X连锁无汗性外胚叶发育不全家系ED1基因的突变检测

目的探讨国内X连锁无汗性外胚叶发育不全家系中ED1基因的突变情况，为该病的遗传咨询、产前诊断、确诊携带者提供依据。方法收集2个X连锁无汗性外胚叶发育不全家系及1个散发患者的外周血样本，盐析法提取基因组DNA，采用聚合酶链反应（polymerase chain reaction，PCR）和直接测序对ED1基因进行突变检测。结果家系一患者ED1基因第9外显子发生错义突变（1045G〉A），家系二和散发患者ED1基因第3外显子发生错义突变，分别为467G〉A和466C〉T。结论ED1基因的错义突变可导致X连锁无汗性外胚叶发育不全。这3个突变与国外学者的报道一致。     

颅骨锁骨发育不全患者RUNX2基因突变检测——附1例报告

目的：研究颅骨锁骨发育不全（CCD）患者的RUNX2基因突变。方法：对1例患者进行全身健康状况及口腔专科检查,明确诊断为颅骨锁骨发育不全。提取患者全血基因组DNA,PCR扩增RUNX2基因,BLAST同源序列分析,检测基因突变位点。体外分离培养患者来源的牙囊细胞及正常对照牙囊细胞,cDNA测序验证基因突变。结果：患者RUNX2基因第2外显子插入TG突变,牙囊细胞cDNA测序结果相同,该突变型为c．309_310insTG。结论：成功发现了RUNX2基因新致病突变,补充了国内外CCD致病基因的突变位点数据库。     

锁骨颅骨发育不全综合征(CCD)1例报告

目的：分析1例锁骨颅骨发育不全综合征的典型病例。为临床正确诊断该类遗传性疾病提供临床依据。方法：对1例锁骨颅骨发育不全综合征患进行临床检查、染色体检查、并对其家族成员进行家系调查。结果：临床确诊锁骨颅骨发育不全综合征，主要临床表现为异常发育的锁骨，囟门的闭合不全，多生牙，身材矮小等一系列骨骼的改变。家系调查被诉怀疑有相关病患发生，染色体检查未见异常。结论：锁骨颅骨发育不全综合征是一种由于常染色体变异所造成的骨骼发育异常。及时正确地诊断该疾病，对于病患的进一步的正畸及修复治疗非常重要。     

家族性颅骨锁骨发育不全综合征患者的临床及影像学特征分析鄢

目的：研究家族性颅骨锁骨发育不全综合征患者的临床及影像学特征,为临床诊断提供依据。方法：对1例家系患者进行颅颌面及全身骨骼检查,拍摄全景片、头颅侧位片、胸部正位片、手及足正位片,分析患者的颅面部及全身骨骼特征。结果：该家族性颅骨锁骨发育不全综合征患者表现为前额突出,面中部发育不足,鼻背塌陷,眼距增宽,食指中节指骨发育不良,远节指骨过短,跖骨轻度弯曲。口内表现为多数乳牙滞留,恒牙迟萌、多生牙、错牙合。结论：分析颅骨锁骨发育不全综合征患者的临床及影像学特征有助于临床医生及时准确的诊断和治疗。     

外胚叶发育不全一家系的基因型分析

目的:分析外胚叶发育不全家系的表型特点和遗传特征,并对家系基因型进行分析。方法:收集1个外胚叶发育不全家系,采用临床检查和家系调查的方法,调查并记录先证者及家系成员的病史和体格检查资料。对家系成员EDAR基因开放阅读框内外显子编码区及外显子-内含子接头区核苷酸序列进行分析。结果:收集到的家系为常染色体显性遗传,患者临床表现典型,家系内表现度差异小。家系成员EDAR基因开放阅读框内未检测到基因突变。结论:本研究收集的外胚叶发育不全家系临床症状明显,致病基因排除EDAR基因。     

颅骨锁骨发育不良综合征患者RUNX2基因突变检测

目的鉴定4个颅骨锁骨发育不良（cleidocranial dysplasia,CCD）家系RUNX2基因突变点。方法采用先证者查证法,对各家系成员进行全身健康状况及口腔专科检查,明确CCD诊断;抽取先证者及其父母外周静脉血,提取基因组DNA,PCR扩增RUNX2基因并测序,BLAST同源分析。结果在4个CCD家系患者中均检测到RUNX2不同的突变位点,家系中健康成员同一位点均为野生型序列,进一步证实RUNX2基因是CCD患者的致病基因。其中家系4的c.475G〉C错义突变是此次检测到的新突变位点;家系2的c.673C〉T以及家系3的c.1171C〉G突变位点在中国CCD患者中首次检出;家系1的c.674G〉A,R225Q是国外文献报道突变率最高的位点。结论本研究拓展了国内外CCD基因层次的研究领域,证实RUNX2基因的单倍体不足是CCD的致病原因。     

一颅锁骨发育不全综合征家族的RUNX2基因分析研究

目的 检测一个颅锁骨发育不全综合征（CCD）家系RUNX2基因突变情况。方法 采用先证者查证法,对CCD家系各成员进行全身健康状况及口腔专科检查,拍摄X线片;抽取先证者及其父母、姐姐外周静脉血,提取基因组DNA,聚合酶链反应（PCR）扩增RUNX2基因并测序,将先证者及其父母、姐姐RUNX2基因测序结果进行Blastn比较分析。结果 在先证者RUNX2基因的外显子2上发现了一个C→T突变,此突变来自母系染色体该基因568位点的基因突变;密码子CGG→TGG引起RUNX2编码的转录因子第190位保守的精氨酸变成色氨酸,突变型为c.568C>T。结论 c.568C>T突变是导致该家系发病的分子基础。     

牙本质发育不全Ⅱ型的遗传异质性研究

目的：明确牙本质涎磷蛋白(dentin sialophosphoprotein，DSPP)是否为该家系的致病基因，并对该家系做进一步的基因定位研究。方法：通过DNA测序方法对DSPP基因进行突变检测，用位于4q21区域的7个微卫星位点对家系进行遗传连锁分析。结果：测序结果显示DSPP在该家系中不存在突变，基因定位研究表明致病基因在该家系位于IMS1534和DSPP之间。结论：DSPP在该家系不是致病基因，牙本质发育不全Ⅱ型存在遗传异质性。     

遗传性牙本质发育不全Ⅱ型DSPP基因新突变

目的分析我国遗传性牙本质发育不全Ⅱ型(dentinogenesisimperfectatypeⅡ,DGI-Ⅱ)患者DSPP基因突变特征,从分子水平探讨DGI-Ⅱ的发病机制。方法抽提2个汉族遗传性牙本质发育不全Ⅱ型家系患者外周静脉血基因组DNA,应用聚合酶链反应及DNA测序技术,结合序列分析方法,对2个家系共13名家庭成员的DSPP基因1～4号外显子及其邻近序列进行突变分析。结果家系A中的患者在DSPP的第4外显子发生Asn164Tyr突变;家系B的患者在DSPP第4外显子发生Cys159Trp突变。结论这两个突变系是国内外尚未报道的新突变。     

无汗性外胚层发育不全患者EDA基因突变检测

目的:检测无汗性外胚层发育不全患者的EDA基因的突变。方法:提取无汗性外胚层发育不全综合症患者的基因组DNA,采用PCR方法扩增EDA基因外显子,直接将PCR产物送测序。结果:该患者EDA基因存在突变:-48位碱基A突变为G。结论:该患者EDA基因存在突变:-48位碱基A突变为G,该突变位点国内外未见报道。     

Evidence of Intrafamilial Variability of CBFA1/RUNX2 Expression in Cleidocranial Dysplasia – a Family Study

AIM: To investigate the phenotypical expression of an identical mutation of the CBFA1/RUNX2 gene within a family with cleidocranial dysplasia. PATIENTS AND METHOD: A five-member family underwent clinical examination. Two members, father and son, showed dissimilar symptoms of cleidocranial dysplasia. The two affected patients were examined for syndrome-typical symptoms, and the genotype was determined by molecular-genetic analysis. RESULTS: In both patients an identical missense mutation (G146R) in exon 2 of the CBFA1/RUNX2 gene was identified. In father and son the dental disturbances were similarly clearly expressed. However, the craniofacial skeleton of the son exhibited fewer dysostotic ossification features than that of the father. In the three clinically healthy family-members no mutation of the CBFA1/RUNX2 gene was found. CONCLUSION: In two patients with cleidocranial dysplasia an identical missense mutation in the CBFA1/RUNX2 gene leading to a divergent craniofacial phenotype was determined. The results indicate marked variability in the phenotypical expression of CBFA1/RUNX2 mutations.     

Identification of a stop codon mutation in the CBFA1 runt domain from a patient with cleidocranial dysplasia and cleft lip

We examined a patient with cleidocranial dysplasia (CCD) and cleft lip and found a new stop codon mutation in CBFA1. This mutation was a heterozygous C-to-T transition in exon 3 of CBFA1. This nucleotide change converts a CAA codon to a TAA (stop) codon at amino acid position Gln195 in the runt domain of CBFA1.     

Orthodontic and oral surgery therapy in cleidocranial dysplasia

A cleidocranial dysplasia is an autosomal dominant inherited condition consisting of generalized skeletal disorder. Associated dental signs are present in 93,5%; failure of tooth eruption with multiple supernumerary teeth, dilaceration of roots, crown germination, microdontia, high arched palate, midface hypoplasia, high gonion angle. The molecular- genetic analysis revealed a missense mutation in the CBFA1 gene located on chromosome 6p21, which is considered to be etiological factor for CCD. Orthodontic and oral surgery therapy of a 13 year-old child with CCD was performed due to aesthetic and functional problems. The supernumerary germs were removed and the teeth were aligned with orthodontic appliances. Temporary functional rehabilitation was solved with partial denture. The presented case and the literature data support the importance of early diagnosis of CCD. The good collaboration of the orthodontic and maxillo-facial surgery specialists help achieve the correct rehabilitation of the patient.     

Atypical expression of cleidocranial dysplasia: clinical and molecular-genetic analysis

Cleidocranial dysplasia (CCD) and the Rubinstein-Taybi syndrome (RTS) are two rare congenital syndromes that have many clinical signs in common. We present an 18-year-old-patient with untypical CCD expression who was misdiagnosed with RTS at the age of 2 years. An extensive craniofacial examination was carried out with respect to morphological and dental aspects. The molecular-genetic analysis of two underlying genes (CBFA1 and CBP) for CCD and RTS was performed using SSCP, direct sequencing and FISH. While the clinical examination showed uncharacteristic CCD symptoms with some findings common for RTS, the molecular-genetic analysis revealed a missense mutation in the CBFA1 gene, which is considered to be the etiological factor for CCD. Our findings with this patient presented clear evidence for the wide morphologic variety that can be related to a certain gene such as CBFA1. The diagnosis of rare diseases is currently based on the clinical phenomenology of small groups or single cases. The use of molecular-genetic biology extends the horizon of diagnostic and scientific possibilities. In this patient, it allowed us to compare the clinically diagnosis to molecular-genetic data. We conclude that molecular-genetic analysis may be a helpful tool in the differential diagnosis of many congenital diseases such as CCD and RTS.     

Delayed tooth eruption and suppressed osteoclast number in the eruption pathway of heterozygous Runx2/Cbfa1 knockout mice

Genetic studies have recently identified a mutation of one allele of runt-related gene 2 (RUNX2/CBFA1) as the cause for an autosomal-dominant skeletal disorder, cleidocranial dysplasia (CCD), which is characterised by hypoplasia of the clavicles and calvariae and widened sutures and fontanelles. In addition, CCD is frequently affected with multiple supernumerary teeth and the impaction and delayed eruption of teeth, the causes of all these dental abnormalities are still unknown. To clarify the cellular mechanism of the delayed tooth eruption in CCD, the process of tooth eruption was examined in heterozygous Runx2/Cbfa1 (mouse homolog of RUNX2/CBFA1) knockout mice, known to mimic most of the bone abnormalities of CCD. The timing of the appearance of maxillary and mandibular teeth into the oral cavity was significantly delayed in heterozygous mutant mice compared with wild-type mice. From postnatal days 8 to 10, an active alveolar bone resorption and a marked increase of the osteoclast surfaces was observed in the eruption pathway of both genotypes, but this increase was significantly suppressed in the mutant mice. In contrast, the osteoclast surfaces did not show a significant difference between the two genotypes in the future cortical area of femora. These results suggest that haploinsufficiency of Runx2/Cbfa1 does not effect the femoral bone remodelling but is insufficient for the active alveolar bone resorption essential for the prompt timing of tooth eruption. These results also suggest the possibility that impaired recruitment of osteoclasts is one of the cellular mechanisms of delayed tooth eruption in CCD patients.