Proteasomal inhibition attenuates craniofacial malformations in a zebrafish model of Treacher Collins Syndrome.

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.

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.

Fishing the molecular bases of Treacher Collins syndrome.

Treacher Collins syndrome (TCS) is an autosomal dominant disorder of craniofacial development, and mutations in the TCOF1 gene are responsible for over 90% of TCS cases. The knowledge about the molecular mechanisms responsible for this syndrome is relatively scant, probably due to the difficulty of reproducing the pathology in experimental animals. Zebrafish is an emerging model for human disease studies, and we therefore assessed it as a model for studying TCS. We identified in silico the putative zebrafish TCOF1 ortholog and cloned the corresponding cDNA. The derived polypeptide shares the main structural domains found in mammals and amphibians. Tcof1 expression is restricted to the anterior-most regions of zebrafish developing embryos, similar to what happens in mouse embryos. Tcof1 loss-of-function resulted in fish showing phenotypes similar to those observed in TCS patients, and enabled a further characterization of the mechanisms underlying craniofacial malformation. Besides, we initiated the identification of potential molecular targets of treacle in zebrafish. We found that Tcof1 loss-of-function led to a decrease in the expression of cellular proliferation and craniofacial development. Together, results presented here strongly suggest that it is possible to achieve fish with TCS-like phenotype by knocking down the expression of the TCOF1 ortholog in zebrafish. This experimental condition may facilitate the study of the disease etiology during embryonic development.

Mandibulofacial dysostosis, acral anomalies and frontonasal dysplasia: a new form of acrofacial dysostosis.

We describe a stillborn female with acrofacial dysostosis and frontonasal dysplasia. She had protrusion of the forehead, with marked hypertelorism and absence of the nose but with the rhinencephalon present. Autopsy showed wide cranial sutures, severe hydrocephalus with separation of the right and left hemispheres of the brain, preservation of the olfactory bulb and first and second cranial nerves. The child also had small kidneys bilaterally, rectal atresia and an absent anus with rectovaginal fistula. These clinical findings suggest a new form of acrofacial dysostosis.

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.

Síndrome de Treacher Collins com atresia coanal: relato de caso e revisão de suas características / Treacher Collins syndrome with choanal atresia: a case report and review of disease features

A Síndrome de Treacher Collins ou disostose mandibulofacial apresenta-se com deformidades crânio-faciais, tendo expressão e severidade variável. É uma malformacão congênita que envolve o primeiro e segundo arcos branquiais. A Síndrome de Treacher Collins é rara e sua incidência está estimada em uma faixa de 1:40000 a 1:70000 nascidos vivos. Esta síndrome é caracterizada por anormalidades dos pavilhões auriculares, hipoplasia dos ossos da face, obliqüidade antimongolóide das fendas palpebrais com coloboma palpebral inferior e fissura palatina. A Síndrome de Treacher Collins raramente está associada com atresia coanal. Estes pacientes são apropriadamente acompanhados por uma equipe multidisciplinar que inclui cirurgiões crânio-faciais, oftalmologistas, fonoaudiologistas, cirurgiões dentistas e otorrinolaringologistas. Relatamos neste artigo um caso raro de Síndrome de Treacher Collins com atresia coanal, uma revisão da patologia e intervencão multidisciplinar.

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.

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.

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.

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.

Síndrome de Goldenhar-Gorlin / Goldenhar-Gorlin syndrome

Os autores fazem revisäo bibliográfica e apresentaçäo de umc aso clínico da síndrome de Goldenhar-Gorlin (Displasia-aurículo-vertebral - Microssomia Hemifacial)