Treacher Collins Syndrome

Treacher Collins Syndrome

Treacher Collins Syndrome is a genetic craniofacial syndrome characterised by hypoplasia, external ear and eyelid malformations and visual disturbance.

Summary Card

Definition
A genetic syndrome with bilateral abnormalities of the first and second branchial arches combining Tessier cleft numbers 6-9.

Aetiology
Sporadic or autosomal dominant inheritance of variable penetrance. TCOF1 is the commonest genetic mutation.

Clinical Features
Pathology of the first and second branchial arches results in deficiencies and excess in bone and soft tissue of the face.

Management
In the acute setting, airway and nutrition are the focus. Longer-term reconstruction focuses on ocular, auricular and mandibular treatments.

Flashcards
Evidence-based flashcards to improve your active recall.

References
Evidence-based citations with current literature.


Definition of Treacher Collins Syndrome

Treacher Collins Syndrome is a genetic craniofacial syndrome characterised by bilateral abnormalities of the first and second branchial arches combining Tessier cleft numbers 6-9.

This condition was first described by Berry in 1889 and later by Treacher Collins in 1900, who was a British Ophthalmologist​1.

Treacher Collins Syndrome

It is also known as mandibulofacial dysostosis, Franceschetti Syndrome2, first and second branchial arch syndrome, or Tessier Cleft 6,7,8.


Aetiology of Treacher Collins


Key Point

The majority of Treacher Collins is the sporadic inheritance of variable penetrance. It can also be caused by autosomal dominant mutations with TCOF1.


The incidence of Treacher Collins syndrome is approximately ~1/50,000 live births.

From a genetic perspective, it is linked to changes in genes on chromosome 5:

  • Autosomal dominant inheritance in 40%
  • Sporadic inheritance in 60%
  • Variable penetrance
  • Linked to TCOF1​3​, PLORIC​4​, POLR1D​4​

There is no general consensus on the pathophysiology of Treacher Collins Syndrome. There are two main theories:

  1. Failure of the facial and mandibular facial processes to fuse​5​.
  2. Manifestation of a combined Tessier 6, 7, 8 facial clefts​6​.

💡
Fun Fact: TCOF1 is the most common gene and is associated with the underproduction of treacle protein, a neural crest precursor.


Clinical Features of Treacher Collins


Key Point

Treacher Collins syndrome is a condition affecting first and second branchial arches. This results in deficiencies and excess bone and soft tissue of the face.


Treacher Collins syndrome affects structures of the first and second branchial arches. This results in abnormalities in the eyes, face, mouth, facial bones, and ears. These clinical features are illustrated in the diagram below.

Clinical Features of Treacher Collins Syndrome

Bone

  • Skull: reduced cranial base angle (basilar kyphosis).
  • Mandible: hypoplasia, shortened ramus, class II malocclusion,
  • Maxilla:  anterior open bite,  absent or ankylosing TMJ.
  • Zygoma: hypoplastic, absent or clefted
  • Orbit: absent lateral orbital walls cause downward palpebral fissures.

💡
Tip: Synostosis is not a typical feature of Treacher Collins syndrome

Soft Tissue

  • Eyelashes: absent medially, lower eyelid colobomas
  • Eyelid: upper lateral half is redundant, which creates a "pseudoptosis."
  • Tarsus: absent
  • Canthus: absent or medially displaced lateral canthus
  • Nose: wide nasal bridge, dorsal hump and poor tip projection.  
  • Muscles: hypoplastic or absent masticators, hypoplastic temporalis
  • Palate: 2° cleft palate (36%) and VPI, or high-arched ​7,10.
  • Ear: microtia or cryptotia, hypoplastic meatus, absent middle ear ossicle, extra auricle8

Function

  • Vision: loss, amblyopia, lateral canthal vertical dystopia
  • Hearing: conductive hearing loss
  • Speech: speech delay    
  • Lacrimal system: absent


Management of Treacher Collins


Key Point

In the acute setting, airway and nutrition are the focus. Longer-term reconstruction focuses on ocular, auricular and mandibular treatments.

Acute Treatment

In the acute setting, airway and nutrition are the primary goals. Airway compromise and poor feeding are issues relating to maxillary hypoplasia, mandibular hypoplasia, and narrow pharyngeal diameter.

  • Prone positioning or nasopharyngeal airway
  • Tube feeding if failure to thrive

Reconstruction

The reconstructive strategy should be individualised to the patient. The goal is to restore function, treat deficits or excesses and improve cosmesis.

Surgical techniques to consider include:

  • Bone graft: orbital floor, zygomatic hypoplasia
  • Costochondral graft: TMJ reconstruction, mandibular deformities
  • Mandible: advancements, distraction, Le Fort I osteotomy
  • Oculoplastics: Lateral Canthopexy
  • Soft Tissue Flaps: ear reconstruction,
  • Rhinoplasty: dorsum hump and loss of nasal tip projection

Each department has specific guidelines for its patient cohort. Generally speaking, the following timeline is recommended:

  • Orbital Reconstruction: >7 years after bone development  
  • Mandible: during early teenage years
  • Middle ear: after external ear reconstruction  


Flashcards

Evidence-based flashcards are designed for active recall and spaced repetition using the Feynman Technique.

They are continually updated for thePlasticsPro users.


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