The van der Woude syndrome in a large kindred: variability, penetrance, genetic risks

The heterogeneous genetic architectures of orofacial clefts

Orofacial clefts (OFCs) are common, affecting 1:1000 live births. OFCs occur across a phenotypic spectrum - including cleft lip (CL), cleft lip and palate (CLP), or cleft palate (CP) - and can be further subdivided based on laterality, severity, or specific structures affected. Herein we review what is known about the genetic architecture underlying each of these subtypes, considering both shared and subtype-specific risks. While there are more known genetic similarities between CL and CLP than CP, recent research supports both shared and subtype-specific genetic risk factors within and between phenotypic classifications of OFCs. Larger sample sizes and deeper phenotyping data will be of increasing importance for the discovery of novel genetic risk factors for OFCs and various subtypes going forward.

Novel IRF6 variant in orofacial cleft patients from Durban, South Africa

BACKGROUND

To date, there are over 320 variants identified in the IRF6 gene that cause Van der Woude syndrome or popliteal pterygium syndrome. We sequenced this gene in a South African orofacial cleft cohort to identify the causal IRF6 variants in our population.

METHOD

Saliva samples from 100 patients with syndromic and non-syndromic CL ± P were collected. Patients were recruited from the cleft clinics at two public, tertiary hospitals in Durban, South Africa (SA), namely Inkosi Albert Luthuli Central Hospital (IALCH) and KwaZulu-Natal Children's Hospital (KZNCH). We prospectively sequenced the exons of IRF6 in 100 orofacial cleft cases, and where possible, we also sequenced the parents of the individuals to determine the segregation pattern.

RESULTS

Two variants were identified; one novel (p.Cys114Tyr) and one known (p.Arg84His) missense variant in IRF6 gene were identified. The patient with the p.Cys114Tyr variant was non-syndromic with no clinical VWS phenotype expected of individuals with IRF6 coding variants, and the patient with the p.Arg84His had phenotypic features of popliteal pterygium syndrome. The p.Arg84His variant segregated in the family, with the father also being affected.

CONCLUSIONS

This study provides evidence that IRF6 variants are found in the South African population. Genetic counselling is essential for affected families, particularly in the absence of a known clinical phenotype since it helps with the plans for future pregnancies.

Congenital ankyloblepharon in a newborn with an IRF6 mutation

We present the case of a boy born at 41 weeks' gestational age who was found to have multiple anatomic anomalies, including abnormalities of the oral cavity, eyelids, and digits. He had ankyloblepharon that was localized to the lateral portion of the palpebral fissure bilaterally. Genetic testing confirmed a mutation in the interferon regulatory factor 6 (IRF6) gene, a known etiology for a spectrum of rare disorders that includes eyelid abnormalities. We present a novel surgical technique for bedside ankyloblepharon repair and describe the relevant clinical features of this case.

Rare disorders have many faces: in silico characterization of rare disorder spectrum

Background

The diagnostic journey for many rare disease patients remains challenging despite use of latest genetic technological advancements. We hypothesize that some patients remain undiagnosed due to more complex diagnostic scenarios that are currently not considered in genome analysis pipelines. To better understand this, we characterized the rare disorder (RD) spectrum using various bioinformatics resources (e.g., Orphanet/Orphadata, Human Phenotype Ontology, Reactome pathways) combined with custom-made R scripts.

Results

Our in silico characterization led to identification of 145 borderline-common, 412 rare and 2967 ultra-rare disorders. Based on these findings and point prevalence, we would expect that approximately 6.53%, 0.34%, and 0.30% of individuals in a randomly selected population have a borderline-common, rare, and ultra-rare disorder, respectively (equaling to 1 RD patient in 14 people). Importantly, our analyses revealed that (1) a higher proportion of borderline-common disorders were caused by multiple gene defects and/or other factors compared with the rare and ultra-rare disorders, (2) the phenotypic expressivity was more variable for the borderline-common disorders than for the rarer disorders, and (3) unique clinical characteristics were observed across the disorder categories forming the spectrum.

Conclusions

Recognizing that RD patients who remain unsolved even after genome sequencing might belong to the more common end of the RD spectrum support the usage of computational pipelines that account for more complex genetic and phenotypic scenarios.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02217-9.

A Blueprint for Identifying Phenotypes and Drug Targets in Complex Disorders with Empirical Dynamics

A central challenge in medicine is translating from observational understanding to mechanistic understanding, where some observations are recognized as causes for the others. This can lead not only to new treatments and understanding, but also to recognition of novel phenotypes. Here, we apply a collection of mathematical techniques (empirical dynamics), which infer mechanistic networks in a model-free manner from longitudinal data, to hematopoiesis. Our study consists of three subjects with markers for cyclic thrombocytopenia, in which multiple cells and proteins undergo abnormal oscillations. One subject has atypical markers and may represent a rare phenotype. Our analyses support this contention, and also lend new evidence to a theory for the cause of this disorder. Simulations of an intervention yield encouraging results, even when applied to patient data outside our three subjects. These successes suggest that this blueprint has broader applicability in understanding and treating complex disorders.

Novel IRF6 mutations in Chinese Han families with Van der Woude syndrome

BACKGROUND

Interferon Regulatory Factor 6 (IRF6) gene encodes a member of the IRF family of transcription factors. Mutations in IRF6 cause Van der Woude Syndrome (VWS), which is the most common malformation of syndromic orofacial clefts in humans.

METHODS

Here, we performed sequencing studies of six families with VWS in the Chinese Han population. The entire IRF6-coding region and the exon-intron boundaries including exons 3-8 and part of exon 9 were screened among all the collected family members by Sanger sequencing.

RESULTS

We found a novel splice site variant c.175-6T>A, two novel missense variants (p.Lys66Arg and p.Pro107Thr), in addition with a previously reported missense variant (p.Leu87Phe), which were all located in and nearby exon 4 of IRF6. Meanwhile, a novel frameshift variant p.G257Vfs*46 in exon 7 of IRF6 was also detected. All the mutations presented to be co-segregated in each family.

CONCLUSION

Our study has advanced the understanding of the genetic architecture of VWS and provides the basis for genetic counseling, antenatal diagnosis, and gene therapy of high risk groups.

Surgical, Speech, and Audiologic Outcomes in Patients With Orofacial Cleft and Van der Woude Syndrome

OBJECTIVE

The purpose of this study was to investigate the surgical, speech, and audiologic outcomes in patients with Van der Woude syndrome (VWS) and compare them to patients with nonsyndromic cleft palate with or without cleft lip (NS-CP ± L) treated at the same institution.

DESIGN

Retrospective chart review.

SETTING

A single children's hospital at a major academic institution.

PATIENTS

The records of 18 patients with VWS who had been treated at a single institution from 1989 to 2017 have been retrospectively examined. Thirty-eight patients with NS-CP ± L who were also treated at the same institution during that same time frame were selected to closely match sex and date of birth.

MAIN OUTCOME MEASURES

Demographic, clinical, surgical, and speech pathology data were gathered from medical charts.

RESULT

By age 4, 88% of subjects with VWS and 76% of subjects with NS-CP ± L (P = 0.732) had been, or were actively involved in, speech therapy. By age 10, 100% of remaining subjects with VWS and 58% of remaining subjects with NS-CP ± L remained involved in speech therapy (P = 0.027).About 33% of patients with VWS and 16% of patients with NS-CP ± L had a secondary procedure for velopharyngeal dysfunction (VPD) (P = 0.171).

CONCLUSION

The VWS group had more than twice the rate of secondary procedures for VPD repair, and a higher rate of continuing involvement for speech therapy at age 10. No differences were found in the rate of participation in speech therapy at or by age 4.

Nonsyndromic familial congenital lower lip pits

Congenital pits on lower lips unassociated with any syndrome are a rare developmental malformation. Vermilion border of the lower lip is the most common site of occurrence. Mostly, these lip pits are inherited as an autosomal dominant trait with variable penetrance. The females are more affected than males. This is a case report of a 7-year-old female child with nonsyndromic congenital lower lip pits, where two of her other family members were also affected.

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.

Update on 13 Syndromes Affecting Craniofacial and Dental Structures

Care of individuals with syndromes affecting craniofacial and dental structures are mostly treated by an interdisciplinary team from early childhood on. In addition to medical and dental specialists that have a vivid interest in these syndromes and for whom these syndromes are of evident interest, experts of scientific background-like molecular and developmental geneticists, but also computational biologists and bioinformaticians-, become more frequently involved in the refined diagnostic and etiological processes of these patients. Early diagnosis is often crucial for the effective treatment of functional and developmental aspects. However, not all syndromes can be clinically identified early, especially in cases of absence of known family history. Moreover, the treatment of these patients is often complicated because of insufficient medical knowledge, and because of the dental and craniofacial developmental variations. The role of the team is crucial for the prevention, proper function, and craniofacial development which is often combined with orthognathic surgery. Although the existing literature does not provide considerable insight into this topic, this descriptive review aims to provide tools for the interdisciplinary team by giving an update on the genetics and general features, and the oral and craniofacial manifestations for early diagnosis. Clinical phenotyping together with genetic data and pathway information will ultimately pave the way for preventive strategies and therapeutic options in the future. This will improve the prognosis for better functional and aesthetic outcome for these patients and lead to a better quality of life, not only for the patients themselves but also for their families. The aim of this review is to promote interdisciplinary interaction and mutual understanding among all specialists involved in the diagnosis and therapeutic guidance of patients with these syndromal conditions in order to provide optimal personalized care in an integrated approach.

Treatment of lower lip pits in Van der Woude syndrome: a systematic review

The presence of lower lip pits in individuals with Van der Woude syndrome (VWS) may cause discomfort due to saliva secretion. Furthermore, one of the main complaints in relation to lip pits is poor aesthetics, which often affects quality of life. The aim of this systematic review was to identify the best technique for the surgical removal of lower lip pits in terms of aesthetic and functional characteristics. A search of the PubMed, Embase, Web of Science, Science Direct, and Scopus databases was performed on December 27, 2016, which retrieved 88 records without duplicates. Among these papers, three ultimately met all eligibility criteria. The three studies included a total of 61 individuals, with follow-up ranging from 6 months to 10 years and sample collection from 10 to 24 years. The findings demonstrated that the outcome of surgical removal of lower lip pits was better with the use of vertical wedge excision, inverted-T lip reduction, Mutaf-Goldstein technique and modified simple excision than with simple excision. Simple excision may result in postoperative complications, such as mucocele and pit recurrence.

Surgical management of lower lip pits in Van der Woude syndrome

Van der Woude syndrome (VDWS) is characterized by the presence of lower lip pits which may be of concern to patients due to aesthetic considerations. By presenting three clinical cases, we provide an overview of the surgical techniques currently available to treat labial pits. Fusiform excision with dissection of the entire pit is still the most commonly used procedure and it generally yields good functional and aesthetic outcomes. The split-lip advancement technique and the inverted T-lip reduction nonetheless represent good surgical alternatives. Proper management of the lower pits that occur with VDWS requires thorough knowledge of the available surgical procedures.

Toward an orofacial gene regulatory network

Orofacial clefting is a common birth defect with significant morbidity. A panoply of candidate genes have been discovered through synergy of animal models and human genetics. Among these, variants in interferon regulatory factor 6 (IRF6) cause syndromic orofacial clefting and contribute risk toward isolated cleft lip and palate (1/700 live births). Rare variants in IRF6 can lead to Van der Woude syndrome (1/35,000 live births) and popliteal pterygium syndrome (1/300,000 live births). Furthermore, IRF6 regulates GRHL3 and rare variants in this downstream target can also lead to Van der Woude syndrome. In addition, a common variant (rs642961) in the IRF6 locus is found in 30% of the world's population and contributes risk for isolated orofacial clefting. Biochemical studies revealed that rs642961 abrogates one of four AP-2alpha binding sites. Like IRF6 and GRHL3, rare variants in TFAP2A can also lead to syndromic orofacial clefting with lip pits (branchio-oculo-facial syndrome). The literature suggests that AP-2alpha, IRF6 and GRHL3 are part of a pathway that is essential for lip and palate development. In addition to updating the pathways, players and pursuits, this review will highlight some of the current questions in the study of orofacial clefting.

Anatomic Severity, Midfacial Growth, and Speech Outcomes in Van der Woude/Popliteal Pterygium Syndromes Compared to Nonsyndromic Cleft Lip/Palate

OBJECTIVE

To summarize the clinical characteristics and surgical and speech outcomes for patients with Van der Woude/popliteal pterygium syndromes (VWS/PPS) and to compare them with a historic cohort of patients with nonsyndromic cleft lip/cleft palate (CL/P).

DESIGN

Retrospective chart review.

SETTING

Tertiary care center.

PATIENTS

All patients with VWS/PPS seen at Boston Children's Hospital from 1979 to 2012: 28 patients with VWS (n = 21)/PPS (n = 7) whose mean age was 17.3 ± 10.4 years, including 18 females (64%) and 10 males (36%); 18 patients (64%) had a family history of VWS/PPS.

MAIN OUTCOME MEASURES

Cleft type, operative procedures, speech, and midfacial growth. Data were compared with historic cohorts of patients with nonsyndromic CL/P treated at one tertiary care center.

RESULTS

There were 24 patients (86%) with CP±L, Veau types I (n = 4, 17%), II (n = 4, 17%), III (n = 5, 21%), and IV (n = 11, 46%). Nine patients (38%) had palatal fistula after palatoplasty. Fourteen of 23 (61%) patients with CL/P age 5 years or older had midfacial retrusion, and 10 (43%) required a pharyngeal flap for velopharyngeal insufficiency. Fisher's exact test demonstrated higher frequencies of Veau type IV CP±L (P = .0016), bilateral CL±P (P = .0001), and complete CL±P (P < .0001) in VWS/PPS compared with nonsyndromic patients. Incidences of midfacial retrusion (P = .0001), palatal fistula (P < .0001), and need for pharyngeal flap (P = .0014) were significantly greater in patients with VWS/PPS.

CONCLUSIONS

Patients with VWS/PPS have more severe forms of labiopalatal clefting and higher incidences of midfacial retrusion, palatal fistula, and velopharyngeal insufficiency following primary repair as compared with nonsyndromic CL/P.

Van der woude syndrome with short review of the literature

Van der Woude syndrome (VWS) is a rare autosomal dominant condition with high penetrance and variable expression. Clinical manifestation of this autosomal dominant clefting syndrome includes bilateral midline lower lip pits, cleft lip, and cleft palate along with hypodontia. These congenital lip pits appear as a malformation in the vermilion border of the lip, with or without excretion. Discomfort caused by spontaneous or induced drainage of saliva/mucus when pressure is applied or during a meal as well as poor aesthetic match is one of the main complaints of patients with congenital lip fistula. The pits are treated by surgical resection. Dentists should be aware of the congenital lip pits as in Van der Woude syndrome because they have been reported to be associated with a variety of malformations or other congenital disorders. Here, the authors report a rare case of Van der Woude syndrome with short review of the literature.

Single-cell RNA-seq reveals dynamic, random monoallelic gene expression in mammalian cells

Expression from both alleles is generally observed in analyses of diploid cell populations, but studies addressing allelic expression patterns genome-wide in single cells are lacking. Here, we present global analyses of allelic expression across individual cells of mouse preimplantation embryos of mixed background (CAST/EiJ × C57BL/6J). We discovered abundant (12 to 24%) monoallelic expression of autosomal genes and that expression of the two alleles occurs independently. The monoallelic expression appeared random and dynamic because there was considerable variation among closely related embryonic cells. Similar patterns of monoallelic expression were observed in mature cells. Our allelic expression analysis also demonstrates the de novo inactivation of the paternal X chromosome. We conclude that independent and stochastic allelic transcription generates abundant random monoallelic expression in the mammalian cell.

Developmental disorders of the dentition: an update

Dental anomalies are common congenital malformations that can occur either as isolated findings or as part of a syndrome. This review focuses on genetic causes of abnormal tooth development and the implications of these abnormalities for clinical care. As an introduction, we describe general insights into the genetics of tooth development obtained from mouse and zebrafish models. This is followed by a discussion of isolated as well as syndromic tooth agenesis, including Van der Woude syndrome (VWS), ectodermal dysplasias (EDs), oral-facial-digital (OFD) syndrome type I, Rieger syndrome, holoprosencephaly, and tooth anomalies associated with cleft lip and palate. Next, we review delayed formation and eruption of teeth, as well as abnormalities in tooth size, shape, and form. Finally, isolated and syndromic causes of supernumerary teeth are considered, including cleidocranial dysplasia and Gardner syndrome.

Novel mutations mapping to the fourth sodium channel domain of Nav1.7 result in variable clinical manifestations of primary erythromelalgia

We identified and clinically investigated two patients with primary erythromelalgia mutations (PEM), which are the first reported to map to the fourth domain of Nav1.7 (DIV). The identified mutations (A1746G and W1538R) were cloned and transfected to cell cultures followed by electrophysiological analysis in whole-cell configuration. The investigated patients presented with PEM, while age of onset was very different (3 vs. 61 years of age). Electrophysiological characterization revealed that the early onset A1746G mutation leads to a marked hyperpolarizing shift in voltage dependence of steady-state activation, larger window currents, faster activation kinetics (time-to-peak current) and recovery from steady-state inactivation compared to wild-type Nav1.7, indicating a pronounced gain-of-function. Furthermore, we found a hyperpolarizing shift in voltage dependence of slow inactivation, which is another feature commonly found in Nav1.7 mutations associated with PEM. In silico neuron simulation revealed reduced firing thresholds and increased repetitive firing, both indicating hyperexcitability. The late-onset W1538R mutation also revealed gain-of-function properties, although to a lesser extent. Our findings demonstrate that mutations encoding for DIV of Nav1.7 can not only be linked to congenital insensitivity to pain or paroxysmal extreme pain disorder but can also be causative of PEM, if voltage dependency of channel activation is affected. This supports the view that the degree of biophysical property changes caused by a mutation may have an impact on age of clinical manifestation of PEM. In summary, these findings extent the genotype-phenotype correlation profile for SCN9A and highlight a new region of Nav1.7 that is implicated in PEM.

The key role of epigenetics in the persistence of asexual lineages

Asexual organisms, often perceived as evolutionary dead ends, can be long-lived and geographically widespread. We propose that epigenetic mechanisms could play a crucial role in the evolutionary persistence of these lineages. Genetically identical organisms could rely on phenotypic plasticity to face environmental variation. Epigenetic modifications could be the molecular mechanism enabling such phenotypic plasticity; they can be influenced by the environment and act at shorter timescales than mutation. Recent work on the asexual vertebrate Chrosomus eos-neogaeus (Pisces: Cyprinidae) provides broad insights into the contribution of epigenetics in genetically identical individuals. We discuss the extension of these results to other asexual organisms, in particular those resulting from interspecific hybridizations. We finally develop on the evolutionary relevance of epigenetic variation in the context of heritability.

Lower lip pits in a patient with van der Woude syndrome

van der Woude syndrome (VWS) is a congenital malformation characterized by lower lip pits with or without cleft lip or cleft palate. It is an autosomal-dominant inherited disorder with variable expression in clinical manifestation. Microdeletion in chromosome bands 1q32-q41 and recently identified mutation in interferon regulatory factor 6 gene (IRF6) have been reported to cause VWS. We report a case of VWS with lower lip pits as its main clinical manifestation without associated cleft in lip or palate. No mutation or deletion was found in the IRF6 gene or promoter site, indicating the heterogeneity of this defect.

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.

Reconstruction of the lower lip in Van der Woude syndrome

Van der Woude syndrome (VWS) is a congenital disease characterized by labial cysts, accessory salivary glands, congenital lower lip pits, fistula, and paramedian sinuses, and is often accompanied by cleft lip and palate. VWS is an autosomal dominant craniofacial syndrome, which represents only lower lip pits due to variable gene expression. The principles of VWS surgery include excision of lower lip pits and accessory glands, reconstruction of the lip and nose, and correction of accompanying anomalies. In this article, we present a technique with dermal allograft reconstruction to prevent deformities after excision of the accessory gland in the lower lip pit.

Taurodontism and Van der Woude syndrome. Is there an association?

OBJECTIVE

To report the occurrence of taurodontism in a clinical sample of Van der Woude syndrome (VWS) and describe its association with hypodontia and cleft type.

MATERIALS AND METHODS

This retrospective, cross-sectional study was carried out on chart reviews and radiographs of 13 persons with VWS. Mean age was 10 years 11 months +/- 1 year 5 months. Panoramic radiographs were used to confirm the presence or absence of teeth and to measure crown body and root lengths of mandibular first molars. Three-dimensional cone beam computed tomography (CT) scans were available on two persons with VWS. Both volumetric and linear measurements were obtained.

RESULTS

The occurrence of taurodontism of the mandibular first molar was 35%: 27% hypodont and 8% mesodont. Of the 13 subjects with VWS, 6 (4 males and 2 females) had at least one tooth identified with taurodontism. Half of the cases were unilateral and half were bilateral, and all of the unilateral cases were on the left side. Five of the six subjects with taurodontism had missing incisors and premolars. Taurodontism was two times more frequent in those who were missing their second premolars than in those who had their second premolars. There was no correlation between cleft type and presence of taurodontism. The cone beam CT pilot study on two persons showed very abnormal morphology of both crown and roots, which was not apparent on the standard panoramic radiograph. Both the volumetric and linear measurements of the ratio of crown body to root were highly indicative of taurodontism. Further genetic studies are needed.

CONCLUSION

There is a likely association between VWS and taurodontism.

Abnormal brain structure in adults with Van der Woude syndrome

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.

Clinical and genetic features of Van der Woude syndrome in two large families in Brazil

OBJECTIVE

This report describes the clinical and genetic features of two large and unrelated families with Van der Woude syndrome in Brazil, emphasizing the range of anomalies found within and between the families.

PATIENTS

Family 1 included 54 descendants spanning five generations, with 12 (22.23%) individuals manifesting Van der Woude syndrome. In family 2, examinations comprised 17 descendants distributed over four generations, and 8 (47.06%) people presented features of Van der Woude syndrome.

RESULTS

In family 1, the first two generations were not affected, but the other three generations had affected members showing a unique association of lip pits and cleft lip/palate with equilibrated gender distribution. In family 2, all generations were affected, and the clinical expression of disease was heterogeneous, including members with isolated clefts, isolated lip pits, and association of cleft lip/palate with lip pits. In both families, affected members transmitted their traits to descendants in an autosomal dominant mode of inheritance with apparent low penetrance in family 1, but high penetrance in family 2. Patients were treated surgically by cheiloplasty and/or palatoplasty with satisfactory results.

CONCLUSIONS

Van der Woude syndrome was transmitted by an autosomal dominant pattern with variable expressivity and penetrance and equilibrated gender distribution. Physicians should be aware of the variety of malformations that can be associated with Van der Woude syndrome. Genetic counseling in Van der Woude syndrome affected families is important, because a high percentage of descendants can have some kind of clefting.

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.

Hypoplasia and hypodontia in Van der Woude syndrome

OBJECTIVE

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.

DESIGN AND SETTING

Retrospective case-control study from the Center for Craniofacial Anomalies, University of California, San Francisco, California.

PATIENTS AND PARTICIPANTS

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.

MAIN OUTCOME MEASURES

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.

RESULTS

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.

CONCLUSIONS

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.

Van der Woude Syndrome in Twins

This article discusses monozygotic twin patients with Van der Woude syndrome, the most common form of syndromic cleft lip and palate, who have concordant manifestations. The syndrome has an autosomal dominant hereditary pattern with variable expressivity and a high degree of penetrance with clinical features, including lower lip sinuses with a cleft lip, cleft palate, or both. Some mutations have been found to cause this disorder. Genetic counseling and informing patients about inheritance is crucial. The appearance, etiology, genetic aspects, differential diagnosis, and treatment modalities are discussed. To the authors' knowledge, this is the third report of monozygotic concordant twins with this syndrome in the literature.

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.

Two missense mutations in the IRF6 gene in two Japanese families with Van der Woude syndrome

Van der Woude syndrome (VWS) is a common autosomal dominant disorder with cleft lip and/or palate and lower lip pits. Its prevalence is estimated to be 1/33,600 in the Finnish Population, and 1/47,813 in the Japanese. We performed mutation analysis of the IRF6 gene by direct sequencing in 2 unrelated Japanese families that consist of a total of 3 affected members with cleft lip and palate associated with lower lip pits. Consequently, we found novel base substitutions, 25C>T, in IRF6-exon 3 in a boy, his mother, and his phenotypically normal maternal grandmother in one of the families. A known mutation, 250C>T, was identified in exon 4 of a girl and her unaffected father in the other family. The same mutations were never observed among 190 healthy Japanese. The results indicate incomplete penetrance and variable expressivity in the families. Because 25C>T and 250C>T predict to lead to R9W and R84C substitutions, respectively, at the most conserved DNA binding domain of IRF6, and because arginine at positions 9 and 84 is highly conserved among IRFs, the 2 mutations may lead to abolish the DNA binding activity in the developing craniofacial region. To our knowledge, this is the first report of IRF6 mutations observed in Japanese VWS patients.

Novel IRF6 mutations in Japanese patients with Van der Woude syndrome: two missense mutations (R45Q and P396S) and a 17-kb deletion

Three Japanese families with Van der Woude syndrome (VWS) were screened for mutations in the interferon regulatory factor 6 gene (IRF6) by sequencing its entire coding region. Two novel missense mutations, R45Q in exon 3 and P396S in exon 9, were identified in families 1 and 2, respectively. In family 3, no causative base change was found by the sequencing analysis, but a deletion involving exons 4-9 was suggested by multiplex PCR analysis. To confirm the deletion and to determine its 5'- and 3'-boundaries, we amplified a DNA fragment containing a heterozygous polymorphic site in exon 2 by using a 5'-upstream forward PCR primer and eight different reverse primers located 3'-downstream of exon 2. The amplified product was subjected to nested PCR to generate a DNA fragment containing the polymorphic site. When a reverse primer located within the deletion was used for the first PCR amplification, only the nondeletion allele was detected after the second PCR. Repeated analyses with eight different reverse primers allowed us to map the boundaries of the deletion, and subsequently a heterozygous 17,162-bp deletion involving exons 4-9 was identified. Since IRF6 mutations in a significant portion of VWS patients remain undetected by conventional sequencing analysis, it may be important to search for a large deletion in those patients. Our simple methods to identify deletions and to determine the boundaries of a deletion would facilitate the identification of such patients.

Syngnathia and Van der Woude syndrome: a case report and literature review

OBJECTIVE

Syngnathia is a rare anomaly involving soft tissue or bony adhesions between the maxilla and mandible. We review the literature and present a case of syngnathia associated with Van der Woude syndrome. Syngnathia can have very different etiologies, but this has rarely been reported in Van der Woude syndrome. Treatment of this condition is rarely discussed in the literature because of a paucity of case reports.

RESULTS

Oral adhesion (syngnathia) in our patient was caused by a mandibular to maxillary fibrous band. Surgical treatment was successful. Clinical implications and review of literature for the treatment of this rare association of syngnathia and Van der Woude syndrome are discussed.

Van der Woude syndrome with sensorineural hearing loss, large craniofacial sinuses, dental pulp stones, and minor limb anomalies: report of a four-generation Thai family

A four-generation Thai family affected with Van der Woude syndrome is reported. The disorder appeared to be originally inherited from a person who was half Thai and half Pakistani. The lip lesions found in this family were varied and did not appear to be related to other phenotypes. There were some clinical manifestations possibly specific for the condition in this family. They included sensorineural hearing loss, prominent frontal bone, large frontal/sphenoidal/maxillary sinuses with increased mastoid air cells, long tooth roots, dental pulp stones, ankyloglossia, brachydactyly of hands, brachyphalangy, and hyperphalangy of toes, and single flexion crease of the fifth fingers. Fluorescence in situ hybridization analysis revealed no visible deletion at a 1q32-41 region.

Mixed clefting type in Rapp-Hodgkin syndrome

Mixed clefting type (MCT) is the rare occurrence of cleft lip, with or without cleft palate, and cleft palate alone in the same pedigree. Here we present a family with Rapp-Hodgkin syndrome (RHS) that manifests MCT, and use this rare finding to suggest that RHS may be related not only to phenotypically similar syndromes, but seemingly dissimilar ones as well. RHS has obvious phenotypic overlap with other ectodermal dysplasia-clefting syndromes (EDCS), such as ectrodactyly-ectodermal dysplasia-clefting syndrome (EEC) and ankyloblepharon-ectodermal dysplasia-clefting syndrome (AEC), all of which show MCT. MCT is also found in the allelic disorders van der Woude syndrome (VDW) and popliteal-pterygium syndrome (PPS). Therefore, while VDW and PPS have little clinical overlap with the EDCS, the common finding of MCT may indicate closer relationships at the developmental or genetic level.

A cephalometric study of facial growth in van der Woude syndrome

OBJECTIVE

To test the hypothesis that maxillary growth and lower lip form in patients with van der Woude syndrome (VDW) is different from patients with non-syndromic cleft lip and palate.

DESIGN AND SETTING

Retrospective, case-control study at a tertiary cleft center, Chang Gung Memorial Hospital, Taipei, Taiwan.

PATIENTS AND PARTICIPANTS

Records of 53 patients with VDW, who presented for treatment during the years 1968 through 1998 were obtained. Twenty-three of 53 patients had received at least one lateral cephalogram during the course of their treatment. Of these 23, in 17 it was possible to find non-syndromic case controls with identical cleft type, sex, and method of cleft palate repair, with year of birth matching within 1 year of the corresponding VDW patient. For these 17 pairs of VDW and non-syndromic cleft controls, cephalogram acquisition dates were checked to see how well the corresponding pairs matched. A total of 43 pairs of cephalograms were deemed to be acceptably matched because the ages at acquisition differed by less than 15% of the VDW patient's age.

MAIN OUTCOME MEASURES

Thirteen measurements were derived from the 11 standard lateral cephalometric landmarks recorded on each cephalogram. The data were classified into five groups according to age at time of cephalogram, and sets of paired non-syndromic cleft and VDW measurements were tested for differences using a Wilcoxon signed rank sum test in two ways, first including all cleft types and then including only those patients with complete bilateral cleft lip and palate. A longitudinal growth analysis considering the movement of the skeletal A and B points was performed on the patients with complete bilateral cleft lip and palate.

RESULTS

For the osseous measurements, anteroposterior maxillary length as described by the anterior nasal spine (ANS)-posterior maxillary point distance was statistically significantly shorter in the VDW patients of age 13 years and older, by 5.3 mm. Maxillary height, as described by the nasion-ANS distance was shorter in the VDW patients, closely approaching statistical significance in the age range 7 through 11 years. The lip soft tissue measurements showed significantly greater protrusion over several age ranges in the VDW patients. The longitudinal growth analysis showed a significantly more inferior vertical position of the B point in the controls.

CONCLUSIONS

This study demonstrates a few statistically significant differences in maxillary growth and lip conformation between VDW and matching controls. Small sample sizes for each age group hamper the ability to fully interpret or generalize the pattern of these differences.

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

van der Woude syndrome (VWS), which has been mapped to 1q32-41, is characterized by pits and/or sinuses of the lower lip, cleft lip/palate (CL/P), cleft palate (CP), bifid uvula, and hypodontia (H). The expression of VWS, which has incomplete penetrance, is highly variable. Both the occurrence of CL/P and CP within the same genealogy and a recurrence risk <40% for CP among descendants with VWS have suggested that the development of clefts in this syndrome is influenced by modifying genes at other loci. To test this hypothesis, we have conducted linkage analysis in a large Brazilian kindred with VWS, considering as affected the individuals with CP, regardless of whether it is associated with other clinical signs of VWS. Our results suggest that a gene at 17p11.2-11.1, together with the VWS gene at 1p32-41, enhances the probability of CP in an individual carrying the two at-risk genes. If this hypothesis is confirmed in other VWS pedigrees, it will represent one of the first examples of a gene, mapped through linkage analysis, which modifies the expression of a major gene. It will also have important implications for genetic counseling, particularly for more accurately predicting recurrence risks of clefts among the offspring of patients with VWS.

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.

Linkage of Van der Woude syndrome (VWS) to REN and exclusion of the candidate gene TGFB2 from the disease locus in a large pedigree

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.