先天性牙齿缺失患者EDA基因突变检测及其表现型分析

目的：探讨EDA基因突变在单纯型和综合征型先天性牙齿缺失患者中的检出率，并汇总EDA基因突变的患者口内恒牙缺失情况，尝试分析EDA基因突变相关的恒牙列缺失牙位分布特点。方法：临床收集到174例（143例单纯型、31例综合征型）先天性牙齿缺失患者以及451名正常对照者，通过采集外周静脉血或者取颊黏膜拭子，提取基因组DNA，PCR扩增EDA基因编码区并测序，与数据库筛查比对。对于EDA基因突变的患者，记录汇总口内缺失牙位，对比不同牙位缺失率的差异。结果：共检测出33例EDA突变患者，单纯型先天性牙齿缺失患者中EDA基因突变检出率为9.09%（13/143），综合征型先天性牙齿缺失患者中EDA基因突变检出率为64.52%（20/31），检测出10种尚未见报道的EDA基因突变。EDA突变相关的先天缺牙患者中，牙列左、右同名牙缺失数目几乎没有差异，单纯型患者缺失恒牙数（15.9 ± 6.4）比综合征型患者少（23.9 ± 4.3）。EDA突变相关的单纯型先天缺牙患者中，上颌中切牙，上、下颌第一磨牙缺牙率较低；下颌中切牙，上、下颌侧切牙，上颌第一前磨牙缺牙率较高。EDA突变相关的综合征型先天缺牙患者中，各牙位缺牙率均较高，上颌中切牙，上、下颌尖牙，上、下颌第一磨牙缺牙率相对较低。结论：EDA突变检测和表现型分析有助于更全面了解EDA基因以及其在外胚层器官发育中的功能。

EDA mutation screening and phenotype analysis in patients with tooth agenesis

Objective:To screen the ectodysplasin A (EDA)gene mutation in the patients with non-syndromic tooth agenesis and ectodermal dysplasia,and to analyze the phenotype of missing teeth pattern in these two groups of patients.Methods:In the study,174 patients with tooth agenesis (143:non-syn-dromic,31:ectodermal dysplasia)and 451 health control volunteers were enrolled from the clinic,and the genome DNA was extracted from either peripheral blood or oral mucosal swab.The coding region of EDA gene was then amplified by PCR,sequenced and blasted to online NCBI database.The missing teeth were recorded for all patients,and the missing teeth from patients with EDA mutation were com-pared among the different dentition sites.Results:33 patients were identified with EDA mutation.In the non-syndromic patients,13 /143(9.09%)were identified with EDA mutation,while in patients with ec-todermal dysplasia,20 /31 (64.52%)were found with EDA mutation.Ten novel EDA mutations were identified (c.769G >Cp.G257R],c.936C >Gp.I312M],c.223G >Ap.E75K],c.1166C >Tp. P389L],c.133G >Cp.G45R],c.1109G >Ap.E370K],c.914G >Tp.S305I],c.916C >Tp. Q306X],c.602G >Tp.G201V],c.88 -89insGp.A30GfsX69]).For each dentition site there was no statistic difference in the number of missing teeth between the left and right sides,so the number from both sides were combined later in the analysis.In the patients with EDA mutation,the non-syndromic pa-tients had fewer missing teeth (15.9 ±6.4 missing teeth for each,207 /364 in total)than the patients with ectodermal dysplasia (23.9 ±4.3,478 /560).In the non-syndromic patients with EDA mutation, the maxillay central incisors and first molars were less affected,with the same missing rate as 19.2% (5 /26).While the mandibular central incisors (with a missing rate of 76.9%,20 /26),the maxillary late-ral incisors (the missing rate:88.5%,23 /26 ),the mandibular lateral incisors (the missing rate:80.8%,21 /26),and the maxillary first premolars (the missing rate:80.8%,21 /26)were more likely to be missing.In the ectodermal dysplasia patients with EDA mutation,only maxillary central incisors (the missing rate:60%,24 /40),maxillary canines (the missing rate:70%,28 /40),mandibular ca-nines (the missing rate:67.5%,27 /40),maxillary first molars (the missing rate:65%,26 /40)and mandibular first molars (the missing rate:72.5%,29 /40)had higher possibility of persistence.Teeth at other dentition sites were more likely to be affected (the minimum missing rate:87.5%,35 /40). Conclusion:The findings would help to reveal the EDA gene and its function in ectodermal organogene-sis.