Detección polimórfica del rs104893850 de MSX1 y rs28933373 de PAX9 en personas con agenesia dental no sindrómica / Polymorphic detection of rs104893850 of MSX1 and rs28933373 of PAX9 in people with non syndromic dental agnesia

Introducción: la agenesia dental no sindrómica (ADNS) genera efec- tos negativos en la salud oral y psicosocial de los seres humanos. El determinante genético desempeña un papel importante en su desarrollo. Objetivo: determinar la frecuencia de los polimorfismos rs104893850 de MSX1 y rs28933373 de PAX9 en pacientes de seis a 18 años con ADNS. Material y métodos: estudio transversal prolectivo en el cual se revisaron individuos de seis a 18 años sin defectos congénitos y originarios del estado de Durango. Después de haber obtenido su con- sentimiento para formar parte del estudio, se estableció el diagnóstico de ADNS a través de una inspección clínica odontológica y un examen radiográfico. Se tomó una muestra de sangre capilar para la genotipi- ficación de los polimorfismos a través de la técnica de qPCR-HRM. Resultados: de un total de 124 individuos, 77 (62%) mujeres y 47 (38%) hombres; sólo 39 presentaron ADNS. En el análisis polimórfico de rs104893850 de MSX1 y rs28933373 de PAX9 se obtuvo 94.9% y 84.6% respectivamente de homocigotos mutados. Conclusiones: se obtuvo una alta frecuencia de hipodoncia, el diente que mostró más agenesia fue el órgano dentario 18. Las mutaciones polimórficas están presentes en una alta proporción de agenesia dental (AU)

Introduction: non-syndromic dental agenesis (NSDA) generates negative oral health and psychosocial effects in humans. The genetic determinant plays an important role in its development. Objective: to determine the frequency of MSX1 rs104893850 and PAX9 rs28933373 polymorphisms in patients aged 6 to 18 years with NSDA. Material and methods: prolective cross-sectional study, in which individuals aged 6 to 18 years without congenital defects and from the city of Durango were reviewed. After obtaining their consent to be part of the study, the diagnosis of NSDA was established through a clinical dental inspection, a radiographic examination and a capillary blood sample was taken for the genotyping of the polymorphisms through the qPCR-HRM technique. Results: out of a total of 124 individuals, 77 (62%) females and 47 (38%) males; only 39 presented ADNS. In the polymorphic analysis of rs104893850 of MSX1 and rs28933373 of PAX9 we obtained 94.9% and 84.6% respectively of mutated homozygotes. Conclusions: a high frequency of hypodontia was obtained, and the tooth that presented the most agenesis was dental organ 18. Polymorphic mutations are present in a high proportion for dental agenesis (AU)

Novel MSX1 variants identified in families with nonsyndromic oligodontia / 国际口腔科学杂志·英文版

The goal of this study was to identify MSX1 gene variants in multiple Chinese families with nonsyndromic oligodontia and analyse the functional influence of these variants. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify the causal gene variants in five families with nonsyndromic oligodontia, and a series of bioinformatics databases were used for variant confirmation and functional prediction. Phenotypic characterization of the members of these families was described, and an in vitro analysis was performed for functional evaluation. Five novel MSX1 heterozygous variants were identified: three missense variants [c.662A>C (p.Q221P), c.670C>T (p.R224C), and c.809C>T (p.S270L)], one nonsense variant [c.364G>T (p.G122*)], and one frameshift variant [c.277delG (p.A93Rfs*67)]. Preliminary in vitro studies demonstrated that the subcellular localization of MSX1 was abnormal with the p.Q221P, p.R224C, p.G122*, and p.A93Rfs*67 variants compared to the wild type. Three variants (p.Q221P, p.G122*, and p.A93Rfs*67) were classified as pathogenic or likely pathogenic, while p.S270L and p.R224C were of uncertain significance in the current data. Moreover, we summarized and analysed the MSX1-related tooth agenesis positions and found that the type and variant locus were not related to the severity of tooth loss. Our results expand the variant spectrum of nonsyndromic oligodontia and provide valuable information for genetic counselling.

Progress in genetic research on tooth agenesis associated with Wnt/beta-catenin signaling pathway / 中华医学遗传学杂志

Tooth agenesis is the most common form of congenital craniofacial dysplasia seen in stomatology clinics, which may be caused by genetic and/or environmental factors. Tooth development is regulated by a series of signaling pathways, and variants in any of these strictly balanced signaling cascades can result in tooth agenesis and/or other oral defects. Notably, variants of genes of the Wnt/beta-catenin signaling pathway are important cause for both non-syndromic and syndromic tooth agenesis. This article has provided a review for the molecular genetics of tooth agenesis associated with Wnt/beta-catenin signaling pathway, which may shed lights on the etiology and molecular mechanism of this disease.

"Maxillary lateral incisor partial anodontia sequence": a clinical entity with epigenetic origin

ABSTRACT The relationship between maxillary lateral incisor anodontia and the palatal displacement of unerupted maxillary canines cannot be considered as a multiple tooth abnormality with defined genetic etiology in order to be regarded as a "syndrome". Neither were the involved genes identified and located in the human genome, nor was it presumed on which chromosome the responsible gene would be located. The palatal maxillary canine displacement in cases of partial anodontia of the maxillary lateral incisor is potentially associated with environmental changes caused by its absence in its place of formation and eruption, which would characterize an epigenetic etiology. The lack of the maxillary lateral incisor in the canine region means removing one of the reference guides for the eruptive trajectory of the maxillary canine, which would therefore, not erupt and /or impact on the palate. Consequently, and in sequence, it would lead to malocclusion, maxillary atresia, transposition, prolonged retention of the deciduous canine and resorption in the neighboring teeth. Thus, we can say that we are dealing with a set of anomalies and multiple sequential changes known as sequential development anomalies or, simply, sequence. Once the epigenetics and sequential condition is accepted for this clinical picture, it could be called "Maxillary Lateral Incisor Partial Anodontia Sequence."

RESUMO A relação entre a anodontia parcial do incisivo lateral e o deslocamento palatino do canino superior não irrompido não pode ser considerada uma anomalia dentária múltipla com etiopatogenia genética definida, a ponto de ser considerada como uma "síndrome". Os genes envolvidos sequer foram identificados e localizados no genoma humano, e nem mesmo presumiu-se em qual cromossomo se localizaria o gene responsável. O deslocamento palatino do canino superior em casos de anodontia parcial do incisivo lateral superior está potencialmente associado às mudanças ambientais provocadas pela sua ausência no local de formação e erupção, o que caracterizaria uma etiologia epigenética para essa associação. A falta do incisivo lateral superior na região canina implica em tirar um dos guias referenciais da trajetória eruptiva do canino superior, que ficaria, assim, não irrompido e/ou impactado no palato. Como consequência, e em sequência, promove-se uma má oclusão, atresia maxilar, transposição, retenção prolongada do canino decíduo e reabsorções nos dentes vizinhos. Dessa forma, pode-se afirmar que estamos frente a um conjunto de anomalias e alterações múltiplas sequenciais conhecido como anomalias de desenvolvimento sequencial ou, simplesmente, sequência. Uma vez aceita a condição epigenética e sequencial para esse quadro clínico, ele poderia ser chamado de "Sequência da Anodontia Parcial do Incisivo Lateral Superior".

Msx1 Gene Variant - its Association in Isolated Hypodontia: A Case Control Genetic study!!!.

INTRODUCTION: Non‑syndromic tooth agenesis is a congenital anomaly with significant medical, psychological, and social ramifications. There is sufficient evidence to hypothesize that locus for this condition can be identified by candidate genes. AIM OF THE STUDY: The aim of this study was to test whether MSX1 671 T > C gene variant was involved in etiology of non‑syndromic tooth agenesis in Raichur patients. MATERIALS AND METHODS: Blood samples were collected with informed consent from 50 subjects having non‑syndromic tooth agenesis and 50 controls. Genomic deoxyribonucleic acid (DNA) was extracted from the blood samples, polymerase chain reaction (PCR) was performed, and restriction fragment length polymorphism (RFLP) was performed for digestion products that were evaluated. RESULTS: The results showed positive correlation between MSX1671 T > C gene variant and non‑syndromic tooth agenesis in Raichur patients. CONCLUSION: MSX1 671 T > C gene variant may be a good screening marker for non‑syndromic tooth agenesis in Raichur patients.

PAX9 polymorphism and susceptibility to sporadic non-syndromic severe anodontia: a case-control study in southwest China

Our research aimed to look into the clinical traits and genetic mutations in sporadic non-syndromic anodontia and to gain insight into the role of mutations of PAX9, MSX1, AXIN2 and EDA in anodontia phenotypes, especially for the PAX9. Material and Methods The female proband and her family members from the ethnic Han families underwent complete oral examinations and received a retrospective review. Venous blood samples were obtained to screen variants in the PAX9, MSX1, AXIN2, and EDA genes. A case-control study was performed on 50 subjects with sporadic tooth agenesis (cases) and 100 healthy controls, which genotyped a PAX9 gene polymorphism (rs4904210). Results Intra-oral and panoramic radiographs revealed that the female proband had anodontia denoted by the complete absence of teeth in both the primary and secondary dentitions, while all her family members maintained normal dentitions. Detected in the female proband were variants of the PAX9 and AXIN2 including A240P (rs4904210) of the PAX9, c.148C>T (rs2240308), c.1365A>G (rs9915936) and c.1386C>T (rs1133683) of the AXIN2. The same variants were present in her unaffected younger brother. The PAX9 variations were in a different state in her parents. Mutations in the MSX1 and EDA genes were not identified. No significant diferences were found in the allele and genotype frequencies of the PAX9 polymorphism between the controls and the subjects with sporadic tooth agenesis. Conclusions These results suggest that the association of A240P with sporadic tooth agenesis still remains obscure, especially for different populations. The genotype/phenotype correlation in congenital anodontia should be verified. .

Bases moleculares de la agenesia dental no sindrómica: revisión de la información bibliográfica / Molecular bases of non-syndromic dental agenesis: a review of the literature

Este trabajo pretende actualizar los conocimientos acerca de las bases moleculares de la agenesia dental no sindrómica. Más de doscientos genes codifican múltiples proteínas con funciones necesarias para el desarrollo dental. Los factores de transcripción MSXC-1 y PAX-9 son fundamentales para activar la expresión proteica sinérgica de la cascada de señalización de las proteínas morfogénicas óseas, responsables de la progresión secuencial de la odontogénesis. En busca de las posibles causas de agenesias dentarias no sindrómicas, se han detectado dieciocho mutaciones de tipo missense de pares de dominio del gen humano PAX-9, mutaciones de haplo-insuficiencia funcional de los genes PAX-9 y MSX-1 y múltiples polimorfismos de localizaciones diversas. En todos los casos fue notable la disminución del nivel de expresión de las proteínas mutantes (a las que los genes antes mencionados codifican como transcriptores), la cual afectó la capacidad de unión al ADN de éstas. El impacto deletéreo de estas mutaciones para generar agenesias dentarias selectivas continúa siendo objeto de estudio.

Transcriptional analysis of the human PAX9 promoter

OBJECTIVES: PAX9 belongs to the Pax family of transcriptional factor genes. This gene is expressed in embryonic tissues such as somites, pharyngeal pouch endoderm, distal limb buds and neural crest-derived mesenchyme. Polymorphisms in the upstream promoter region of the human PAX9 have been associated with human non-syndromic tooth agenesis. In the present study, we verified the in vitro mRNA expression of this gene and the luciferase activity of two constructs containing promoter sequences of the PAX9 gene. MATERIAL AND METHODS: Embryonic tissues were obtained from digits, face, and midbrain/hindbrain regions. Fragments containing PAX9 promoter sequences were cloned into reporter plasmids and were transfected into the different cell cultures. mRNA were extracted from primary cell cultures. RESULTS: The semi-quantitative RT-PCR results showed that in vitro E13.5 limb bud and CNS cells express PAX9, but cells derived from the facial region do not. Moreover, the luciferase assay showed that protein activity of the constructed vector was weaker than pgl3 -basic alone. CONCLUSIONS: The present results suggest that the promoter sequences analyzed are not sufficient to drive PAX9 gene transcription.

Role of genes in oro-dental diseases.

In oral cavity, the spectrum of diseases due to genetic alterations ranges from developmental disturbances of teeth to the pre-cancerous and cancerous lesions. Of late, significant progress has been made in the molecular analysis of tumors. With molecular genetic testing emerging as diagnostic, prognostic, and therapeutic approach, a review of genetic alterations ranging from the development of oro-facial structures to the tumors in the head and neck region are addressed in this article. The functional regulatory aspect of genes in relation to oro-facial structures are discussed separately, i.e., in relation to tooth genesis, tooth agenesis (non-syndromic, syndromic), tooth structural alterations, syndromic oro-facial defects, bone diseases, skin diseases (genodermatoses), and malignant tumors. In this literature, various genes involved in the development of the oro-facial structures and tooth in particular are discussed. The genetic basis of disorders in the tooth development (agenesis, hypodontia), tooth structural defects like amelogenesis imperfecta (AI), dentinogenesis imperfecta (DI), and oro-facial structural alterations (various syndromes) are explained.

Triagem de mutação no éxon 3 do gene IRF6 em indivíduos com fissura labiopalatina e agenesia dentária: padronização de protocolo para seqüenciamento de DNA genômico a partir de saliva / Screening of mutation in IRF6 gene of subjects with cleft lip and palate and tooth agenesis: protocol standardization for sequencing of genomic DNA extracted from saliva

A fissura labiopalatina e a agenesia dentária são consideradas alterações do desenvolvimento embrionário. Esses fenótipos ocorrem em decorrência da interação de fatores genéticos e ambientais, caracterizando um padrão de herança multifatorial. Entre os genes candidatos a esses fenótipos destaca-se o IRF6. Para esses estudos genéticos podem ser usadas diferentes metodologias, dentre elas o seqüenciamento direto. A proposta deste estudo foi primeiramente padronizar um protocolo para seqüenciamento direto de DNA genômico a partir de saliva e então investigar mutações ou polimorfismos no éxon 3 do gene IRF6 em indivíduos com fissura de lábio e palato unilateral não-sindrômica e agenesia dentária. Fizeram parte do estudo 120 voluntários distribuídos em quatro grupos: Grupo 1 30 indivíduos com fissura e agenesia dentária; Grupo 2 - 30 indivíduos somente com fissura; Grupo 3 - 30 indivíduos somente com agenesia dentária e Grupo 4 - Controle. Para análise do éxon 3 do gene IRF6 foi coletada saliva, e a partir desse material foram testados três protocolos para extração de DNA genômico. Além disso, durante a padronização do protocolo para seqüenciamento direto foram avaliadas metodologias diferentes para outras três etapas da preparação das amostras: purificação do produto de PCR, otimização na utilização do BigDye® v3.1 Terminator na reação de seqüenciamento e purificação do produto da reação de seqüenciamento. As amostras foram seqüenciadas em Analisador Genético ABI 3130XL e os resultados analisados por meio de programas de computador específicos. Foram pesquisadas, nos eletroferogramas referentes ao éxon 3 do gene IRF6, variações nas seqüências de cada indivíduo. Os resultados mostraram que o protocolo de extração de DNA a partir de saliva utilizando InstaGeneTM Matrix associado à proteinase K e dodecil sulfato de sódio 1% foi o que apresentou melhores resultados na quantidade e qualidade do DNA extraído. Em relação à purificação do produto de PCR, o método de...

Cleft lip and palate and tooth agenesis are considered changes in embryonic development. These phenotypes occur as a result of the interaction of genetic and environmental factors, suggesting a multifactorial inheritance pattern. Among the candidate genes for these phenotypes IRF6 appears as one of the most important. Direct sequencing, among other techniques, can be used to perform such genetic studies. The aim of this study was to standardize a protocol for direct sequencing of genomic DNA extracted from whole saliva to allow further search of mutations or polymorphisms in exon 3 of IRF6 gene in individuals with nonsyndromic cleft lip and palate and tooth agenesis. Volunteers were 120 subjects divided into four groups: Group 1 - 30 individuals with tooth agenesis and cleft, Group 2 - 30 individuals with cleft only, Group 3 - 30 individuals with tooth agenesis only, and Group 4 - Control. For the analysis of the exon 3 of IRF6 gene, saliva was collected to test three protocols for the extraction of genomic DNA. Additionally, during the protocol standardization for direct sequencing, different methodologies for the other three steps of sample preparation were evaluated: purification of PCR product, optimization of the use of BigDye® v3.1 Terminator, and purification of the sequencing product. The samples were sequenced on ABI 3130XL Genetic Analyzer, and the results were analyzed using specific softwares. Heterozygous and homozygous variations in the sequences of the exon 3 of IRF6 gene of each individual were searched in the electropherograms. The results showed that the protocol for DNA extraction from saliva using InstageneTM Matrix associated with proteinase K and 1% sodium dodecyl sulfate showed the best results in the quantity and quality of the extracted DNA. As far as the purification of the PCR product, the method of choice was the purification in specific columns. BigDye® v3.1 was used with success in a volume 2 L per reaction, and the purification...

Hypodontia and microdontia associated with hereditary ectodermal dysplasia

Hypodontia and associated conditions like Hereditary Ectodermal Dysplasia [HED] and microdontia markedly influence on physical, functional and psychosocial maturation of the affected individuals. Thorough evaluation, proper counseling and careful treatment planning employing a multidisciplinary approach are keys to a successful, long-term management. This case report describes the prosthodontic management of a young man with hypodontia and microdontia

Agenesia del tercer molar en una etnia originaria del Norte de Chile: atacameños o Lican Antai / Third molar agenesis in native ethnia from north of Chile: atacamenos or Lican Antai

Agenesia es la ausencia de dientes por alteraciones genéticas aisladas o sindrómicas. La agenesia del tercer molar está asociada a malformaciones y considerada por diversos autores consecuencia de la evolución humana (Larmour et al., 2005). Son los dientes con mayor prevalencia de agenesia junto a los segundos premolares e incisivos laterales (Fuller & Denehy, 1984). La prevalencia varía entre 9 y 37 por ciento (McNamara & Foley, 2006), en tanto, Arboleda et al. (2006) señalan una prevalencia del 20 por ciento. La literatura señala variables estadísticas porcentuales, por género, por arcada dentaria, por lado y por diente, con escasos artículos sobre grupos originarios de Chile. La población en estudio consistió en 33 hombres y 57 mujeres de 16 a 55 años, de la etnia atacameña, sin exodoncias del tercer molar ni tratamientos ortodónticos y sin malformaciones congénitas. Se determinó el grado de mestizaje mediante técnica serológica de hemo-aglutinación y por aplicación de la fórmula de Bernstein, que demostró 56 por ciento de mezcla indígena. A cada individuo se le tomó radiografía panorámica para observar presencia o ausencia de terceros molares. Se determina un 26,7 por ciento de individuos con agenesia de uno o más terceros molares, con mayor porcentaje en hombres. En la muestra y en hombres hay mayor agenesia de terceros molares mandibulares; en cambio, en mujeres existe mayor agenesia de terceros molares maxilares. Predominan agenesias izquierdas, lo mismo se comprueba en mujeres, mientras en hombres se comprueba igual porcentaje bilateral. Predomina la agenesia de dos molares en ambos sexos. No existen diferencias estadísticas significativas al 95 por ciento y los resultados coinciden con la literatura. La investigación representa un aporte a la antropología del Norte de Chile, pero considerando lo reducido de la muestra, no fue posible determinar variables étnicas.

Agenesis is the absence of teeth by genetic alterations, single or as syndrome. Agenesis of third molar is associated to malformations and is considered by diverse authors a consequence of the human evolution (Larmour et al., 2005). The third molars together with second premolars and lateral incisors are the teeth with greater prevalence of agenesis (Fuller & Denehy, 1984). The prevalence varíes between 9 percent and 37 percent (McNamara & Foley, 2006); Arboleda et al. (2006) indicated a prevalence of 20 percent. Literature indicate variable percentage, by gender, dental arches, side and tooth, with few arricies on original groups of Chile. The population in study consisted of 33 men and 57 women between 16 and 55 years of the ethnic group of atacameños, without extractions of third molar ñor orthodontic treatments and without congenital malformations. Hybridism was determined by means of serum technique by blood agglutination and by application of the formula of Bernstein, demonstrated a 56 percent of indigenous mixture. To each individual a panoramic x-ray was taken to observe presence or absence of third molars. A 26.7 percent of individuals with agenesis of one or more third molars was determined, with greater percentage among males. Agenesis lower third molar predominates in the sample and in men; however in women are greater agenesis upper third molar. In addition, agenesis predominates of the left side in both sexes, while in men equal bilateral percentage is verified. Agenesis of two molars predominates in both sexes. Statistical analyses did not show significant differences at the 95 percent level, and the results, in general, agree with those in the literature. This research represents a contribution to the anthropology of the north of Chile, but it is not possible to determine ethnic variables considering the small sample in study.

Estudio genético de una familia chilena con tres fenotipos dentales diferentes / Genetic studies of a Chilean family with three different dental anomalies

Background: Congenital dental anomalies can affect up to 25 percent of the population. Aim: To report the genetic study of a family with dental anomalies. Material and methods: We studied a Chilean family presenting with three independent dental phenotypes: third molar agenesis, supernumerary teeth, and dentinal dysplasia type I. We searched for mutations in candidate genes proposed for tooth agenesis and supernumerary teeth: IRF6, FGFR1, MSX1, MSX2, PAX9, PRDM16 and TGFA. We also studied DSPP as a candidate gene for dentinal dysplasia type I. Results: We did not find mutations in FGFR1, MSX2, PAX9, PRDM16, or TGFA. We found a MSX1 mutation (G16D) in both affected and unaffected family members. Also, we found a genetic variation not described before in IRF6 in the dentinal dysplasia type I case. Conclusions: Further investigation is necessary to evaluate if these variants are functional in nature. Finally, we are reporting a mutation in DSPP in an asymptomatic 2-year-old child, which illustrates the ethical pitfalls of interpreting molecular data for genetic counseling of young and/or asymtomatic individuals.

Dental findings in GAPO syndrome: case report

This article reports the case of a young female adult with GAPO syndrome who presented as a peculiar dental finding unerupted primary and permanent dentitions, which resembled total anodontia on clinical examination. A cephalometric analysis was performed to investigate the alterations in facial bone development. This is the 9th GAPO syndrome case reported in a Brazilian patient.

Este artigo relata o caso de um jovem paciente, gênero feminino, portadora da síndrome de GAPO, apresentando impacções dos dentes decíduos e permanentes, sugerindo anodontia total no exame clínico. Foi realizada uma análise cefalométrica para investigar as alterações no desenvolvimento ósseo facial. Este é o nono caso descrito no Brasil

Síndrome de rapp hodgkin: a propósito de un caso: Centro de Recuperación Nutricional "Dr. Pastor Oropeza" San Cristóbal Estado Táchira-Venezuela noviembre 2003 / Rapp-Hodgkin syndrome: a purpose of a case: Centro de Recuperación Nutricional Dr. Pastor Oropeza San Cristóbal stado Táchira-Venezuela november 2003

La displasia ectodérmica hereditaria (DEH), representa un grupo de disturbios caracterizados por aplasia o displasia de estructuras y tejidos derivados del ectodermo. Las estructuras generalmente afectadas incluyen el cabello, piel, uñas, dientes y diversas glándulas. Esta condición representa un disturbio raro y se estima su frecuencia de un caso a cada 10.000 ó 100.000 nacimientos. La detección de la DEH en recién nacidos y en los primeros años de la infancia puede ser tarea difícil, debido a pocos cabellos y pelos, así como la ausencia de dientes, son características muy comunes durante esos períodos. Después de los primeros años de vida el diagnóstico es realizado con mayor facilidad, basados en la historia clínica del paciente y el examen físico. Es importante resaltar que en muchas circunstancias la DEH puede presentar características semejantes o hasta estar asociada a otros síndromes, tales como a ectocractilia displasia ectodérmica (EEC), síndrome trico-rino-falangeral y enfermedad de Robinson. El tratamiento de la DEH es exitosa cuando se establece el diagnóstico en el período adecuado o sea en la infancia. Un control multidisciplinario, instituido en los primeros años de vida del paciente, puede minimizar las posibles complicaciones odontológicas y médicas.

Estudo da relação de genes e agenesia dentária em uma população brasileira / The relationship between dental agenesis and genes in Brazilian population

O principal fator etiológico da agenesia dentária é a hereditariedade. Os genes MSX1 e PAX9 estão comprovadamente associados com o ligodontia. O objetivo deste trabalho foi averiguar a existência de associação desses genes com hipodontia em uma população brasileira. Esta pesquisa foi desenvolvida na Faculdade de Odontologia de uma instituição pública de ensino superior, em duas etapas. Na primeira parte, foram avaliadas 1034 radiografias panorâmicas, de crianças de 6 a 12 anos de ambos os gêneros, com a finalidade de se identificar a ocorrência de anodontias. Das radiografias analisadas, 519 eram de crianças do gênero masculino e 515 crianças do gênero feminino, sendo encontrados 39 casos de agenesia dentária, perfazendo uma prevalência de 3,77%. A esses 39 casos de agenesia dentária, para a segunda parte deste estudo, foram acrescentados mais 116 probandos provenientes de clínicas odontológicas privadas das cidades do Rio de Janeiro totalizando 155 pacientes com ausência congênita de, pelo menos, 1 dente permanente, a exceção dos terceiros molarares. A coleta do material biológico foi realizada de acordo com protocolo padrão e amplificado por reações em cadeia de polimerase (PCR). Através de seqüenciamento direto das regiões codificantes, não foram encontradas mutações potencialmente patogênicas nos genes MSX1 e PAX9. Esses resultados sugerem que outros genes candidatos devem desempenhar um papel na hipodontia em seres humanos.