Treacher Collins and Nager Syndrome
Treacher Collins Syndrome, also termed Franceschetti Syndrome (TCFS), results from a bilateral combination of clefts through the malar and lateral orbital bones that occurs in approximately 1 in 25,000 births. Known as Tessier clefts 6, 7 and 8, these result in a flattened cheek prominence, and downward slanting deficient lower eyelids. The mandible and ears are also underdeveloped. The primary functional problems associated with Treacher Collins Syndrome are related to airway, occlusion, hearing and abnormalities of the eyelids. Nager syndrome has the features of Treacher Collins Syndrome but it is also associated with defects of the limbs.
Treacher Collins syndrome presents with different severities. That is, sometimes the syndrome is so mild that it is hard to tell if a child even has the syndrome. Other times, it can be quite severe. The following is a list of traits that a child may, or may not have.
- Narrow forehead
- Retrusive and small lower jaw and chin
- Downward slanting of the eyes
- Lower eyelid and eyelash defects
- Malformation of the ears
- Cleft palate
- Small or absent thumb (Nager syndrome)
These children require evaluation by a craniofacial team with experienced geneticists, surgeons, dentists, speech and hearing specialists, and psychosocial therapists. When breathing difficulties are present, airway management is the highest priority. Subsequent treatments include correction of orbital and jaw problems, reconstruction of eyelids and ears, speech and hearing correction, and orthodontics.
Evaluation by a skilled geneticist is required due to the frequency of associated abnormalities of the vertebrae, heart, and urinary system. Treatment planning requires a craniofacial team to sequence reconstructive surgery; ear reconstruction, jaw reconstruction, soft tissue reconstruction of the cheeks and eyes, as well as address airway issues.
Treacher Collins Syndrome has been shown to occur with the same frequency in boys and girls. Currently, no one knows what causes this condition. In over 60% of cases both the mother and father of a child born with Treacher Collins Syndrome have normal genes, and the mother does “everything right” during her pregnancy. The process of bringing genes together from a mother and father is quite complicated. Once in awhile, a gene can be changed in the process. The gene for Treacher-Collins Syndrome has been identified and is sometimes called the “Treacle gene.” This gene is located on chromosome 5q. Treacher Collins Syndrome can be inherited, and is transmitted in what geneticists call an “autosomal dominant pattern.” This means that if a child affected with Treacher Collins Syndrome decides to have children when he or she is grown, there is a 50% chance of having a baby who also has Treacher Collins Syndrome.
Nager syndrome is another autosomal dominant disorder characterized by patients with faces similar to individuals with Treacher Collins Syndrome. These patients also have “bird-like” features and their mandibles are typically small and recessed with an obtuse angle. Their distinction lies in the fact that they have more severe ear deformities than patients with Treacher Collins. They also have characteristic upper and lower extremity defects. The genetic mutation associated with this deformity is currently unknown.
The treatment of the mandibular malformations in these patients varies based on the degree of underlying pathology. Patients with minimal deformity require either no treatment or a sliding genioplasty (chin augmentation), in order to normalize facial appearance. The majority of patients however, have more severe forms of micrognathia (small lower jaw) and require some form of bone grafting or orthognathic surgery to generate an adequate repair. Bone grafting of the mandible with costochondral rib grafts has traditionally been performed in the prepubescent years in order to augment mandibular projection. Definitive orthognathic surgery is typically delayed until the facial skeletal maturity, with adult teeth erupted, in order to decrease the incidence of post surgical skeletal relapse.
Patients with severe bilateral micrognathia can be treated at an early age via mandibular distraction osteogenesis. Distraction offers the advantage over traditional mandibular reconstructive approaches in that it can be done earlier and allows for over projection on the growing child’s skeleton to account for later growth. Probably the greatest advantage of mandibular distraction is its enlargement of the airway and often permits decannulation of a tracheostomy.
Patients with Treacher Collins Syndrome and Nager Syndrome frequently also require reconstructive surgery of the lower eyelid and ear. Ear reconstruction can begin at age 7-10 and are usually completed in 2-3 stages. We recommend the use of autogenous rib cartilage to carve and craft the new ear. In our hands, this produces the most acceptable, long lasting result.
Prior to these reconstructions, all patients will receive a full evaluation by our team audiologist, otolaryngologist, and speech therapist. A full examination of the middle and inner ear structures will be performed in order to develop a plan for future ear reconstruction and to optimize both hearing and subsequent speech development. In many cases, a bone conducting hearing aid can be created which will solve the majority of the hearing problems. In those which it cannot, further treatment alternatives will be discussed and customized to meet each individuals needs.
Lower eyelid reconstruction can begin as early as age six. Simple procedures such as medial or lateral canthopexies can be used to correct abnormal lid position in many cases. However, in patients with severe underlying cheekbone deficiencies, bone grafting to the cheek is required to give the lid a good foundation on which to rest, prior to moving any soft tissue. Without this support, the lids themselves would sink back down to their presurgical position. Lastly, when virtually no lower lid is present, a vascularized transfer of upper lid skin and muscle to the lower lid may be indicated.