Treacher Collins Syndrome (TCS)

Also known as

  • Franceschetti-Klein syndrome

TCS is a genetic condition affecting the growth and development of bones and tissue of the face. The severity of the symptoms expressed in affected indivuals varies greatly. TCS does not affect intelligence.

Condition details

Symptoms of TCS can vary greatly between affected inviduals. Some may be severely affected, whilst in others, it's barely noticeable. The most common symptoms are: • Under-developed cheekbones • Small jaw (upper and lower) • 'Notching' of the lower eye-lid (downwards slanting eyes) • Very few or absent lower eyelashes • Malformed/missing ears • Conductive hearing loss In severe cases, under-developed facial bones may lead to breathing problems. Nearly 60% of cases are caused by a new mutation in the TCOF1 gene, i.e. the condition is not inherited. In other cases, it is inherited from an affected parent or parents who are carriers of either the POLR1C or POLR1D genes. TCS is managed by a muti-disciplinary team. Some people may require a tracheostomy to assist breathing. Where a hearing loss is present, this is usually treated with a bone conduction hearing aid. Diagnosis usually confirmed with genetic testing to find one of the known TCS-causing genes.

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Photos of affected individuals

Click images to enlarge.

  • No baby imageBaby
  • No toddler imageToddler
  • No child 4-10 imageChild 4-10
  • No child 10-18 imageChild 10-18
  • No adult imageAdult

Typical age range of first manifestation

  • Can manifest in Baby
  • Does not manifest in Toddler
  • Does not manifest in Child 4-10
  • Does not manifest in Child 10-18
  • Does not manifest in Adult


Lay terms Clinical terms
  • hypoplasia of the zygomatic bones and mandible
  • external ear abnormalities
  • coloboma (notching) of the lower eyelid
  • absence of the lower eyelashes
  • and preauricular hair displacement onto the cheeks. About 40%-50% of individuals have conductive hearing loss attributed most commonly to malformation (including ankylosis
  • hypoplasia
  • or absence) of the ossicles and hypoplasia of the middle ear cavities. Inner ear structures tend to be normal. Other less common abnormalities include cleft palate with or without cleft lip and unilateral or bilateral choanal stenosis or atresia. (ref: Gene Reviews
  • Sara Huston Katsanis
  • MS and Ethylin Wang Jabs
  • MD).

Affected genes identified to date


Inheritance patterns

Is Autosomal recessive Is Autosomal dominant

Are carriers affected?

TCOF1 carriers are affected, howeever the there can be varying degrees of severity. Carries of POLR1C or POLR1D genes are unaffected as these are recessive genes.

How many are affected?

1 in every 50,000 people

Support groups and organisations

Treacher Collins Family Support Group
Tel (01603) 433736

Known experts

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