Overview

Treacher Collins syndrome (TCS) is a congenital defect that affects a group of skull and facial bones in a child. This condition affects 1 in 50,000 live births, 40% of cases involving a family history, while the remaining 60% occur due to gene mutations.¹ The condition occurs due to issues in early face and ear development.

People born with this condition can have different symptoms. Some may have only mild changes around the eyes that are hard to notice, while others may have more severe facial differences. These can include: downward-slanting eye openings, changes in the position of the inner corners of the eyes, small or misshapen ears, a lower-than-usual hairline, and an underdeveloped upper and lower jaw. Physical features due to TCS tend to be symmetrical.

Small or misshapen ears can cause hearing loss and speech delays, whilst a small lower jaw may lead to breathing difficulties, and a cleft palate (which happens in about 40% of cases). In some cases, intellectual disability and other health issues, like heart problems, can also occur due to the genetic cause of the condition.

Understanding Treacher Collins Syndrome

Causes

TCS is usually caused by changes (mutations) in certain genes, mainly the TCOF1 gene, but also POLR1D and POLR1C. These genes are important for early facial development. When they don't work properly, they lead to problems in how the bones and tissues of the face form.

In most cases (about 60%), the genetic change happens for the first time in the child and is not inherited from the parents. In about 40% of cases, it runs in families. However, some cases follow a different pattern of inheritance. 

The severity of the condition can vary, even within the same family, and there is no clear link between the specific gene mutation and how severe the symptoms will be.^2,3 

Clinical Features of Treacher Collins Syndrome 

Treacher Collins syndrome mainly affects the development of the face and head. People with TCS often have underdeveloped facial bones, especially the lower jaw (in about 78% of cases) and the cheekbones (in about 81% of cases). This can cause problems with how the teeth fit together, leading to an open bite, widely spaced or misaligned teeth, and sometimes missing teeth. Many people with TCS also have a high-arched or cleft palate (about 28% of cases).⁴ Differences in the eye are common, including downward-slanting eyes (seen in 89% of cases) and notches in the lower eyelids (69%). The eyelashes in the inner corners of the eyes may also be missing.

The ears can also be affected, with changes in their shape, size, or position. Some people may be born without an opening in their ear canal, and the tiny bones inside the middle ear may be irregular, missing, or fused together. Because of this, most people with TCS have hearing loss due to sound not being able to travel properly through the ear. However, complete deafness from nerve damage is rare.⁴

Diagnosis: Diagnosis of TCS can be confirmed based on clinical and radiographic findings. X-ray and computed tomography (CT) scans show that the bones in the lower jaw are underdeveloped, and the cheekbones are smaller than usual. The lower jaw is shorter, leading to crowded teeth. The scans also show changes in the angles of the jawbone. The scans also show that both outer ears are underdeveloped, and the ear canals are either very small or missing. The middle ear structures are also affected, with small or missing ear bones, which can contribute to hearing loss. There are no issues found in the sinuses.⁵

How Treacher Collins Syndrome Affects a Child’s Development and Management

Upper Airway

TCS patients suffer from obstructive sleep apnea. Obstructive sleep apnea is when you stop breathing during sleep due to some blockage in your trachea (windpipe).¹

A person with Treacher Collins syndrome (TCS) may have serious breathing problems caused by a small, lower jaw or the tongue blocking the airway. If changing sleeping positions or other non-surgical methods don’t help, doctors may recommend surgery to open the airway.²

Common surgical procedures include:

• Mandibular distraction osteogenesis – a procedure that slowly stretches the lower jaw to make it larger.
• Tongue-lip adhesion – a surgery that temporarily moves the tongue forward to keep it from blocking the airway.
• Tracheostomy – a procedure where a small hole is made in the neck to help with breathing in severe cases.

For some patients, additional procedures like genioplasty distraction osteogenesis (to reshape the chin) and hyoid advancement (to improve airway support) may be needed if the first surgery does not work well.

The main goals of these surgeries are to avoid or remove a breathing tube (tracheostomy) and to improve breathing, especially during sleep. While these procedures can also help with the alignment of the teeth and appearance of the lower jaw, more surgeries may be needed as the face continues to grow.

Dentition and Palate

About one-third of people with Treacher Collins syndrome (TCS) are born with a cleft palate, which is a gap in the roof of the mouth. The timing of cleft palate surgery is usually the same as for children without TCS. However, studies show that people with TCS may have a higher chance of developing small openings (fistulas) in the repaired palate. This may happen because the tissues in the mouth do not have enough blood flow for proper healing. The shape and structure of the mouth, including a small opening and a high-arched palate, can make cleft palate surgery more challenging.⁵ Speech and language therapy is especially important for people with TCS, as surgery alone may not fully correct speech issues. 

Problems with how the teeth fit together (malocclusion) are very common in people with Treacher Collins syndrome (TCS), affecting up to 94% of patients. Most often, this includes an open bite (where the front teeth don’t touch when the mouth is closed) and teeth that are not in the right position. Because of these dental issues, experts recommend closely monitoring a child's teeth and oral hygiene from an early age. Once all the permanent teeth come in, orthodontic treatment (like braces) may help improve the alignment and function of the teeth.²

Ear Malformation and Hearing

Ear problems are very common in people with Treacher Collins syndrome (TCS), affecting up to 87% of patients. The ears may be smaller than normal (microtia) or, in some cases, missing entirely (anotia). The ears and hairline may also be positioned lower than usual in nearly half of patients. Many people with TCS have narrow or blocked ear canals, and the middle ear may be poorly developed or missing. Because of this, up to 96% of patients experience some level of hearing loss. The more severe the ear canal issues, the greater the hearing loss tends to be.^1,2

Hearing problems can also lead to speech delays or difficulties, especially if left untreated. To help manage these issues, it is important to see specialists such as an ear, nose, and throat (ENT) doctor, an audiologist (hearing specialist), and a speech therapist to improve communication and language development.

Hearing problems in Treacher Collins syndrome (TCS) are usually managed with special headbands that hold a bone-anchored hearing aid (BAHA). These devices help improve hearing while a child is still growing. Using a BAHA early on is important as it helps prevent delays in speech and language development. Later, when the child is older and their skull is more developed, doctors can perform ear reconstruction surgery in stages. After the ear is fully formed, a permanent bone-anchored hearing aid can be placed for better long-term hearing support.²

Periorbital Features

People with Treacher Collins syndrome (TCS) often have underdeveloped facial structures, especially around the eyes. A common feature is downward-slanting eyes, which happens because the bones around the outer corners of the eyes are smaller or missing.

Many individuals also have underdeveloped cheekbones, which makes the face appear narrower and flatter. Other eye-related issues can include:

• Gaps in the lower eyelids or iris (coloboma)
• Eyelids that turn outward (ectropion)
• Missing eyelashes on the inner part of the eyelid
• Tear duct problems, leading to excessive tearing (epiphora)
• Eye movement issues (strabismus), lazy eye (amblyopia), cataracts, vision problems, or even vision loss

Because the bones around the eyes are unevenly developed, the eye sockets (orbits) may also have an irregular shape.

Surgery for Treacher Collins syndrome (TCS) is usually done in stages, with the first priority being to protect the eyes from dryness and damage. One common procedure, tarsorrhaphy, helps keep the eyes moist by partially closing the eyelids.

To improve the appearance of the lower eyelids, different surgical techniques can be used, such as Z-plasty (a technique to reduce scarring and improve eyelid position), skin and muscle grafts, or canthopexy (a procedure to adjust the outer corners of the eyes). However, these surgeries often leave some visible scars and may not always achieve perfect results.

For underdeveloped cheekbones, doctors usually recommend bone grafting, which involves adding bone to reshape the face. This is typically done in late childhood, often after age 7, to allow for better long-term results.²

Summary

Treacher Collins Syndrome (TCS) is a rare genetic condition affecting facial and skull development. It occurs in about 1 in 50,000 births, with 40% of cases inherited and 60% caused by new gene mutations. TCS primarily results in underdeveloped facial bones, downward-slanting eyes, small or misshapen ears, and potential hearing loss. Other complications may include breathing difficulties, cleft palate, and dental abnormalities.

Diagnosis is based on clinical features and imaging studies. Treatment focuses on managing breathing, hearing, dental, and eye-related issues. Surgical procedures like jaw reconstruction, cleft palate repair, and ear reconstruction can help improve function and appearance. Early interventions, including speech therapy and hearing aids, are essential for better development and quality of life.