Possible germline mosaicism in a pedigree with Treacher Collins syndrome: A case report and brief review.

Treacher Collins syndrome (TCS) is a rare congenital craniofacial disorder, typically inherited as an autosomal dominant condition. Here, we report on a family in which germline mosaicism for TCS was likely present. The proband was diagnosed with TCS based on the typical clinical features and a pathogenic variant TCOF1 (c.4369_4373delAAGAA, p.K1457Efs*12). The mutation was not detected in his parents' peripheral blood DNA samples, suggesting a de novo mutation had occurred in the proband. However, a year later, the proband's mother became pregnant, and the amniotic fluid puncture revealed that the fetus carried the same mutation as the proband. Prenatal ultrasound also indicated a maxillofacial dysplasia with unilateral microtia. The mother then disclosed a previous birth history in which a baby had died of respiratory distress shortly after birth, displaying a TCS-like phenotype. Around the same time, the proband's father was diagnosed with mild bilateral conductive hearing loss. Based on array data, we concluded that the father may have had germline mosaicism for TCOF1 mutation. Our findings highlight the importance of considering germline mosaicism in sporadic de novo TCOF1 mutations when providing genetic consulting, and prenatal diagnosis is important when the proband's parents become pregnant again.

Assessment of craniofacial and dental characteristics in individuals with treacher collins syndrome. A review.

Treacher Collins Syndrome (TCS) is a genetic disorder with predominantly autosomal dominant inheritance, associated with different mutations in specific genes. This review aimed to evaluate the facial, temporomandibular, zygomatic and bucco-dental phenotype in TCS individuals, and describe surgical and non-surgical solutions for each case in order to improve the quality of life of these individuals. A review of the literature on the craniofacial characteristics of the TCS was carried out, using the PICO strategy, and then a systematic search method was performed in Medline, Scopus, LILACS and SCIELO databases, identifying articles of impact and relevance until 10 June 2020, 240 articles were recovered and only 35 fulfilled the selection criteria. We found the main craniofacial and oral morphological characteristics of these individuals, and the possible functional alterations inducing repercussion in the stomatognathic apparatus. Among other characteristics, the most representative include hypoplasia in the zygomatic and mandibular complex, which can cause difficulty in breathing and feeding. In some cases, cleft palate and malocclusions such as anterior open bite may lead to Angle's Class II malocclusion, sometimes causing problems in the temporomandibular joint. In conclusion, individuals with TCS have specific craniofacial features including maxillary hypoplasia, altered orbital zones, mandibular retrognathia, and temporomandibular disorders. Oral deformities produce to a higher prevalence of caries and calculus formation because of poor hygiene due to the malformations present in these patients.

Treacher Collins syndrome: A novel TCOF1 mutation and monopodial stapes.

Treacher Collins syndrome (TCS: OMIM 154500) is an autosomal dominant craniofacial disorder belonging to the heterogeneous group of mandibulofacial dysostoses. OBJECTIVE: To investigate four Treacher Collins syndrome patients of the Sgaw Karen family living in Thailand. METHOD: Clinical examination, hearing tests, lateral cephalometric analyses, Computed tomography, whole exome sequencing and Sanger direct sequencing were performed. RESULTS: All of the patients affected with Treacher Collins syndrome carried a novel TCOF1 mutation (c.4138_4142del; p.Lys1380GlufsTer12), but clinically they did not have the typical facial gestalt of Treacher Collins syndrome, which includes downward-slanting palpebral fissures, colobomas of the lower eyelids, absence of eyelashes medial to the colobomas, malformed pinnae, hypoplastic zygomatic bones and mandibular hypoplasia. Lateral cephalometric analyses identified short anterior and posterior cranial bases, and hypoplastic maxilla and mandible. Computed tomography showed fusion of malleus and incus, sclerotic mastoid, hypoplastic middle ear space with a soft tissue remnant, dehiscence of facial nerve and monopodial stapes. CONCLUSION: Treacher Collins syndrome in Sgaw Karen patients has not been previously documented. This is the first report of monopodial stapes in a TCS patient who had a TCOF1 mutation. The absence of a common facial phenotype and/or the presence of monopodial stapes may be the effects of this novel TCOF1 mutation.

[Progress of diagnosis and treatment of upper respiratory obstruction in patients with Treacher Collins syndrome].

OBJECTIVE: To summarize the progress of diagnosis and treatment of upper respiratory obstruction in patients with Treacher Collins syndrome (TCS). METHODS: The domestic and abroad literature about the diagnosis and treatment of upper respiratory obstruction in patients with TCS was extensively reviewed and analyzed. RESULTS: TCS is an autosomal-dominant craniofacial developmental syndrome. It is often accompanied by midface and/or mandibular hypoplasia, soft tissue hypertrophy, and other respiratory tissue developmental abnormalities, which can lead to different degrees of upper respiratory obstruction symptoms. Respiratory obstruction in patients with TCS is affected by many factors, and the obstructive degree are different. Early detection of the causes and obstructive sites and adopted targeted treatments can relieve the symptoms of respiratory obstruction and avoid severe complications. CONCLUSION: Due to the low incidence of TCS, there is still a lack of high-quality research evidence to guide clinical treatment. Large-scale and prospective clinical studies are needed to provide new ideas for the treatment and prevention of upper respiratory obstruction.

Mandibulofacial dysostosis with microcephaly: a syndrome to remember.

Mandibulofacial dysostosis with microcephaly (MFDM) is a rare condition that causes abnormalities of the head and face. Other major extracranial malformations may also be found. The authors present a case of an MFDM in a 35 weeks newborn with antenatal growth restriction. The patient required resuscitation at birth and was diagnosed with oesophageal atresia with tracheoesophageal fistula at day 1. At physical examination he presented multiple congenital malformations including prominent forehead, plagiocephaly, low-set ears, malformed auricles, hypertelorism, downward-slanting eyes, micrognathia, everted lower lip, short neck, wide-spaced nipples and inguinal hernia. Imaging investigation showed dysplasia of the inner ear with agenesis of the vestibular-cochlear nerves and global cerebral atrophy. Analysis of the EFTUD2 gene revealed that the patient was a heterozygous carrier of a pathogenic mutation (c.831_832del[p.Lys277Asnsf*7]), which has not been previously described. This case illustrates the challenges faced in diagnosing and treating MFDM patients.

Preferential Associated Malformation in Patients With Anotia and Microtia.

OBJECTIVE: Few epidemiological studies have investigated the external ear malformations anotia and microtia. The authors' study aimed to investigate the relationships between age, sex, type of microtia, and birth place and associated malformation as seen in 1 private Japanese clinic. METHODS: Cases of anotia/microtia that presented in Nagata Microtia and Reconstructive Plastic Surgery Clinic (Saitama, Japan) between 2005 and 2018 were included in the study. The authors identified 1896 patients with anotia/microtia with or without associated malformation. Most were primary cases, with some secondary reconstruction cases wherein the primary surgery was performed at another hospital. Cases were classified with Nagata classification; lobule type, small concha type, concha type, and anotia. Cryptotia was also observed in this study. RESULTS: Among the patients, 61.1% were male, 85.4% had unilateral defects (69.0% LB), and 59.1% had a right-sided defect. Most patients were less than 1 year old (15.0%) or 8 to 10 years old (5.5%-6.3%) on first examination, while 58% were from the Kanto region, including Tokyo. Regarding concomitant disorders, 32.7% had an accompanying malformation, while 13.3% had associated syndromes (eg, craniofacial microsomia, Treacher Collins syndrome). To conclude, in the authors' clinic, most cases of anotia/microtia were LB, unilateral, and seen in male patients. Information regarding several characteristic clinical features was obtained, especially that clefts and musculoskeletal deformities of the skull/face and jaw were the main accompanying malformations.

A Morphological Classification Scheme for the Mandibular Hypoplasia in Treacher Collins Syndrome.

BACKGROUND: Mandibular hypoplasia is a hallmark of Treacher Collins syndrome (TCS), and its severity accounts for significant functional morbidity. The purpose of this study is to develop a mandibular classification scheme. METHODS: A classification scheme was designed based on three-dimensional computed tomography (3D-CT) scans to assess 3 characteristic features: degree of condylar hypoplasia, mandibular plane angle (condylion-gonion-menton), and degree of retrognathia (sella-nasion-B point angle). Each category was graded from I to IV and a composite mandible classification was determined by the median value among the 3 component grades. RESULTS: Twenty patients with TCS, aged 1 month to 20 years, with at least one 3D-CT prior to mandibular surgery were studied. Overall, 33 3D-CTs were evaluated and ordered from least to most severe phenotype with 10 (30%) Grade 1 (least severe), 14 (42%) Grade 2, 7 (21%) Grade 3, and 2 (7%) Grade 4 (most severe). Seven patients had at least 2 longitudinal scans encompassing an average 5.7 (range 5-11) years of growth. Despite increasing age, mandibular classification (both components and composite) remained stable in those patients over time (P = 0.2182). CONCLUSION: The authors present a classification scheme for the TCS mandible based on degree of condylar hypoplasia, mandibular plane angle (Co-Go-Me angle), and retrognathia (SNB angle). While there is a natural progression of the mandibular morphology with age, patients followed longitudinally demonstrate consistency in their classification. Further work is needed to determine the classification scheme's validity, generalizability, and overall utility.

[Clinical diagnosis of Treacher Collins syndrome and the efficacy of using BAHA].

Objective:To evaluate the efficacy of soft or implanted BAHA in the patients of Treacher Collins syndrome(TCS).Method:Six patients of TCS were studied. The Teber scoring system was used to evaluate the deformity degree. The air and bone auditory thresholds were assessed by auditory brain stem response(ABR). The infant-toddler meaningful auditory integration scale(IT-MAIS) was used to assess the auditory development at three time levels: baseline,3 months and 6 months. The hearing threshold and speech recognition score were measured under unaided and aided conditions. Result:The average score of deformity degree was 14.0±0.6. The TCOF1 gene was tested in two patients. The bone conduction hearing thresholds of patients was（18.0±4.5）dBnHL and the air conduction hearing thresholds was （70.5±7.0）dBnHL. The IT-MAIS total, detection and perception scores were improved significantly after wearing softband BAHA and approached the normal level in the 2 patients under 2 years old. The hearing thresholds of 6 patients in unaided and softband BAHA conditions were（65.8±3.8）dBHL and （30.0±3.2）dBHL (P<0.01) respectively, and 1 implanted BAHA was 15 dBHL. The speech recognition scores of 3 patients in unaided and softband BAHA conditions were（31.7±3.5）% and（86.0±1.7）%(P<0.05) respectively, and 1 implanted BAHA was 96%. Conclusion:Whenever the patient was diagnosed as TCS by the clinical manifestations and genetic testing, BAHA system could help to rehabilitate the hearing to a normal condition.

[The research progress of Treacher Collins syndrome].

Treacher Collins syndrome (TCS, OMIM 154500), also known as Franceschetti-Klein syndrome, is a rare disorder that affects the first and second branchial arches. The estimated incidence is 1/50 000 live births. Mutations in TCOF1 (78%-93%) and POLR1C or POLR1D (8%) cause the disease. Most of TCS cases are inherited in a dominant pattern, while a small proportion are inherited in a recessive pattern. TCS has a variable phenotype with typical clinical characteristics including downward-slant of palpebral fissure, malar hypoplasia, mandibular hypoplasia and microtia. TCS management is a multidisciplinary affair, as interventions range from reconstructive to psychosocial. For hearing rehabilitation, TCS patients may have the choices of BAHA, ponto, vibrant soundbridge or bonebridge implantation. In this review, we summarize the TCS clinical malformations, diagnosis, genetics, management and auditory rehabilitation.

Mandibulofacial Dysostosis with Microcephaly: Mutation and Database Update.

Mandibulofacial dysostosis with microcephaly (MFDM) is a multiple malformation syndrome comprising microcephaly, craniofacial anomalies, hearing loss, dysmorphic features, and, in some cases, esophageal atresia. Haploinsufficiency of a spliceosomal GTPase, U5-116 kDa/EFTUD2, is responsible. Here, we review the molecular basis of MFDM in the 69 individuals described to date, and report mutations in 38 new individuals, bringing the total number of reported individuals to 107 individuals from 94 kindreds. Pathogenic EFTUD2 variants comprise 76 distinct mutations and seven microdeletions. Among point mutations, missense substitutions are infrequent (14 out of 76; 18%) relative to stop-gain (29 out of 76; 38%), and splicing (33 out of 76; 43%) mutations. Where known, mutation origin was de novo in 48 out of 64 individuals (75%), dominantly inherited in 12 out of 64 (19%), and due to proven germline mosaicism in four out of 64 (6%). Highly penetrant clinical features include, microcephaly, first and second arch craniofacial malformations, and hearing loss; esophageal atresia is present in an estimated ∼27%. Microcephaly is virtually universal in childhood, with some adults exhibiting late "catch-up" growth and normocephaly at maturity. Occasionally reported anomalies, include vestibular and ossicular malformations, reduced mouth opening, atrophy of cerebral white matter, structural brain malformations, and epibulbar dermoid. All reported EFTUD2 mutations can be found in the EFTUD2 mutation database (http://databases.lovd.nl/shared/genes/EFTUD2).

Treacher Collins Syndrome: A Systematic Review of Evidence-Based Treatment and Recommendations.

BACKGROUND: No reviews or guidelines are available on evidence-based treatment for the multidisciplinary approach in Treacher Collins syndrome. The authors' aim is to provide an evidence-based review of multidisciplinary treatment of Treacher Collins syndrome based on levels of evidence and supported with graded recommendations. METHODS: A systematic search was performed by means of the PubMed, Web-of-Science, Embase, and Cochrane Central databases (1985 to January of 2014). Included were clinical studies (with five or more Treacher Collins syndrome patients) related to therapy, diagnosis, or risk of concomitant diseases. Level of evidence of the selected articles was rated according to the American Society of Plastic Surgeons evidence-based clinical practice guidelines. After two panelists had reviewed each abstract separately, a consensus method was used to solve any disagreements concerning article inclusion. RESULTS: Of the 2433 identified articles, 63 studies (Level of Evidence II through V) were included. Conclusions and recommendations were extracted consecutively for the following items: upper airway; ear, hearing, and speech; the eye, eyelashes, and lacrimal system; growth, feeding, and swallowing; the nose; psychosocial factors; and craniofacial reconstruction. CONCLUSIONS: In this systematic review, current evidence for the multidisciplinary treatment of Treacher Collins syndrome is provided, recommendations for treatment are made, and a proposed algorithm for treatment is presented. Although some topics are well supported, others, especially ocular, nasal, speech, feeding, and swallowing problems, lack sufficient evidence. In addition, craniofacial surgical reconstruction lacks a sufficient level of evidence to provide a sound basis for a full treatment protocol. Despite the rarity of the syndrome, more research is needed to compare outcomes of several surgical treatments, especially in orbitozygomatic/maxillary regions.

Reduced three-dimensional nasal airway volume in treacher collins syndrome and its association with craniofacial morphology.

BACKGROUND: Airway insufficiency decreases quality of life and may be life threatening in patients with Treacher Collins syndrome. The authors calculated the three-dimensional nasal airway volume in patients with Treacher Collins syndrome to identify correlations between nasal airway volume and craniofacial morphology and provide guidance for surgical planning. METHODS: Thirty nonoperated patients with Treacher Collins syndrome were compared with 35 unaffected age- and gender-matched controls. Anatomic variables of the cranial base, the maxilla complex, and internal diameters of nasal airway were compared between patients and control subjects using three-dimensional craniometric analyses. In the Treacher Collins group, the relation of craniofacial morphology to nasal airway volume was assessed separately. Statistical analyses were performed using independent sample t tests and Pearson correlation coefficient analyses. RESULTS: Nasal airway volume was decreased 38.6 percent in patients with Treacher Collins syndrome relative to controls (p = 0.001). A positive correlation of maxillary position and nasal airway volume was shown in Treacher Collins patients (r = +0.463, p = 0.013). Maxillary, nasal bone, and orbitale width were also positively correlated with nasal airway volume (r = +0.582, p = 0.001; r = +0.408, p = 0.035; and r = +0.677, p < 0.001, respectively). Shortened internal diameters of the nasal airway all positively correlated with nasal airway volume. CONCLUSIONS: Nasal airway volume is reduced in patients with Treacher Collins syndrome. Reduced projection of the maxilla and transverse maxillary deficiency are correlated with reduced nasal airway volume and are primarily responsible for obstruction of the nasal airway. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

The neural crest: a versatile organ system.

The neural crest is the name given to the strip of cells at the junction between neural and epidermal ectoderm in neurula-stage vertebrate embryos, which is later brought to the dorsal neural tube as the neural folds elevate. The neural crest is a heterogeneous and multipotent progenitor cell population whose cells undergo EMT then extensively and accurately migrate throughout the embryo. Neural crest cells contribute to nearly every organ system in the body, with derivatives of neuronal, glial, neuroendocrine, pigment, and also mesodermal lineages. This breadth of developmental capacity has led to the neural crest being termed the fourth germ layer. The neural crest has occupied a prominent place in developmental biology, due to its exaggerated migratory morphogenesis and its remarkably wide developmental potential. As such, neural crest cells have become an attractive model for developmental biologists for studying these processes. Problems in neural crest development cause a number of human syndromes and birth defects known collectively as neurocristopathies; these include Treacher Collins syndrome, Hirschsprung disease, and 22q11.2 deletion syndromes. Tumors in the neural crest lineage are also of clinical importance, including the aggressive melanoma and neuroblastoma types. These clinical aspects have drawn attention to the selection or creation of neural crest progenitor cells, particularly of human origin, for studying pathologies of the neural crest at the cellular level, and also for possible cell therapeutics. The versatility of the neural crest lends itself to interlinked research, spanning basic developmental biology, birth defect research, oncology, and stem/progenitor cell biology and therapy.

Hearing rehabilitation with single-stage bilateral vibroplasty in a child with Franceschetti syndrome.

Hearing is of utmost importance for normal speech and social development. Even children who have mild or unilateral permanent hearing loss may experience difficulties with understanding speech, as well as problems with educational and psycho-social development. The increasing advantages of middle-ear implant technologies are opening new perspectives for restoring hearing. Active middle-ear implants can be used in children and adolescents with hearing loss. In addition to the well-documented results for improving speech intelligibility and quality of hearing in sensorineural hearing loss active middle-ear implants are now successfully used in patients with conductive and mixed hearing loss. In this article we present a case of successful, single-stage vibroplasty, on the right side with the fixation of the FMT on the stapes and PORP CLiP vibroplasty on the left side in a 6-year-old girl with bilateral mixed hearing loss and multiple dyslalia associated with Franceschetti syndrome (mandibulofacial dysostosis). CT revealed bilateral middle-ear malformations as well as an atretic right and stenotic left external auditory canal. Due to craniofacial dysmorphia airway and (post)operative, management is significantly more difficult in patients with a Franceschetti syndrome which in this case favoured a single-stage bilateral procedure. No intra- or postoperative surgical complications were reported. The middle-ear implants were activated 4 weeks after surgery. In the audiological examination 6 months after surgery, the child showed 100% speech intelligibility with activated implants on each side.

Limbal dermoid in Nager acrofacial dysostosis: a rare case report.

Nager syndrome, also called preaxial acrofacial dysostosis, comprises two groups of defects involving the limbs and craniofacial region, respectively. This syndrome is rare and only 70 cases have been reported in the literature. The exact cause of this syndrome is unknown, but there is indication that it is genetically based. Ocular manifestations of this syndrome include widely separated downward slanting eyes, absence of eyelashes, ptosis of upper eyelids and colobomas on the inner aspect of lower eyelids. We report limbal dermoid in a patient with Nager syndrome. We did not find such an association of "Limbal dermoid in Nager acrofacial dysostosis syndrome" on PubMed using Nager acrofacial dysostosis, limbal dermoid and ocular manifestations as the keywords.

[Clinical and genetic analysis of a patient with Treacher Collins syndrome in TCOF1 gene].

OBJECTIVE: To analyze the clinical and genetic features of a patient with Treacher Collins syndrome (TCS), and identify the mutation in TCOF1 gene. METHOD: The medical history was taken, and general physical examinations and otological examinations were conducted in this patient. Genomic DNA was extracted from this patient and his parents and complete TCOF1 gene coding exons were amplified by specific PCR primers. Direct sequencing was carried out to identify the mutations. The raw data was analyzed with GeneTool software and molecular biological website. RESULT: We detected a heterozygous c. 1639 delAG mutation in exon 11 of TCOF1, which resulted in a truncated protein lacking normal function. This mutation is a novel mutation and the second case identified in exon 11 of in TCS. CONCLUSION: TCS patient reported in this study has unique clinical phenotype. TCOF1 gene mutation is the specific risk factor.