Agneta Karsten

Dominant Mutations in GRHL3 Cause Van der Woude Syndrome and Disrupt Oral Periderm Development

Mutations in interferon regulatory factor 6 (IRF6) account for ∼70% of cases of Van der Woude syndrome (VWS), the most common syndromic form of cleft lip and palate. In 8 of 45 VWS-affected families lacking a mutation in IRF6, we found coding mutations in grainyhead-like 3 (GRHL3). According to a zebrafish-based assay, the disease-associated GRHL3 mutations abrogated periderm development and were consistent with a dominant-negative effect, in contrast to haploinsufficiency seen in most VWS cases caused by IRF6 mutations. In mouse, all embryos lacking Grhl3 exhibited abnormal oral periderm and 17% developed a cleft palate. Analysis of the oral phenotype of double heterozygote (Irf6(+/-);Grhl3(+/-)) murine embryos failed to detect epistasis between the two genes, suggesting that they function in separate but convergent pathways during palatogenesis. Taken together, our data demonstrated that mutations in two genes, IRF6 and GRHL3, can lead to nearly identical phenotypes of orofacial cleft. They supported the hypotheses that both genes are essential for the presence of a functional oral periderm and that failure of this process contributes to VWS.

Mapping of the second locus for the Van der Woude syndrome to chromosome 1p34

The Van der Woude syndrome (VWS) is a dominantly inherited developmental disorder characterized by pits and/or sinuses of the lower lip, cleft lip and/or cleft palate. It is the most common cleft syndrome. VWS has shown remarkable genetic homogeneity in all populations, and so far, all families reported have been linked to 1q32-q41. A large Finnish pedigree with VWS was recently found to be unlinked to 1q32-q41. In order to map the disease locus in this family, a genome wide linkage scan was performed. A maximum lod score of 3.18 was obtained with the marker D1S2797, thus assigning the disease locus to chromosomal region 1p34. By analyses of meiotic recombinants an ∼30 cM region of shared haplotypes was identified. The results confirm the heterogeneity of the VWS syndrome, and they place the second disease locus in 1p34. This finding has a special interest because the phenotype in VWS closely resembles the phenotype in non-syndromic forms of cleft lip and palate.

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.

Dental Occlusion After Veau-Wardill-Kilner Versus Minimal Incision Technique Repair of Isolated Clefts of the Hard and Soft Palate

OBJECTIVE To compare the Veau-Wardill-Kilner technique with a technique similar to the minimal incision technique described by Mendosa et al. on the basis of surgical complications and dentoalveolar status in the deciduous dentition. DESIGN Retrospective study of medical and dental records and casts. PATIENTS A consecutive series of 129 Caucasian children born with isolated cleft palate between 1980 and 1992. MAIN OUTCOME MEASURES From medical records, the variables of time for surgery, blood loss, complications in the immediate postoperative period, and frequency of fistulas were evaluated. On dental casts, the variables of sagittal, transversal, and vertical relations; structure of the palatal mucosa; and height of the palatal vault were studied. RESULTS Time for surgery was shorter in the extensive clefts repaired with a Veau-Wardill-Kilner technique. Blood loss was higher using the Veau-Wardill-Kilner technique. The width of the upper jaw was significantly narrower in the Veau-Wardill-Kilner group, compared with the minimal incision group. Scar tissue and pits of the palate were more frequently found in the Veau-Wardill-Kilner group. CONCLUSIONS The minimal incision technique in this study has been shown to result in better development of the upper jaw with a better dental occlusion and palatal mucosa with significantly less scar tissue.

Linkage Analysis of Candidate Regions in Swedish Nonsyndromic Cleft Lip with or without Cleft Palate Families

OBJECTIVE To analyze linkage of five candidate regions for nonsyndromic cleft lip with or without palate (CLP) on chromosome 2p13, 4q, 6p23, and 19q13; in addition chromosome 1q32, the locus for van der Woude syndrome, on Swedish CLP families. DESIGN Three to five linked microsatellite markers were selected from each candidate region. Polymerase chain reaction (PCR) with fluorescent-labeled microsatellite markers was performed on DNA samples from the participating families. Electrophoresis of the PCR products was performed on a laser-fluorescent DNA sequencer. The genotype data were analyzed with multipoint linkage analysis. Modes of inheritance tested included two autosomal dominant, an autosomal recessive, and a nonparametric model. Multipoint logarithm of odds (LOD) scores were also calculated by assuming genetic heterogeneity. PARTICIPANTS Nineteen Swedish multigenerational families with at least two first-degree relatives affected with CLP. Greater than 50% of the families studied show vertical transmission of the clefting phenotype and both inter- and intrafamilial variability were noted. RESULTS Cumulative multipoint LOD scores for the whole group of families calculated under autosomal dominant modes of inheritance were negative in all regions and less than -2 except chromosome 6p23. LOD scores calculated under recessive inheritance and the nonparametric model were inconclusive. There was no significant evidence of genetic heterogeneity among the sample group. CONCLUSIONS The group of Swedish CLP families did not demonstrate significant linkage to any of the five candidate regions examined. This might suggest a new but yet unknown CLP locus or loci in this family group. However, because linkage could not be excluded in some individual families, they should still be tested with candidate genes from these regions.

Novel and de novo mutations of the IRF6 gene detected in patients with Van der Woude or popliteal pterygium syndrome

The interferon regulatory factor 6 gene (IRF6) has been identified as the major Van der Woude (VWS) syndrome and popliteal pterygium (PPS) syndrome gene with mutations in the majority of the kindreds. We have studied altogether 17 kindreds from Sweden, Finland, Norway, Thailand and Singapore, and report here 10 mutations, six of them previously unseen. In two kindreds, we could document de novo mutations, both of them changing a codon for a glutamine residue to a stop. No mutation could be detected in the four VWS kindreds from Finland, suggesting a founder effect for a mutation in an atypical noncoding position. Our findings demonstrate that several distinct mutations occur in the Swedish population, and confirm the general notion of a broad spectrum of IRF6 mutations underlying the VWS/PPS phenotypes.

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.

Association and Mutation Analyses of the IRF6 Gene in Families With Nonsyndromic and Syndromic Cleft Lip and/or Cleft Palate

Objectives (1) To detect interferon regulatory factor 6 gene (IRF6) mutations in newly recruited Van der Woude syndrome (VWS) and popliteal pterygium syndrome (PPS) families. (2) To test for association, in nonsyndromic cleft lip and/or cleft palate (NSCL/P) and in VWS/PPS families, the single nucleotide polymorphism (SNP) rs642961, from the IRF6 enhancer AP-2α region, alone or as haplotype with rs2235371, a coding SNP (Val274Ile). Design IRF6 mutation screening was performed by direct sequencing and genotyping of rs642961 and rs2235371 by TaqMan technology. Patients Seventy-one Swedish NSCL/P families, 24 Finnish cleft palate (CP) families, and 24 VWS/PPS families (seven newly recruited) were studied. Results Allelic and genotypic frequencies in each phenotype were compared to those of the controls, and no significant difference could be observed. IRF6 gene mutation was detected in six of the seven new VWS/PPS families. Association analysis of the entire VWS/PPS sample set revealed the A allele from rs642961 to be a risk allele. Significant association was detected in the Swedish CP subset of our NSCL/P collection where the G-C haplotype for rs642961-rs2235371 were at risk (P= .013). Conclusions Our results do not support the previously reported association between the A allele of rs642961 and the NSCL phenotype. However, in the VWS/PPS families, the A allele was a risk allele and was, in a large majority (>80%), transmitted on the same chromosome as the IRF6 mutation.

Scandcleft randomised trials of primary surgery for unilateral cleft lip and palate: 1. Planning and management

Abstract Background and aims: Longstanding uncertainty surrounds the selection of surgical protocols for the closure of unilateral cleft lip and palate, and randomised trials have only rarely been performed. This paper is an introduction to three randomised trials of primary surgery for children born with complete unilateral cleft lip and palate (UCLP). It presents the protocol developed for the trials in CONSORT format, and describes the management structure that was developed to achieve the long-term engagement and commitment required to complete the project. Method: Ten established national or regional cleft centres participated. Lip and soft palate closure at 3–4 months, and hard palate closure at 12 months served as a common method in each trial. Trial 1 compared this with hard palate closure at 36 months. Trial 2 compared it with lip closure at 3–4 months and hard and soft palate closure at 12 months. Trial 3 compared it with lip and hard palate closure at 3–4 months and soft palate closure at 12 months. The primary outcomes were speech and dentofacial development, with a series of perioperative and longer-term secondary outcomes. Results: Recruitment of 448 infants took place over a 9-year period, with 99.8% subsequent retention at 5 years. Conclusion: The series of reports that follow this introductory paper include comparisons at age 5 of surgical outcomes, speech outcomes, measures of dentofacial development and appearance, and parental satisfaction. The outcomes recorded and the numbers analysed for each outcome and time point are described in the series. Trial registration: ISRCTN29932826.

A comparison of hand-tracing and cephalometric analysis computer programs with and without advanced features—accuracy and time demands

The aim of this study was to evaluate the basic and advanced features of five different cephalometric analysis computer programs. The level of measurement agreement with hand-tracing and time demands was examined. The material consisted of 30 digital lateral radiographic images. Twenty-three measurements were calculated by one operator both manually and using five different cephalometric analysis software programs. Intraclass correlation coefficient (ICC) was used to detect differences in measurement agreement between hand-tracing and basic features as well as between hand-tracing and advanced features. Coefficient of variation (CV) was used to assess intra-user error and a Students t-test to determine time differences. Of the 23 measurements tested for each procedure, one [(Ii to NB (mm)] showed better agreement with hand-tracing when the advanced features were used, 20 showed good agreement with hand-tracing for both basic and advanced features, while two (AB on FOP and Ii to A/Pog) showed poor intra-user reproducibility. Hand-tracing took a significantly longer time (P < 0.001) than both the basic and advanced features. The advanced features took a significantly longer time (P < 0.001) than the basic features. Both basic and advanced features showed good measurement agreement with the hand-tracing technique. The use of the basic features minimizes the time requirements for analysis. A computerized tracing technique, which consists of either basic or advanced feature, can be regarded as less time consuming and equally reliable to hand-tracing as far as cephalometric measurements are concerned.