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Objective: Here we trained an automatic phenotype assessment tool to recognize syndromic ears in two syndromes in fetuses-=CHARGE and Mandibulo-Facial Dysostosis Guion Almeida type (MFDGA)-versus controls., Method: We trained an automatic model on all profile pictures of children diagnosed with genetically confirmed MFDGA and CHARGE syndromes, and a cohort of control patients, collected from 1981 to 2023 in Necker Hospital (Paris) with a visible external ear. The model consisted in extracting landmarks from photographs of external ears, in applying geometric morphometry methods, and in a classification step using machine learning. The approach was then tested on photographs of two groups of fetuses: controls and fetuses with CHARGE and MFDGA syndromes., Results: The training set contained a total of 1489 ear photographs from 526 children. The validation set contained a total of 51 ear photographs from 51 fetuses. The overall accuracy was 72.6% (58.3%-84.1%, p < 0.001), and 76.4%, 74.9%, and 86.2% respectively for CHARGE, control and MFDGA fetuses. The area under the curves were 86.8%, 87.5%, and 90.3% respectively for CHARGE, controls, and MFDGA fetuses., Conclusion: We report the first automatic fetal ear phenotyping model, with satisfactory classification performances. Further validations are required before using this approach as a diagnostic tool., (© 2024 The Authors. Prenatal Diagnosis published by John Wiley & Sons Ltd.)

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&#95;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., (© 2024 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

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.

Mandibulofacial dysostosis with microcephaly (MFDM) is due to haploinsufficiency of spliceosomal GTPase EFTUD2. Features include microcephaly, craniofacial dysmorphology, developmental disability, and other anomalies. We surveyed parents of individuals with MFDM to expand knowledge about health, development, and parental concerns. Participants included attendees of the inaugural MFDM family conference in June 2019 and members of the MFDM online group. To explore MFDM variable expressivity, we offered targeted Sanger sequencing for untested parents. Forty-seven parents participated in the survey. 59% of individuals with MFDM were male, with mean age 6.4 years (range 8 months to 49 years). Similar to the literature (n = 123), common features include microcephaly, cleft palate, choanal stenosis, tracheoesophageal fistula, heart problems, and seizures. New information includes airway intervention details, age-based developmental outcomes, rate of vision refractive errors, and lower incidences of prematurity and IUGR. Family concerns focused on development, communication, and increased support. Targeted Sanger sequencing for families of seven individuals demonstrated de novo variants, for a total of 91.9% de novo EFTUD2 variants (n = 34/37). This study reports the largest single cohort of individuals with MFDM, expands phenotypic spectrum and inheritance patterns, improves understanding of developmental outcomes and care needs, and identifies development as the biggest concern for parents., (© 2020 Wiley Periodicals LLC.)

Background: Treacher Collins syndrome-1 (TCS1; OMIM# 154500) is a rare autosomal dominant disease that is defined by congenital craniofacial dysplasia. Here, we report four sporadic and one familial case of TCS1 in Chinese patients with clinical features presenting as hypoplasia of the zygomatic complex and mandible, downslanting palpebral fissures, coloboma of the lower eyelids, and conductive hearing loss., Materials and Methods: Audiological, radiological, and physical examinations were performed. Targeted next-generation sequencing (NGS) was performed to examine the genetics of this disease in five probands, and Sanger sequencing was used to confirm the identified variants. A literature review discusses the pathogenesis, treatment, and prevention of TCS1., Results: We identified a novel insertion of c.939&#95;940insA (p.Gly314Argfs*35; NM&#95;001135243.1), a novel deletion of c.1766delC (p.Pro589Leufs*7), two previously reported insertions of c.1999&#95;2000insC (p.Arg667Profs*31) and c.4218&#95;4219insG (p.Ser1407Valfs*23), and one previously reported deletion of c.4369&#95;4373delAAGAA (p.Lys1457Glufs*12) in the TCOF1 gene. All five cases exhibited a degree of interfamilial and intrafamilial phenotypic variability. A review of the literature revealed no clear evidence of a genotype-phenotype correlation in TCS1., Conclusion: Our results expand the variant spectrum of TCOF1 and highlight that NGS is essential for the diagnosis of TCS and that genetic counseling is beneficial for guiding prevention., (© 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

The spliceosome is a complex of RNA and proteins that function together to identify intron-exon junctions in precursor messenger-RNAs, splice out the introns, and join the flanking exons. Mutations in any one of the genes encoding the proteins that make up the spliceosome may result in diseases known as spliceosomopathies. While the spliceosome is active in all cell types, with the majority of the proteins presumably expressed ubiquitously, spliceosomopathies tend to be tissue-specific as a result of germ line or somatic mutations, with phenotypes affecting primarily the retina in retinitis pigmentosa, hematopoietic lineages in myelodysplastic syndromes, or the craniofacial skeleton in mandibulofacial dysostosis. Here we describe the major spliceosomopathies, review the proposed mechanisms underlying retinitis pigmentosa and myelodysplastic syndromes, and discuss how this knowledge may inform our understanding of craniofacial spliceosomopathies., (© 2020 Wiley Periodicals LLC.)

Background: Treacher Collins syndrome (TCS) is the most common mandibulofacial dysostosis with an autosomal dominant or rarely recessive manner of inheritance. It is still challenging to make a definite diagnosis for affected fetuses with TCS only depending on the ultrasound screening. Genetic tests can contribute to the accurate diagnosis for those prenatal cases., Methods: Targeted exome sequencing was performed in a fetus of a Chinese family, who presenting an abnormal facial appearance by prenatal 2D and 3D ultrasound screening, including micrognathia, nasal bridge pit, and abnormal auricle. The result was validated with multiplex ligation-dependent probe amplification (MLPA) and real-time quantitative PCR (qPCR)., Results: A novel 2-6 exons deletion of TCOF1 gene was identified and confirmed by the MLPA and qPCR in the fetus, which was inherited from the affected father with similar facial anomalies., Conclusion: The heterozygous deletion of 2-6 exons in TCOF1 results in the TCS of this Chinese family. Our findings not only enlarge the spectrum of mutations in TCOF1 gene, but also highlight the values of combination of ultrasound and genetics tests in diagnosis of craniofacial malformation-related diseases during perinatal period., (© 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

Purpose: Treacher Collins syndrome (TCS) is a rare autosomal dominant mandibulofacial dysostosis, with a prevalence of 0.2-1/10,000. Features include bilateral and symmetrical malar and mandibular hypoplasia and facial abnormalities due to abnormal neural crest cell (NCC) migration and differentiation. To date, three genes have been identified: TCOF1, POLR1C, and POLR1D. Despite a large number of patients with a molecular diagnosis, some remain without a known genetic anomaly., Methods: We performed exome sequencing for four individuals with TCS but who were negative for pathogenic variants in the known causative genes. The effect of the pathogenic variants was investigated in zebrafish., Results: We identified three novel pathogenic variants in POLR1B. Knockdown of polr1b in zebrafish induced an abnormal craniofacial phenotype mimicking TCS that was associated with altered ribosomal gene expression, massive p53-associated cellular apoptosis in the neuroepithelium, and reduced number of NCC derivatives., Conclusion: Pathogenic variants in the RNA polymerase I subunit POLR1B might induce massive p53-dependent apoptosis in a restricted neuroepithelium area, altering NCC migration and causing cranioskeletal malformations. We identify POLR1B as a new causative gene responsible for a novel TCS syndrome (TCS4) and establish a novel experimental model in zebrafish to study POLR1B-related TCS.

Catel-Manzke syndrome is characterized by hand anomalies, Robin sequence, cardiac defects, joint hyperextensibility, and characteristic facial features. Approximately 40 patients with Catel-Manzke have been reported, all with the pathognomonic bilateral or unilateral hyperphalangy caused by an accessory bone between the second metacarpal and proximal phalanx known as Manzke dysostosis. Here we present the first case of molecularly confirmed Catel-Manzke syndrome with Robin sequence but without Manzke dysostosis., (© 2019 Wiley Periodicals, Inc.)

Background: Patients with Treacher-Collins syndrome (TCS) are frequently affected by congenital ear deformities. The external ear in patients with TCS tends to have both abnormal morphology and reduced overall volume. Previous studies considered a correlation exists between TCS mandibular skeletal features and external ear volume. The purpose of this study was to assess the external ear volume in patients with TCS 3-dimensionally. Furthermore, this study evaluated the relationship between mandibular morphology, external ear profile, and external ear volume., Methods: A total of 36 nonoperated patients with TCS were compared to 39 age- and gender-matched normal controls. Morphologic variables of the mandible and the external ear were compared between TCS group and controls by 3-dimensional cephalometrics. The external ear volume and morphologic variables were analyzed with independent sample T-tests and Pearson correlation coefficient analyses (level of evidence: level III)., Results: The external ear volume was reduced by approximately 50% in patients with TCS compared to controls (P < 0.001). External ear length and width were positively correlated with external ear volume (length: r = 0.809, P < 0.001 on left and r = 0.732, P < 0.001 on right; width: r = 0.518, P = 0.001 on left and r = 0.447, P < 0.010 on right). A negative correlation of right ear inclination angle and external ear volume was shown in patients with TCS (r = -0.396, P = 0.027). However, no correlation was shown for the mandibular anatomic variables., Conclusions: Three-dimensional analysis confirmed that external ear volume is significantly reduced in patients with TCS. The external ear dimensions and orientation correlated significantly with ear volume. There was no intrinsic association between the severity of mandibular deformity and external ear volume.

Treacher Collins Syndrome (TCS) is a congenital disease characterized by defects in the craniofacial skeleton and absence of mental alterations. Recently we modelled TCS in zebrafish (Danio rerio) embryos through the microinjection of Morpholino® oligonucleotides blocking the translation of the ortholog of the main causative gene (TCOF1). We showed that Cnbp, a key cytoprotective protein involved in normal rostral head development, was detected in lower levels (without changes in its mRNA expression) in TCS-like embryos. As previous reports suggested that Cnbp is degraded through the proteasomal pathway, we tested whether proteasome inhibitors (MG132 and Bortezomib (Velcade®, Millennium laboratories)) were able to ameliorate cranial skeleton malformations in TCS. Here we show that treatment with both proteasome inhibitors produced a robust craniofacial cartilage phenotype recovery. This recovery seems to be consequence of a decreased degradation of Cnbp in TCS-like embryos. Critical TCS manifestations, such as neuroepithelial cell death and cell redox imbalance were attenuated. Thus, proteasome inhibitors may offer an opportunity for TCS molecular and phenotypic manifestation's prevention. Although further development of new safe inhibitors compatible with administration during pregnancy is required, our results encourage this therapeutic approach., (Copyright © 2019 Elsevier Inc. All rights reserved.)

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., (Copyright © 2018 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.)

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.

Ribosome biogenesis is a global process required for growth and proliferation in all cells, but disruptions in this process surprisingly lead to tissue-specific phenotypic disorders termed ribosomopathies. Pathogenic variants in the RNA Polymerase (Pol) I subunit POLR1A cause Acrofacial Dysostosis-Cincinnati type, which is characterized by craniofacial and limb anomalies. In a zebrafish model of Acrofacial Dysostosis-Cincinnati type, we demonstrate that polr1a-/- mutants exhibit deficient 47S rRNA transcription, reduced monosomes and polysomes and, consequently, defects in protein translation. This results in Tp53-dependent neuroepithelial apoptosis, diminished neural crest cell proliferation and cranioskeletal anomalies. This indicates that POLR1A is critical for rRNA transcription, which is considered a rate limiting step in ribosome biogenesis, underpinning its requirement for neuroepithelial cell and neural crest cell proliferation and survival. To understand the contribution of the Tp53 pathway to the pathogenesis of Acrofacial Dysostosis-Cincinnati type, we genetically inhibited tp53 in polr1a-/- mutant embryos. Tp53 inhibition suppresses neuroepithelial apoptosis and partially ameliorates the polr1a mutant phenotype. However, complete rescue of cartilage development is not observed due to the failure to improve rDNA transcription and neural crest cell proliferation. Altogether, these data reveal specific functions for both Tp53-dependent and independent signaling downstream of polr1a in ribosome biogenesis during neural crest cell and craniofacial development, in the pathogenesis of Acrofacial Dysostosis-Cincinnati type. Furthermore, our work sets the stage for identifying Tp53-independent therapies to potentially prevent Acrofacial dysostosis-Cincinnati type and other similar ribosomopathies., (© The Author(s) 2018. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Treacher Collins syndrome (TCS) is a craniofacial developmental disorder whose key feature is a combination of symptoms. For example, a patient could have bilateral downward slanting of the palpebral fissures, colobomas of the lower eyelids, hypoplasia of the facial bones, cleft palate, malformation of the external ears, and atresia of the external auditory canals. TCS3 is caused by mutations of the polr1c gene, which encodes RNA polymerase I and III subunit C (POLR1C). There have been two known missense mutations (Arg279-to-Gln [R279Q] and Arg279-to-Trp [R279W]) at the Arg-279 position. However, it remains to be clarified whether or how both or each individual mutation affects the cellular properties of POLR1C. Here we show that TCS3-associated missense mutations cause aberrant intracellular localization of POLR1C, inhibiting chondrogenic differentiation. The wild type POLR1C is normally localized in the nuclei. The R279Q or R279W mutant is primarily found to be localized in the lysosome. Expression of the R279Q or R279W mutant in mouse chondrogenic ATDC5 cells decreases phosphorylation of 4E-BP1 and ribosomal S6 proteins, which belong to the mammalian target of rapamycin (mTOR) signaling involved in critical roles in the lysosome. Furthermore, expression of the R279Q or R279W mutant inhibits chondrogenic differentiation in ATDC5 cells. Taken together, TCS3-associated mutation leads to the localization of POLR1C into the lysosome and inhibits chondrogenic differentiation, possibly explaining a portion of the pathological molecular basis underlying Treacher Collins syndrome., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Many craniofacial disorders are caused by heterozygous mutations in general regulators of housekeeping cellular functions such as transcription or ribosome biogenesis. Although it is understood that many of these malformations are a consequence of defects in cranial neural crest cells, a cell type that gives rise to most of the facial structures during embryogenesis, the mechanism underlying cell-type selectivity of these defects remains largely unknown. By exploring molecular functions of DDX21, a DEAD-box RNA helicase involved in control of both RNA polymerase (Pol) I- and II-dependent transcriptional arms of ribosome biogenesis, we uncovered a previously unappreciated mechanism linking nucleolar dysfunction, ribosomal DNA (rDNA) damage, and craniofacial malformations. Here we demonstrate that genetic perturbations associated with Treacher Collins syndrome, a craniofacial disorder caused by heterozygous mutations in components of the Pol I transcriptional machinery or its cofactor TCOF1 (ref. 1), lead to relocalization of DDX21 from the nucleolus to the nucleoplasm, its loss from the chromatin targets, as well as inhibition of rRNA processing and downregulation of ribosomal protein gene transcription. These effects are cell-type-selective, cell-autonomous, and involve activation of p53 tumour-suppressor protein. We further show that cranial neural crest cells are sensitized to p53-mediated apoptosis, but blocking DDX21 loss from the nucleolus and chromatin rescues both the susceptibility to apoptosis and the craniofacial phenotypes associated with Treacher Collins syndrome. This mechanism is not restricted to cranial neural crest cells, as blood formation is also hypersensitive to loss of DDX21 functions. Accordingly, ribosomal gene perturbations associated with Diamond-Blackfan anaemia disrupt DDX21 localization. At the molecular level, we demonstrate that impaired rRNA synthesis elicits a DNA damage response, and that rDNA damage results in tissue-selective and dosage-dependent effects on craniofacial development. Taken together, our findings illustrate how disruption in general regulators that compromise nucleolar homeostasis can result in tissue-selective malformations.

Orbito-palpebral reconstruction is a challenge in Treacher Collins syndrome (TCS). This study investigates orbital phenotypes in TCS using cephalometry and orbital shape analysis. Eighteen TCS and 52 control patients were included in this study, using the Dr Warehouse database. Orbital cephalometry was based on 20 landmarks, 10 planes, 16 angles, and 22 distances. Orbits were segmented. Registration-based, age-specific mean models were generated using semi-automatic segmentation, and aligned and compared using color-coded distance maps - mean absolute distance (MAD), Hausdorff distance (HD), and Dice similarity coefficient (DSC). Symmetry was assessed by mirroring and DSC computing. Central orbital depth (COD) and medial orbital depth (MOD) allowed 100% of orbits to be classified. COD and lateral orbital depth (LOD) were different from the controls. Average MAD between TCS and controls was ≤1.5 mm, while for HD it was >1.5 mm, and for DSC <1. TCS orbits were more asymmetrical than controls, and orbital volumes were smaller when age was considered as a confounding factor, and had a trend for normalization with age. This report emphasizes the importance of combining different morphometric approaches in the phenotype characterization of non-trivial structures such as the orbit, and supports composite skeletal and soft-tissue strategies for the management of the peri-orbital region., (Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Treacher Collins syndrome (TCS) is a rare congenital birth disorder (1 in 50,000 live births) characterized by severe craniofacial defects. Recently, the authors' group unfolded the pathogenesis of polr1c Type 3 TCS by using the zebrafish model. Facial development depends on the neural crest cells, in which polr1c plays a role in regulating their expression. In this study, the authors aimed to identify the functional time window of polr1c in TCS by the use of photo-morpholino to restore the polr1c expression at different time points. Results suggested that the restoration of polr1c at 8 hours after fertilization could rescue the TCS facial malformation phenotype by correcting the neural crest cell expression, reducing the cell death, and normalizing the p53 mRNA expression level in the rescued morphants. However, such recovery could not be reproduced if the polr1c is restored after 30 hours after fertilization., (Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Background: The aim of this study was to identify cephalometric measurements associated with clinical severity in patients with Treacher Collins syndrome., Methods: A retrospective single-institution review of patients with Treacher Collins syndrome was conducted. Preoperative cephalograms and computed tomographic scans (n = 30) were evaluated. Fifty cephalometric measurements were compared to age-specific normative data using analysis of variance. These cephalometric measurements and the patient's Pruzansky classification were correlated to clinical severity using Spearman analysis. Clinical severity was defined as severe (required tracheostomy), moderate (obstructive sleep apnea, oral cleft, or gastrostomy-tube), or mild (absence of listed comorbidities). Cephalometric measurements with a strong correlation (r > 0.60) were identified as predictors of clinical severity., Results: Cephalograms of the study population contained 30 measurements that were found to be significantly different from normative data (p < 0.01). These measurements were related largely to maxillary/mandibular projection, maxillary/mandibular plane angle, mandibular morphology, facial height, facial convexity, and mandible/throat position. Ten of these 30 statistically significant measurements in addition to Pruzansky classification were found to be strongly correlated (r > 0.60) to clinical severity. These measurements include the following: mandibular projection/position (sella-nasion-pogonion, r = -0.64; hyoid-menton, r = -0.62); posterior facial height (posterior facial height/anterior facial height, r = 0.60; condyle-gonion, r = -0.66); maxillary/mandibular plane angle (sella-nasion-mandibular plane, r = 0.62; Frankfort horizontal-mandibular plane, r = 0.61; sella-nasion-palatal plane, r = 0.69; sella-nasion-symphysis, r = -0.69); and Pruzansky classification (r = 0.82)., Conclusion: Specific cephalometric measurements of increased mandibular retrognathia, decreased posterior facial height, more obtuse maxillary/mandibular plane angle and more obtuse symphysis notch angle are strongly correlated to increased clinical severity in patients with Treacher Collins syndrome.

Craniofacial anomalies account for approximately one-third of all congenital birth defects reflecting the complexity of head and facial development. Craniofacial development is dependent upon a multipotent, migratory population of neural crest cells, which generate most of the bone and cartilage of the head and face. In this review, we discuss advances in our understanding of the pathogenesis of a specific array of craniofacial anomalies, termed facial dysostoses, which can be subdivided into mandibulofacial dysostosis, which present with craniofacial defects only, and acrofacial dysostosis, which encompasses both craniofacial and limb anomalies. In particular, we focus on Treacher Collins syndrome, Acrofacial Dysostosis-Cincinnati Type as well as Nager and Miller syndromes, and animal models that provide new insights into the molecular and cellular basis of these congenital syndromes. We emphasize the etiologic and pathogenetic similarities between these birth defects, specifically their unique deficiencies in global processes including ribosome biogenesis, DNA damage repair, and pre-mRNA splicing, all of which affect neural crest cell development and result in similar tissue-specific defects. WIREs Dev Biol 2017, 6:e263. doi: 10.1002/wdev.263 For further resources related to this article, please visit the WIREs website., (© 2017 Wiley Periodicals, Inc.)

Triphalangeal thumb‑polysyndactyly syndrome (TPT‑PS) is an autosomal dominant disorder with complete penetrance and a variable expression consisting of opposable triphalangeal thumbs, duplication of the distal thumb phalanx, pre‑axial polydactyly and duplication of the big toes (hallux). The causative gene of TPT‑PS has been mapped to 7q36.3. Sonic hedgehog (SHH) expressed in the zone of polarizing activity (ZPA) has an important role in defining the anterior‑posterior axis and numbers of digits in limb bud development. Point mutation or duplication in the ZPA regulatory sequence (ZRS), a cis‑regulator of SHH, will lead to TPT‑PS. The present study describes a 1‑year‑old female congenital heart disease (CHD) patient with TPT‑PS phenotype. In this Han Chinese family with TPT‑PS, high resolution single nucleotide polymorphism array technology identified a novel 0.29 Mb duplication comprising ZRS at 7q36.3 where LMBR1 is located. Additionally, a novel deletion of 22q11.21 was detected in the proband with Tetralogy of Fallot. However, the parents and other relatives of the patient did not harbor this genomic lesion nor CHD. The findings supported the hypothesis that an increased copy number variation of ZRS is the genetic mechanism underlying the phenotype of TPT‑PS, and corroborated that 22q11.21 deletion is a genetic cause of CHD.

Treacher Collins Syndrome (TCS) is a rare congenital disease (1:50 000 live births) characterized by craniofacial defects, including hypoplasia of facial bones, cleft palate and palpebral fissures. Over 90% of the cases are due to mutations in the TCOF1 gene, which codifies the nucleolar protein Treacle. Here we report a novel TCS-like zebrafish model displaying features that fully recapitulate the spectrum of craniofacial abnormalities observed in patients. As it was reported for a Tcof1 +/- mouse model, Treacle depletion in zebrafish caused reduced rRNA transcription, stabilization of Tp53 and increased cell death in the cephalic region. An increase of ROS along with the overexpression of redox-responsive genes was detected; furthermore, treatment with antioxidants ameliorated the phenotypic defects of craniofacial anomalies in TCS-like larvae. On the other hand, Treacle depletion led to a lowering in the abundance of Cnbp, a protein required for proper craniofacial development. Tcof1 knockdown in transgenic zebrafish overexpressing cnbp resulted in barely affected craniofacial cartilage development, reinforcing the notion that Cnbp has a role in the pathogenesis of TCS. The cnbp overexpression rescued the TCS phenotype in a dose-dependent manner by a ROS-cytoprotective action that prevented the redox-responsive genes' upregulation but did not normalize the synthesis of rRNAs. Finally, a positive correlation between the expression of CNBP and TCOF1 in mesenchymal cells from both control and TCS subjects was found. Based on this, we suggest CNBP as an additional target for new alternative therapeutic treatments to reduce craniofacial defects not only in TCS but also in other neurocristopathies.

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., Competing Interests: The authors have declared that no competing interests exist.

Treacher Collins syndrome (TCS) is a rare, autosomal-dominant disorder characterized by craniofacial deformities, and is primarily caused by mutations in the Tcof1 gene. This article was aimed to perform a comprehensive literature review and systematic bioinformatic analysis of Tcof1-related molecular networks in TCS. First, the up- and down-regulated genes in Tcof1 heterozygous haploinsufficient mutant mice embryos and Tcof1 knockdown and Tcof1 over-expressed neuroblastoma N1E-115 cells were obtained from the Gene Expression Omnibus database. The GeneDecks database was used to calculate the 500 genes most closely related to Tcof1. Then, the relationships between 4 gene sets (a predicted set and sets comparing the wildtype with the 3 Gene Expression Omnibus datasets) were analyzed using the DAVID, GeneMANIA and STRING databases. The analysis results showed that the Tcof1-related genes were enriched in various biological processes, including cell proliferation, apoptosis, cell cycle, differentiation, and migration. They were also enriched in several signaling pathways, such as the ribosome, p53, cell cycle, and WNT signaling pathways. Additionally, these genes clearly had direct or indirect interactions with Tcof1 and between each other. Literature review and bioinformatic analysis finds imply that special attention should be given to these pathways, as they may offer target points for TCS therapies.

Treacher Collins Syndrome (TCS) is a rare congenital birth disorder (1 in 50,000 live births) characterized by severe craniofacial defects, including the downward slanting palpebral fissures, hypoplasia of the facial bones, and cleft palate (CP). Over 90% of patients with TCS have a mutation in the TCOF1 gene. However, some patients exhibit mutations in two new causative genes, POLR1C and POLR1D, which encode subunits of RNA polymerases I and III, that affect ribosome biogenesis. In this study, we examine the role of POLR1C in TCS using zebrafish as a model system. Our data confirmed that polr1c is highly expressed in the facial region, and dysfunction of this gene by knockdown or knock-out resulted in mis-expression of neural crest cells during early development that leads to TCS phenotype. Next generation sequencing and bioinformatics analysis of the polr1c mutants further demonstrated the up-regulated p53 pathway and predicted skeletal disorders. Lastly, we partially rescued the TCS facial phenotype in the background of p53 mutants, which supported the hypothesis that POLR1C-dependent type 3 TCS is associated with the p53 pathway., (Copyright © 2016 Elsevier B.V. All rights reserved.)

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)., (© 2015 WILEY PERIODICALS, INC.)

Less than one hundred cases of the acrofacial dysostosis, Nager syndrome, have been described. The cardinal features of Nager syndrome are micrognathia, midface retrusion and limb malformations, predominately of the radial ray of upper extremities. Within the past three years haploinsufficiency of SF3B4 has been confirmed as the major cause of Nager syndrome. Different loss-of-function point-mutations in SF3B4 have been found in approximately 2/3 of patients diagnosed with Nager syndrome. Whole gene deletions of SF3B4 have also been suggested to be the cause of Nager syndrome in SF3B4 point mutation negative patients. Only four prenatal cases displaying Nager-like features in the 2nd or 3rd trimester which have been genetically confirmed with SF3B4 point-mutation after birth have been described. We report a case of a 12-week-old fetus with micrognathia, malformed wrists, bilateral club foot and short long bones diagnosed prenatally by chromosomal microarray with a de novo 0.4 Mb deletion at chromosome 1q21.2 involving SF3B4. To our knowledge, this is the first report of Nager syndrome caused by a SF3B4 whole gene deletion. The case presented also shows that high-resolution chromosomal microarray in early pregnancy can confirm Nager syndrome caused by SF3B4-deletion prenatally., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

The endothelin receptor type A (EDNRA) signaling pathway is essential for the establishment of mandibular identity during development of the first pharyngeal arch. We report four unrelated individuals with the syndrome mandibulofacial dysostosis with alopecia (MFDA) who have de novo missense variants in EDNRA. Three of the four individuals have the same substitution, p.Tyr129Phe. Tyr129 is known to determine the selective affinity of EDNRA for endothelin 1 (EDN1), its major physiological ligand, and the p.Tyr129Phe variant increases the affinity of the receptor for EDN3, its non-preferred ligand, by two orders of magnitude. The fourth individual has a somatic mosaic substitution, p.Glu303Lys, and was previously described as having Johnson-McMillin syndrome. The zygomatic arch of individuals with MFDA resembles that of mice in which EDNRA is ectopically activated in the maxillary prominence, resulting in a maxillary to mandibular transformation, suggesting that the p.Tyr129Phe variant causes an EDNRA gain of function in the developing upper jaw. Our in vitro and in vivo assays suggested complex, context-dependent effects of the EDNRA variants on downstream signaling. Our findings highlight the importance of finely tuned regulation of EDNRA signaling during human craniofacial development and suggest that modification of endothelin receptor-ligand specificity was a key step in the evolution of vertebrate jaws., (Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

The production of ribosomes is ubiquitous and fundamental to life. As such, it is surprising that defects in ribosome biogenesis underlie a growing number of symptomatically distinct inherited disorders, collectively called ribosomopathies. We previously determined that the nucleolar protein, NOL11, is essential for optimal pre-rRNA transcription and processing in human tissue culture cells. However, the role of NOL11 in the development of a multicellular organism remains unknown. Here, we reveal a critical function for NOL11 in vertebrate ribosome biogenesis and craniofacial development. Nol11 is strongly expressed in the developing cranial neural crest (CNC) of both amphibians and mammals, and knockdown of Xenopus nol11 results in impaired pre-rRNA transcription and processing, increased apoptosis, and abnormal development of the craniofacial cartilages. Inhibition of p53 rescues this skeletal phenotype, but not the underlying ribosome biogenesis defect, demonstrating an evolutionarily conserved control mechanism through which ribosome-impaired craniofacial cells are removed. Excessive activation of this mechanism impairs craniofacial development. Together, our findings reveal a novel requirement for Nol11 in craniofacial development, present the first frog model of a ribosomopathy, and provide further insight into the clinically important relationship between specific ribosome biogenesis proteins and craniofacial cell survival.

Background: Children with Treacher Collins syndrome frequently present with obstructive sleep apnea and respiratory insufficiency. The purpose of this study was to three-dimensionally calculate upper airway volume in these patients. The authors also assessed the correlation between bony craniofacial morphology and spatial position with airway volume., Methods: Thirty Treacher Collins syndrome patients who have not been operated on were compared with a sample of 35 age- and sex-matched unaffected controls. Upper airway volume was stratified into retropalatal and retroglossal aspects. Three-dimensional craniometric findings were compared between patients and controls. Among Treacher Collins syndrome patients, the authors assessed the relationship of craniofacial morphology and spatial positioning to airway volume. Statistical analyses included independent sample t tests and Pearson correlation coefficient analyses., Results: Decreased total upper airway volume (p = 0.034) was found in the Treacher Collins syndrome group, attributable primarily to a decrease in retroglossal airway volume (p = 0.009). Regarding three-dimensional craniometric variables, maxillary and mandibular length (r = 0.76, p < 0.001; and r = 0.68, p < 0.001), and the anterior and posterior cranial base (r = 0.61, p < 0.001; and r = 0.77, p < 0.001) were positively correlated with airway volume in Treacher Collins syndrome patients. Transverse internal diameters of the upper airway were also positively correlated with airway volume (r = 0.635, p = 0.001; and r = 0.511, p = 0.006); however, no correlation was shown for the anteroposterior airway diameters., Conclusions: Three-dimensional analysis revealed diminished upper airway volume in Treacher Collins syndrome, with the retroglossal region being the most severely constricted. Maxillomandibular dysmorphologies, and their relationship to the cranial base, correlated significantly with airway findings.

Nager syndrome belongs to the group of acrofacial dysostosis, which are characterized by the association of craniofacial and limb malformations. Recently, exome sequencing studies identified the SF3B4 gene as the cause of this condition in most patients. SF3B4 encodes a highly conserved protein implicated in mRNA splicing and bone morphogenic protein (BMP) signaling. We performed SF3B4 sequencing in 14 families (18 patients) whose features were suggestive of Nager syndrome and found nine mutations predicted to result in loss-of-function. SF3B4 is the major gene responsible for autosomal dominant Nager syndrome. All mutations reported predict null alleles, therefore precluding genotype-phenotype correlations. Most mutation-negative patients were phenotypically indistinguishable from patients with mutations, suggesting genetic heterogeneity., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The skeleton affords a framework and structural support for vertebrates, while also facilitating movement, protecting vital organs, and providing a reservoir of minerals and cells for immune system and vascular homeostasis. The mechanical and biological functions of the skeleton are inextricably linked to the size and shape of individual bones, the diversity of which is dependent in part upon differential growth and proliferation. Perturbation of bone development, growth and proliferation, can result in congenital skeletal anomalies, which affect approximately 1 in 3000 live births [1]. Ribosome biogenesis is integral to all cell growth and proliferation through its roles in translating mRNAs and building proteins. Disruption of any steps in the process of ribosome biogenesis can lead to congenital disorders termed ribosomopathies. In this review, we discuss the role of ribosome biogenesis in skeletal development and in the pathogenesis of congenital skeletal anomalies. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Mandibulofacial dysostosis, Guion-Almeida type (MFDGA) is a recently delineated multiple congenital anomalies/mental retardation syndrome characterized by the association of mandibulofacial dysostosis (MFD) with external ear malformations, hearing loss, cleft palate, choanal atresia, microcephaly, intellectual disability, oesophageal atresia (OA), congenital heart defects (CHDs), and radial ray defects. MFDGA emerges as a clinically recognizable entity, long underdiagnosed due to highly variable presentations. The main differential diagnoses are CHARGE and Feingold syndromes, oculoauriculovertebral spectrum, and other MFDs. EFTUD2, located on 17q21.31, encodes a component of the major spliceosome and is disease causing in MFDGA, due to heterozygous loss-of-function (LoF) mutations. Here, we describe a series of 36 cases of MFDGA, including 24 previously unreported cases, and we review the literature in order to delineate the clinical spectrum ascribed to EFTUD2 LoF. MFD, external ear anomalies, and intellectual deficiency occur at a higher frequency than microcephaly. We characterize the evolution of the facial gestalt at different ages and describe novel renal and cerebral malformations. The most frequent extracranial malformation in this series is OA, followed by CHDs and skeletal abnormalities. MFDGA is probably more frequent than other syndromic MFDs such as Nager or Miller syndromes. Although the wide spectrum of malformations complicates diagnosis, characteristic facial features provide a useful handle., (© 2014 WILEY PERIODICALS, INC.)

In the present article we report a cholesteatoma of the hypotympanum extending to the jugular foramen in a 16-year-old male with Treacher Collins syndrome. Preoperative imaging excluded jugular paraganglioma and set the diagnosis of cholesteatoma. We discuss the operative treatment via a large hypotympanotomy and creation of an open hypotympanic cavity. To the authors' knowledge this is the first description of hypotympanal cholesteatoma with such an extension, being treated through this approach., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

During vertebrate craniofacial development, neural crest cells (NCCs) contribute to most of the craniofacial pharyngeal skeleton. Defects in NCC specification, migration and differentiation resulting in malformations in the craniofacial complex are associated with human craniofacial disorders including Treacher-Collins Syndrome, caused by mutations in TCOF1. It has been hypothesized that perturbed ribosome biogenesis and resulting p53 mediated neuroepithelial apoptosis results in NCC hypoplasia in mouse Tcof1 mutants. However, the underlying mechanisms linking ribosome biogenesis and NCC development remain poorly understood. Here we report a new zebrafish mutant, fantome (fan), which harbors a point mutation and predicted premature stop codon in zebrafish wdr43, the ortholog to yeast UTP5. Although wdr43 mRNA is widely expressed during early zebrafish development, and its deficiency triggers early neural, eye, heart and pharyngeal arch defects, later defects appear fairly restricted to NCC derived craniofacial cartilages. Here we show that the C-terminus of Wdr43, which is absent in fan mutant protein, is both necessary and sufficient to mediate its nucleolar localization and protein interactions in metazoans. We demonstrate that Wdr43 functions in ribosome biogenesis, and that defects observed in fan mutants are mediated by a p53 dependent pathway. Finally, we show that proper localization of a variety of nucleolar proteins, including TCOF1, is dependent on that of WDR43. Together, our findings provide new insight into roles for Wdr43 in development, ribosome biogenesis, and also ribosomopathy-induced craniofacial phenotypes including Treacher-Collins Syndrome.

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.

Mandibulofacial dysostosis is part of a clinically and genetically heterogeneous group of disorders of craniofacial development, which lead to malar and mandibular hypoplasia. Treacher Collins syndrome is the major cause of mandibulofacial dysostosis and is due to mutations in the TCOF1 gene. Usually patients with Treacher Collins syndrome do not present with intellectual disability. Recently, the EFTUD2 gene was identified in patients with mandibulofacial dysostosis associated with microcephaly, intellectual disability and esophageal atresia. We report on two patients presenting with mandibulofacial dysostosis characteristic of Treacher Collins syndrome, but associated with unexpected intellectual disability, due to a large deletion encompassing several genes including the TCOF1 gene. We discuss the involvement of the other deleted genes such as CAMK2A or SLC6A7 in the cognitive development delay of the patients reported, and we propose the systematic investigation for 5q32 deletion when intellectual disability is associated with Treacher Collins syndrome.

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., (© 2013 Wiley Periodicals, Inc.)

Background: Mutations in EFTUD2 were proven to cause a very distinct mandibulofacial dysostosis type Guion-Almeida (MFDGA, OMIM #610536). Recently, gross deletions and mutations in EFTUD2 were determined to cause syndromic esophageal atresia (EA), as well. We set forth to find further conditions caused by mutations in the EFTUD2 gene (OMIM *603892)., Methods and Results: We performed exome sequencing in two familial cases with clinical features overlapping with MFDGA and EA, but which were previously assumed to represent distinct entities, a syndrome with esophageal atresia, hypoplasia of zygomatic complex, microcephaly, cup-shaped ears, congenital heart defect, and intellectual disability in a mother and her two children [AJMG 143A(11):1135-1142, 2007] and a supposedly autosomal recessive oto-facial syndrome with midline malformations in two sisters [AJMG 132(4):398-401, 2005]. While the analysis of our exome data was in progress, a recent publication made EFTUD2 mutations highly likely in these families. This hypothesis could be confirmed with exome as well as with Sanger sequencing. Also, in three further sporadic patients, clinically overlapping to these two families, de novo mutations within EFTUD2 were identified by Sanger sequencing. Our clinical and molecular workup of the patients discloses a broad phenotypic spectrum, and describes for the first time an instance of germline mosaicism for an EFTUD2 mutation., Conclusions: The clinical features of the eight patients described here further broaden the phenotypic spectrum caused by EFTUD2 mutations or deletions. We here show, that it not only includes mandibulofacial dysostosis type Guion-Almeida, which should be reclassified as an acrofacial dysostosis because of thumb anomalies (present in 12/35 or 34% of patients) and syndromic esophageal atresia [JMG 49(12). 737-746, 2012], but also the two new syndromes, namely oto-facial syndrome with midline malformations published by Mégarbané et al. [AJMG 132(4): 398-401, 2005] and the syndrome published by Wieczorek et al. [AJMG 143A(11): 1135-1142, 2007] The finding of mild phenotypic features in the mother of one family that could have been overlooked and the possibility of germline mosaicism in apparently healthy parents in the other family should be taken into account when counseling such families.

Background and Purpose: Treacher Collins syndrome is an autosomal dominant craniofacial disorder affecting derivatives of the first and second branchial arches. Given the conflicting reports in the literature regarding the extent of anterior-posterior and vertical (superior-inferior) dysplasia of the cranial base, maxilla, and mandible, this study was designed to provide a comprehensive lateral cephalometric assessment of the craniofacial morphology of unoperated patients with Treacher Collins syndrome., Methods: The records of 45 patients with Treacher Collins syndrome registered at the Institute of Reconstructive Plastic Surgery of the NYU Langone Medical Center from the period of 1975 to 2008 were reviewed. Inclusion criteria included (1) patients between with the ages of 5 and 17 years, (2) no history of prior surgical intervention to correct skeletal deformity, and (3) diagnostic quality lateral cephalograms. Twenty patients satisfied the inclusion criteria with 12 male and 8 female patients in the sample and a mean age at the time of the lateral cephalogram of 8.8 years (range 5.2 to 16.7 years). Thirty angular and linear variables were measured to assess anterior-posterior and vertical (superior-inferior) position of the cranial base, maxilla, and mandible. Each patient's measurements were compared to age-matched and sex-matched control samples derived from the Moyers growth studies. The mean and standard deviation for each variable was then determined., Results: Lateral cephalometric analysis showed decreased anterior, posterior, and total cranial base lengths and a reduced cranial base angle. The anteroposterior dimension or length of the maxilla is deficient and the maxilla is positioned posteriorly with respect to the cranial base. Both anterior and posterior facial heights (superior-inferior dimension) are decreased. Lower face height is increased, whereas total face is decreased. The maxillary and functional occlusal planes are tipped upwards posteriorly. The mandibular morphology is characteristically small in both body length and total mandibular length, and the maximum ramus width is also deficient. The mandibular plane angle and gonial angle are increased. The mandible is retropositioned., Conclusions: A lateral cephalometric analysis is described that provides a skeletal basis for the hallmark clinical findings associated with Treacher Collins syndrome. This is of importance because an understanding of the underlying skeletal dysmorphology may shed light on the etiology and growth pattern, and impacts the overall treatment planning for skeletal correction.

The human facial dysostoses can be subdivided into mandibulofacial dysostoses (MFDs) and acrofacial dysostoses (AFDs). The craniofacial phenotypes of the two groups of patients are similar. Both types are thought to be related to abnormal migration of neural crest cells to the pharyngeal arches and the face. The craniofacial anomalies shared by the two groups consist of downslanting palpebral fissures, coloboma of the lower eyelid, from which the eyelashes medial to the defect may be absent, hypoplasia of the zygomatic complex, micrognathia, and microtia, which is often associated with hearing loss. These facial deformities are associated with limb anomalies in the AFDs. All MFDs present with the typical craniofacial phenotype, but some have additional features that help to distinguish them clinically: intellectual disability, microcephaly, chest deformity, ptosis, cleft lip/palate, macroblepharon, or blepharophimosis. The limb anomalies in the AFDs can be classified into pre-axial, post-axial, and others not fitting into the first two AFD types. Of the pre-axial types, Nager syndrome and of the post-axial types, Miller syndrome are the best-known disorders of their AFD subgroups. Several other AFDs with unknown molecular genetic bases, including lethal ones, have been described. This article reviews the MFDs and AFDs published to date., (© 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.)

Some mutations of the DHODH (dihydro-orotate dehydrogenase) gene lead to postaxial acrofacial dysostosis or Miller syndrome. Only DHODH is localized at mitochondria among enzymes of the de novo pyrimidine biosynthesis pathway. Since the pyrimidine biosynthesis pathway is coupled to the mitochondrial RC (respiratory chain) via DHODH, impairment of DHODH should affect the RC function. To investigate this, we used siRNA (small interfering RNA)-mediated knockdown and observed that DHODH knockdown induced cell growth retardation because of G₂/M cell-cycle arrest, whereas pyrimidine deficiency usually causes G₁/S arrest. Inconsistent with this, the cell retardation was not rescued by exogenous uridine, which should bypass the DHODH reaction for pyrimidine synthesis. DHODH depletion partially inhibited the RC complex III, decreased the mitochondrial membrane potential, and increased the generation of ROS (reactive oxygen species). We observed that DHODH physically interacts with respiratory complexes II and III by IP (immunoprecipitation) and BN (blue native)/SDS/PAGE analysis. Considering that pyrimidine deficiency alone does not induce craniofacial dysmorphism, the DHODH mutations may contribute to the Miller syndrome in part through somehow altered mitochondrial function.

Purpose: Temporomandibular joint malformation is a complex deformity in Treacher-Collins syndrome (TCS); however, it is not well characterized. This study aimed to better clarify this pathology by volumetrically assessing the mandibular condyle in patients with TCS compared with normal controls and the relative contribution of the condyle to hemimandibular volume., Materials and Methods: A retrospective, cross-sectional analysis of pediatric patients with TCS and unaffected controls was performed. The study sample was comprised of Treacher Collins patients. The predictor variable in this study was disease status (TCS diagnosis vs control), and the outcome variable was condylar volume. Demographic information was collected, and 3-dimensional computed tomographic data were analyzed by computerized segmentation (Materialise). Volumes were obtained for TCS condyles and compared with age-matched controls using the Student t test., Results: Three-dimensional computed tomographic scans were identified in 10 patients with TCS (20 sides) and 14 control subjects (28 sides). The TCS group included 4 female and 6 male patients (age, 0.3 to 213 mo; average age, 66.5 mo). The control cohort included 7 female and 7 male subjects (average age, 68.8 mo). Evaluation of the mandibular condyle showed that patients with TCS had a significantly smaller condylar volume than control patients (TCS, 178.28 ± 182.74 mm(3); control, 863.55 ± 367.20 mm(3); P < .001). Additional intragroup analysis showed no significant differences between the left and right condylar volumes in the TCS group (P = .267). In addition, the condyle for patients with TCS represented a smaller proportion of hemimandibular volume compared with controls (1.37% vs 4.19%, respectively; P < .001)., Conclusions: The results of the this study suggest that condylar volumes are significantly smaller in patients with TCS compared with age-matched controls, and the condyle represents a smaller fraction of the total mandibular volume for patients with TCS than in unaffected children. In addition, there is considerable variability of condylar size in patients with TCS. These facts portend treatment decisions because a functional temporomandibular joint is necessary and may need to be reconstructed as a first stage before effective implementation of distraction procedures., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Treacher Collins syndrome (TCS) is a facial dysostosis, the hallmark being bilateral malar hypoplasia. The purpose of this study is to morphologically classify the TCS malar deformity and to volumetrically characterise both the TCS zygoma and masseter muscle, including for left-right symmetry, compared to controls. We hypothesise that the TCS zygoma will be smaller than controls and zygomatic deficiency will portend masseteric hypoplasia., Methods: Demographic and computed tomography (CT) data were recorded. The CT scans were converted into three-dimensional facial renderings, and the zygomatic morphology was grossly evaluated. A classification was reported based on malar structure and presence/absence of normal zygomaticomaxillary complex articulations. The zygoma and masseter muscles were then digitally isolated using 3-D planning software (Materialise, Leuven, Belgium). Volumes and sidedness ratios were calculated and compared using two-sided t-tests., Results: 58 sides were identified (24 TCS: 34 controls), mean age of 60.0 months and normally distributed. The phenotypic dysmorphology was graded as mild, moderate or severe (I, II and III, respectively). TCS malar and masseteric volumes were significantly smaller than controls (p < 0.0001 in both cases). The TCS zygomatic side-side symmetry ratio was 0.66 ± 0.28, compared to 0.97 ± 0.02 for controls (p = 0.002). The TCS masseteric side-side ratio was 0.74 ± 0.20, compared to 0.92 ± 0.09 for controls (p = 0.001)., Conclusions: A range of zygomatic hypoplasia exists in TCS (mild-severe). The decrease in malar volume occurs in concert with masseteric hypoplasia, and the left and right sides are not equally affected., (Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Introduction: Pierre Robin sequence (PR) and Treacher Collins syndrome (TC) are congenital disorders associated with multiple craniofacial abnormalities. The mandibular malformations linked with these maladies are closely associated with the form and function of the temporalis muscle. Despite these associations, a paucity of research has been directed at quantifying how these malformations affect the tissues of the temporal region. In this paper, we seek to quantify differences in the temporalis muscle and the temporal fat pad using a novel CT-derived analytic program to examine craniofacial morphomic indices within these patient groups in comparison to normal age-matched controls. We posit that the temporalis muscle and temporal fat pad, like other derivatives of the first branchial arch, are hypoplastic in patients with TC and PR compared to age-matched controls., Methods: High-throughput image analysis was used to reconstruct the 3-dimensional (3D) anatomy and quantify morphomic measures of the temporalis muscle and temporal fat pad in children with PR, TC, and age-matched controls. These steps were completed in a semi-automated method using algorithms programmed in MATLAB v13.0. The 3D reconstructions were analyzed in 3 children with PR (6 temporal regions), 3 children with TC (6 temporal regions), and a control group of 19 children (38 temporal regions). We also quantified the same measurements in a localized "core" sample in the area of greatest thickness, providing a more consistent sample of the tissue position. Relationships between the temporal muscle and fat pad values and craniofacial abnormality type were assessed using Wilcoxon nonparametric test using exact distribution, with a P value of less than 0.05 being deemed significant., Results: The mean age of our patients was 6.0 years in PR and 4.5 years in TC cohorts. We were able to establish an automated methodology to quantify the temporalis muscle and temporal fat pad based on CT characteristics. Localized temporalis volume and localized temporalis area were significantly smaller in children with PR than in the control group. Total temporalis fat volume and localized temporalis area were significantly less in children with TC than in the control group. When compared to each other, the PR group had small morphomic values compared to TC group., Conclusions: There are significant morphomic differences in the temporalis muscle and the temporal fat pad in children with either PR or TC when compared to age-matched control group which can be measured from pre-existing CT scans. Specifically, both of these test groups show decreases in the morphomic measures of the temporalis region. The quantification of these changes corroborates and objectifies the clinical findings associated with these congenital deformities while simultaneously allowing for preoperative planning. Furthermore, this finding confirms that the hypoplasia seen in these patient populations is not only hypoplasia of the mandible but also of the surrounding functional matrix, which includes the temporalis muscle and temporal fat pad.

Background: High-throughput DNA sequencing platforms have become widely available. As a result, personal genomes are increasingly being sequenced in research and clinical settings. However, the resulting massive amounts of variants data pose significant challenges to the average biologists and clinicians without bioinformatics skills., Methods and Results: We developed a web server called wANNOVAR to address the critical needs for functional annotation of genetic variants from personal genomes. The server provides simple and intuitive interface to help users determine the functional significance of variants. These include annotating single nucleotide variants and insertions/deletions for their effects on genes, reporting their conservation levels (such as PhyloP and GERP++ scores), calculating their predicted functional importance scores (such as SIFT and PolyPhen scores), retrieving allele frequencies in public databases (such as the 1000 Genomes Project and NHLBI-ESP 5400 exomes), and implementing a 'variants reduction' protocol to identify a subset of potentially deleterious variants/genes. We illustrated how wANNOVAR can help draw biological insights from sequencing data, by analysing genetic variants generated on two Mendelian diseases., Conclusions: We conclude that wANNOVAR will help biologists and clinicians take advantage of the personal genome information to expedite scientific discoveries. The wANNOVAR server is available at http://wannovar.usc.edu, and will be continuously updated to reflect the latest annotation information.