Visual Clues for Treacher Collins Syndrome
How is Treacher Collins syndrome diagnosed by simple visual assessment? Children affected by Treacher Collins syndrome, also known as Mandibulofacial Dysostosis, generally can be identified through a variety of physical characteristics. Many of these features are prominent when the child is an infant and can sometimes even be seen via ultrasound when it is in the womb. Most commonly, however, these visual abnormalities will be diagnosed at birth by the doctor through simple examination.
One of the most identifiable characteristics are ear, eye, mouth and other facial problems. The child’s ears can be smaller than average, deformed, set lower on the head or even missing altogether. Sometimes the ear can develop in the womb without an ear canal, causing deafness. Eyes often slope downward or have no lower eyelids, causing extreme visual impairment. Other problems impact the jaws and teeth, limiting the ability of a child to properly open or close his or her mouth. Treacher Collins syndrome is also responsible for many instances of cleft palate. Facial features commonly present also include a lack of fully-developed cheekbones or brow bones.
As the child develops, these symptoms can become even more prominent. Despite the fact that the actual intelligence of those suffering from the disease, most experience difficulties in speech and hearing due to the malformations.
Confirming the Diagnosis of Treacher Collins Syndrome
How is Treacher Collins syndrome diagnosed through other means? In order to confirm the presence of the disease or to ensure that a child without prevalent signs of Treacher Collins syndrome, doctors often employ a number of technologically advanced diagnostic techniques. Commonly, physicians use either CT scanners or MRI machines to see details not available on the surface. Sometimes, they even simply take an X-ray to see bone structure, which helps identify features not readily seen from visual examinations.
Since Treacher Collins syndrome is a genetic disorder, the most successful diagnostic tool used by the medical community is a genetic test. While previously used only in special circumstances, the genetic test for Treacher Collins syndrome is now utilized on a routine basis, even occasionally conducted when the child is still developing in the womb.
Mutations in the TCOF1 gene show whether a person suffers from the disorder. This is located on the chromosome band 5q31.3-33.3. This gene is responsible for producing the codes that develop treacle protein. Treacle protein has been found to be the main active component in trafficking craniofacial development in humans. When a mutation is present in the gene, it causes the protein to prematurely terminate, preventing the proper formation of certain features.
The diagnostic procedure can identify which of the 20 known mutations are present in the gene, although the exact effects between the different types are not specific. Five of the mutations are insertions, 11 are deletions, two are spicing mutations and two are considered nonsense. Each of these results in the introduction of codons that call for the premature termination of the protein.
When asking “How is Treacher Collins syndrome diagnosed?” one must understand the different ways in which the medical community attempts to identify the disease. While the physical features have long been used as a preliminary diagnosis, modern technology helps in finding the exact dynamics of this genetic disorder.
“Treacher Collins Syndrome” eMedicine: https://emedicine.medscape.com/article/946143-overview
“Treacher-Collins Syndrome” New York Times: https://health.nytimes.com/health/guides/disease/treacher-collins-syndrome/overview.html
Cleft Palate. (Supplied by The Wu’s Photo Land at Flickr; Creative Commons 2.0; https://www.flickr.com/photos/photowu/168759551/)
This post is part of the series: The Genetics of Treacher Collins Syndrome
Treacher Collins syndrome, also known as Mandibulofacial Dysostosis, is caused by mutations in the TCOF1 gene. This gene impacts the treacle protein, which impacts the development of craniofacial features such as the ears, eyes, mouth and bone structure.