Van der Woude syndrome with novel variants: a case series.

Prevalence and nonrandom distribution of exonic mutations in interferon regulatory factor 6 in 307 families with Van der Woude syndrome and 37 families with popliteal pterygium syndrome

Van der Woude syndrome (VWS) is a genetic syndrome that leads to typical phenotypic traits, including lower lip pits and cleft lip/palate (CLP). The majority of VWS-affected patients harbor a pathogenic variant in the gene encoding for the transcription factor interferon regulatory factor 6 (IRF6), a crucial regulator of orofacial development, epidermal differentiation and tissue repair. However, most of the underlying mechanisms leading from pathogenic IRF6 gene variants to phenotypes observed in VWS remain poorly understood and elusive. The availability of one VWS individual within our cohort of CLP patients allowed us to identify a novel VWS-causing IRF6 variant and to functionally characterize it. Using VWS patient-derived keratinocytes, we reveal that most of the mutated IRF6_VWS transcripts are subject to a non-sense-mediated mRNA decay mechanism, resulting in IRF6 haploinsufficiency. While moderate levels of IRF6_VWS remain detectable in the VWS keratinocytes, our data illustrate that the IRF6_VWS protein, which lacks part of its protein-binding domain and its whole C-terminus, is noticeably less stable than its wild-type counterpart. Still, it maintains transcription factor function. As we report and characterize a so far undescribed VWS-causing IRF6 variant, our results shed light on the physiological as well as pathological role of IRF6 in keratinocytes. This acquired knowledge is essential for a better understanding of the molecular mechanisms leading to VWS and CLP.

Cognitive dysfunction in adults with Van der Woude syndrome

Van der Woude Syndrome (VWS) is an autosomal dominant condition characterized by a cleft lip and/or palate along with pits on the lower lip. These pits are associated with salivary glands, leading to clinical manifestations such as secretions and, in some cases, infections, which may influence the surgical approach. The goal of treatment is to improve cosmetic appearance and to repair the pits, thereby preventing recurrent infections. This study aims to emphasize the prevalence and significance of this syndrome among individuals with cleft lip and/or palate. In this study, the frequency and epidemiological characteristics of VWS among patients with cleft lip and/or palate were examined through a single-center retrospective analysis conducted between 2016 and 2021. A total of 1633 patients were included in this study, of whom 21 were identified as having VWS. The prevalence of VWS among patients with cleft lip and/or palate was found to be 1.3%. The average number of surgeries was 2.1 for patients without VWS and 2.8 for VWS patients. The female-to-male ratio among VWS patients was 1.6. The most common associated condition was bilateral cleft lip and palate. Secondary lip surgeries were more frequent in patients with VWS than without VWS. Since the repair of the pits on the lip is also necessary in VWS, surgical treatment is more complex compared with patients with cleft lip and palate alone. Achieving satisfactory functional and cosmetic outcomes in patients with Van der Woude Syndrome requires more surgical interventions than in patients without VWS.

Van der Woude syndrome (VWS) is an autosomal dominant disorder manifested in cleft lip and/or palate and lip pits. Isolated clefts of the lip and/or palate (ICLP) have both genotype and phenotype overlap with VWS. Subjects with ICLP have abnormalities in brain structure and function. Given the similarities between VWS and ICLP, the current study was designed to evaluate the pattern of brain structure of adults with VWS. Fourteen adults with VWS were compared to age- and gender-matched healthy controls. Brain structure was evaluated using magnetic resonance imaging. All subjects with VWS had enlarged volumes of the anterior regions of the cerebrum. Men with VWS had reduced volumes of the posterior cerebrum. Anterior cerebrum volume was negatively correlated with intelligent quotient in the subjects with VWS indicating that the enlargement of this brain region was 'pathologic.' The pattern of brain structure in VWS is nearly identical to those seen in ICLP. In addition, men are affected more severely. Pathologic enlargement of the tissue and a gender effect with men affected more severely are common features of neurodevelopmental disorders supporting the notion that the brain structure of VWS and ICLP may be because of abnormal brain development.

Van der Woude syndrome (VWS) is a common form of syndromic cleft lip and palate and accounts for approximately 2% of all cleft lip and palate cases. Distinguishing characteristics include cleft lip with or without cleft palate, isolated cleft palate, bilateral lip pits, hypodontia, normal intelligence, and an autosomal-dominant mode of transmission with a high degree of penetrance. Previously, the VWS locus was mapped to a 1.6-cM region in 1q32-q41 between D1S491 and D1S205, and a 4.4-Mb contig of YAC clones of this region was constructed. In the current investigation, gene-based and anonymous STSs were developed from the existing physical map and were then used to construct a contig of sequence-ready bacterial clones across the entire VWS critical region. All STSs and BAC clones were shared with the Sanger Centre, which developed a contig of PAC clones over the same region. A subset of 11 clones from both contigs was selected for high-throughput sequence analysis across the approximately 1.1-Mb region; all but two of these clones have been sequenced completely. Over 900 kb of genomic sequence, including the 350-kb VWS critical region, were analyzed and revealed novel polymorphisms, including an 8-kb deletion/insertion, and revealed 4 known genes, 11 novel genes, 9 putative genes, and 3 psuedogenes. The positional candidates LAMB3, G0S2, HIRF6, and HSD11 were excluded as the VWS gene by mutation analysis. A preliminary gene map for the VWS critical region is as follows: [see text] 41-TEL. The data provided here will help lead to the identification of the VWS gene, and this study provides a model for how laboratories that have a regional interest in the human genome can contribute to the sequencing efforts of the entire human genome.

Van der Woude syndrome (VWS) is an autosomal dominant disorder associated with one or more of the following features: clefting of the primary or secondary palate, hypodontia or lower lip pits. It has been estimated to account for 2% of all cases of cleft lip and palate. VWS is one of the rare disorders in which clefting of the primary and secondary palate may be seen to segregate as components associated with the same gene. Because of its autosomal dominant inheritance, VWS is readily accessable to linkage analysis as a preliminary step in the identification of the molecular abnormality underlying the clefting effect in the primary and secondary palate. A reported linkage between REN and VWS has promoted us to use pHRnX3.6 (REN) and several markers surrounding REN for a linkage analysis in a large Swiss family. In a second step, linkage analysis was performed to study restriction fragment length polymorphisms for the candidate gene TGFB2 and other loci recently mapped to the candidate region 1q32-1q41. Evidence for linkage (theta = 0.00, lod score = 3.01) between REN and VWS could be confirmed in this pedigree. TGFB2 demonstrated recombination with the disease locus and is unlikely to be causative in VWS. The results of a multipoint linkage analysis showed that VWS was flanked by D1S65 and TGFB2 at a maximum location score of 20.3.

<p>Orofacial clefts are a heterogeneous group of craniofacial malformations that affect the lip and/or palate and represent the most common craniofacial birth defect in humans. In 30% of patients the cleft is accompanied by additional physical or cognitive abnormalities. Hundreds of these clefting syndromes have been described, many of which have Mendelian inheritance patterns. The most common of these is Van der Woude syndrome (VWS), caused by mutations in the transcription factor <em>IRF6</em> (Kondo et al. 2002). The other 70% of patients lack additional features and are considered nonsyndromic. The etiology of nonsyndromic clefts is complex and involves the combined action of multiple genetic variants interacting with environmental factors.</p> <p>A common approach for identifying genetic risk factor for complex disorders such as nonsyndromic cleft lip with or without cleft palate (NSCL/P) is the genome wide association study (GWAS). We pursued a locus on 1p22 shown to be associated with NSCL/P by Beaty et al. (2010). Through a combination of expression studies in a mouse model and mutation screening in NSCL/P patients, we identified <em>ARHGAP29</em> as a novel gene for NSCL/P and the likely etiologic gene at this locus. We identified eight rare variants in NSCL/P patients absent in controls including a nonsense and a frameshift mutation. These rare variants are reminiscent of previous resequencing studies that reported rare coding mutations in 20 different candidate genes for NSCL/P. We reviewed these variants and compared them with variants found in over 7000 exomes from the 1000 Genomes Project (1kGP) and NHLBI Exome Sequencing Project (ESP) to identify the variants and genes most likely to contain etiologic rare variants. We found good support for a role for rare variants in NSCL/P, particularly for <em>MSX1</em> and genes of the FGF signaling pathway.</p> <p>We next performed several studies to understand the genetic architecture of syndromic forms of clefting, focusing on VWS and popliteal pterygium syndrome (PPS), which is allelic to VWS. We compiled all of the nearly 300 published <em>IRF6</em> mutations and compared the distribution of these mutations with IRF6 variants obtained from the 1kGP and ESP exomes. We found that mutations causing VWS were significantly over-represented in the DNA-binding domain and for the most part were absent from control exomes, indicating that they are likely to be truly causative for VWS or PPS. These mutations in VWS and PPS only account for 70% of VWS and 97% of PPS. We next hypothesized that mutations in <em>RIPK4</em>, which causes an autosomal recessive pterygia syndrome, could underlie the remaining VWS and/or PPS cases. We found novel homozygous mutations in <em>RIPK4</em> in two PPS patients. This result has significant clinical ramifications, as counseling of recurrence risk is very different for PPS patients whose disease is caused by dominant <em>IRF6</em> mutations compared to recessive <em>RIPK4</em> mutations.</p> <p>Finally, to understand the variable expressivity of VWS and PPS we performed an association study to identify genetic modifiers. We also looked for genotype-phenotype correlations between the type and location of <em>IRF6</em> mutations. Although we did not find strong evidence that the candidate genes we selected from GWAS of NSCL/P or other clefting syndromes are modifiers of the VWS or PPS phenotypes, several marginal associations suggest that members of the <em>IRF6</em> gene regulatory network could act as modifiers. Finally, we found evidence of a larger genotype-phenotype correlation by demonstrating that mutation-negative VWS families have a deficiency of cleft lip phenotypes. Together this work has advanced our understanding of the genetic basis of this diverse set of cleft lip and palate disorders, informing both the biology of craniofacial development and the clinical care of patients affected by these disorders.</p>

The purpose of this study was (1) to assess maxillary development in cleft individuals with Van der Woude syndrome (VWS) and (2) to compare hypodontia in VWS and nonsyndromic cleft matched controls. Retrospective case-control study from the Center for Craniofacial Anomalies, University of California, San Francisco, California. The sample consisted of 15 individuals with Van der Woude syndrome and 15 nonsyndromic cleft lip and/or palate controls paired for age, gender, and cleft type in the age range of 5 to 13 years. Cephalograms were digitized, and 31 linear and angular measurements were made. Serial panoramic radiographs were used to assess the presence or absence of permanent teeth. The maxillary sagittal position represented by midface length (Co-A) was significantly shorter in the Van der Woude syndrome subjects than in the matched controls (p = .031), suggesting a trend towards greater maxillary hypoplasia, particularly in Van der Woude syndrome with bilateral cleft lip and/ or palate. Measurements indicating sagittal jaw relationship (ANB angle and the Wits) were significantly smaller in the children with Van der Woude syndrome than in matched controls (p = .008 and p = .006). A significantly larger number of individuals with Van der Woude syndrome than matched controls had missing teeth (p = .014). The mandibular second premolar was missing more frequently in children with Van der Woude syndrome than in the matched controls (p = .031). The differences concerning both maxillary hypoplasia and hypodontia were most marked in the more severe cleft type, represented by bilateral cleft lip and/or palate. Based on these findings, the expectation is that there will be maxillary hypoplasia and hypodontia of greater severity in Van der Woude syndrome than in nonsyndromic clefts.

To analyse the differences between dental age and chronological age and dental anomalies in individuals with Van der Woude syndrome (VWS) and compare with non-syndromic cleft palate (NSCP) and non-cleft controls. In total, 204 oral panoramic radiographs (118 girls and 86 boys) consisting of 51 VWS patients (age x̅ = 8.17 ± 1.34 years), 51 NSCP patients (age x̅ = 8.09 ± 1.41 years), and 102 normative non-cleft children (age x̅ = 8.62 ± 1.24 years) were collected. Dental stages were assessed by the Demirjian method, with the local dental maturity index as reference. Dental anomalies including agenesis were investigated. Statistical differences were determined by One-way ANOVA and regression. Repeatability was calculated by an intra-class correlation test and 95% confidence interval. The difference between dental age and chronological age of the VWS group (0.12 years) and the NSCP group (0.09 years) was significantly lower than the non-cleft group (0.40 years) (P = 0.002). There was no significant difference between the VWS and NSCP groups (P = 0.885). Hypodontia was more prevalent in both the VWS group (37.25%, P = 0.0001) and the NSCP group (19.60%, P = 0.035) compared with the non-cleft group (5.88%). The odds for hypodontia in the VWS group were approximately double compared with the NSCP group. In VWS patients, the most commonly missing teeth were the permanent second premolars and the maxillary permanent laterals incisors. Peg-shaped teeth had a prevalence of 13.70% in VWS patients. In VWS and NSCP patients compared with non-cleft children, the difference in dental age compared with chronological age decreased. Hypodontia occurs at a high prevalence in VWS and NSCP patients compared with non-cleft children.

Van der Woude syndrome (VWS) is an autosomal dominant craniofacial disorder characterized by lip pits, clefting of the primary or secondary palate, and hypodontia. The gene has been localized, by RFLP-based linkage studies, to region 1q32-41 between D1S65-REN and D1S65-TGFB2. In this study we report the linkage analysis of 15 VWS families, using 18 microsatellite markers. Multipoint linkage analysis places the gene, with significant odds of 2,344:1, in a 4.1-cM interval flanked by D1S245 and D1S414. Two-point linkage analysis demonstrates close linkage of VWS with D1S205 (lod score [Z] = 24.41 at theta = .00) and with D1S491 (Z = 21.23 at theta = .00). The results revise the previous assignment of the VWS locus and show in an integrated map of the region 1q32-42 that the VWS gene resides more distally than previously suggested. When information about heterozygosity of the closely linked marker D1S491 in the affected members of the VWS family with a microdeletion is taken into account, the VWS critical region can be further narrowed, to the 3.6-cM interval between D1S491 and D1S414.

Orofacial clefts (OFC) are complex genetic traits that are often classified as syndromic or nonsyndromic clefts. Currently, there are over 500 types of syndromic clefts in the Online Mendelian Inheritance in Man (OMIM) database, of which Van der Woude syndrome (VWS) is one of the most common (accounting for 2% of all OFC). Popliteal pterygium syndrome (PPS) is considered to be a more severe form of VWS. Mutations in the IRF6 gene have been reported worldwide to cause VWS and PPS. Here, we report studies of families with VWS and PPS in sub-Saharan Africa. We screened the DNA of eight families with VWS and one family with PPS from Nigeria and Ethiopia by Sanger sequencing of the most commonly affected exons in IRF6 (exons 3, 4, 7, and 9). For the VWS families, we found a novel nonsense variant in exon 4 (p.Lys66X), a novel splice-site variant in exon 4 (p.Pro126Pro), a novel missense variant in exon 4 (p.Phe230Leu), a previously reported splice-site variant in exon 7 that changes the acceptor splice site, and a known missense variant in exon 7 (p.Leu251Pro). A previously known missense variant was found in exon 4 (p.Arg84His) in the PPS family. All the mutations segregate in the families. Our data confirm the presence of IRF6-related VWS and PPS in sub-Saharan Africa and highlights the importance of screening for novel mutations in known genes when studying diverse global populations. This is important for counseling and prenatal diagnosis for high-risk families.

To analyse prevalence, pattern, and severity of taurodontism in individuals with Van der Woude syndrome (VWS) exhibiting cleft palate and compare with aged-matched non-syndromic cleft palate (NSCP) and non-cleft controls. One hundred and seventy-eight dental panoramic tomographs (DPTs) (105 girls and 73 boys) consisting of 42 VWS patients (x¯=8.55±1.02years), 42 NSCP patients (x¯=8.59±1.02years), and 94 normative non-cleft children (x¯=8.79±1.16years) were assessed and their first permanent molars evaluated. Measurement 3 of the taurodontism index developed by Shifman and Chanannel with the Tulensalo modification was used. Prevalence, pattern, and severity were compared between groups. Statistical differences were determined by one-way analysis of variance and Fisher test. Repeatability was calculated by Cohens Kappa test. The prevalence of taurodontic molars was 59.5% in VWS, 45.2% in NSCP, and 26.6% in non-cleft controls. The prevalence and severity of taurodontism in VWS and NSCP were significantly higher than in non-cleft children in all first permanent molars. There was no significant difference in prevalence and severity between VWS and NSCP. The odds for having taurodontism in the VWS group was approximately double compared to the NSCP group. Most of the taurodontic molars showed hypotaurodontism and taurodontism occurred bilaterally more frequently than unilaterally. This study shows a higher prevalence of taurodontism in VWS and NSCP. Most taurodontic molars are hypotaurodontic and most occur bilaterally.

Van der Woude syndrome (VWS) is an autosomal dominant craniofacial disorder representing the most frequent form of syndromic cleft lip and palate. Other characteristic features are pits of the lower lip and hypodontia. The gene shows high penetrance and seems to play an important role in orofacial development determined by the tissues involved and their formation during different periods of craniofacial development. Although most individuals affected with VWS show Mendelian inheritance, one patient with a macroscopic deletion and multiple malformations including two primary features of VWS has been described in the literature, indicating hemizygosity is compatible with the VWS phenotype. We report here the allelic loss of a stable and highly polymorphic microsatellite (D1S205) from region 1q32-41 in one family with VWS. Classical manifestations of the syndrome superimposed on developmental delay in all affected members of the family, the absence of cytogenetic abnormalities, the reproducibility of the null allele with a new set of primers and close linkage of this marker in a total of 15 VWS families provide strong evidence that the first microdeletion involving the gene for VWS has been identified. Assuming 1 Mb of DNA per cM of genetic distance, the upper bound of the deletion size would amount to 4 Mb.

Linkage Analysis in a Large Brazilian Family with van der Woude Syndrome Suggests the Existence of a Susceptibility Locus for Cleft Palate at 17p11.2-11.1