PAX9基因在2个新疆维吾尔族非综合征型先天缺牙家系中的表达

目的　通过对新疆维吾尔族非综合征型先天缺牙患者PAX9基因突变的检测,为维吾尔族该病发病的分子机制提供依据。方法　采集2个新疆维吾尔族非综合征型先天缺牙家系颊黏膜拭子,提取DNA,采用聚合酶链反应技术结合DNA双向测序技术对患者DNA进行检测。结果　PAX9基因外显子3的85、86位点检测出两个单核苷酸多态性（single nucleotide polymorphisms,SNPs）位点。结论　PAX9基因外显子3的85、86位点的改变可能与新疆维吾尔族非综合征型先天缺牙的发生有关。     

单纯性多数牙缺失家系的AXIN2基因突变分析

目的：通过对AXIN2基因多态性与单纯性多数牙先天缺失关系的探讨，寻找该病发病的可能基因因素。方法对单纯性多数牙先天缺失家系中患者进行临床和实验室相关检查；而后提取基因组DNA ，通过RT?PCR方法对AXIN2基因的外显子进行扩增、测序，同时分析基因突变类型。结果 DNA测序显示，在AXIN2基因的3号外显子及附近的内含子区2例患者出现3个相同类型的基因突变，分别是：c.1365A>G（p.Pro455=），c.956+16A>G（Ⅱ?1：纯合型；Ⅲ?1：杂合型），c.1200+71A>G（纯合型），同时先证者的母亲（Ⅱ?2）出现c.1365A>G和c.1200+71A>G的杂合突变类型。经生物信息软件分析认为均是多态性位点。结论 AXIN2基因的c.956+16A>G，c.1365A>G和c.1200+71A>G突变可能与该家系的单纯性多数牙齿缺失密切相关，但AXIN2在多数牙缺失发生发展各阶段的确切作用还需要进一步的研究。     

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目的检测一非综合征型多数牙齿先天缺失家系的AXIN2基因,探讨其与该家系成员多数牙齿先天缺失的关系。方法本研究于2011年3月至2013年3月在中国医科大学口腔医学院中心实验室完成。对一非综合征型多数牙齿先天缺失家系3代成员共17人,在患者和家属知情同意及中国医科大学口腔医学院伦理委员会批准的前提下,提取其外周静脉全血基因组DNA,用Primer Premier5．0软件设计引物,聚合酶链式反应（PCR）方法扩增AXIN2基因全部外显子后,纯化PCR产物,应用3730DNA序列分析仪双向测序,结合系谱图进行分析。结果该非综合征型多数牙齿先天缺失家系的临床表现符合常染色体显性遗传规律;AXIN2基因测序结果显示：存在1个与牙齿先天缺失相关的错义突变位点c．148C〉T（rs2240308）,以及3个单核苷酸多态（SNP）位点c．1201＋71（rs8078753）、c．1201＋82、c．1201＋100（rs56248738）,其中c．1201＋82为新发现的SNP位点。结论该家系多数牙齿先天缺失可能与AXIN2基因的多个SNP位点有关。     

一先天缺牙家系基因芯片检测分析及FGF20基因的检测

目的 研究一先天缺牙家系的遗传学特点并探寻其可能的致病基因。方法 一先天缺牙家系3代共17人,在患者和家属知情同意及伦理委员会批准的前提下对全部成员进行临床检查和X线辅助检查,抽取其家系成员静脉血,提取DNA,应用基因芯片技术进行基因筛查,对可疑基因FGF20进行聚合酶链式反应（PCR）并测序。结果 该非综合征型先天缺牙家系为3代连续遗传,且没有性别差异,外显率为100%,诊断为常染色体显性遗传;基因芯片检测提示FGF20可能为该家族先天缺牙的致病基因,但经PCR检测未发现突变位点。结论 先天缺牙的致病机制较复杂,可能是多基因联合控制的疾病;基因芯片技术在筛查牙齿先天缺失家系的致病基因方面仍有一定的局限性。     

单纯性先天缺牙患者BMP2/BMP4基因位点分析

目的对BMP2/BMP4基因在单纯性先天缺牙患者中的基因表达进行观察,探讨其在先天缺牙疾病中可能的发病机制。方法提取单纯性先天缺牙患者40例及其家系成员外周静脉血基因组DNA,另选择100例非先天缺牙患者作为对照,应用聚合酶链式反应（PCR）扩增BMP2/BMP4基因编码外显子,纯化、测序,应用DNASTAR软件对测序结果进行对比分析。采用SPSS13.0软件包对数据进行统计学处理。结果40例先天缺牙患者中,共检测到BMP2/BMP4基因 5个突变位点,其中BMP2基因4个突变点：3个错义突变c.109T>G, c.166C>G,c.570A>T,检出率分别为7.5%、2.5%和95%;1个同义突变（c.261A>G）,检出率为100%。3个为dbSNP 数据库中已报道过的多态位点：BMP2SNPs c.109T>G p.Ser37Ala; c.261A>G p.Ser87Ser;c.570A>T p.Arg190Ser;家系先证者BMP2 c.166C>G突变在正常对照组未检出,dbSNP 数据库未报道,也未被收录于致病基因数据库,为新突变位点。BMP4基因检测出错义突变c.455T>C,检出率为55%,为dbSNP 数据库中已报道过的多态位点。与对照组等位基因及基因型比较,无显著差异。结论单纯性先天缺牙可能与BMP2/BMP4基因检出SNPs相关。BMP2c.166C>G杂合突变是新发现的突变,可能是单纯性先天缺牙家系的致病突变。     

Van der Woude综合征家系先天缺牙患者MSX1基因突变的检测

目的探讨MSX1基因与Van der Woude综合征(VWS)家系中缺牙的关系。方法从VWS家系9中伴发缺牙患者2人及家系正常成员2人、60个牙列完整的健康者共64人的静脉血中提取DNA,设计MSX1基因引物,采用PCR方法扩增MSX1基因外显子1、2的编码区,而后对外显子1、2的PCR纯化产物测序,进行序列比对分析。结果 VWS家系9两个缺牙患者MSX1基因中有ivs2+68 C>T多态;伴IRF6基因突变的VWS患者缺牙较多。结论 VWS家系9中先天缺牙患者的牙先天缺失与MSX1基因的ivs2+68 C>T多态可能相关。     

选择性先天缺牙家系的表型与基因型分析：附2例报告

目的: 探讨选择性先天缺牙患者的遗传学病因。方法: 对2例非综合征型先天缺牙患者进行临床检查、家系调查、影像学检查以及外周血采集,通过全外显子测序后与正常人类基因组比对,并进行Sanger测序验证,确定致病基因及突变位点后,进行蛋白结构预测和多物种保守性分析。结果: 2例选择性先天缺牙家系中家系1为散发型,家系2为家族型。全外显子测序结果显示,先证者1和先证者2分别存在LRP6无义突变（II:1, c.C1573T,p.R525X）以及移码突变（II-1, c.4611delT ,p.C1537fs）。蛋白结构分析表明,p.R525X使LRP6蛋白截短,为失功能突变。多物种保守性分析揭示位点在进化过程中高度保守,提示突变具备有害性。结论: 2例选择性先天缺牙家系可能由于LRP6突变导致,为遗传咨询和产前诊断提供了参考。     

单纯型多数牙缺失的PAX9基因新突变一例

苏州大学附属第二医院口腔中心收治单纯型多数牙缺失1例,患者先天缺失恒牙16颗,其他系统无异常,其母与患者有相似表型。收集患者、患者父母及外祖父母外周血,提取DNA,采用PCR结合直接测序进行PAX9、MSX1、WNT10A、WNT10B、AXIN2和EDA等候选基因突变检测,PCR-Sanger测序发现PAX9基因的起...     

多数牙先天缺失可能与MSX1上的3个SNPs相关

目的:探讨多数牙先天缺失患者的MSXl基因突变位点.方法:从4个多数牙先天缺失患者与家庭部分成员、1个唇腭裂并发少数牙先天缺失的患者、1个牙列完整的对照儿童共14人的静脉血中提取DNA,在MSXl基因内设计引物,采用PCR方法扩增MSXl基因外显子1、2的编码区,而后对外显子1、2的PCR纯化产物测序,结合系游进行序列比对分析.结果:发现3个可能的单核苷酸多态性位点(single nucleotide pol-ymorphisms,SNPs).这3个SNPs均位于外显子1中,且来自不同家系的3个患者在这3个位点上同时出现杂合突变.其中,311位点由G变A,对应的密码子由编码甘氨酸的GGC变为编码天门冬氨酸的GAC,发生了错义突变;402位点由C变A,对应的密码子由CCC变为CCA,但仍编码脯氨酸,属同义突变;458位点由C变T,对应的密码子由编码丙氨酸的GCC变为编码缬氨酸的GTC,发生了错义突变.结论:多数牙先天缺失可能与MSX1基因上该3个单核苷酸多态性位点有关.     

PAX9基因上新近发现的一个单核苷酸多态性位点的SNP分析

目的:研究位于PAX9基因外显子3的第89位点上的SNP与多数牙先天缺失的相关性.方法:分别从11名多数牙先天缺失病人,5名少数牙先天缺失病人和38名正常对照者的静脉血样品中提取DNA.采用TaqMan-MGB探针技术对该SNP位点进行单核苷酸多态性研究,利用软件对实验结果进行SNP分型,并行统计分析.结果:突变为纯合子C/C的绝大多数表现为先天缺牙(多数牙先天缺失5例,少数牙先天缺失2例,正常1例).但31例杂合子中只有7例表现为先天缺牙(多数牙先天缺失6例,少数牙先天缺失1例).13例野生型纯合子只有2例表现为少数牙先天缺失,11例完全正常.统计结果表明该位点与多数牙先天缺失相关(P<0.001).结论:多数牙先天缺失可能与PAX9基因外显子3的第89位点上的SNP有关.     

Clinical and genetic evaluation of a Chinese family with isolated oligodontia

Objectives

Oligodontia is defined as the congenital absence of 6 or more permanent teeth excluding the third molar. Tooth agenesis may be classified as syndromic/non-syndromic and as familial/sporadic. To date, more than 300 genes have been found to be involved in tooth development, but only a few of these genes, such as MSX1, PAX9 and AXIN2, are related to the condition of non-syndromic oligodontia. The objective of the present work was to investigate the disease-causing gene of non-syndromic oligodontia in a Han Chinese family and analyse the pathogenesis of mutations that result in oligodontia.

Design

We examined all individuals of the oligodontia family by clinical and radiographic examinations. Based on the clinical manifestations, the candidate genes MSX, PAX9 and AXIN2 were selected to analyse and screen for mutations.

Results

The clinical evaluation suggested that the family might show non-syndromic oligodontia. DNA sequencing of the MSX1 gene revealed two mutations in the two patients with oligodontia: a heterozygotic silent mutation, c.348C > T (P.Gly116=), in exon 1 and a homozygotic deletion of 11 nucleotides (c.469 + 56delins GCCGGGTGGGG) in the intron. However, the silent mutation and the deletion mutation were thought to be known polymorphisms (rs34165410 and rs34341187) by bioinformatics analysis. We did not detect any mutations in the PAX9 and AXIN2 genes of oligodontia patients.

Conclusion

Our finding suggests that identified polymorphisms (c.348C > T and c.469 + 56delins GCCGGGTGGGG) may be responsible for the oligodontia phenotype in this Chinese family, but the association requires further study.     

中国先天性缺失牙患者PAX9基因的新突变

目的 探讨我国先天性缺失牙患者PAX9基因突变的特点，为该病发病的分子机制研究提供依据。方法 应用聚合酶链反应．单链构象多态性(PCR-SSCP)分析方法，对4个常染色体显性遗传少牙畸形家系(共45名成员，22例患者)中的13例患者和9名健康成员、16例散发性牙齿发育不全患者以及196名健康对照者的PAX9基因进行研究。结合DNA序列分析方法，对发现异常SSCP条带的患者进行突变分析。结果 2个少牙畸形家系(家系A和家系B)的先证者出现异常SSCP条带，家系A和家系B内患者均出现与各自先证者相同的异常SSCP条带。经过DNA序列分析，发现PAX9基因第2外显子的2个新突变：碱基插入(109InsG)导致的移码突变，碱基置换(c139T)导致的错义突变。其余家系患者、散发性患者均未发现异常SSCP条带。结论 109InsG和C139T突变扩大了先天性缺失牙患者的PAX9基因突变谱，为我国先天性缺失牙的基因诊断提供依据。     

Novel missense mutations in the AXIN2 gene associated with non-syndromic oligodontia

Objective

Oligodontia, which is the congenital absence of six or more permanent teeth excluding third molars, may contribute to masticatory dysfunction, speech alteration, aesthetic problems and malocclusion. To date, mutations in EDA, AXIN2, MSX1, PAX9, WNT10A, EDAR, EDARADD, NEMO and KRT 17 are known to associate with non-syndromic oligodontia. The aim of the study was to search for AXIN2 mutations in 96 patients with non-syndromic oligodontia.

Design

We performed mutation analysis of 10 exons of the AXIN2 gene in 96 patients with isolated non-syndromic oligodontia.

Results

We identified two novel missense mutations (Exon 3 c.923C > T and Exon 11 c.2490G > C) in two patients. One mutation (c.923C > T) results in a Thr308Met substitution and the other mutation (c.2490G > C) results in a Met830Ile substitution.

Conclusions

This is the first report indicating that mutations in AXIN2 are responsible for oligodontia in the Chinese population. Our findings indicate that AXIN2 can be regarded as a candidate gene for mutation detection in individuals with non-syndromic oligodontia in the Chinese population.     

Sequence analysis of PAX9, MSX1 and AXIN2 genes in a Chinese oligodontia family

Objectives

The goal of our research was to look into the clinical traits and genetic mutations in nonsyndromic oligodontia in a Chinese family and to gain insight into the role of mutations of PAX9, MSX1 and AXIN2 in oligodontia phenotypes.

Materials and methods

6 subjects from a family underwent complete oral examination, including panoramic radiographs. Retrospective data were reviewed and blood samples were collected. PCR primers for PAX9, MSX1, and AXIN2 were designed through the Oligo Primer Analysis Software. PCR products were purified and sequenced using the BigDye Terminator Kit and analysed by the 3730 DNA Analyzer.

Results

The proband missed 4 permanent canines, 2 permanent maxillary lateral incisors, 2 permanent mandibular lateral incisors, and 2 permanent mandibular central incisors, whilst his maternal grandfather lacked only 2 permanent mandibular central incisors. Moreover, the size of some permanent teeth appeared smaller than normal values of crown width of Chinese people. Oligodontia and abnormalities of teeth were not present in other family members. Radiographic examination showed that the proband and the rest of family members retained all germs of the third molars. There was one known mutation A240P (rs4904210) of PAX9 in the coding region in the proband and the maternal family members (II-2, II-3, and II-4), which possibly contributed to structural and functional changes of proteins. No mutations were identified in MSX1 and AXIN2.

Conclusions

Our findings may imply that the PAX9 A240P mutation is a risk factor for oligodontia in the Chinese population. A240P is likely to be a genetic cause of oligodontia though previous literature suggested it as a polymorphism only.     

Investigating the etiology of multiple tooth agenesis in three sisters with severe oligodontia

OBJECTIVES: To describe the dentofacial phenotypes of three sisters with severe non-syndromic oligodontia, to report on the mutation analysis in three genes, previously shown to cause various phenotypes of non-syndromic oligodontia and in two other suspected genes. Based on the phenotypes in the pedigree of this family, the different possible patterns of transmission are discussed. METHODS: Anamnestic data and a panoramic radiograph were taken to study the phenotype of the three sisters and their first-degree relatives. Blood samples were also taken to obtain their karyotypes and DNA samples. Mutational screening was performed for the MSX1, PAX9, AXIN2, DLX1 and DLX2 genes. RESULTS: The probands' pedigree showed evidence for a recessive or multifactorial inheritance pattern. Normal chromosomal karyotypes were found and - despite the severe oligodontia present in all three sisters - no mutation appeared to be present in the five genes studied so far in these patients. CONCLUSIONS: In the three sisters reported, their common oligodontia phenotype is not caused by mutations in the coding regions of MSX1, PAX9, AXIN2, DLX1 or DLX2 genes, but genetic factors most probably play a role as all three sisters were affected. Environmental and epigenetic factors as well as genes regulating odontogenesis need further in vivo and in vitro investigation to explain the phenotypic heterogeneity and to increase our understanding of the odontogenic processes.     

Exclusion of coding region mutations in MSX1, PAX9 and AXIN2 in eight patients with severe oligodontia phenotype

PURPOSE: This paper describes the screening of eight patients with severe oligodontia for PAX9 and AXIN2 mutations. SUBJECTS AND METHODS: Anamnestic data and a panoramic radiograph were collected to study the phenotype of eight patients with oligodontia and their first-degree relatives. A blood sample was taken for a mutational screening for PAX9 and AXIN2 mutations. RESULTS: No mutations were discovered, but a unique nucleotide change in a conserved 5' flanking region of PAX9 was revealed. Earlier screening of the same patients for MSX1 mutations also had a negative outcome. CONCLUSIONS: Considering the discrepancy between the high incidence rate of agenesis and the relatively small number of reported causative mutations in PAX9, MSX1 and AXIN2 genes, the genetic contribution to oligodontia probably is much more heterogeneous than expected so far. Therefore negative results, like the present exclusion data, should be published more often in order to get a better appreciation of the relative contribution of these specific mutations causing oligodontia. In this context the exact number of tested probands also should be mentioned at all cases. Recent evidence of PAX9-MSX1 protein interactions in odontogenesis as well as other genes and developmental factors should receive more attention.     

新疆维、汉大学生恒牙先天缺失情况的调查分析

目的 调查新疆维汉两民族青年人恒牙先天缺失的状况。方法 2008-2009年对新疆高校学生共5150名采取随机、整群抽样的方法 进行恒牙发育异常情况的调查。对总体及维汉两民族先天缺牙情况进行患病率、颌位情况、缺牙数目、好发牙位及同时伴发2种牙齿发育异常的情况进行卡方检验。结果 恒牙先天缺失的总患病率为5.98%,汉族高于维族(P<0.05),维族男性患病率低于女性(P<0.05)。总体及汉族缺牙数目下颌多于上颌(P<0.05),好发牙位为下颌中切牙;总体及维汉均以缺失1颗牙者最多见,且锥形牙与先天缺牙伴发的比率高。结论 恒牙先天缺失的总患病率略低于其他学者的研究,民族间患病率有差异,汉族高于维吾尔族。性别差异、颌位情况、缺牙数目、好发牙位及伴发情况与其他学者的研究基本一致。?