A rare congenital disorder, Treacher Collins syndrome affects the bones and other tissues located in the face. The syndrome is relatively rare, affecting roughly 1 in 50,000 people according to the National Institutes of Health (NIH).
The symptoms of the disorder vary dramatically and range from barely noticeable to very severe, causing significant impairments in some babies. The condition primarily affects the structure of the facial features; however, in severe cases underdevelopment can actually restrict airway and cause life-threatening respiratory concerns. Learn more about the condition, including the typical inheritance pattern and potential treatment options.
What Is Treacher Collins Syndrome?
Treacher Collins syndrome is a disorder that is present from birth (congenital). The condition largely impacts the development of the face, particularly the cheekbones, jaws, ears, and eyelids. Underdevelopment of these facial components also often impacts breathing, swallowing, chewing, speaking, and even hearing.
Also known as mandibulofacial dysostosis and Franschetti-Zwahlen-Klein syndrome, the condition is relatively rare and currently impacts boys and girls equally. The extent to which the condition affects each child varies widely, meaning that some children experience very mild and almost indistinguishable facial changes while others present with extreme disfiguration of the face.
The condition is genetic, so it is typically passed from parent to child. However, there have been a few cases when the syndrome has developed without warning. So understanding the symptoms, causes, and treatments is important for proper identification and effective management of the syndrome in affected children.
Symptoms of Treacher Collins Syndrome
Depending on the severity of the syndrome, symptoms may be almost unnoticeable to extremely severe. Some children develop such severe symptoms that the condition becomes life-threatening. Common symptoms of Treacher Collins syndrome include:
- Lazy eye, poor focus, and vision loss.
- Notching and/or sparse or absent eyelashes, particularly in the lower lids.
- Underdeveloped cheekbones and jaw.
- Absent, small, or rotated ears.
- Displaced hair growth, such as in front of the ears.
- Cleft palate with or without a cleft lip.
- Underdeveloped or blocked airways.
- Incomplete skull formation.
- Underdeveloped nose.
- Displaced teeth.
Complications of TCS
In some cases, children may develop hearing loss due to the underdevelopment of the bones in the face as well as incomplete development or unusual placement of the ears. Treacher Collins syndrome also can cause delays in speech and motor development. Other potential complications include:
- Sleep apnea.
- Eating difficulties.
- Eye infections.
- Cognitive delay.
Causes of Treacher Collins Syndrome
The condition is caused by a genetic mutation of one or several of the genes on the 5th chromosome that are responsible for how the baby’s face develops in utero. In roughly 40 percent of cases, one parent has a mutated gene as well that he or she passes to the child. The donor parent may be so mildly impacted by the syndrome that he or she is unaware of his or her own genetic condition.
In the other 60 percent of cases, the condition begins randomly as the result of a new genetic change not inherited from either parent. There is nothing that can be done to prevent or even predict this type of random genetic mutation.
The three genes currently known to cause Treacher Collins syndrome include:
- TCOF1 – A dominant gene, a child only needs to inherit one copy of this genetic mutation from either parent to develop the condition. Defects of this gene are responsible for roughly 80 percent of TCS cases.
- POLR1C – A recessive gene, a child needs to receive a copy of this gene from each parent to develop the disease. If the parents are both carriers of this mutation, they have a 25 percent chance of having a child with the disease.
- POLR1D – This gene has been reported as being both dominant and recessive, so it shares characteristics with each of the other responsible genetic mutations.
Diagnosis of Treacher Collins Syndrome
An accurate diagnosis is an important first step in treatment for this genetic condition. Your doctor will carefully evaluate your child to determine his or her condition before suggesting treatment options. The evaluation process will likely include:
- A physical exam.
- A thorough medical history.
- Genetic testing – In some cases this step is unnecessary because the clinical features alone are distinguishable enough to deliver a diagnosis.
Treatment for TCS
The condition is incurable, so treatment typically centers on correcting the facial features as well as managing any symptoms that may limit your child’s abilities. Depending on the severity of the condition, your doctor will devise a treatment plan that may involve:
- Genetic counseling – This component of treatment may be provided for the affected individual or whole family depending on the inheritance pattern of the condition.
- Audiology support – If there is a significant hearing loss, hearing aids or other devices may be provided to reduce deficits.
- Dental work – Dental care including orthodontics may be used to help correct your child’s bit.
- Speech therapy – If the underdevelopment of the face affects the child’s communication skills, a speech pathologist will assist to improve speech and language skills as well as issues with chewing and swallowing.
- Surgery – Depending on the severity of the condition, surgery may be able to improve both the function and appearance of the facial features.
Common Surgical Options for Treacher Collins Syndrome
Surgery is one of the most common therapies utilized to treat issues with underdevelopment of the facial bones and tissue. The timing of surgery is dependent on the child’s age and developmental stage as well as the impact of the deformity on the child’s ability to function. In any cases, common surgical options include:
- Eyelid reconstruction.
- Cleft palate closure.
- Facial bone repair.
- Ear reconstruction.
- Jaw repositioning.
In most cases, reconstructive surgery restores usable function and improves the child’s quality of life.
A rare genetic disorder, Treacher Collins syndrome impacts the growth and development of the head and can cause facial defects as well as hearing loss. Fortunately, the condition does not typically alter a child’s intelligence or cognitive ability. And while the condition is not curable, reconstructive surgery and other treatment options are generally effective for improving the child’s overall quality of life.