Treacher Collins Syndrome (TCS) is a hereditary condition that leads to facial deformities. The proper medical term for this condition is Mandibulofacial Dysostosis (MFD1), and it is characterized by underdeveloped jawbones and cheekbones. The syndrome occurs across all races, affecting males and females equally, and is thought to affect 1 in every 50,000 people. For the most part, TCS is diagnosed at birth, but it may also be diagnosed by an ultrasound before the baby is born. If the child has a mild case of TCS, it may not be immediately diagnosed at the time of birth.
What are the Characteristics of Treacher Collins Syndrome?
TCS affects the appearance of the head and face. The characteristics include:
- Eyes that slant downwards
- An indentation in the lower eyelids, called a coloboma
- Sparse eyelashes
- Underdeveloped cheekbones and eye sockets
- Small and slanting lower jaw
- Small, underdeveloped, and/or unusually formed ears
Problems Associated with Treacher Collins Syndrome
Individuals with TCS are often born with a cleft palate (an opening in the roof of the mouth), which may require surgery, in order to correct it. Surgery may also be required to repair the eye socket, cheekbones, nose, ears, and other affected areas. Some persons with TCS also have further eye abnormalities, which can cause a loss of vision. Eye infections are common in people with TCS, since the eyes tend to dry out easily. About 50% of people with TCS have middle ear defects, which can lead to hearing loss. Children with hearing problems associated with TCS may need hearing aids, and the sooner the detection of hearing loss, the better. TCS may also cause breathing problems and difficulty with eating.
What Causes Treacher Collins Syndrome?
It is believed that TCS is caused by a mutation in the TCOF1 gene on chromosome 5, which controls facial development. This gene gives instructions for the making of a protein known as treacle. Although the specific function of this gene is unknown, it is believed to be crucial in the embryonic development of facial bones and tissues. When the TCOF1 gene mutates, it reduces treacle production in the cells. Scientists believe that this decrease sends a message to the cells that are essential in facial bone development, telling them to self-destruct. The death of these cells is believed to give rise to the abnormalities in facial development that Treacher Collins Syndrome is characterized by.
How is Treacher Collins Syndrome Passed On?
A child has a 50% chance of inheriting TCS from a parent who has it. In 40% of the TCS cases, one parent has the TCS gene. It is also possible for the children of unaffected parents to be born with TCS. This happens as a result of new mutations of the TCOF1 gene. Geneticists are doing research into whether there are other genes that play a role in the development of TCS.
The good news is that children who have Treacher Collins Syndrome develop normally and have normal levels of intelligence. Still, it is vital that their hearing is tested from early, since they benefit greatly from early introduction to programs that help with the development of language.