[Whole exome sequencing and analysis of hypohidrotic ectodermal dysplasia patients].

Objective: To detect gene mutation in patients with hypohidrotic ectodermal dysplasia (HED) by using whole exome sequencing, to analyze the pathogenicity of the mutations, and to provide reference for the genetic diagnosis of HED patients. Methods: Peripheral blood genomic DNA was extracted from each of the HED patients and their family members collected in Peking University School and Hospital of Stomatology from August 2016 to August 2021. Whole exome sequencing and sanger sequencing were performed to detect gene mutations. Functions of the rare variants after the database filtering were analyzed by bioinformatics tools. Results: Three reported mutations of ectodysplasin A (EDA) gene (c.2T>C, c.161A>G, c.467G>A) and a mutation of ectodysplasin A receptor (EDAR) gene (c.871G>A) were detected by whole genome sequencing in four HED patients, and were verified by Sanger sequencing in four HED families. The EDAR gene mutation founded in this research was reported in HED patients for the first time. Bioinformatics tools predicted that the mutations of EDA gene detected in this study were highly species conserved and disease-causing. The combined annotation dependent depletion (CADD) scores of EDA gene mutations c.2T>C, c.161A>G and c.467G>A were 22.5, 26.3 and 25.5 respectively, and the genomic evolutionary rate profiling (GERP) scores were 2.16, 2.26 and 2.18 respectively. The EDAR gene mutation c.871G>A detected in this study was species conserved and possibly disease-causing. The CADD and GERP scores of EDAR gene mutation c.871G>A were 22.0 and 1.93 respectively. Conclusions: Three reported mutations of EDA gene and a previously unreported mutation of EDAR gene were detected in four HED families. Different mutations of EDA gene and EDAR gene could make different influence on the protein function and lead to the occurrence of HED.目的： 对少汗性外胚层发育不良（hypohidrotic ectodermal dysplasia，HED）患者进行基因突变检测及致病性分析，为HED患者的基因诊断提供参考依据。 方法： 收集2016年8月至2021年8月于北京大学口腔医学院·口腔医院儿童口腔科就诊的临床诊断为HED的患儿及其家系成员为研究对象，对患儿及其家系成员行外周血基因组DNA提取，利用全外显子组测序及Sanger测序检测基因突变，进行罕见变异位点筛选，并对筛选出的突变进行生物信息学功能预测。 结果： 共收集到4例HED患者，通过全外显子组测序检测并筛选出3个已报道过的外异蛋白A（ectodysplasin A，EDA）基因突变c.2T>C、c.161A>G、c.467G>A，其中c.2T>C为起始密码子突变。此外还检测出1个未在HED病例中报道过的外异蛋白A受体（ectodysplasin A receptor，EDAR）基因突变c.871G>A。HED患儿及其家系成员的Sanger测序结果证明了上述突变的发生。上述突变的生物信息学功能预测结果显示，本研究检测到的EDA基因突变均具有高度的物种保守性，对EDA蛋白功能有害，c.2T>C、c.161A>G及c.467G>A 3种突变的联合注释依赖耗竭（combined annotation dependent depletion，CADD）数据库评分分值分别为22.5、26.3、25.5，基因组进化速率评测（genomic evolutionary rate profilling，GERP）数据库评分分值分别为2.16、2.26、2.18。EDAR基因突变具有一定的物种保守性，对EDAR蛋白质功能“可能有害”，CADD评分分值为22.0，GERP评分分值为1.93。 结论： 本研究在4个HED家系中检测出3种EDA基因突变和1种EDAR基因突变。EDA基因及EDAR基因上不同位点、不同类型的突变可对蛋白质功能产生影响，导致HED的发生。.