Novel IRF6 mutations in Chinese patients with Van der Woude syndrome

Van der Woude syndrome (VWS) (OMIM 119300) is a dominantly inherited, developmental disorder that is characterized by pits and/or sinuses of the lower lip and a cleft lip and/or cleft palate. Mutations in the interferon regulatory factor 6 gene (IRF6) have been recently identified in patients with VWS, with more than 60 mutations reported. However, the VWS phenotype, IRF6 mutation genotypes, and their interrelationships in Chinese VWS patients have not been studied. Here, we report 11 Chinese families with variable clinical phenotypes of VWS and identified mutations in all patients. Of the 11 mutations, 8 appeared to be novel: CC5.6GT, T342A, 566delA, C748T, C756A, C989A, C1209G, and 1316delT. Seven mutations caused a change or loss of the IRF6 domain. The marked phenotypic variation may be caused by the action of certain modifier genes on IRF6 function.     

Familial non-syndromic cleft lip and palate--analysis of the IRF6 gene and clinical phenotypes

The aim of this study was to characterize Swedish families with non-syndromic cleft lip and/or palate (NSCL/P) for mutations or other sequence variants in the interferon regulatory factor 6 (IRF6) gene, as well as to describe their cleft phenotypes and hypodontia. Seventeen Swedish families with at least two family members with NSCL/P were identified and clinically evaluated. Extracted DNA from blood samples was used for IRF6 mutation screening. Exonic fragments of the IRF6 gene were sequenced and chromatograms were inspected. Statistical analysis was undertaken with marker- and haplotype association tests. No disease-associated IRF6 mutation could be determined in the families analyzed. One new and seven known single nucleotide polymorphisms (SNPs) were detected. The A allele of SNP rs861019 in exon 2 and the G allele of SNP rs7552506 in intron 3 showed association with cleft lip and palate (CLP; odds ratios of 3.1 and 5.45, respectively). Hypodontia was observed more commonly in individuals affected with CL/P as compared with family members without a cleft (P < 0.01). The hypodontia most often affected the cleft area, possibly representing a secondary effect. The distribution of cleft phenotypes in 15 of the 17 families with NSCL/P differed from the mixed cleft types seen in Van der Woude syndrome (VWS), in that CLP did not occur together with an isolated cleft palate within the same family. It was concluded that mutations of the IRF6 gene are not a common cause for cleft predisposition in Swedish NSCL/P families.     

Van der Woude syndrome: dentofacial features and implications for clinical practice

Background:  Van der Woude syndrome (VWS) is the most common clefting syndrome in humans. It is characterized by the association of congenital lower lip fistulae with cleft lip and/or cleft palate. VWS individuals have a high prevalence of hypodontia. Although caused by a single gene mutation, VWS has variable phenotypic expression. This study aimed to describe the range of clinical presentations in 22 individuals with VWS to facilitate its diagnosis.
Methods:  A retrospective study of 22 patients with a diagnosis of VWS was undertaken at the Australian Craniofacial Unit (ACFU) in Adelaide. Three extended families with affected members were included in the study cohort.
Results:  The overall prevalence of lip pits in this study cohort was 86%. Cleft phenotypes included bilateral cleft lip and palate (32%); unilateral cleft lip and palate (32%); submucous cleft palate (23%); and isolated cleft hard and soft palate (9%). Missing permanent teeth were reported in 86% of affected individuals.
Conclusions:  Submucous cleft palate in VWS may go undiagnosed if the lower lip pits are not detected. Associated hypodontia and resultant malocclusions will also require management by a dental team.     

干扰素调节因子6基因致病的Van der Woude综合征的家系调查和遗传特点分析

目的 探讨中国人Van der Woude综合征（VWS）的临床表型及遗传学特点。方法 先证者法收集14个VWS家系并进行口腔专科检查、家系调查及基因突变分析,分析不同VWS家系个体或同一家系不同个体的临床表型,绘制家系图谱,明确遗传方式及致病基因,计算表型分布频率和表型基因频率。结果 VWS家系基本符合常染色体显性遗传特征,患者多数表现为典型的VWS,致病基因为干扰素调节因子6（IRF6）。VWS表型分布频率为：唇瘘91.9%,唇腭裂73.0%,牙畸形8.1%。不同家系个体和同一家系的不同个体临床表型存在明显差异。结论 收集的家系均为常染色体显性遗传,表现度变异大。中国人群VWS致病基因为IRF6,为Ⅰ型VWS。     

一个范德伍德综合征家系的IRF6基因突变检测

目的:对收集的1个湖北Van der Woude综合征(VWS)家系进行临床和遗传特点分析,并进行IRF6基因的突变检测。方法:通过先证者及现场家系调查、临床检查和系谱分析收集VWS家系。在IRF6基因的外显子-内含子接头及9个外显子编码区分别设计引物,经聚合酶链式反应扩增并纯化后直接测序。结果:收集的VWS家系符合常染色体显性遗传特征,家系受累患者共3名(1名男性和2名女性),患者表现为典型的下唇瘘管或凹陷,且合并有唇腭裂和先天缺牙。患者表型在同一家系内有明显差异,且呈逐代加重趋势。在所有患者IRF6基因第412位密码子发现与表型一致的CGA>TGA(c.1234C>T)改变,经查证为一个已知的无义突变。结论:该VWS家系疾病表现度极不一致,是由IRF6基因的1个已知无义突变导致,IRF6是参与颌面部发育的重要基因。     

1个河南van Der Woude综合征家系IRF6基因的突变检测

目的:对1个河南省vanDerWoude综合征(VWS)家系进行IRF6基因的突变检测。方法:在IRF6(interferonregulatoryfactor6)基因内设计引物,经分段PCR(聚合酶链反应)和DNA测序,进行突变检测,运用PIX-ProteinIdentification软件对检测结果进行蛋白二级结构分析。结果:在该家系所有患者IRF6基因的第6密码子,均发现与表型一致的CGC>TGC(r.279c→t)突变,该突变引起IRF6蛋白二级预测结构的改变。结论:vanDerWoude综合征由IRF6基因突变引起,IRF6基因与唇、腭、牙的发育密切相关。     

中国人群非综合征性唇腭裂患者IRF6基因突变检测

目的 探讨干扰素调节因子6(interferon regulatory factor 6, IRF6) 在非综合征性唇腭裂(non-sydromic cleft lip and/or cleft palate,NSCL/P)患者中的突变情况。方法：收集119例NSCL/P患者及288名健康人对照样本的外周血血样并提取DNA。在IRF6基因的全部外显子分别设计引物,PCR扩增其序列,通过测序找出IRF6基因突变,并将这些突变在对照样本中进行验证。结果：共发现5种在正常人中没有的突变,其中4种是新发现的突变。结论：IRF6基因突变在中国人群中参与了非综合征唇腭裂疾病的发生。     

Congenital lower lip pits (Van der Woude syndrome): report of a case

Van der Woude syndrome (VWS) is a rare autosomal dominant disorder that is characterized by a cleft lip and palate with congenital lip pits. This is a report of a case of VWS with sinuses in the lower lip, a cleft in the upper lip, and a supernumerary tooth in the maxilla. The main characteristics of this disorder are discussed. Dental treatment of the patient was performed, but the surgical removal of the sinus was rejected by the parents. This case report brings this condition to the attention of dentists and surgeons and emphasizes lip pits may not always be identical in appearance.     

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。     

Clinical and genetic studies of Van der Woude syndrome in Sweden.

Van der Woude syndrome (VWS) is an autosomal dominant craniofacial disorder characterized by pits of the lower lip, hypodontia and cleft lip and/or cleft palate. It has been reported as the most common form of syndromic orofacial clefting with very high penetrance and varied expressivity. The disease locus for VWS has been mapped to chomosome 1q32, but the gene is yet to be cloned. Here we report a total of 11 Swedish VWS patients: 9 familial cases from two families and two isolated cases. Clinical examination of these patients showed phenotypic variability, even between patients from the same family. Genetic studies were performed using four microsatellite markers from chromosome 1q32. Constitutional deletion in this region was not demonstrated in any of the familial or isolated cases. However, in the two VWS families, linkage analysis using these markers showed positive LOD (logarithm of the odds) scores ranging from 2.56 to 2.88 to all individual markers. The highest LOD score of 3.75 was obtained with the combined haplotypes of D1S491 and D1S205, thus confirming linkage of VWS in these two families to 1q32. We conclude that there is varied expressivity but no evidence of genetic heterogeneity in VWS.     

A novel missense mutation in Van der Woude syndrome: usefulness of fingernail DNA for genetic analysis

Van der Woude syndrome (VWS) is an autosomal-dominant oral facial disorder. To find a gene mutation in a Japanese family using fingernail DNA samples, we performed this study. We hypothesized that a gene mutation in IRF6 might be involved in VWS, and that fingernail DNA samples may be valuable for detecting such mutations. Linkage and haplotype analyses of the family mapped the disease locus to the 1q32-q41 region. Mutation analysis with an improved extraction method for fingernail DNA detected a novel missense mutation (1046A>T, E349V) in exon 7 of IRF6 in all the affected members of the family. Since the E349V change may disturb the hydrophobic core and affect regulatory activity of IRF6, it is most likely that the mutation is causative for VWS in this family. Fingernail DNA is thus useful for linkage and mutation analyses, since the fingernail can be easily obtained non-invasively, sent through the mail, and stored for a long period. We emphasize here the usefulness of fingernail DNA for the genetic analysis of a disease.     

Congenital lip pits and facial clefts

Two families with congenital lower lip pits in association with cleft lip and palate, and isolated cleft palate are described. The presentation, mode of inheritance, aetiology, treatment and genetic significance are reviewed.     

Unraveling human cleft lip and palate research

The focus of this work is to highlight the most recent advances in the understanding of cleft lip and palate occurrence. Information regarding research on long-term outcomes, genes and their interactions with other genes, and gene-environment interactions is compiled to provide the reader with a critical and up-to-date overview on the current knowledge of the etiology of cleft lip and palate. Recent epidemiological evidence strongly suggests that individuals born with clefts have a shorter lifespan and may have a higher incidence of cancer and psychological disorders. IRF6 has been shown to be an important contributor to cleft lip and palate, but the functional variant leading to the defect has not yet been defined. Inactivation of MSX1 and genes in the FGF family has also been shown to lead to cleft lip and palate. In addition, missense mutations in several candidate genes may cause cleft lip and palate, but definitive evidence regarding the biological consequences of these mutations is yet to be unraveled. Maternal cigarette smoking increases the risk of a baby born with clefts, in particular when the mother carries the GSTT1-null variants. The latest approaches in cleft research include the analysis of several additional phenotypical features of the population, with the goal of increasing the statistical power of genetics studies.     

福建范德伍兹综合征1例家系IRF6基因突变的检测

目的检测福建省一范德伍兹综合征(VWS)家系IRF6基因的突变。方法在IRF6(interferonregulatoryfactor6)基因内设计引物,经分段聚合酶链反应(PCR)和DNA测序进行突变检测,运用PIX-ProteinIdentification软件对检测结果进行蛋白二级结构分析。结果在所有患者IRF6基因的第379密码子发现TGG>TGA(r.1400g→a)的碱基变化,该突变引入终止码,引起IRF6蛋白转录提前终止。结论范德伍兹综合征由IRF6基因突变引起,IRF6基因与唇腭、牙齿发育密切相关。     

Van der Woude syndrome: a case report

Among the many disturbances of development and growth that involve the oral and perioral structures, cleft lip and palate is perhaps the commonest. Dental literature is replete with syndromes associated with cleft lip and palate, one of which is Van der Woude syndrome. The characteristics of Van der Woude syndrome is the association of cleft lip and/or palate with distinctive lower lip pits. A case of Van der Woude syndrome in an 11-year-old boy and his sister is presented.     

Popliteal pterygium syndrome in a Swedish family-clinical findings and genetic analysis with the van der Woude syndrome locus at 1q32-q41

The present study describes a Swedish family in which the mother and her son were affected with signs of popliteal pterygium syndrome (PPS, OMIM 119500). Both individuals had bilateral complete cleft lip and palate, oral synechiae, paramedian pits on the lower lip, toe syndactyly and a piece of triangular skin overgrowth on the great toes. The son also presented with soft tissue syndactyly of the 2nd and 3rd fingers. Although popliteal pterygium was not found, the above clinical features were diagnostic for PPS. Chromosomal abnormalities were not revealed in either case by cytogenetic analyses. A test for microdeletion in the VWS region at 1q32-q41 was performed in the family using 5 polymorphic microsatellite markers from the region. The affected son was found to be heterozygous for all 5 markers, suggesting that microdeletion at the VWS region was unlikely. The VWS locus, however, was not excluded by haplotype analysis of the family.     

Popliteal pterygium syndrome in a Swedish family--clinical findings and genetic analysis with the van der Woude syndrome locus at 1q32-q41

The present study describes a Swedish family in which the mother and her son were affected with signs of popliteal pterygium syndrome (PPS, OMIM 119500). Both individuals had bilateral complete cleft lip and palate, oral synechiae, paramedian pits on the lower lip, toe syndactyly and a piece of triangular skin overgrowth on the great toes. The son also presented with soft tissue syndactyly of the 2nd and 3rd fingers. Although popliteal pterygium was not found, the above clinical features were diagnostic for PPS. Chromosomal abnormalities were not revealed in either case by cytogenetic analyses. A test for microdeletion in the VWS region at 1q32-q41 was performed in the family using 5 polymorphic microsatellite markers from the region. The affected son was found to be heterozygous for all 5 markers, suggesting that microdeletion at the VWS region was unlikely. The VWS locus, however, was not excluded by haplotype analysis of the family.     

Congenital lip pits and van der Woude syndrome

Van der Woude syndrome is an autosomal dominant disease characterized by lower lip pits with or without cleft lip and/or cleft palate. The lip pits commonly have salivary glands that drain into them, which leads to salivary flow from the lip pits. Lip pits may be associated with submucosal palatal cleft, velopharyngeal insufficiency, or genitourinary or cardiovascular anomalies. The pits are treated by surgical resection. The authors report a case of van der Woude syndrome with isolated lip pits and speech difficulties that had been unrecognized until the patient was 6 years old. The surgical technique is described to ensure that the often-bifurcating tracts are removed entirely.     

Van der Woude syndrome: clinical presentation in 64 patients.

OBJECTIVE: Van der Woude syndrome, characterized by lip pits and cleft lip/ palate, presents with variable expressions. This retrospective study was designed to obtain a better understanding of its clinical pattern in Taiwanese patients. MATERIALS AND METHODS: Of 13,147 cleft patients treated at the Chang Gung Craniofacial Center from 1976 to 2004, there were 64 with Van der Woude syndrome. Clinical expressions and family histories were collected and analyzed. RESULTS: The male to female ratio was 1:1. The majority had complete cleft types. Severe cleft was found among the patients, with 52% having bilateral cleft lip and palate, 31% having unilateral cleft lip and palate, and 17% having isolated cleft palate. A positive family history was found in 53.1% of the patients. The size, shape, location, and depth of the pits varied among patients. CONCLUSION: Clinical presentations did not always parallel those reported in the literatures. These differences warrant further investigation.     

Van der Woude syndrome: a report of two cases

Van der Woude syndrome is a rare autosomal dominant condition with high penetrance and variable expression. It consists of a cleft lip and/or palate pits on the vermilion of the lower lip, and hypodontia. Two cases of congenital lip pits with cleft lip and alveolus and an isolated cleft palate are described to illustrate the variable presentation of the clinical features and the importance of early recognition of Van der Woude syndrome because of the genetic implications.