Atypical mandibulofacial dysostosis with microcephaly diagnosed through the identification of a novel pathogenic mutation in EFTUD2

BACKGROUND

Mandibulofacial dysostosis with microcephaly (MFDM, OMIM# 610536) is a rare monogenic disease that is caused by a mutation in the elongation factor Tu GTP binding domain containing 2 gene (EFTUD2, OMIM* 603892). It is characterized by mandibulofacial dysplasia, microcephaly, malformed ears, cleft palate, growth and intellectual disability. MFDM can be easily misdiagnosed due to its phenotypic overlap with other craniofacial dysostosis syndromes. The clinical presentation of MFDM is highly variable among patients.

METHODS

A patient with craniofacial anomalies was enrolled and evaluated by a multidisciplinary team. To make a definitive diagnosis, whole-exome sequencing was performed, followed by validation by Sanger sequencing.

RESULTS

The patient presented with extensive facial bone dysostosis, upward slanting palpebral fissures, outer and middle ear malformation, a previously unreported orbit anomaly, and spina bifida occulta. A novel, pathogenic insertion mutation (c.215_216insT: p.Tyr73Valfs*4) in EFTUD2 was identified as the likely cause of the disease.

CONCLUSIONS

We diagnosed this atypical case of MFDM by the detection of a novel pathogenetic mutation in EFTUD2. We also observed previously unreported features. These findings enrich both the genotypic and phenotypic spectrum of MFDM.

The Role of Splicing Factor SF3B4 in Congenital Diseases and Tumors

In eukaryotes, spliceosomes catalyze the splicing of pre-mRNA to mature mRNA. As the core subunit of U2 spliceosome, splicing factor SF3b4 plays not only a crucial role in the splicing process, but also a role in transcription, translation, and cell signal transduction, and participates in the regulation of cell cycle, cell differentiation, and immune deficiency. In recent years, more and more research studies on SF3b4-related diseases, such as Nager syndrome and cancer, have been conducted. It has been found that SF3b4 mutations led to abnormal cell growth and were involved in the development and occurrence of these diseases. In this review, the diseases, mainly congenital diseases and tumors, in which SF3B4 is involved and the pathogenesis of them were summarized, aiming to provide a better understanding of the roles of SF3B4 in the prevention, diagnosis, and treatment of diseases in the future.

Difficult airway management in a patient with Treacher Collins syndrome using two-part surgery

Treacher Collins syndrome (TCS), Franceschetti-Zwahlen-Klein, or mandibulofacial dysostosis, is a rare disorder of craniofacial development (incidence of approximately 1:50.000 live births). TCS is relevant to the anaesthetist because it can cause difficulties in airway management. A case report is presented of a 24 year-old woman who was referred to our institution for facial reconstruction surgery in two stages. In both surgeries Airtraq™ was essential for airway management. By presenting this case, it is intended to show that planning, communication and teamwork are indispensable for patient safety.

A Novel Human Pluripotent Stem Cell-Derived Neural Crest Model of Treacher Collins Syndrome Shows Defects in Cell Death and Migration

The neural crest (NC) is a transient multipotent cell population present during embryonic development. The NC can give rise to multiple cell types and is involved in a number of different diseases. Therefore, the development of new strategies to model NC in vitro enables investigations into the mechanisms involved in NC development and disease. In this study, we report a simple and efficient protocol to differentiate human pluripotent stem cells (HPSC) into NC using a chemically defined media, with basic fibroblast growth factor 2 (FGF2) and the transforming growth factor-β inhibitor SB-431542. The cell population generated expresses a range of NC markers, including P75, TWIST1, SOX10, and TFAP2A. NC purification was achieved in vitro through serial passaging of the population, recreating the developmental stages of NC differentiation. The generated NC cells are highly proliferative, capable of differentiating to their derivatives in vitro and engraft in vivo to NC specific locations. In addition, these cells could be frozen for storage and thawed with no loss of NC properties, nor the ability to generate cellular derivatives. We assessed the potential of the derived NC population to model the neurocristopathy, Treacher Collins Syndrome (TCS), using small interfering RNA (siRNA) knockdown of TCOF1 and by creating different TCOF1+/- HPSC lines through CRISPR/Cas9 technology. The NC cells derived from TCOF1+/- HPSC recapitulate the phenotype of the reported TCS murine model. We also report for the first time an impairment of migration in TCOF1+/- NC and mesenchymal stem cells. In conclusion, the developed protocol permits the generation of the large number of NC cells required for developmental studies, disease modeling, and for drug discovery platforms in vitro.

Altered mRNA Splicing, Chondrocyte Gene Expression and Abnormal Skeletal Development due to SF3B4 Mutations in Rodriguez Acrofacial Dysostosis

The acrofacial dysostoses (AFD) are a genetically heterogeneous group of inherited disorders with craniofacial and limb abnormalities. Rodriguez syndrome is a severe, usually perinatal lethal AFD, characterized by severe retrognathia, oligodactyly and lower limb abnormalities. Rodriguez syndrome has been proposed to be a severe form of Nager syndrome, a non-lethal AFD that results from mutations in SF3B4, a component of the U2 small nuclear ribonucleoprotein particle (U2 snRNP). Furthermore, a case with a phenotype intermediate between Rodriguez and Nager syndromes has been shown to have an SF3B4 mutation. We identified heterozygosity for SF3B4 mutations in Rodriguez syndrome, confirming that the phenotype is a dominant disorder that is allelic with Nager syndrome. The mutations led to reduced SF3B4 synthesis and defects in mRNA splicing, primarily exon skipping. The mutations also led to reduced expression in growth plate chondrocytes of target genes, including the DLX5, DLX6, SOX9, and SOX6 transcription factor genes, which are known to be important for skeletal development. These data provide mechanistic insight toward understanding how SF3B4 mutations lead to the skeletal abnormalities observed in the acrofacial dysostoses.

The acrofacial dysostoses (AFD) are inherited disorders with abnormalities of the facial and limb bones. Rodriguez syndrome is a severe type of AFD that is usually lethal in the immediate perinatal period. Rodriguez syndrome has been proposed to be a severe form of Nager syndrome, a non-lethal AFD that results from mutations in SF3B4, a component of mRNA splicing machinery needed for proper maturation of primary transcripts. Furthermore, a case with a phenotype intermediate between Rodriguez and Nager syndromes has been shown to have an SF3B4 mutation. We found that mutations in SF3B4 produce Rodriguez syndrome, further demonstrating that it is allelic with Nager syndrome. The consequences of the mutations include abnormal splicing and reduced expression in growth plate chondrocytes of genes that are important for proper development of the skeleton, providing mechanistic insight toward understanding how SF3B4 mutations lead to the skeletal abnormalities observed in the acrofacial dysostoses.

Treacher Collins syndrome with multiple congenital heart defects after paroxetine exposure: case report

Treacher Collins syndrome is an autosomal dominant disorder of craniofacial development with an incidence of I in 40,000 to in 70,000 live births. It is characterized by abnormalities of the pinnae which are frequently associated with atresia of the external auditory canals and anomalies of the middle ear ossicles. Rarely congenital heart defects can be present. Prenatal paroxetine exposure may enhance the risks of major malformation, particularly cardiac defects. This article reports a newborn, whose mother used paroxetine during pregnancy, presenting with multiple congenital heart defects associated to typical physical characteristics of Treacher Collins syndrome.

Facial dysostoses: Etiology, pathogenesis and management

Approximately 1% of all live births exhibit a minor or major congenital anomaly. Of these approximately one-third display craniofacial abnormalities which are a significant cause of infant mortality and dramatically affect national health care budgets. To date, more than 700 distinct craniofacial syndromes have been described and in this review, we discuss the etiology, pathogenesis and management of facial dysostoses with a particular emphasis on Treacher Collins, Nager and Miller syndromes. As we continue to develop and improve medical and surgical care for the management of individual conditions, it is essential at the same time to better characterize their etiology and pathogenesis. Here we describe recent advances in our understanding of the development of facial dysostosis with a view towards early in utero identification and intervention which could minimize the manifestation of anomalies prior to birth. The ultimate management for any craniofacial anomaly however, would be prevention and we discuss this possibility in relation to facial dysostosis.

The Comparative Study of Craniofacial Structural Characteristic of Individuals With Different Types of Cleft Palate

To compare craniofacial structural characteristic of individuals with different types of cleft palate and to lay a foundation for better treatment protocol for patients with cleft palate, we chose a sample consisting of 12 patients with Treacher Collin syndrome, 15 patients with Pierre Robin sequence, 40 patients with unilateral complete cleft lip and palate, and 40 patients with isolated cleft palate who met certain criteria. Lateral cephalometric radiographs were obtained from each subject. A total of 22 variables, comprising 11 angular, 9 linear, and 2 ratio measurements, were studied. The z-scores were analyzed during paired Student t test. The data showed us that there seems to be no difference in craniofacial structures between patients with isolated cleft palate and normal persons. Patients with unilateral complete cleft lip and palate who had only cleft lip repaired exhibit such characteristics as midface retrusion, relatively excessive lower facial height, and more obtuse gonial angle. The cranial base areas of individuals with Treacher Collin syndrome and Pierre Robin sequence are similar to those of normal persons. Mandibular hypoplasia in both vertical and horizontal dimensions and maxillary retrusion can be found in patients with Treacher Collin syndrome, while only mandibular hypoplasia in the horizontal dimension can be found in patients with Pierre Robin sequence. The developmental deficiency of craniofacial structures seems to be a separate deformity, not the direct outcome of cleft palate defect.

[Treacher-Collins syndrome: clinical and genetic aspects apropos of 4 cases of which 1 is familial]

Treacher Collins syndrome was first mentioned by Thompson in 1847, and described by Treacher Collins in 1900, then it was called mandibulo-facial dysostosis and well defined by Franceschetti in 1949. It is a very rare affection occurring lin 50.000 live births, which includes facial and auricular anomalies leading to functional, morphological and psychological difficulties due to related handicaps. Treacher Collins syndrome is inherited as autosomal dominant pattern with a variable expressivity and incomplete penetrance of "TCOF1" gene localized at 5q31.3q32. Today the gene is well identified and several mutations have been reported. In this paper we report the case of 4 Tunisian unrelated girls with Treacher Collins syndrome. One of them was born from an affected father. Clinical diagnostic was performed between age 12 days and 2 years demonstrating the large dysmorphic expression. Main clinical features were present in all reported cases. Family at risk might have genetic counselling and probably prenatal diagnostic in some situations. Out of our observations, we gave genetic counselling and proposed ultrasound prenatal diagnosis for two families without molecular study.

Duodenal and biliary atresia associated with facial, thyroid and auditory apparatus abnormalities: a new mandibulofacial dysostosis syndrome?

We report a female child born at 36 weeks of gestation with multiple abnormalities including dysmorphic and coarse facial features with features of mandibulofacial dysostosis that include bilateral microtia with the absence of external auditory meati and Mondini dysplasia as well as, duodenal atresia, intestinal malrotation, anterior displacement of the anus, left hemiaplasia of the thyroid and biliary atresia in sibs. The associations of duodenal atresia with intrahepatic and extrahepatic biliary atresia in sibs have been reported, suggesting an autosomal recessive syndrome. However, the associated external, middle and internal ear anomalies and the thyroid malformation, however, have not been reported in this condition. To the best of our knowledge, this is a hitherto new syndrome with an unknown inheritance.

Microtia, severe micrognathia and absent ossicles: auriculo-condylar syndrome or new entity?

The differential diagnosis of syndromes with anomalies of the first and second branchial arches includes the oculo-auriculo-vertebral syndrome, the Treacher-Collins syndrome, the acrofacial dysostoses (including Nager and Miller syndromes), the dysgnathia complex and the auriculo-condylar syndrome. Isolated microtia may also be present with involvement of other facial structures and distant organs. We report here a patient with first and second branchial arch anomalies, born to consanguineous parents. Pertinent physical findings include severe micrognathia, absence of the upper portion of the helices, atresia of the external meati and absence of the middle ear ossicles, mildly down-slanting palpebral fissures and a highly arched palate with a submucous cleft. Discussion of the differential diagnosis highlights the clinical overlap between these conditions. This constellation of findings may represent a more severe manifestation of the auriculo-condylar syndrome or a previously undescribed syndrome.

Craniofacial Structures and Dental Development in Three Patients With Nager Syndrome

In Finland, 3 patients have been diagnosed with Nager syndrome (NS) during the last 17 years. Thus the incidence for NS in Finland is 3:1,000,000. The craniofacial structures and dental development of these patients were studied clinically and radiographically at the age of 3-4 years, and compared to age-matched controls and to the norms of the Finnish population. The striking structural finding was a severely short, retrognathic and posteriorly rotated mandible. Especially the ramus was deficient; its height was, on average, less than one-third of that of the control group. All children were tracheostomized neonatally. At the age of 3-4, the lower pharyngeal airway was still severely obstructed or completely closed. Nasopharyngeal airway was wide and the soft palate was missing in all patients. All patients had a complete deciduous dentition, but agenesis of permanent teeth (ranging from 2-10 missing teeth) was observed in each patient. Accelerated dental development was found in two subjects. Condylar ankylosis or severely limited mouth opening were observed. The present findings give new information and quantify earlier observations of craniofacial structures and dental development in NS. Analysis of facial structures suggests that if surgical intervention is needed to enable better breathing, the goal of the structural correction should be aimed at the most deficient structure, namely the ramus height. As a result of severe dentofacial deviation, a treatment process through the growth requires multidisciplinary teamwork of surgeons, pediatrists, orthodontists and prosthodontists.

A new syndrome with growth and mental retardation, mandibulofacial dysostosis, microcephaly, and cleft palate

We report on two new Brazilian cases and reviewed two previously reported patients with a characteristic combination of signs including mandibulofacial dysostosis, a clinical suggestion of trigonocephaly, microcephaly, unusual ears with skin tags, and cleft palate. Follow-up of these patients revealed growth and mental retardation, and severe language and speech delay. A review of the literature and database programs did not find any syndromes that matched this constellation of findings. We believe that this combination of signs represents a new mandibulofacial dysostosis syndrome whose etiology is unknown.

A novel heterozygous deletion in the EVC2 gene causes Weyers acrofacial dysostosis

Weyers acrofacial dysostosis (MIM 193530) is an autosomal dominant disorder clinically characterized by mild short stature, postaxial polydactyly, nail dystrophy and dysplastic teeth. Ellis-van Creveld syndrome (EvC, MIM 225500) is an autosomal recessive disorder with a similar, but more severe phenotype. Mutations in the EVC have been identified in both syndromes. However, the EVC mutations only occur in a small proportion of EvC patients. Recently, mutations in a new gene, EVC2, were found to be associated with other EvC cases. The EVC and EVC2 are located close to each other in a head-to-head configuration and may be functionally related. In this study, we report identification of a novel heterozygous deletion in the EVC2 that is responsible for autosomal dominant Weyers acrofacial dysostosis in a large Chinese family. This constitutes the first report of Weyers acrofacial dysostosis caused by this gene. Hence, the spectrum of malformation syndromes due to EVC2 mutations is further extended. Our data provides conclusive evidence that Weyers acrofacial dysostosis and EvC syndrome are allelic and genetically heterogeneous conditions.

Treacher Collins Syndrome with choanal atresia: a case report and review of disease features

Treacher Collins Syndrome - or mandibulofacial dysostosis – is a rare condition that presents several craniofacial deformities of different levels. This is a congenital malformation involving the first and second branchial arches. Incidence is estimated to range between 1-40,000 to 1-70,000 of live births. The disorder is characterized by abnormalities of the auricular pinna, hypoplasia of facial bones, antimongoloid slanting palpebral fissures with coloboma of the lower eyelids and cleft palate. Treacher Collins Syndrome is rarely associated with choanal atresia. A multidisciplinary team, including craniofacial surgeon, ophthalmologist, speech therapist, dental surgeon and otorhinolaryngologist, is the most appropriate setting to manage these patients. This study reports a rare case of Treacher Collins Syndrome with choanal atresia, presenting literature review and multidisciplinary intervention.

Mutational analysis of the TCOF1 gene in 11 Japanese patients with Treacher Collins Syndrome and mechanism of mutagenesis

Treacher Collins Syndrome (TCS) (OMIM 154500) is a congenital, craniofacial disorder inherited as an autosomal dominant trait. The responsible gene for TCS, TCOF1, was mapped to 5q32-33.1 and identified in 1996. Since then, TCOF1 mutations in patients with TCS have been reported from Europe, North and South America, however, no TCS cases from an Asian country have been molecularly characterized. Here we report mutational analysis for 11 Japanese patients with TCS for the first time, and have identified TCOF1 mutations in 9 of them. The mutations detected were various, but most likely all the mutations are predicted to result in a truncated gene product, known as treacle. One mutation frequently reported was included in our cases, but no missense mutations were detected. These findings are similar to those for the previous studies for TCS in other races. We have speculated about the molecular mechanisms of the mutations in most cases. Collectively, we have defined some of the characteristic molecular features commonly observed in TCS patients, irrespective of racial difference.

Acrofacial dysostosis type Rodríguez

The acrofacial dysostoses (AFD) are a clinically and causally heterogeneous group of conditions characterized by mandibulofacial dysostosis and a variety of limb anomalies. Several abnormalities affecting different internal organs and the central nervous system (CNS) have been described. Depending on the type of limb defects, two major groups have been delineated: (1) with predominantly pre-axial anomalies, Nager type AFD, and (2) with predominantly post-axial involvement, Genee-Wiedemann form of AFD, also known as POADS, respectively. Other forms of "true AFD" have been described as Kelly, Reynolds, Arens (also Tel Aviv form), Rodríguez (or Madrid form), Richieri-Costa, and Patterson-Stevenson-Fontaine types. However, whether they are distinct entities or represent variants of the same condition remains unclear. Rodríguez AFD was described as a new lethal form of AFD in three affected sibs with severe mandibular hypoplasia, severe predominantly pre-axial limb deficiencies, absent fibulae and ribs, and internal organ anomalies, the most remarkable of which are arrhinencephaly and abnormal lung lobulation. We present a newborn girl with Rodríguez type of AFD, who died a few days after the birth due to respiratory failure. The phenotype and the cause of this condition are discussed.

Newly recognized autosomal recessive acrofacial dysostosis syndrome resembling Nager syndrome

We report on two patients with a unique constellation of anomalies resembling the Nager acrofacial dysostosis syndrome. Clinical manifestations which differentiate their condition from Nager syndrome include: microcephaly, cleft lip and palate, a peculiar beaked nose, blepharophimosis, microtia, symmetrical involvement of the thumbs, and great toes and developmental delay. We postulate that the inheritance is autosomal recessive on the basis of similarly affected male and female sibs.

Acrofacial dysostosis (AFD) with preaxial limb hypoplasia (Nager AFD) and club foot diagnosed in a fetus from 1812 in the anatomical collections at the University of Halle, Germany

The Anatomical Collections of the Department of Anatomy and Cell Biology at the University of Halle, Germany, comprise more than 8,000 specimens, about 600 of them congenital anomalies. The collection of abnormal human and animal specimens began with the private collections of Johann Friedrich Meckel the Elder (1724-1774), his son Philipp Friedrich Theodor Meckel (1755-1803), and his grandson Johann Friedrich Meckel the Younger (1781-1833). Meckel the Younger founded the science of developmental pathology in Germany. Radiographical techniques, computer tomographic methods (CT), magnetic resonance imaging (MRI), and molecular cytogenetic techniques, for example, comparative genomic hybridization (CGH) were used to diagnose abnormal human fetuses in the Meckel Collection. On examination of one of the human fetuses, originally described by JF Meckel the Younger in 1812 or earlier, we found striking clinical manifestations including mandibulofacial defects and preaxially malformed limbs. With respect to external findings, we propose that the condition is acrofacial dysostosis (AFD) with preaxial limb hypoplasia (Nager AFD) in combination with club foot, tibial torsion, and single umbilical artery. We used genetic analyses to test whether the observed limb malformations could be caused by aneuploidy. CGH-ratio profiles of all chromosomes were apparently normal. It is likely that Meckel's specimen is the earliest known fetus with Nager AFD.

Nager syndrome (preaxial acrofacial dysostosis): a case report

The Nager syndrome is a rare condition associated with craniofacial malformations such as micrognathia, zygomatic hypoplasia, cleft palate, and preaxial limb deformities. This report features a case of the Nager syndrome occurring in a 4-year-old boy showing microdontia, thumb duplication and radioulnar synostosis, and ventricular septum defect, characteristics not usually encountered in the published cases.

Laryngeal malformation in the Richieri-Costa-Pereira acrofacial dysostosis: description of two new patients

We describe laryngeal malformations and voice disorders in two new patients with the autosomal recessive Richieri-Costa and Pereira form of acrofacial dysostosis. This report confirms the data on the first five patients we had already presented in 1996.

External auditory canal duplication anomalies associated with congenital aural atresia

Maldevelopment of the first branchial cleft can produce a broad spectrum of anomalies in its derivative structure, the external auditory canal (EAC). Failure of the cleft to develop normally can result in either the absence of a normally patent EAC (atresia, or stenosis) or a duplication anomaly (cyst, sinus, or fistula). Despite their common origins, the coexistence of these anatomical abnormalities is quite unusual. We present four patients with both aural atresia and duplication anomalies of the EAC. Three patients had non-syndromic unilateral aural atresia and presented with periauricular lesions originating from the first branchial cleft. The other patient had a variant of Treacher Collins syndrome and presented with draining infra-auricular fistulae. The classification and management of first branchial cleft anomalies is reviewed in light of these cases. An understanding of the embryogenesis of the external ear is necessary to successfully recognize and treat this spectrum of deformities. A classification system is presented that encompasses the full spectrum of first cleft anomalies.

A profile of the features and speech in patients with mandibulofacial dysostosis

PURPOSE

To present a profile of the features and speech in patients with mandibulofacial dysostosis (MFD). Data were collected on occlusion, palatal condition, hearing, resonance, voice, and articulation.

PATIENTS

Thirty patients with MFD ranging in age from 1.6 to 21.0 years.

STUDY DESIGN

Retrospective and prospective cross-sectional designs.

SETTING

Pediatric tertiary care hospital.

RESULTS

Sixty percent of the patients had an open bite. Isolated cleft palate was found in 37% with other types of cleft conditions occurring less frequently. Twenty-three percent underwent tracheostomy. All patients demonstrated hearing loss, 93% were conductive and 7% were mixed. Resonance, voice, and articulation were also affected. Seventy-seven percent had aberrant resonance including hypernasality, hyponasality, mixed hyper- and hyponasality or muffled resonance, which was found in 40% of the patients. Voice quality was abnormal in 63%. All patients had articulation errors. Although overlap between categories occurred, results showed that 60% had errors related to malocclusion, 30% demonstrated errors usually associated with velopharyngeal inadequacy and 50% had general articulatory or phonological errors that could be attributed to other causes.

CONCLUSIONS

The features and speech of patients with MFD are complex. The speech disorders may have multiple overlapping etiologies that require careful differential diagnosis. This is imperative to establish appropriate treatment regimens and evaluate clinical outcomes.

Further delineation of mandibulofacial dysostosis: Toriello type

We report a boy who presented with mild mandibulofacial dysostosis, growth retardation with microcephaly, bilateral hearing loss, thoracic deformity with a cardiac valvular lesion and bilateral cryptorchidism. The pattern of malformations differs from the classical Treacher Collins syndrome. We consider it to be mandibulofacial dysostosis (MFD), Toriello type with some additional features.

Temporomandibular region in the Franceschetti's Syndrome. Anatomical study

Franceschetti's syndrome is a rare, non-fatal, hereditary malformation, usually bilateral, which symmetrically affects orbits, mandible and ear. The authors propose an anatomical description of the temporomandibular region after the dissection of a newborn baby suffering from Franceschetti's Syndrome, dead soon after the birth. A discussion on the different etiopathogenical theories is made. The authors conclude that an alteration of the development of nerve trigeminal branches is the cause of the malformations.

Mandibular distraction osteogenesis in very young patients to correct airway obstruction

The purpose of this study was to measure changes in the airway cross-sectional area of pediatric patients with micrognathia and obstructive airway symptoms after treatment by mandibular distraction. The measurements obtained were correlated with the clinical outcomes.Ten patients, ranging in age from 3 months to 8 years, underwent measurement and distraction. Eight patients were under 30 months of age. Six were diagnosed with Pierre Robin sequence, two with Treacher Collins syndrome, and two with Nager syndrome. All patients had retrognathia of greater than 8 mm and obstructive airway symptoms while awake that had resulted in tracheostomy (3), repeated apnea monitor triggering (5), or abnormal sleep study (2). Cephalometric analysis was performed pretreatment and posttreatment by distraction. The effective airway space was defined with the following boundaries: a horizontal line from the tip of the odontoid to the velum, the uvula tip to the tongue base along the shortest line, the tongue base down to the base of the epiglottis, and the horizontal line to the posterior pharynx. These lines were traced for each cephalogram, the outline was digitized, and the area was calculated by computer. An analysis of the square area change was done by paired t test. The range of distraction was 8 to 22 mm; the mean effective airway increase was 67.5 percent, with a range of 26 to 120 percent. Measurable airway increase occurred in all patients who underwent distraction, and all patients showed clinical improvement. Six patients with Pierre Robin sequence became asymptomatic, with normal sleep, feeding, and weight gain. Two patients with Nager syndrome and tracheostomies were decannulated and were asymptomatic postdistraction. One patient with Treacher Collins syndrome without tracheostomy became asymptomatic after mandibular distraction; one patient failed to distract because of premature consolidation and continued to require a cannula. Mandibular distraction seems to provide a consistent change in tongue base position that improves obstructive airway symptoms by increasing measured effective airway space. The potential for mandibular distraction exceeds the simple correction of malocclusion also by eliminating soft-tissue obstruction of the micrognathic airway. Airway improvement is independent of the syndrome diagnosed. Mandibular distraction osteogenesis may be useful to avoid or decannulate existing tracheostomy in infants with micrognathia.

Flexor digitorum longus accessorius in the club foot of an infant with Nager syndrome

The case of a male infant is reported who had club foot on the right side and pes adductus on the left side in combination with acrofacial dysostosis; he also demonstrated preaxial anomalies of the upper limbs indicative of Nager syndrome. In addition, an unusual aberrant muscle was discovered during surgical correction of the right club foot.

[Distraction osteogenesis of the mandible in 2 children with obstruction of the upper respiratory tract due to micrognathia]

A girl approximately 2 years old with Pierre Robin sequence had periods of nocturnal respiratory insufficiency as a consequence of micrognathia and a boy nearly 4 years old with Nager syndrome and tracheostomy was retarded in his speech development, had problems swallowing and often had respiratory tract infections. The obstruction of the upper respiratory tract was resolved by performing a distraction osteogenesis of the lower jaw. A tracheostomy was avoided or else removed. The girl became more active and there was an improvement in the boy's speech development. Distraction osteogenesis is a good alternative to the current practice of mandibular reconstruction in micrognathic patients, which involves extensive bone grafts.

Treacher Collins syndrome: current evaluation, treatment, and future directions

OBJECTIVE

Treacher Collins syndrome (TCS) is an inherited disorder in which there are general bilateral symmetric anomalies of the structures within the first and second branchial arches. In general, there is complete penetrance and variable expressivity of the trait. The craniofacial rehabilitation of a child with TCS is tailored to the extent of the deformities involved: the orbitozygomatic region, the maxillomandibular region, the nose, facial soft tissues, and external and middle ear structures.

CONCLUSION

This article reviews the range of clinical features and specific dysmorphology observed in TCS. Functional and aesthetic objectives are discussed, and a comprehensive staged reconstructive approach is outlined, which may be used as a roadmap for treatment planning.

Increased levels of apoptosis in the prefusion neural folds underlie the craniofacial disorder, Treacher Collins syndrome

Treacher Collins syndrome (TCS) is an autosomal dominant disorder of human craniofacial development that results from loss-of-function mutations in the gene TCOF1. Although this gene has been demonstrated to encode the nucleolar phosphoprotein treacle, the developmental mechanism underlying TCS remains elusive, particularly as expression studies have shown that the murine orthologue, Tcof1, is widely expressed. To investigate the molecular pathogenesis of TCS, we replaced exon 1 of Tcof1 with a neomycin-resistance cassette via homologous recombination in embryonic stem cells. Tcof1 heterozygous mice die perinatally as a result of severe craniofacial anomalies that include agenesis of the nasal passages, abnormal development of the maxilla, exencephaly and anophthalmia. These defects arise due to a massive increase in the levels of apoptosis in the prefusion neural folds, which are the site of the highest levels of Tcof1 expression. Our results demonstrate that TCS arises from haploinsufficiency of a protein that plays a crucial role in craniofacial development and indicate that correct dosage of treacle is essential for survival of cephalic neural crest cells.

[Syndromes 11. Treacher collins syndrome]

Treacher Collins syndrome is seen once in 10.000 births. Inheritance is autosomal dominant with variable expressivity. The most prominent symptoms are antimongoloid slant of the eyelids, hypo- or even aplasia of the zygomata, very hypoplastic mandible with receding chin, deformed ear lobes and conductive hearing loss. With two to three operations a considerable improvement can be achieved. The correction of the eyelids is often the most difficult problem.

Mandibulo-facial dysostosis: comparison study of a neonate with mandibulo-facial dysostosis and a normal neonate

Mandibulo-facial dysostosis (MFD) is a malformative syndrome with autosomal dominant transmission and variable expressivity that mainly affects derivatives of the first and second branchial arches. The subsurface anatomy of this condition is still partly unexplored since there have been only four reported dissections of MFD. A detailed dissection of the head and neck of a neonate with MFD is described and compared with a normal neonate. Theories of the pathogenesis are discussed on the basis of these observations.

Treacher-Collins syndrome and co-existing dermatomyositis

BACKGROUND

Treacher-Collins syndrome, an autosomal dominantly inherited malformation of structures derived from the first and second branchial arch, has an incidence of 1:10,000 newborns. The prevalence of dermatomyositis at less than 24 years of age has been estimated at 1 per 100,000. The occurrence of both Treacher-Collins syndrome and dermatomyositis combined in the same patient should occur once in every 1,000,000,000 subjects.

METHODS

We report a patient with Treacher-Collins syndrome who developed dermatomyositis at the age of 5 years.

RESULTS

No other patient with both Treacher-Collins syndrome and an autoimmune disease has been reported. The thymus originates from the third branchial pouch and is unaffected by the syndrome. In Treacher-Collins syndrome the affected gene has been mapped to the fifth chromosome, while dermatomyositis is related to HLA B8 and DR3, coded on the sixth chromosome. No immunologic alteration has been described in patients with Treacher-Collins syndrome.

CONCLUSION

This is the first report of a patient with Treacher-Collins syndrome and dermatomyositis. There is no genetic or physiopathologic explanation for the concurrence of both conditions.

A nager acrofacial dysostosis syndrome patient with severe respiratory distress syndrome (RDS)

Nager acrofacial dysostosis is characterized by radial defect and the facial manifestations like Treacher-Collins syndrome. There are few reports about this syndrome in Japan. We report a typical Japanese Nager syndrome patient. He was complicated with respiratory distress syndrome.

Clinical appearance of spontaneous and induced first and second branchial arch syndromes

The clinical appearance was investigated of 29 patients with mandibulofacial dysostosis, 26 with hemifacial microsomia, and seven with thalidomide-induced malformations affecting derivatives of the first and second branchial arches. Malformations of the external ear, ear canal, middle ear, zygoma, maxilla, mandible, and lower eye lid were prominent features of the syndromes. Facial nerve and 6th cranial nerve paralysis as well as anophthalmia or microphthalmia were seen only in patients with hemifacial microsomia and in the thalidomide-induced syndrome. We compared the clinical results with those in an animal model in which an induced first and second branchial arch syndrome depends on disturbed migration of neural crest cell during early embryogenesis. The critical time for a similar process in humans would be between the 20th and 29th days of pregnancy.

Multi-facial anomalies in mandibulofacial dysostosis. A report of three cases

Mandibulofacial dysostosis is readily recognized on the basis of a characteristic facial appearance caused by hard and soft tissue abnormalities of the face, including malformations of the ear. Generally, the abnormality is symmetrical. The psychological and social stigma associated with severe facial deformity makes this syndrome one of the most challenging reconstructive problems presented to the craniomaxillofacial surgeon.

A new form of mandibulofacial dysostosis with macroblepharon and macrostomia

We report on a girl aged 7 years with normal mental development but an unusual form of mandibulofacial dysostosis. The hallmarks of the syndrome are a round, flat face, severe hypertelorism, downslanting palpebral fissures extending to the temples, a broad nasal base, anteverted nares, small, posteriorly rotated ears, a long, smooth philtrum, a thin upper lip, striking macrostomia, retrognathism with reduced height of the mandible, and irregularly placed teeth, some to them missing.

Laryngeal malformations in the Richieri-Costa and Pereira form of acrofacial dysostosis

We report on laryngeal malformations in 5 subjects, 4 females and 1 male, with the autosomal-recessive Richieri-Costa and Pereira form of acrofacial dysostosis. Characteristics of the voice are described.

Radiocephalometric evaluation of a family with mandibulofacial dysostosis

Persons from four generations of a family with mandibulofacial dysostosis (MFD), known as Treacher Collins (TC) Syndrome, were examined for the presence of clinical signs traditionally associated with this syndrome. In this family, 14 adults, who had been judged trait bearers by an earlier family study were included in this study. Maxillary and mandibular study models were taken of affected and unaffected family members. Panoramic cephalograms and lateral radiographs were taken. The lateral cephalograms were traced and digitized on a computer system and compared. The 117 cephalometric values of the trait bearers were compared with known standard values and nontrait bearing family members. In the trait bearing group, 81 of the 117 values and, in the nontrait bearing group, 72 of the 117 values were significantly different (p < 0.05) when comparing mean values to the accepted normal range. The interfamily comparison between trait-bearing and nontrait members revealed nine values to be significantly different. This indicates that cephalometric analysis of these patients, some of whom have minimal clinical expression of the gene, may have potential value for screening and further characterization of this condition. The results also suggest that intrafamily comparisons may be of greater value for diagnostic confirmation of TC than comparison with literature norms.

Diagnostic difficulties in cases of sudden death in infants with mandibular hypoplasia

Infants with mandibular hypoplasia are at risk of sudden death from cardiorespiratory arrest secondary to upper airway obstruction. To evaluate diagnostic difficulties that may occur at autopsy in such infants, the autopsy files at the Adelaide Children's Hospital (ACH) for 36 years, 1959 to 1994, were reviewed. Eight cases were identified (age range, 2 days to 10 months; mean age, 2.2 months; male/female ratio, 5:3). In all cases, death was considered most likely due to airway obstruction related to mandibular hypoplasia or its treatment. Although death occurred in the hospital in five cases, one infant suddenly collapsed at home while feeding and died, and two infants were unexpectedly found dead in their cribs at home. Three infants had defined genetic syndromes. Although all the infants had histories of antemortem airway obstruction, one infant had normal oxygen saturation studies before hospital discharge, and one infant had a tracheostomy. Acute bronchopneumonia was an exacerbating factor in one case. Assessment of mandibular size is important in any infant who dies unexpectedly; and if hypoplasia is found, careful review of the clinical details for evidence of airway obstruction is necessary to help distinguish these cases from sudden infant death syndrome (SIDS). Sudden death may, however, occur in infants with mandibular hypoplasia in spite of apparent clinical stability before death with no significant recent episodes of oxygen desaturation.

Repeated mandibular lengthening in Treacher Collins syndrome: a case report

A patient with mandibular hypoplasia associated with Treacher Collins syndrome was treated by bilateral distraction osteogenesis. Since less than optimal length was provided by the first distraction, a second corticotomy was performed in the newly formed bone 6 months after the first distraction. Thus bone gained by distraction osteogenesis was subjected to distraction once again. New bone formation occurred after the second lengthening. This case illustrated that distraction osteogenesis may be applied to the mandible at the site of previous distraction.