Genetic counseling<unk>  is inherited in an autosomal dominant manner and the penetrance of the affected gene is almost complete. Some recent investigations, though, described some rare cases in which the penetrance in<unk>  was not complete. Causes may be a variable expressivity, an incomplete penetrance or germline mosaicism. Only 40% of the mutations are inherited. The remaining 60% are a result of a de novo mutation, where a child has a new mutation in the responsible gene and did not inherit it from either parent. In the outcome of the disease, inter- and intrafamilial variability occurs. This suggests that when an affected child is born, it is important to investigate the parents to determine whether the affected gene is present, because the parent could have a mild form of the disease that has not been diagnosed. In this case, the risk of having another affected child is 50%. If the parents do not have the affected gene, the recurrence risk appears to be low. In following generations, the severity of the clinical symptoms increases. Prenatal diagnosis Mutations in the main genes responsible for<unk>  can be detected with chorionic villus sampling or amniocentesis. Rare mutations may not be detected by these methods. Ultrasonography can be used to detect craniofacial abnormalities later in pregnancy, but may not detect milder cases. Clinical findings<unk>  is often first suspected with characteristic symptoms observed during a physical exam. However, the clinical presentation of<unk>  can resemble other diseases, making diagnosis difficult. The OMENS classification was developed as a comprehensive and stage-based approach to differentiate the diseases. This acronym describes five distinct dysmorphic manifestations, namely orbital asymmetry, mandibular hypoplasia, auricular deformity, nerve development, and soft-tissue disease. Orbital symmetry * O0: normal orbital size, position * O1: abnormal orbital size * O2: abnormal orbital position * O3: abnormal orbital size and position Mandible * M0: normal mandible * M1: small mandible and glenoid fossa with short ramus * M2: ramus short and abnormally shaped # 2A: glenoid fossa in anatomical acceptable position # 2B: Temperomandibular joint inferiorly (TMJ), medially, anteriorly displaced, with severely hypoplastic condyle * M3: Complete absence of ramus, glenoid fossa, and TMJ Ear * E0: normal ear * E1: Minor hypoplasia and cupping with all structures present * E2: Absence of external auditory canal with variable hypoplasia of the auricle * E3: Malposition of the lobule with absent auricle, lobular remnant usually inferior anteriorly displaced Facial nerve * N0: No facial nerve involvement * N1: Upper facial nerve involvement (temporal or zygomatic branches) * N2: Lower facial nerve involvement (buccal, mandibular or cervical) * N3: All branches affected Soft tissue * S0: No soft tissue or muscle deficiency * S1: Minimal tissue or muscle deficiency * S2: Moderate tissue or muscle deficiency * S3: Severe tissue or muscle deficiency Radiographs A few techniques are used to confirm the diagnosis in<unk> . An orthopantomogram (OPG) is a panoramic dental X-ray of the upper and lower jaw. It shows a two-dimensional image from ear to ear. Particularly, OPG facilitates an accurate postoperative follow-up and monitoring of bone growth under a mono- or double-distractor treatment. Thereby, some<unk>  features could be seen on OPG, but better techniques are used to include the whole spectrum of<unk>  abnormalities instead of showing only the jaw abnormalities. Another method of radiographic evaluation is taking an X-ray image of the whole head. The lateral cephalometric radiograph in<unk>  shows hypoplasia of the facial bones, like the malar bone, mandible, and the mastoid. Finally, occipitomental radiographs are used to detect hypoplasia or discontinuity of the zygomatic arch. CT scan A temporal-bone CT using thin slices makes it possible to diagnose the degree of stenosis and atresia of the external auditory canal, the status of the middle ear cavity, the absent or dysplastic and rudimentary ossicles, or inner ear abnormalities such as a deficient cochlea. Two- and three-dimensional CT reconstructions with VRT and bone and skin-surfacing are helpful for more accurate staging and the three-dimensional planning of mandibular and external ear reconstructive surgery. Differential diagnosis Other diseases have similar characteristics to<unk> . In the differential diagnosis, one should consider the acrofacial dysostoses. The facial appearance resembles that of<unk> , but additional limb abnormalities occur in those persons. Examples of these diseases are Nager syndrome and Miller syndrome. The oculoauriculovertebral spectrum should also be considered in the differential diagnosis. An example is hemifacial microsomia, which primarily affects development of the ear, mouth, and mandible. This anomaly may occur bilaterally. Another disease which belongs to this spectrum is Goldenhar syndrome, which includes vertebral abnormalities, epibulbar dermoids and facial deformities.
Treacher Collins syndrome
Miller syndrome
ATR-16 syndrome
Hemifacial microsomia
ATR-X syndrome
Nager acrofacial dysostosis
LIG4 syndrome
Otocephaly