Treacher Collins syndrome

The signs and symptoms of Treacher Collins syndrome vary greatly, ranging from almost unnoticeable to severe. Most affected people have underdeveloped facial bones, particularly the cheek bones, and a very small jaw and chin (micrognathia). Some people with this condition are also born with an opening in the roof of the mouth called a cleft palate. In severe cases, underdevelopment of the facial bones may restrict an affected infant's airway, causing potentially life-threatening respiratory problems.^[3]

People with Treacher Collins syndrome often have eyes that slant downward, sparse eyelashes, and a notch in the lower eyelids called a coloboma. Some people have additional eye abnormalities that can lead to vision loss. The condition is also characterized by absent, small, or unusually formed ears. Defects in the middle ear (which contains three small bones that transmit sound) cause hearing loss in about half of affected people. People with Treacher Collins syndrome usually have normal intelligence.^[3] 

You can read additional information about the features of Treacher Collins syndrome through MedlinePlus and GeneReviews.

Treacher Collins syndrome (TCS) is caused by changes (mutations) in any of several genes: TCOF1 (in over 80% of cases), POLR1C, or POLR1D. In a few cases, the genetic cause of the condition is unknown.

These genes appear to play important roles in the early development of bones and other tissues of the face. They are involved in making proteins that help make ribosomal RNA (rRNA). rRNA is a chemical needed to make new proteins that are necessary for normal function and survival of cells. Mutations in these genes can reduce the production of rRNA, which may cause cells involved in the development of facial bones and tissues to die early. This premature cell death may lead to the signs and symptoms of TCS. It is still unclear why the effects of these mutations are generally limited to facial development.^[1]

There is currently no cure for Treacher Collins syndrome (TCS).^[4] Treatment is tailored to the specific needs of each affected person. Ideally, treatment is managed by a multidisciplinary team of craniofacial specialists.

Newborns may need special positioning or tracheostomy to manage the airway. Hearing loss may be treated with bone conduction amplification, speech therapy, and/or educational intervention.^[5]

In many cases, craniofacial reconstruction is needed. Surgery may be performed to repair cleft palate, to reconstruct the jaw, or to repair other bones in the skull. The specific surgical procedures used and the age when surgery is performed depends on the severity of the abnormalities, overall health and personal preference.^[4]

There are some possible treatments that are being investigated. Researchers are looking for ways to inhibit a protein called p53, which helps the body to kill off unwanted cells.^[4][5] In people with TCS, p53 is abnormally activated, leading to the loss of specific cells and ultimately causing features of TCS. It has been proposed that inhibiting the production of p53 (or blocking its activation) may help to treat affected people. However, more research is needed to determine if this type of treatment is effective and safe.^[4]

Researchers are also studying the use of stems cells found in fat tissue to be used alongside surgery in people with TCS and other craniofacial disorders. Early studies have shown that surgical outcomes may be improved using these stem cells to help stimulate the regrowth of affected areas. However, this therapy is still experimental and controversial.^[4][5]

Usually, people with Treacher Collins syndrome grow to become functioning adults with normal intelligence.^[6] With proper management, life expectancy is approximately the same as in the general population.^[5] In some cases, the prognosis depends on the specific symptoms and severity in the affected person. For example, very severe cases of TCS can cause perinatal death because of a compromised airway.^[7]