypoplasia of the zygomatic bone (HP:0010669): Underdevelopment of the zygomatic bone. That is, a reduction in size of the zygomatic bone, including the zygomatic process of the temporal bone of the skull, which forms part of the zygomatic arch. Evidence: PCS. Frequency: 5/8. (PMID:21131976)
- Anotia (HP:0009892): Complete absence of any auricular structures. Evidence: PCS. Frequency: 1/4. (PMID:24603435)
- Microretrognathia (HP:0000308): A form of developmental hypoplasia of the mandible in which the mandible is mislocalised posteriorly. Evidence: PCS. Frequency: 2/4. (PMID:24603435)
- Microtia (HP:0008551): Underdevelopment of the external ear. Evidence: PCS. Frequency: 7/9. (PMID:21131976)
- 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:24603435)
- Conductive hearing impairment (HP:0000405): An abnormality of vibrational conductance of sound to the inner ear leading to impairment of sensory perception of sound. Evidence: PCS. Frequency: 8/12. (PMID:21131976;PMID:24603435)
- Lower eyelid coloboma (HP:0000652): A short discontinuity of the margin of the lower eyelid. Evidence: PCS. Frequency: 3/8. (PMID:21131976)
- Retrognathia (HP:0000278): An abnormality in which the mandible is mislocalised posteriorly. Evidence: PCS. Frequency: 1/4. (PMID:24603435)
- Autosomal dominant inheritance (HP:0000006): 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 heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:21131976)
- Micrognathia (HP:0000347): Developmental hypoplasia of the mandible. Evidence: PCS. Frequency: 11/13. (PMID:21131976;PMID:24603435)