Exclusion of PAX9 and MSX1 mutation in six families affected by tooth agenesis. A genetic study and literature review.

Victoria Tallón-Walton,Maria-Cristina Manzanares-Céspedes,Pekka Nieminen,Sirpa Arte,Ivan Valdivia-Gandur,Patricia Carvalho-Lobato

doi:10.4317/medoral.19173

Victoria Tallón-Walton, Maria-Cristina Manzanares-Céspedes + Show 4 more

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https://doi.org/10.4317/medoral.19173

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Abstract

Objectives: In the present study, it is described the phenotypical analysis and the mutational screening, for genes PAX9 and MSX1, of six families affected by severe forms of tooth agenesis associated with other dental anomalies and systemic entities. Study Design: Six families affected by severe tooth agenesis associated with other dental anomalies and systemic entities were included. Oral exploration, radiological examination, medical antecedents consideration and mutational screening for PAX9 and MSX1 were carried out. Results: No mutations were discovered despite the fact that numerous teeth were missing. An important phenotypical variability was observed within the probands, not being possible to establish a parallelism with the patterns associated to previously described PAX9 and MSX1 mutations. Conclusions: These results bring us to conclude that probably other genes can determine phenotypical patterns of dental agenesis in the families studied, different than the ones described in the mutations of PAX9 and MSX1. Moreover, epigenetic factors can be involved, as those that can reduce gene dosage and other post-transcriptional modulation agents, causing dental agenesis associated or not with systemic anomalies. Key words:Maxillofacial development, tooth agenesis, PAX9 gene, MSX1 gene, gene mutation.

Highlights

Many terms appear in the literature to describe the congenital absence of a dental organ, being the more accepted classification: hypodontia, defined as the congenital missing of one to five teeth excluding the third molars; oligodontia, as the absence of more than six teeth, excluding the third molars, and anodontia, defined as the complete lack of teeth
We present the analysis of the phenotype and the genotype of six families affected by severe tooth agenesis associated with other dental anomalies and systemic entities, in which mutations of genes PAX9 and MSX1 were not identified
In the present work, we present the analysis of the phenotype and the genotype of the genes PAX9 and

Summary

Introduction

Many terms appear in the literature to describe the congenital absence of a dental organ, being the more accepted classification: hypodontia, defined as the congenital missing of one to five teeth excluding the third molars; oligodontia, as the absence of more than six teeth, excluding the third molars, and anodontia, defined as the complete lack of teeth. These alterations can appear associated with systemic entities and multiorgan syndrome, in isolated, sporadic forms or as an isolated family trait. Numerous different mutations in two transcription factors, MSX1 and PAX9, have been identified in families affected by oligodontia. Several different mutations in this transcription factor have been identified in families with oligodontia, being affected most of the molars [20,21,22,23,24,25,26,27,28]

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