Treacher Collins syndrome is a rare genetic birth defect that often causes deformities in the size and shape of various facial features. In some cases, symptoms are so mild that they generally go unnoticed, even by patients.

In many other cases, Treacher Collins syndrome causes significant physical deformities, including underdeveloped cheekbones and jawbones, deformity of the roof of the mouth (cleft palate), eyelid problems and ear deformities. Hearing loss and breathing difficulties are also commonly associated with this condition.

A single gene abnormality causes Treacher Collins syndrome. This gene is found on chromosome 5. A mutation of this gene may occur during its development or through transfer of a mutated gene from parent to child.

Early diagnosis of Treacher Collins syndrome – well before a child’s first birthday – is essential. Physical deformities of the syndrome may interfere with proper breathing or feeding of infants. Hearing loss often associated with the syndrome can lead to language and other developmental difficulties. A physician will likely perform a physical examination and collect a patient’s medical history. Genetic testing and hearing tests may also be performed.

Treacher Collins syndrome is a rare birth defect that often causes deformities in the size and shape of various facial features. Affected areas of the face include the ears, eyelids, cheekbones, and the upper and lower jaws. 

Treacher Collins syndrome is also known as Franceschetti-Zwalen-Klein syndrome or mandibulofacial dysostosis. The condition occurs in one in every 50,000 live births, according to the National Institutes of Health.

An English physician named Edward Treacher Collins was the first to describe this syndrome in 1900. Children who are affected may experience a range of symptoms from mild to severe. In some cases, symptoms are so mild that they can only be detected by an expert.

However, in other cases the physical signs of Treacher Collins syndrome can be very obvious. Symptoms may include underdeveloped cheekbones and jawbones, deformity of the roof of the mouth (cleft palate), eyelid problems and ear deformities. Because deformities of the outer and middle ear are common, hearing loss often accompanies the syndrome.

A single gene abnormality causes Treacher Collins syndrome. This gene is found on chromosome 5, and the normal function of the gene is unknown. More than 50 different changes in the gene have been associated with Treacher Collins syndrome. A recent study found that during embryonic development, an abnormally high level of cell death in cells called neural crest cells occurs in babies with Treacher Collins syndrome, leading to the facial abnormalities.

In more than half of cases, the gene mutation that causes Treacher Collins syndrome occurs spontaneously during embryonic development. There is no evidence that a mother’s lifestyle choices during pregnancy affect this mutation.

However, the Treacher Collins gene mutation is autosomal dominant, which means that if one parent has the mutation, they have a 1 in 2 chance of passing the mutation on to their child. A parent with Treacher Collins syndrome may have one normal gene and one altered gene. If the altered gene is passed on to a child, Treacher Collins syndrome can result. About 40 percent of people with Treacher Collins syndrome also have a parent with the syndrome, according to the National Craniofacial Association. Both males and females are affected equally by Treacher Collins syndrome.

In some cases, the physical signs of Treacher Collins syndrome are so mild they can only be detected by an expert. In other cases, these signs may be obvious. For example, the nose, throat and jaw tend to be underdeveloped in patients with Treacher Collins syndrome, while the mouth is usually enlarged.

Ear abnormalities are common in patients with Treacher Collins syndrome. The ears may be small, low-set or almost completely absent. Other ear abnormalities include absence of the external auditory canal, prominent outer ears, the presence of ear tags (extra bits of skin in front of the ear) and preauricular pits (little holes in front of the opening of the external ear).

A cleft palate is also associated with Treacher Collins syndrome in 33 percent of cases. This occurs when the roof of the mouth (palate) is either underdeveloped or split.

Drooping eyelids are another common feature of Treacher Collins syndrome. These often give a child a saddened appearance. In some cases, a small notch is missing from the lower eyelid, a condition known as coloboma. The eye may be abnormally shaped and there may be few eyelashes on the lower eyelid.

Other physical signs of Treacher Collins syndrome include:

• Tendency toward dry eyes, which can lead to infection
• Flat cheekbones
• Scalp hair that extends to the cheeks
• Abnormally small or absent thumbs

Breathing problems often accompany Treacher Collins syndrome because airway space is reduced due to small, undeveloped jaws that position the tongue farther back in the mouth. Colds and infections can exacerbate breathing problems due to congestion and swelling of tissue lining the airway.   

Conductive hearing loss is also frequently associated with Treacher Collins syndrome. "Conductive" means the impairment is a result of abnormalities in the structure of the outer auditory canal and middle ear bones. While the degree of hearing loss may vary, there is usually about a 40 percent loss in each ear that does not diminish to the level of deafness. In most cases, hearing loss affects both ears and is significant enough to hinder a child’s ability to hear the human voice.

Early diagnosis of Treacher Collins syndrome – well before a child’s first birthday – is essential. Infants with physical signs or complications of the syndrome (e.g., a cleft palate, airway problems) often have difficulty breathing and/or feeding. Hearing loss associated with Treacher Collins syndrome can lead to language and other developmental difficulties. Parents who notice signs of the syndrome in their child should consult their child’s physician.

A physician will begin by performing a complete physical examination and compiling a thorough medical history of the child and parents. Genetic testing may be ordered to identify the specific gene mutation that causes the syndrome.  

A hearing test will be performed to identify the extent of any hearing damage associated with the syndrome. Children with jaws that are smaller than normal and restricted airways may also be tested for sleep apnea, a condition in which breathing temporarily ceases during sleep.

Preparing questions in advance can help patients and parents have more meaningful discussions with their physicians regarding their or their child’s treatment options. The following questions related to Treacher Collins syndrome may be helpful:

1. When will I first see signs of Treacher Collins syndrome in my child?
   
   
2. What tests will you need to perform to identify Treacher Collins syndrome?
   
   
3. What is the likely cause of my child’s Treacher Collins syndrome?
   
   
4. What are my child’s treatment options?
   
   
5. Which surgeries will be necessary? When will they begin and end?
   
   
6. How costly are these surgeries? Are they likely to be covered by insurance?
   
   
7. What expectations should I have regarding my child’s appearance following surgery?
   
   
8. How will you treat my child’s hearing loss?
   
   
9. Is speech therapy necessary for my child?
   
   
10. Is psychotherapy necessary for my child?  Can you recommend someone?
    
    
11. Should I be tested for Treacher Collins syndrome?