非综合征型多数牙先天缺失家系中PAX9新突变的研究及PAX9突变导致非综合征型先天缺牙基因型—表型分析

A novel PAX9 variant in a Chinese family with non-syndromic oligodontia and genotype-phenotype analysis of PAX9 variants

目的 在中国多个非综合征型先天缺牙家系中鉴定PAX9突变,并研究PAX9突变导致非综合征型先天缺牙的基因型—表型关系,为先天缺牙基因诊断提供依据。方法 收集自2018年至2023年期间于河北医科大学口腔医院就诊的44例非综合征型多数牙缺失患者。采集先证者及其核心家系成员外周血进行全外显子组测序(WES),并用Sanger测序验证其突变,通过生物信息学工具对突变体进行了致病性分析和功能预测。在PubMed等检索出与先天缺牙相关PAX9突变的55篇文章共232例患者,分析PAX9突变基因型—表型关系。结果 在中国家庭中发现了一个新的PAX9基因移码突变c.447delG (p.Pro150Argfs*62)和一个已报道的PAX9基因错义突变c.406C>T (p.Gln136*)。通过生物信息学分析和三维结构建模,预测发现该移码突变具有致病性,突变导致PAX9蛋白提前终止,结构与功能受损严重。总结PAX9基因型—表型关系发现,携带PAX9突变的非综合征型先天缺牙患者最容易缺失第二磨牙。结论 发现非综合征型先天缺牙新的PAX9基因移码突变c.447delG(p.Pro150Argfs*62),扩展先天缺牙PAX9突变谱。非综合征型先天缺牙PAX9突变最易感牙位为第二磨牙,PAX9突变导致的乳牙缺失均为乳磨牙缺失。

Objective This study aimed to identify PAX9 variants in non-syndromic tooth agenesis families of China,as well as to analyze the genotype-phenotype of non-syndromic tooth agenesis caused by PAX9 variants,which can provide a basis for the genetic diagnosis of tooth agenesis.Methods We collected the data of 44 patients with non-syndromic oligodontia who underwent treatment at Stomatological Hospital of Hebei Medical University between 2018 and 2023.Whole-exome sequencing was performed on the peripheral blood of the proband and its core family members,and the variants were verified by Sanger sequencing.Pathogenicity analysis and function prediction of the variants were performed using bioinformatics tools.The correlation between the genotype of PAX9 variant and its corresponding phenotype was examined by reviewing 55 publications retrieved from PubMed.The studies involved 232 tooth agenesis patients with PAX9 variants.Results A novel PAX9 c.447delG(p.Pro150Argfs*62) and a reported PAX9 c.406C>T(p.Gln136*) were identified in two Chinese families.Through bioinformatics analysis and three-dimensional structural modeling,we postulated that the frameshift variant was pathogenic.The outcome was the premature cessation of PAX9 protein,which caused severe structural and functional deficiencies.Summarizing the PAX9 genotype-phenotype relationship revealed that patients carrying the PAX9 variant commonly led to loss of the second molars.Conclusion We identified the novel PAX9 c.447delG(p.Pro150Argfs*62) in a Chinese family of non-syndromic oligodontia,expanding the known variant spectrum of PAX9.The most susceptible tooth position for PAX9 variants of tooth agenesis was the second molars and the deciduous molars during the deciduous dentition.