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Abstract：
Mutations in PAX9 are the most common genetic cause of tooth agenesis (TA). The aim of this study was to systematically review the profiles of the TA and PAX9 variants and establish their genotype-phenotype correlation. Forty articles were eligible for 178 patients and 61 mutations (26 in frame and 32 null mutations). PAX9 mutations predominantly affected molars, mostly the second molar, and the mandibular first premolar was the least affected. More missing teeth were found in the maxilla than the mandible, and with null mutations than in-frame mutations. The number of missing teeth was correlated with the locations of the in-frame mutations with the C-terminus mutations demonstrating the fewest missing teeth. The null mutation location did not influence the number of missing teeth. Null mutations in all locations predominantly affected molars. For the in-frame mutations, a missing second molar was commonly associated with mutations in the highly conserved paired DNA-binding domain, particularly the linking peptide (100% prevalence). In contrast, C-terminus mutations were rarely associated with missing second molars and anterior teeth, but were commonly related to an absent second premolar. These finding indicate that the mutation type and position contribute to different degrees of loss of PAX9 function that further differentially influences the manifestations of TA. This study provides novel information on the correlation of the PAX9 genotype-phenotype, aiding in the genetic counseling for TA.
摘要：
PAX9中的突变是牙齿发育不全（TA）的最常见遗传原因。这项研究的目的是系统地回顾TA和PAX9变体的概况，并建立它们的基因型-表型相关性。40篇文章符合178名患者和61个突变（26个框内和32个无效突变）。PAX9突变主要影响磨牙，主要是第二磨牙，下颌第一前磨牙受影响最小.上颌骨的缺失牙齿比下颌骨多，并且具有无效突变而不是框内突变。缺失牙齿的数量与框内突变的位置相关，C端突变表明缺失牙齿最少。无效突变位置不影响缺失牙齿的数量。所有位置的空突变主要影响磨牙。对于框内突变，缺失的第二磨牙通常与高度保守的配对DNA结合域中的突变有关，特别是连接肽(100%患病率)。相比之下,C端突变很少与第二磨牙和前牙缺失相关，但通常与第二前磨牙缺失有关。这些发现表明，突变类型和位置导致PAX9功能的不同程度丧失，从而进一步差异影响TA的表现。这项研究提供了有关PAX9基因型-表型相关性的新信息，协助助教的遗传咨询。
