Treacher Collins Syndrome variously referred to as zygoauromandibular dysplasia, mandibulofacial dysostosis, and Treacher Collins Franceschetti syndrome is a genetic condition typified by the erratic development of the facial bones and tissues. TCS is a rare hereditary disorder that interferes with the smooth and healthy development of tissues and bones inside the face. Compromised development makes the head, face, nose, eyes, and ears appear out of proportion.
The degree of deformity or distortion of the chin, cheekbones, eyes, ears, and lips could range from severe to mild. Specifying Treacher Collins Syndrome’s rarity, the condition is diagnosed in 1 neonate out of every 50,000 live births. Quite a good number of those affected by TCS also have cleft palate identified by an opening in the mouth’s roof. The underdeveloped facial bones, in some cases, also causes airways to become narrowed leading to breathing problems that could be life-threatening.
Generally, TCS happens to be an autosomal dominant-the disorder is the outcome of a new genetic mutation in over 50% of the cases instead of inheriting the gene from the parents. Mutations or alterations involving the POLR1D, POLR1C or TCOF1 genes trigger the syndrome. However, it is mutations related to the TCOF1 gene that causes TCS in the majority of the cases.
The genetic etiology remains idiopathic (unknown cause) for those TCS cases where a specific mutating gene cannot be identified.
The symptoms of Treacher’s Collins Syndrome could be barely noticeable or might be extreme, depending upon the severity of the disorder. So, the harshness or mildness of the symptoms could differ from one individual to the other. Signs are almost always noticeable on the affected person’s face, marked by abnormally or poorly developed structures. The affected areas commonly include:
- Eyes (indentations in lower eyelids, drooping eyelids, eyelids angling downwards, the complete or partial absence of eyelashes on lower eyelids, and so on. Vision loss is also common in numerous cases)
- Jaw and cheekbones (underdeveloped mandible and zygomatic bone, retracted tongue, insufficient teeth occlusion, and so on. The child could experience swallowing or breathing problems if the underdevelopment is pronounced.)
- Airways (airways could be constricted due to incomplete development of facial bones)
- Ears (could be malformed, small, turned around or even could be absent)
- Hairs (developing frontally, around the ears and the margin of the cheekbones)
- Mouth (cleft palate sometimes accompanied by a cleft lip)
- Cranium or skull
Deafness could also happen due to anomalous or inconsistent development of the three bones of the middle ear (malleus, incus, and stapes) or the ear canal. There could be delayed development of gross and fine motor skills in affected children.
As mentioned above, medical scientists and researchers have been able to identify three specific genes till date whose transmutations lead to the genetic condition. These genes are:
- TCOF1 (responsible for stimulating the disorder in 90-95% of the cases)
In roughly 8% of TCS cases, transmutations in POLR1C or POLR1D genes are behind the syndrome. As for the remaining proportion, the gene (and its mutations) causing the disorder, remains unknown or unidentified. The abovementioned genes have a key role to play in the timely growth and development of the tissues and bones of the face.
Nevertheless, if and when these genes mutate, specific cells responsible for promoting bone and tissue development, turn against themselves and become self-destructive. About 40% of the individuals with TCS inherit the abnormal gene from either their father or mother (inheritance from both parents is extremely rare). The balance 60% develops the disorder because of a gene which has mutated for the first time.
Babies born to families where one or more members are carrying any one of the causatives above genes are at increased risk of contracting the condition.
Physicians take the following steps for correctly diagnosing the presence of a mutating gene which causes TCS:
- Past medical records
- Physical examinations
- Genetic assays
- Radiographic tests
CT scans and X-rays are two types of radiographic examinations that diagnosticians use extensively for establishing the abnormal development of cheekbones or jawbones. Sometimes, the physician performs a craniofacial computed tomography scan for reviewing the ear canals, skull, neck, and ear anatomical structures. The CT scan enables the doctor to confirm whether the infant also suffers from hearing loss.
Most doctors do away with genetic testing as they’re able to form an opinion, simply by observing the symptoms. After the primary diagnosis is complete, the doctor may go in for specialized assays to determine the syndrome’s graveness. Advanced testing helps the doctor to check for:
- The tendency of oropharyngeal impediment (related with airways)
- Cleft palate or cleft lip
- Swallowing difficulty
Treatment & Coping with TCS
An effective treatment or remedial therapy for TCS is yet to be found. Existing treatment plans are tailored around the specific circumstances of a particular patient. Usually, a team of doctors, each representing a distinct field of medical science is involved in caregiving. These medical or health professionals generally comprise:-
- An ENT specialist
- Speech therapist
- Craniofacial surgeon
If the disorder has been detected and diagnosed in newborns, the treatment course generally entails carrying out operations that help the neonates to breathe normally. Doctors advise and demonstrate how to position their babies so that the latter feels comfortable. More often, the surgeon performs a tracheostomy (making an incision in the windpipe) to enable the baby or infant to respire without any difficulty.
Hearing loss can be corrected through hearing aids and speech therapy. Areas of the face that have developed anomalously can be reconstructed and corrected as well. The type or types of surgical procedures that an individual can opt for invariably depends upon his or her age.
Prognosis & Lifespan
It has been observed that individuals with TCS are almost as normal as those without. Those having TCS grow up to become healthy and responsible adults. If proper and due care is accorded, they can go on to live as long as the rest of the unaffected populace.