Functional Analysis of Ectodysplasin-A Mutations in X-Linked Nonsyndromic Hypodontia and Possible Involvement of X-Chromosome Inactivation.

Yuhua Pan,Fu Xiong,Xiangyu Huang,Xinchen Yao,Ling Peng,Qi Zeng,Ting Lu,Buling Wu

doi:10.1155/2021/7653013

Abstract

Background Mutations of the Ectodysplasin-A (EDA) gene are generally associated with syndrome hypohidrotic ectodermal dysplasia or nonsyndromic tooth agenesis. The influence of EDA mutations on dentinogenesis and odontoblast differentiation has not been reported. The aim of this study was to identify genetic clues for the causes of familial nonsyndromic oligodontia and explore the underlying mechanisms involved, while focusing on the role of human dental pulp stem cells (hDPSCs). Materials and Methods Candidate gene sequences were obtained by PCR amplification and Sanger sequencing. Functional analysis was conducted, and the pathogenesis associated with EDA mutations in hDPSCs was investigated to explore the impact of the identified mutation on the phenotype. Capillary electrophoresis (CE) was used to detect X-chromosome inactivation (XCI) in the blood of female carriers. Results In this study, we identified an EDA mutation in a Chinese family: the missense mutation c.1013C>T (Thr338Met). Transfection of hDPSCs with a mutant EDA lentivirus decreased the expression of EDA and dentin sialophosphoprotein (DSPP) compared with transfection of control EDA lentivirus. Mechanistically, mutant EDA inhibited the activation of the NF-κB pathway. The CE results showed that symptomatic female carriers had a skewed XCI with a preferential inactivation of the X chromosome that carried the normal allele. Conclusions In summary, we demonstrated that EDA mutations result in nonsyndromic tooth agenesis in heterozygous females and that, mechanistically, EDA regulates odontogenesis through the NF-κB signalling pathway in hDPSCs. Due to the large heterogeneity of tooth agenesis, this study provided a genetic basis for individuals who exhibit similar clinical phenotypes.

Highlights

Tooth agenesis, the congenital absence of one or more permanent teeth, is the most common abnormality affecting the function and aesthetics of patients
nonsyndromic hypodontia (NSH) has been reported to be associated with mutations in ectodysplasin-A (EDA), ectodysplasin-A receptor (EDAR), EDAR-associated death domain (EDARADD), wnt family member 10A (WNT10A), wnt family member 10B (WNT10B), paired box 9 (PAX9), msh homeobox 1 (MSX1), axis inhibition protein 2 (AXIN2), and inhibitor of nuclear factor kappa B kinase regulatory subunit gamma (IKBKG) [5,6,7]
EDA mutations could cause syndromic hypodontia (SH), which appears as an X-linked hypohidrotic ectodermal dysplasia (XLHED) clinical feature, and they have been linked to isolated tooth agenesis, most likely due to complete or partial disruption of the EDA signalling pathway [8, 9]

Summary

Introduction

The congenital absence of one or more permanent teeth, is the most common abnormality affecting the function and aesthetics of patients. Congenital tooth agenesis has been divided into nonsyndromic hypodontia (NSH) and syndromic hypodontia (SH) based on the systemic conditions of the patient [1, 2]. EDA mutations could cause SH, which appears as an X-linked hypohidrotic ectodermal dysplasia (XLHED) clinical feature, and they have been linked to isolated tooth agenesis, most likely due to complete or partial disruption of the EDA signalling pathway [8, 9]. Mutations of the Ectodysplasin-A (EDA) gene are generally associated with syndrome hypohidrotic ectodermal dysplasia or nonsyndromic tooth agenesis. We demonstrated that EDA mutations result in nonsyndromic tooth agenesis in heterozygous females and that, mechanistically, EDA regulates odontogenesis through the NF-κB signalling pathway in hDPSCs. Due to the large heterogeneity of tooth agenesis, this study provided a genetic basis for individuals who exhibit similar clinical phenotypes

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