RESUMO
CHARGE syndrome is a rare autosomal dominant syndrome characterized by multiple congenital anomalies including coloboma, heart defects, ear anomalies, and developmental delay, caused by pathogenic variants in the CHD7 gene. The discovery of the molecular basis of this syndrome increased the number of cases reported and expanded the phenotype and clinical variability. Limb anomalies are occasional clinical findings in this syndrome, present in about 30% of reported cases. The occurrence of limb anomalies in this syndrome suggests that it should be considered as part of the phenotypic spectrum. Here, we describe an individual with CHARGE syndrome presenting unilateral monodactyly.
Assuntos
Síndrome CHARGE , DNA Helicases , Fenótipo , Humanos , Síndrome CHARGE/genética , Síndrome CHARGE/diagnóstico , Síndrome CHARGE/patologia , Síndrome CHARGE/complicações , DNA Helicases/genética , Proteínas de Ligação a DNA/genética , Masculino , Feminino , Mutação , Deformidades Congênitas dos Membros/genética , Deformidades Congênitas dos Membros/patologia , Deformidades Congênitas dos Membros/diagnósticoRESUMO
Bosma arhinia microphthalmia syndrome (BAMS, OMIM #603457) is a rare autosomal dominant disorder caused by heterozygous variation in the SMCHD1 gene on chromosome 18p11. Clinically, it is characterized by microphthalmia, absence or hypoplasia of nose, choanal atresia, anosmia, palatal abnormalities, hypogonadotropic hypogonadism, and cryptorchidism. Here we report a Brazilian patient with a likely pathogenic variation in SMCHD1 gene (c.1418A>T; p.Glu473Val) presenting hemiarhinia associated with short stature and hypogonadotropic hypogonadism. Due to the clinical variability of BAMS, we considered that hemiarhinia, without microphthalmia, in the present case, can be considered a mild form of BAMS and could be considered for screening of SMCHD1 gene variation.
Assuntos
Atresia das Cóanas , Proteínas Cromossômicas não Histona , Microftalmia , Mutação de Sentido Incorreto , Fenótipo , Criança , Humanos , Masculino , Atresia das Cóanas/genética , Atresia das Cóanas/patologia , Proteínas Cromossômicas não Histona/genética , Microftalmia/genética , Microftalmia/patologia , Mutação de Sentido Incorreto/genética , Feminino , Recém-Nascido , Adolescente , AdultoRESUMO
Craniofacial microsomia (CFM), also known as the oculo-auriculo-vertebral spectrum, is a congenital disorder characterized by hypoplasia of the mandible and external ear due to tissue malformations originating from the first and second branchial arches. However, distinguishing it from other syndromes of branchial arch abnormalities is difficult, and causal variants remain unidentified in many cases. In this report, we performed an exome sequencing analysis of a Brazilian family with CFM. The proband was a 12-month-old boy with clinical findings consistent with the diagnostic criteria for CFM, including unilateral mandibular hypoplasia, microtia, and external auditory canal abnormalities. A heterozygous de novo nonsense variant (c.713C>G, p.S238*) in PUF60 was identified, which was predicted to be pathogenic in silico. PUF60 has been reported as a causal gene in Verheij syndrome, but not in CFM. Although the boy showed craniofacial abnormalities and developmental delay that overlapped with Verheij syndrome, the facial asymmetry with unilateral hypoplasia of the mandible observed in this case did not match the previously reported phenotypes of PUF60 variants. Our findings expand the phenotypic range of PUF60 variants that cover CFM and Verheij syndrome.
Assuntos
Síndrome de Goldenhar , Fenótipo , Humanos , Masculino , Síndrome de Goldenhar/genética , Síndrome de Goldenhar/patologia , Síndrome de Goldenhar/diagnóstico , Lactente , Fatores de Processamento de RNA/genética , Proteínas Repressoras/genética , Sequenciamento do Exoma , Mandíbula/anormalidades , Mandíbula/patologia , Linhagem , Códon sem Sentido/genéticaRESUMO
Low-pass whole genome sequencing (LP-WGS) has been applied as alternative method to detect copy number variants (CNVs) in the clinical setting. Compared with chromosomal microarray analysis (CMA), the sequencing-based approach provides a similar resolution of CNV detection at a lower cost. In this study, we assessed the efficiency and reliability of LP-WGS as a more affordable alternative to CMA. A total of 1363 patients with unexplained neurodevelopmental delay/intellectual disability, autism spectrum disorders, and/or multiple congenital anomalies were enrolled. Those patients were referred from 15 nonprofit organizations and university centers located in different states in Brazil. The analysis of LP-WGS at 1x coverage (>50kb) revealed a positive testing result in 22% of the cases (304/1363), in which 219 and 85 correspond to pathogenic/likely pathogenic (P/LP) CNVs and variants of uncertain significance (VUS), respectively. The 16% (219/1363) diagnostic yield observed in our cohort is comparable to the 15%-20% reported for CMA in the literature. The use of commercial software, as demonstrated in this study, simplifies the implementation of the test in clinical settings. Particularly for countries like Brazil, where the cost of CMA presents a substantial barrier to most of the population, LP-WGS emerges as a cost-effective alternative for investigating copy number changes in cytogenetics.
Assuntos
Variações do Número de Cópias de DNA , Sequenciamento Completo do Genoma , Humanos , Variações do Número de Cópias de DNA/genética , Sequenciamento Completo do Genoma/economia , Sequenciamento Completo do Genoma/métodos , Brasil , Masculino , Feminino , Criança , Deficiência Intelectual/genética , Deficiência Intelectual/diagnóstico , Análise Custo-Benefício , Análise em Microsséries/economia , Análise em Microsséries/métodos , Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/diagnóstico , Pré-Escolar , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/diagnóstico , Países em Desenvolvimento , Adolescente , Transtornos do Neurodesenvolvimento/genética , Transtornos do Neurodesenvolvimento/diagnóstico , Testes Genéticos/economia , Testes Genéticos/métodosRESUMO
The oculoauriculofrontonasal syndrome (OAFNS) is a rare condition, with unknown etiology, characterized by the association of frontonasal dysplasia (FND) and oculoauriculovertebral spectrum (OAVS). Main clinical findings include widely spaced eyes, epibulbar dermoid, broad nose, mandibular hypoplasia, and preauricular tags. Here, we describe a case series of 32 Brazilian individuals with OAFNS and review the literature ascertaining individuals presenting phenotypes compatible with the diagnosis of OAFNS, aiming to refine the phenotype. This series emphasizes the phenotypic variability of the OAFNS and highlights the occurrence of rare craniofacial clefts as a part of the phenotype. The ectopic nasal bone, a hallmark of OAFNS, was frequent in our series, reinforcing the clinical diagnosis. The absence of recurrence, consanguinity, chromosomal, and genetic abnormalities reinforces the hypothesis of a nontraditional inheritance model. The phenotypic refinement provided by this series contributes to an investigation regarding the etiology of OAFNS.
Assuntos
Anormalidades do Olho , Síndrome de Goldenhar , Humanos , Orelha Externa/anormalidades , Anormalidades do Olho/diagnóstico , Anormalidades do Olho/genética , Coluna Vertebral/anormalidades , Síndrome de Goldenhar/diagnóstico , FenótipoRESUMO
Auriculocondylar syndrome (ACS) is a rare craniofacial disorder characterized by mandibular hypoplasia and an auricular defect at the junction between the lobe and helix, known as a "Question Mark Ear" (QME). Several additional features, originating from the first and second branchial arches and other tissues, have also been reported. ACS is genetically heterogeneous with autosomal dominant and recessive modes of inheritance. The mutations identified to date are presumed to dysregulate the endothelin 1 signaling pathway. Here we describe 14 novel cases and reassess 25 published cases of ACS through a questionnaire for systematic data collection. All patients harbor mutation(s) in PLCB4, GNAI3, or EDN1. This series of patients contributes to the characterization of additional features occasionally associated with ACS such as respiratory, costal, neurodevelopmental, and genital anomalies, and provides management and monitoring recommendations.
Assuntos
Otopatias , Orelha/anormalidades , Otopatias/genética , Humanos , Linhagem , FenótipoRESUMO
OBJECTIVE: The aim of this study was to compare the dentoskeletal pattern of Treacher Collins syndrome (TCS) and nonsyndromic Pierre Robin sequence (PRS). DESIGN: Retrospective. SETTING: Single center. PATIENTS: Eighteen patients diagnosed with TCS (Group TCS) or PRS (Group PRS) in rehabilitation treatment at a single center. Group TCS was composed of 9 patients (4 male, 5 female) with a mean age of 12.9 years (standard deviation = 4.8). Group PRS was composed of 9 patients paired by age and sex with group TCS. MAIN OUTCOME MEASURE(S): Cone beam computed tomography-derived cephalometric images taken before the orthodontic or the orthodontic-surgical treatment were analyzed using Dolphin Imaging (Dolphin Imaging 11.0 & Management Solutions). Variables evaluating the cranial base, the maxillary and mandibular skeletal components, maxillomandibular relationship, the vertical components and the dentoalveolar region were measured. Intergroup comparisons were performed using t tests. The significance level considered was 5%. RESULTS: Intergroup differences in the mandible size and growth pattern were observed. Group TCS showed a smaller mandibular length (Co-Go, Co-Gn) and a higher palatal plane (SN-Palatal Plane) and mandibular plane angles (SN-Go.Gn) compared to group PRS. No differences between TCS and PRS were observed for the sagittal position of the maxilla, maxillomandibular relationship, and dental components. CONCLUSIONS: Treacher Collins syndrome presented a decreased mandible and a more severe vertical growth pattern compared to PRS.
Assuntos
Disostose Mandibulofacial , Síndrome de Pierre Robin , Cefalometria , Feminino , Humanos , Masculino , Mandíbula/diagnóstico por imagem , Disostose Mandibulofacial/diagnóstico por imagem , Síndrome de Pierre Robin/diagnóstico por imagem , Estudos RetrospectivosRESUMO
INTRODUCTION: Treacher Collins syndrome (TCS) and nonsyndromic Pierre Robin sequence (PRS) share mandibular deficiency as a similar clinical finding. This study aimed to compare the mandibular size and morphology of subjects with TCS and PRS. METHODS: Group TCS was composed of 17 subjects (7 male, 10 female) with a mean age of 11.5 years (standard deviation, 4.4) from a single center. Group PRS was composed of 17 subjects paired by age and sex with group TCS. Preorthodontic cone-beam computed tomography examinations of all patients were evaluated using Mimics Innovation Suite 17.0 (Materialise, Leuven, Belgium). Nine 3-dimensional measurements were performed in segmented 3D images of the mandible. Intragroup comparisons were performed using paired t tests. Intergroup comparisons were performed using analysis of variance and Tukey tests. The significance level considered was 5%. RESULTS: TCS showed a significant dimensional difference between less and more affected sides for ramus, condyles, and mandibular body. The mandibular dimensions in PRS were more symmetrical. Group TCS presented a smaller mandibular effective length and mandibular body length compared with PRS. The condyle width and height and the ramus width were also decreased in TCS. The gonial angle was greater in TCS compared with the PRS group. CONCLUSIONS: Young subjects with TCS presented a smaller, more vertical, and more asymmetrical mandible compared with nonsyndromic PRS.
Assuntos
Disostose Mandibulofacial , Síndrome de Pierre Robin , Adolescente , Cefalometria , Criança , Feminino , Humanos , Imageamento Tridimensional , Masculino , Mandíbula/diagnóstico por imagem , Disostose Mandibulofacial/diagnóstico por imagem , Síndrome de Pierre Robin/diagnóstico por imagem , Estudos RetrospectivosRESUMO
Biallelic loss-of-function mutations in the RNA-binding protein EIF4A3 cause Richieri-Costa-Pereira syndrome (RCPS), an autosomal recessive condition mainly characterized by craniofacial and limb malformations. However, the pathogenic cellular mechanisms responsible for this syndrome are entirely unknown. Here, we used two complementary approaches, patient-derived induced pluripotent stem cells (iPSCs) and conditional Eif4a3 mouse models, to demonstrate that defective neural crest cell (NCC) development explains RCPS craniofacial abnormalities. RCPS iNCCs have decreased migratory capacity, a distinct phenotype relative to other craniofacial disorders. Eif4a3 haploinsufficient embryos presented altered mandibular process fusion and micrognathia, thus recapitulating the most penetrant phenotypes of the syndrome. These defects were evident in either ubiquitous or NCC-specific Eif4a3 haploinsufficient animals, demonstrating an autonomous requirement of Eif4a3 in NCCs. Notably, RCPS NCC-derived mesenchymal stem-like cells (nMSCs) showed premature bone differentiation, a phenotype paralleled by premature clavicle ossification in Eif4a3 haploinsufficient embryos. Likewise, nMSCs presented compromised in vitro chondrogenesis, and Meckel's cartilage was underdeveloped in vivo. These findings indicate novel and essential requirements of EIF4A3 for NCC migration and osteochondrogenic differentiation during craniofacial development. Altogether, complementary use of iPSCs and mouse models pinpoint unique cellular mechanisms by which EIF4A3 mutation causes RCPS, and provide a paradigm to study craniofacial disorders.
Assuntos
Pé Torto Equinovaro/genética , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Fator de Iniciação 4A em Eucariotos/genética , Fator de Iniciação 4A em Eucariotos/metabolismo , Deformidades Congênitas da Mão/genética , Síndrome de Pierre Robin/genética , Animais , Osso e Ossos/metabolismo , Região Branquial/metabolismo , Diferenciação Celular/genética , Movimento Celular , Condrogênese/genética , Pé Torto Equinovaro/metabolismo , Anormalidades Craniofaciais/genética , Anormalidades Craniofaciais/metabolismo , Modelos Animais de Doenças , Deformidades Congênitas da Mão/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Camundongos , Crista Neural/crescimento & desenvolvimento , Crista Neural/metabolismo , Osteogênese/genética , Síndrome de Pierre Robin/metabolismoRESUMO
Here we report on a Brazilian child who presented semilobar holoprosencephaly, frontonasal encephaloceles and bilateral cleft lip and palate. Malformations also included agenesis of the corpus callosum, abnormal cortical gyres, dilation of the aqueduct, bilateral endolymphatic sac, bilateral cystic cocci-vestibular malformation, and a cribriform defect. The 3D TC craniofacial images showed abnormal frontonasal transition region, with a bone bifurcation, and partial agenesis of nasal bone. The trunk and upper and lower limbs were normal. To our knowledge, this rare association of holoprocensephaly with frontonaso-orbital encephaloceles without limb anomalies has never been reported before. Karyotype was normal. SNP-array showed no copy-number alterations but revealed 25% of regions of homozygosity (ROH) with normal copy number, indicating a high coefficient of inbreeding, which significantly increases the risk for an autosomal recessive disorder. Whole exome sequencing analysis did not reveal any pathogenic or likely pathogenic variants. We discuss the possible influence of two variants of uncertain significance found within the patient's ROHs. First, a missense p.(Gly394Ser) in PCSK9, a gene involved in the regulation of plasma low-density lipoprotein cholesterol. Second, an inframe duplication p.(Ala75_Ala81dup) in SP8, a zinc-finger transcription factor that regulates signaling centers during craniofacial development. Further studies and/or the identification of other patients with a similar phenotype will help elucidate the genetic etiology of this complex case.
Assuntos
Fenda Labial/diagnóstico , Fenda Labial/genética , Fissura Palatina/diagnóstico , Fissura Palatina/genética , Encefalocele/diagnóstico , Encefalocele/genética , Holoprosencefalia/diagnóstico , Holoprosencefalia/genética , Anormalidades Múltiplas/diagnóstico , Anormalidades Múltiplas/genética , Encéfalo/anormalidades , Encéfalo/diagnóstico por imagem , Mapeamento Cromossômico , Estudos de Associação Genética , Predisposição Genética para Doença , Homozigoto , Humanos , Imageamento Tridimensional , Imageamento por Ressonância Magnética , Masculino , Fenótipo , Polimorfismo de Nucleotídeo Único , Síndrome , Tomografia Computadorizada por Raios X , Sequenciamento do ExomaRESUMO
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.
Assuntos
Alopecia/genética , Disostose Mandibulofacial/genética , Receptor de Endotelina A/genética , Alopecia/patologia , Animais , Sequência de Bases , Endotelina-1/metabolismo , Exoma/genética , Humanos , Hibridização In Situ , Disostose Mandibulofacial/patologia , Dados de Sequência Molecular , Morfolinos/genética , Mutação de Sentido Incorreto/genética , Linhagem , RNA Mensageiro/administração & dosagem , Reação em Cadeia da Polimerase em Tempo Real , Receptor de Endotelina A/metabolismo , Análise de Sequência de DNA , Síndrome , Tomografia Computadorizada por Raios X , Peixe-Zebra , Zigoma/patologiaRESUMO
The Richieri-Costa-Pereira syndrome (RCPS) is an autosomal-recessive acrofacial dysostosis caused by mutations in EIF4A3, characterized by mandibular cleft comprising other craniofacial anomalies and limb defects such as cleft palate/Robin Sequence, microstomia, absence of mandibular central incisors, minor ear anomalies, clubfeet and first and 5 ray defects. The findings from this study are useful for better understanding the morphological consequences of disorders of EIF4A3, and having a better picture of the anatomic characteristics of the syndrome for a better therapeutic planning. Twenty-four angular and linear variables were measured to assess anteroposterior and vertical (superior-inferior) position of the cranial base, maxilla, mandible, and facial profile. The cephalometric radiographic analysis was performed on 9 individuals with RCPS, obtained at a mean age of 10.3 years, and compared with randomly selected age-matched 9 controls, without clefts and with well-balanced faces, with mean age of 10.6 years (both groups range 8.1 to 13.7 years). t test was used for analysis of means and Levene test for equality of variances. The syndrome group presented severe mandibular hypoplasia and retrognathism (Pâ=â0.009, Pâ=â0.001), greater facial convexity (N'PnPog and N'SnPog, Pâ<â0.05) in syndrome group compared with the control group (Pâ=â0.003, Pâ=â0.004). In conclusion, in the RCPS group, most craniofacial defects affect the lower facial third, considering the severely affected mandible.
Assuntos
Pé Torto Equinovaro/diagnóstico por imagem , Deformidades Congênitas da Mão/diagnóstico por imagem , Anormalidades Maxilomandibulares/diagnóstico por imagem , Síndrome de Pierre Robin/diagnóstico por imagem , Crânio/diagnóstico por imagem , Adolescente , Estudos de Casos e Controles , Cefalometria , Criança , Pé Torto Equinovaro/patologia , Feminino , Deformidades Congênitas da Mão/patologia , Humanos , Anormalidades Maxilomandibulares/patologia , Masculino , Síndrome de Pierre Robin/patologia , Crânio/patologiaRESUMO
Richieri-Costa-Pereira syndrome is an autosomal-recessive acrofacial dysostosis characterized by mandibular median cleft associated with other craniofacial anomalies and severe limb defects. Learning and language disabilities are also prevalent. We mapped the mutated gene to a 122 kb region at 17q25.3 through identity-by-descent analysis in 17 genealogies. Sequencing strategies identified an expansion of a region with several repeats of 18- or 20-nucleotide motifs in the 5' untranslated region (5' UTR) of EIF4A3, which contained from 14 to 16 repeats in the affected individuals and from 3 to 12 repeats in 520 healthy individuals. A missense substitution of a highly conserved residue likely to affect the interaction of eIF4AIII with the UPF3B subunit of the exon junction complex in trans with an expanded allele was found in an unrelated individual with an atypical presentation, thus expanding mutational mechanisms and phenotypic diversity of RCPS. EIF4A3 transcript abundance was reduced in both white blood cells and mesenchymal cells of RCPS-affected individuals as compared to controls. Notably, targeting the orthologous eif4a3 in zebrafish led to underdevelopment of several craniofacial cartilage and bone structures, in agreement with the craniofacial alterations seen in RCPS. Our data thus suggest that RCPS is caused by mutations in EIF4A3 and show that EIF4A3, a gene involved in RNA metabolism, plays a role in mandible, laryngeal, and limb morphogenesis.
Assuntos
Pé Torto Equinovaro/genética , RNA Helicases DEAD-box/genética , Fator de Iniciação 4A em Eucariotos/genética , Deformidades Congênitas da Mão/genética , Síndrome de Pierre Robin/genética , Alelos , Sequência de Aminoácidos , Animais , Osso e Ossos/anormalidades , Criança , Pré-Escolar , Mapeamento Cromossômico , RNA Helicases DEAD-box/metabolismo , Fator de Iniciação 4A em Eucariotos/metabolismo , Feminino , Humanos , Masculino , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Conformação Proteica , Peixe-Zebra/anormalidadesRESUMO
Mandibulofacial dysostosis (MFD) Bauru type (OMIM 604830) is a rare genetic condition characterized mainly by malar hypoplasia, orofacial cleft, and micrognathia. Here, we describe the clinical and radiographic sings of 13 individuals (12 female and 1 male) from eight unrelated kindreds with MFD Bauru type, including four previously reported cases, treated at the Hospital for Rehabilitation of Craniofacial Anomalies. The clinical phenotype was characterized by severe underdevelopment of mandible, midface hypoplasia, orofacial cleft, bitemporal narrowing, mild upper eyelid down slanting, high nasal bridge, thick and everted lower lip, minor ears abnormalities, and hearing loss. Radiographic aspects included downslanting of zygomatic arch, maxillary hypoplasia, microretrognathia, hypoplastic mandibular condyles, and ectopic external auditory canal. Recurrence was observed in two of eight families and the affected distribution pattern was compatible with autosomal dominant inheritance in one and autosomal recessive in another, indicating possible genetic heterogeneity for this condition. Clinical and radiographic findings in this report contribute to the delineation of this rare MFD.
RESUMO
Auriculocondylar syndrome, mainly characterized by micrognathia, small mandibular condyle, and question mark ears, is a rare disease segregating in an autosomal dominant pattern in the majority of the families reported in the literature. So far, pathogenic variants in PLCB4, GNAI3, and EDN1 have been associated with this syndrome. It is caused by a developmental abnormality of the first and second pharyngeal arches and it is associated with great inter- and intra-familial clinical variability, with some patients not presenting the typical phenotype of the syndrome. Moreover, only a few patients of each molecular subtype of Auriculocondylar syndrome have been reported and sequenced. Therefore, the spectrum of clinical and genetic variability is still not defined. In order to address these questions, we searched for alterations in PLCB4, GNAI3, and EDN1 in patients with typical Auriculocondylar syndrome (n = 3), Pierre Robin sequence-plus (n = 3), micrognathia with additional craniofacial malformations (n = 4), or non-specific auricular dysplasia (n = 1), which could represent subtypes of Auriculocondylar syndrome. We found novel pathogenic variants in PLCB4 only in two of three index patients with typical Auriculocondylar syndrome. We also performed a detailed comparative analysis of the patients presented in this study with those previously published, which showed that the pattern of auricular abnormality and full cheeks were associated with molecularly characterized individuals with Auriculocondylar syndrome. Finally, our data contribute to a better definition of a set of parameters for clinical classification that may be used as a guidance for geneticists ordering molecular testing for Auriculocondylar syndrome. © 2017 Wiley Periodicals, Inc.
Assuntos
Otopatias/diagnóstico , Orelha/anormalidades , Predisposição Genética para Doença , Micrognatismo/diagnóstico , Mutação , Fosfolipase C beta/genética , Síndrome de Pierre Robin/diagnóstico , Adulto , Criança , Orelha/patologia , Otopatias/classificação , Otopatias/genética , Otopatias/patologia , Endotelina-1/genética , Feminino , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/genética , Expressão Gênica , Genes Dominantes , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Micrognatismo/classificação , Micrognatismo/genética , Micrognatismo/patologia , Linhagem , Fenótipo , Síndrome de Pierre Robin/classificação , Síndrome de Pierre Robin/genética , Síndrome de Pierre Robin/patologia , Terminologia como AssuntoRESUMO
Auriculocondylar syndrome (ACS) is a rare craniofacial disorder with mandibular hypoplasia and question-mark ears (QMEs) as major features. QMEs, consisting of a specific defect at the lobe-helix junction, can also occur as an isolated anomaly. Studies in animal models have indicated the essential role of endothelin 1 (EDN1) signaling through the endothelin receptor type A (EDNRA) in patterning the mandibular portion of the first pharyngeal arch. Mutations in the genes coding for phospholipase C, beta 4 (PLCB4) and guanine nucleotide binding protein (G protein), alpha inhibiting activity polypeptide 3 (GNAI3), predicted to function as signal transducers downstream of EDNRA, have recently been reported in ACS. By whole-exome sequencing (WES), we identified a homozygous substitution in a furin cleavage site of the EDN1 proprotein in ACS-affected siblings born to consanguineous parents. WES of two cases with vertical transmission of isolated QMEs revealed a stop mutation in EDN1 in one family and a missense substitution of a highly conserved residue in the mature EDN1 peptide in the other. Targeted sequencing of EDN1 in an ACS individual with related parents identified a fourth, homozygous mutation falling close to the site of cleavage by endothelin-converting enzyme. The different modes of inheritance suggest that the degree of residual EDN1 activity differs depending on the mutation. These findings provide further support for the hypothesis that ACS and QMEs are uniquely caused by disruption of the EDN1-EDNRA signaling pathway.
Assuntos
Otopatias/genética , Orelha/anormalidades , Genes Dominantes , Genes Recessivos , Mutação , Fenótipo , Sequência de Aminoácidos , Substituição de Aminoácidos , Análise Mutacional de DNA , Otopatias/diagnóstico , Otopatias/metabolismo , Endotelina-1/genética , Endotelina-1/metabolismo , Feminino , Genótipo , Humanos , Masculino , Dados de Sequência Molecular , Linhagem , Alinhamento de Sequência , Transdução de SinaisRESUMO
Craniofrontonasal syndrome (CFNS), an X-linked disorder caused by loss-of-function mutations of EFNB1, exhibits a paradoxical sex reversal in phenotypic severity: females characteristically have frontonasal dysplasia, craniosynostosis and additional minor malformations, but males are usually more mildly affected with hypertelorism as the only feature. X-inactivation is proposed to explain the more severe outcome in heterozygous females, as this leads to functional mosaicism for cells with differing expression of EPHRIN-B1, generating abnormal tissue boundaries-a process that cannot occur in hemizygous males. Apparently challenging this model, males occasionally present with a more severe female-like CFNS phenotype. We hypothesized that such individuals might be mosaic for EFNB1 mutations and investigated this possibility in multiple tissue samples from six sporadically presenting males. Using denaturing high performance liquid chromatography, massively parallel sequencing and multiplex-ligation-dependent probe amplification (MLPA) to increase sensitivity above standard dideoxy sequencing, we identified mosaic mutations of EFNB1 in all cases, comprising three missense changes, two gene deletions and a novel point mutation within the 5' untranslated region (UTR). Quantification by Pyrosequencing and MLPA demonstrated levels of mutant cells between 15 and 69%. The 5' UTR variant mutates the stop codon of a small upstream open reading frame that, using a dual-luciferase reporter construct, was demonstrated to exacerbate interference with translation of the wild-type protein. These results demonstrate a more severe outcome in mosaic than in constitutionally deficient males in an X-linked dominant disorder and provide further support for the cellular interference mechanism, normally related to X-inactivation in females.
Assuntos
Anormalidades Craniofaciais/genética , Anormalidades Craniofaciais/patologia , Efrina-B1/genética , Inativação do Cromossomo X/genética , Criança , Pré-Escolar , Anormalidades Craniofaciais/metabolismo , Efrina-B1/biossíntese , Efrina-B1/metabolismo , Feminino , Deleção de Genes , Hemizigoto , Heterozigoto , Humanos , Lactente , Recém-Nascido , Masculino , Mosaicismo , Linhagem , Fenótipo , Mutação Puntual , Caracteres SexuaisRESUMO
Mandibulofacial dysostosis with microcephaly (MFDM) is a rare sporadic syndrome comprising craniofacial malformations, microcephaly, developmental delay, and a recognizable dysmorphic appearance. Major sequelae, including choanal atresia, sensorineural hearing loss, and cleft palate, each occur in a significant proportion of affected individuals. We present detailed clinical findings in 12 unrelated individuals with MFDM; these 12 individuals compose the largest reported cohort to date. To define the etiology of MFDM, we employed whole-exome sequencing of four unrelated affected individuals and identified heterozygous mutations or deletions of EFTUD2 in all four. Validation studies of eight additional individuals with MFDM demonstrated causative EFTUD2 mutations in all affected individuals tested. A range of EFTUD2-mutation types, including null alleles and frameshifts, is seen in MFDM, consistent with haploinsufficiency; segregation is de novo in all cases assessed to date. U5-116kD, the protein encoded by EFTUD2, is a highly conserved spliceosomal GTPase with a central regulatory role in catalytic splicing and post-splicing-complex disassembly. MFDM is the first multiple-malformation syndrome attributed to a defect of the major spliceosome. Our findings significantly extend the range of reported spliceosomal phenotypes in humans and pave the way for further investigation in related conditions such as Treacher Collins syndrome.
Assuntos
GTP Fosfo-Hidrolases/genética , Haploinsuficiência/genética , Disostose Mandibulofacial/genética , Microcefalia/genética , Ribonucleoproteína Nuclear Pequena U5/genética , Anormalidades Múltiplas/genética , Alelos , Sequência de Aminoácidos , Criança , Pré-Escolar , Estudos de Coortes , Exoma , Feminino , Humanos , Lactente , Masculino , Dados de Sequência Molecular , Mutação/genética , Estrutura Terciária de Proteína/genética , Splicing de RNA/genética , Spliceossomos/genéticaRESUMO
Mutations in solute carrier family 26 (sulfate transporter), member 2 (SLC26A2) gene result in a spectrum of autosomal recessive chondrodysplasias that range from the mildest recessive form of multiple epiphysial dysplasia (rMED) through the most common diastrophic dysplasia (DTD) to lethal atelosteogenesis type II and achondrogenesis IB. The clinical variability has been ascribed to quantitative effect of mutations of the sulfate transporter activity. Here we describe two Brazilian sisters, born to healthy and non consanguineous parents, with Robin sequence, mild shortening of upper and lower limbs, brachymetacarpalia/tarsalia, additional and accelerated carpal ossification, marked genu valgum, and multiple epiphysial dysplasia. This phenotype was intermediate between DTD and rMED, and both girls have a compound heterozygous mutations for the SLC26A2, a Finnish founder mutation (c.-26 + 2T>C), and R279W. This combination of mutations has been observed in individuals with different phenotypes, including DTD, DTD variant, and rMED. The distinct phenotype of our cases reinforces the hypothesis that other factors may be influencing the phenotype as previously suggested.
Assuntos
Proteínas de Transporte de Ânions/genética , Ossos do Carpo/patologia , Nanismo/genética , Extremidades/patologia , Mutação/genética , Osteogênese , Síndrome de Pierre Robin/genética , Adulto , Brasil , Criança , Nanismo/diagnóstico , Feminino , Heterozigoto , Humanos , Masculino , Osteocondrodisplasias , Fenótipo , Síndrome de Pierre Robin/diagnóstico , Irmãos , Transportadores de SulfatoRESUMO
Laryngeal structural anomalies were described in 13 cases of Richieri-Costa Pereira syndrome, and four previously reported cases were reviewed. The 17 individuals examined had the typical laryngeal anomalies and vocal disorders previously described. The new findings are the laryngeal microweb observed in three cases and arytenoid anteriorization movement observed in 14 cases.