TreacherCollins Syndrome (TCS), Treacher-Collins syndrome, also known as TreacherCollins-Franceschetti syndrome, Mandibulafacial dysostosis, also known as mandibulofacial dysplasia syndrome, is pathologically based on craniofacial The prevalence of TCS in newborns is 0.2-0.4 per 10,000, but there is no significant sex difference (independent of gender). 40% of TCS patients have a family history (the disease is likely to be inherited by the newborn if one of the parents has the disease) and 60% of patients present with a de novo mutation (the parents have no manifestations of the disease, but the newborn has the disease). The disease is inherited by 60% of patients with de novo mutations (parents who do not have the disease but have the disease in their newborns). The majority of patients with TCS are due to mutations in the TCOF1 locus, which account for 81-93% of cases, and the POLR1C and POLR1D loci. About 2% of patients are associated with POLR1C and POLR1D; there are some other related genes that are unknown. These three loci play an important role in the development of facial bones and other tissues. If one parent manifests TCS, how is TCS passed on to the child? Here, we will talk about it. The inheritance of TCS needs to be analyzed in terms of genes: chromosomes are aggregates formed by the deep compression of genetic material with hereditary properties in cells, and are called chromosomes (chromatin) because they are easily dyed dark by alkaline dyes. It carries the genetic information (genes) of human beings. There are 22 pairs of autosomes and one pair of sex chromosomes in each person, for a total of 23 pairs. As the word implies, autosomes are not associated with sex and sex chromosomes are associated with gender. The manifestation of a genetic disorder is associated with at least one pair of genes. If one of the parents is a TCS patient, then it is important to analyze whether the TCS-related genes in that patient are on one or one pair of chromosomes. Assuming that it is the father who carries is one TCS-related gene on a pair of chromosomes, the inheritance diagram is as follows: From the above diagram, we can see that both parents inherit half of their genes to the son and half to the daughter. If the father’s pair of chromosomes contains a pair of inherited genes, then, in the next generation of sons and daughters, all of them will theoretically be TCS patients. II. Clinical manifestations From this figure, the characteristics of TCS patients are very obvious. And these clinical features will be accompanied by related clinical manifestations. 1. Eyes: Most patients with TCS are associated with eye problems, such as lower eyelid defects, hypoplasia of the medial eyelashes, downward displacement of the external canthus, and missing eyelashes. As a result, there is loss of vision with strabismus and refractive error. 2. Ear: The auricular deformity is accompanied by atresia of the external auditory canal, which is usually symmetrical. Most cases show malformation of the auricular and middle ear cavities, occasionally accompanied by malformation of the inner ear. The majority of cases show malformation of the ear and middle ear cavity, and occasionally the inner ear. 3. Maxillofacial: zygomatic bone hypoplasia, resulting in poor jaw development, mandibular hypoplasia, associated malocclusion of teeth, and short chin. 4, cleft palate: cleft palate can cause ventilation difficulties, resulting in breathing difficulties. 5. Oral malformations: 60% of patients with TCS develop dental malformations, which include, dental hypoplasia (33%), malformed enamel development (30%) and first molar ectasia (13%). In some cases, oral malformations are accompanied by hypoplasia of the jaws, resulting in malocclusion, difficulty in ingestion and difficulty in closing the mouth. Other manifestations, nasal malformation, arched palate, upper eyelid defect, wide eye spacing, posterior nasal foramen atresia, macroglossia, and displaced hair in the ear. Cranial deformities do not occur in patients with TCS. Facial deformities can be associated with slow growth, but usually no intellectual problems are present. III. Treatment options Patients with TCS require treatment in a variety of ways. Teeth, cleft palate and mandible need to be treated in a maxillofacial surgery consultation, eye disease is treated in ophthalmology, and microtia is treated in otology. Maxillofacial surgery and ophthalmology will give a treatment plan according to the appropriate condition. Here, we need to discuss the treatment of the child’s ear. Theoretically, patients with TCS who have microtia or hearing problems are treated similarly to other congenital external middle ear malformations alone. In the case of microtia (auricular malformation) with hearing problems, a hearing examination needs to be performed when the patient is six months old and the hearing intervention plan will be determined based on the hearing examination results. In the case of conductive hearing loss, the patient will need to wear a bone-conduction hearing aid and wait to wear one suitable for surgery. From six months to six weeks of age, bone conduction hearing aids are worn; after six years of age, otoplasty and hearing reconstruction are performed depending on the patient’s condition and needs. Otoplasty and hearing reconstruction typically lasts for two years. The method of otoplasty is also chosen preoperatively, and currently, the otoplasty is performed using autologous rib cartilage; with advances in technology, Medpore stents are also an option. For hearing reconstruction, the treatment plan depends on the development of the patient’s ear. For patients in good condition, external otoplasty – tympanic reconstruction is an option; for those in average condition but with stapes, vibrating sound bridges can be implanted; for those in slightly poor condition, bone conduction implants, such as Baha and bone bridges, are performed. Above, a 1-year-old girl wearing a softband bone bridge bone-conduction hearing aid Above, a foreign TCS patient wearing a softband bone bridge In the case of sensorineural deafness, the hearing intervention program is determined according to the degree of hearing loss. For example, a patient with severe sensorineural deafness will need a cochlear implant to restore hearing. The following diagram shows the flow chart of otoplasty and hearing reconstruction for reference: Therefore, the treatment of TCS patients, the pre-testing is as important as the hearing intervention and the post-treatment. And the whole treatment process is a complex, multidisciplinary and regular one. Please seek medical treatment scientifically.