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

Abstract BackgroundMutations of the Ectodysplasin-A (EDA) gene are generally associated with other developmental anomalies (syndrome hypohidrotic ectodermal dysplasia) or as an isolated condition (non-syndromic tooth agenesis). The influence of EDA mutations on dentinogenesis and odontoblast differentiation have not been reported. The aim of the present study was to identify genetic clues for familial nonsyndromic oligodontia and explore the underlying mechanisms, focusing on the role of human dental pulp stem cells (hDPSCs).MethodsThe candidate genes sequences were performed by PCR amplification and Sanger sequencing. Functional analysis and pathogenesis associated with EDA mutations in hDPSCs were also investigated to explore the impact of the identified mutation on this phenotype. Capillary electrophoresis (CE) was used to detect X chromosome inactivation (XCI) on the blood of female carrier.ResultsIn this study, we identified a reported EDA mutation in a Chinese family：a missense mutation c.1013C>T (Thr338Met). Transfection of hDPSCs with mutant EDA lentivirus decreased the expression of EDA and dentin sialophosphoprotein (DSPP) compared with those transfected with control EDA lentivirus. Mechanically, the mutant EDA inhibited the activation of the NF-κB pathway. The results of CE showed that symptomatic female carrier had a skewed XCI with a preferential inactivation of the X chromosome carrying the normal allele.ConclusionIn summary, we demonstrated EDA mutation result in non-syndromic tooth agenesis in heterozygous females and mechanically EDA regulates odontogenesis through the NF-κB signaling pathway in human dental pulp stem cells.