Two novel mutations in MSX1 causing oligodontia.

Le Yang,Haitang Yue,Jia Liang,Zhuan Bian,Tao Cai

doi:10.1371/journal.pone.0227287

Abstract

Tooth agenesis is one of the most common developmental anomalies in humans and can affect dental occlusion and speech pronunciation. Research has identified an association between mutations in MSX1, PAX9, EDA, AXIN2, WNT10A, WNT10B and LRP6 and human tooth agenesis. Two unrelated individuals with non-syndromic tooth agenesis and their families were enrolled in this study. Using Sanger sequencing of the candidate genes, we identified two novel mutations: a missense mutation c.572 T>C and a frameshift mutation c.590_594 dup TGTCC, which were both detected in the homeodomain of MSX1. After identifying the mutations, structural modeling and bioinformatics analysis were used to predict the resulting conformational changes in the MSX1 homeodomain. Combined with 3D-structural analysis of other MSX1 mutations, we propose that there is a correlation between the observed phenotypes and alterations in hydrogen bond formation, thereby potentially affecting protein binding.

Highlights

Tooth agenesis is a common developmental anomaly of the human dentition
Several terms are used to describe tooth agenesis: hypodontia is referred as an absence of less than six teeth excluding the third molars; oligodontia is an absence of six or more teeth excluding the third molars; and anodontia is the complete absence of teeth [2]
The majority of cases are caused by genetic mutations, and to date, mutations in the MSX1, PAX9, AXIN2, WNT10A, EDA, EDAR, EDARADD, WNT10B and LRP6 genes have been associated with non-syndromic tooth agenesis (NSTA) cases [14,15,16,17,18,19,20,21,22]

Summary

Introduction

The incidence of tooth agenesis of permanent teeth ranges from 2.2% to 10.1% [1]. Several terms are used to describe tooth agenesis: hypodontia is referred as an absence of less than six teeth excluding the third molars; oligodontia is an absence of six or more teeth excluding the third molars; and anodontia is the complete absence of teeth [2]. Tooth agenesis is classified as syndromic when it is accompanied by other inherited abnormalities including nail dysplasia [3], sparse hair, lack of sweat glands or a cleft lip and palate [4,5,6,7,8], and classified as non-syndromic when the absence of teeth is an isolated characteristic. The etiology of tooth agenesis is complex and not yet completely elucidated [2]. The majority of cases are caused by genetic mutations, and to date, mutations in the MSX1, PAX9, AXIN2, WNT10A, EDA, EDAR, EDARADD, WNT10B and LRP6 genes have been associated with non-syndromic tooth agenesis (NSTA) cases [14,15,16,17,18,19,20,21,22]

Methods

Results

Discussion

Conclusion