microtia

Treacher Collins-Franceschetti Syndrome

Clinical Characteristics
Ocular Features: 

Lid fissures often have an antimongoloid slant.  Many patients (69%) have a coloboma of the lower eyelid (in contradistinction to Goldenhar spectrum syndrome [164210] in which the lid colobomas involve the upper eyelid) with a paucity of lashes and meibomian glands medially.  Colobomas may also involve the iris, choroid and optic nerve.  Other ocular features include blepharoptosis, hypoplasia of the supraorbital ridges, absent lacrimal puncti, underdevelopment of the orbicularis oculi muscle, absence of the tarsal plate, and abnormalities of the lateral canthal tendons.  Strabismus and amblyopia have been reported in a significant number of individuals.

Systemic Features: 

A variety of defects in facial development have been reported, most involving the ears, eyelids, lower jaw, and zygomatic arch.  The characteristic facial phenotype is usually evident at birth.  One-third of patients have a cleft palate.  Microtia or even anotia may be present and a conductive hearing loss can result, especially when the ossicles are malformed or absent.  The pinnae are often malformed, appearing 'crumpled', low-set, and rotated posteriorly.  There may be ear tags and blind fistulas anywhere between the tragus and angle of the mouth.  The mandible and its rami may be hypoplastic causing severe micrognathia that can result in feeding and speaking difficulties, especially when pharyngeal hypoplasia is also present.  The zygomatic arches are often underdeveloped (or even absent) and the midface is flattened.  Arhinia and cleft palate are sometimes seen.  A low hairline may be present.  Intelligence is usually normal.

Genetics

This is an autosomal dominant syndrome secondary to mutations in the TCOF1 gene located at 5q32-q33.1.  A parental gender influence is suggested by at least one study which found an increase in the number of affected offspring from affected mothers compared with those from affected fathers.  Many cases (60%) result from new mutations but a paternal age effect has not been established.  Inter- and intrafamilial clinical variation is wide.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Auditory testing should be done early since corrective action is important in the prevention of developmental delays.  Reconstructive facial surgery can be of great benefit to both cosmesis and function.  Lid reconstruction may be required for corneal protection.

References
Article Title: 

Genotyping in 46 patients with tentative diagnosis of Treacher Collins syndrome revealed unexpected phenotypic variation

Teber OA, Gillessen-Kaesbach G, Fischer S, Bohringer S, Albrecht B, Albert A, Arslan-Kirchner M, Haan E, Hagedorn-Greiwe M, Hammans C, Henn W, Hinkel GK, Konig R, Kunstmann E, Kunze J, Neumann LM, Prott EC, Rauch A, Rott HD, Seidel H, Spranger S, Sprengel M, Zoll B, Lohmann DR, Wieczorek D. Genotyping in 46 patients with tentative diagnosis of Treacher Collins syndrome revealed unexpected phenotypic variation. Eur J Hum Genet. 2004 Nov;12(11):879-90.

PubMed ID: 
15340364

Goldenhar Syndrome Spectrum

Clinical Characteristics
Ocular Features: 

There is considerable clinical heterogeneity in this syndrome.  Upper eyelid colobomas and ocular dermoids or lipdermoids are the primary ocular signs (lower lid colobomas are more common in Treacher Collins-Franceschetti syndrome [154500]).  The caruncles may be dysplastic, displaced or even bilobed.  Iris, optic nerve and chorioretinal colobomas also occur.  Microphthalmia is uncommon.  All ocular features are usually unilateral but are bilateral in a minority of cases.

Systemic Features: 

The facial asymmetry (hemifacial microsomia) can be a striking feature.  The side with microsomia may have a malformed external auricle, preauricular tags, pretragal fistulas, and microtia or even atresia of the external auditory canal.  A wide variety of other anomalies are often found including left lip and palate, mandibular hypoplasia, vertebral anomalies, facial nerve paralysis, congenital heart defects, and conductive hearing loss.  Mental deficits are often present along with features of the autism spectrum in 11%.

Genetics

Most cases are sporadic but other family patterns support autosomal recessive and autosomal dominant inheritance with the latter being the most common.  A locus at 14q32 has been associated with OAVS but so far no mutant gene has been identified.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Some patients benefit from scoliosis and cosmetic surgery.  Assistive hearing devices can be helpful and children especially should be monitored for physical and cognitive development.

References
Article Title: 

Oculo-auriculo-vertebral spectrum: clinical and molecular analysis of 51 patients

Beleza-Meireles A, Hart R, Clayton-Smith J, Oliveira R, Reis CF, Venancio M, Ramos F, Sa J, Ramos L, Cunha E, Pires LM, Carreira IM, Scholey R, Wright R, Urquhart JE, Briggs TA, Kerr B, Kingston H, Metcalfe K, Donnai D, Newman WG, Saraiva JM, Tassabehji M. Oculo-auriculo-vertebral spectrum: clinical and molecular analysis of 51 patients. Eur J Med Genet. 2015 Sep;58(9):455-65.

PubMed ID: 
26206081
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