Van der Woude syndrome: a review. Cardinal signs, epidemiology, associated features, differential diagnosis, expressivity, genetic counselling and treatment

Van der Woude syndrome and amniotic band sequence: A clue to a common genetic etiology? A case report

Rare heterozygous variants in IRF6 (interferon regulatory factor-6) gene cause van der Woude syndrome 1 (VWS1) or Popliteal Pterygium syndrome, two forms of syndromic cleft lip/palate (CLP) that present with a variety of congenital malformations due to impairment ectodermal homeostasis. These malformations include, in addition to CLP, lip pits, pterygia, and intraoral and eyelid fibrous bands. Amniotic band sequence (ABS) is a rare condition of unknown genetic etiology that involves a range of congenital anomalies caused by the entanglement of fibrous bands, which disrupt fetal body parts. However, ABS co-occurs with CLP and other malformations that cannot be explained by this mechanism. Therefore, investigating the genetic relationship between ABS and CLP may provide clues regardind the genes involved in these conditions. Here, we report a case of a girl diagnosed with VWS1, autism, intellectual disability, and congenital right limb anomalies compatible with ABS. Molecular analysis revealed a novel, rare heterozygous missense variant in IRF6 (NM_006147.3:c.970T>C) located in exon 7, inherited from her father. This variant results in the replacement of serine by proline at position 324 of the IRF6 protein with potentially deleterious effects. This report expands the mutational landscape of IRF6 and provides further support for a possible link between the genetics of CLP and ABS.

Predicting Syndromic Status Based on Longitudinal Data from Parental Reports of the Presence of Additional Structural and Functional Anomalies in Children Born with an Orofacial Cleft

Background: Orofacial clefts are the most common craniofacial congenital malformation in humans. Approximately 30% of clefts arise as part of a syndrome or sequence, characterised by co-existing structural and functional anomalies. Many syndromes are thought to be undiagnosed, although the presence of multiple anomalies may indicate the presence of a syndrome or sequence. Aim: To determine the extent to which the presence of additional structural and functional anomalies can help to identify those children with an undiagnosed syndrome. Methods: Secondary data analysis was performed using data from 1701 children born with an orofacial cleft, collected as part of a longitudinal cohort study, the Cleft Collective. Data were collected between 2013 and 2023 across the United Kingdom. The prevalence of structural and functional anomalies and syndromes were explored using descriptive statistics. Logistic regression was used to determine the extent to which anomalies can predict syndromic status. Results: A syndrome and/or sequence was reported in 20.5% children. Among children who reported five or more anomalies, the prevalence of a diagnosed syndrome was 81.5%. When adjusting for cleft subtype and sex, in 27 out of 32 anomalies tested, strong evidence was found to suggest increased odds of having a syndrome if the specific anomaly was present compared to if the anomaly was absent (p-values ranged between 1.4 × 10-30 and 0.002). Conclusions: Children born with a cleft who present with two or more anomalies are much more likely to have a syndrome than those with fewer anomalies and should be prioritised for genetic screening and counselling.

Rare Congenital Upper Lip Pit

Congenital lip pits are characterized by sinuses or fistulas in the lips that can occur in isolation or as part of a genetic disorder. A 6-year-old girl with a right upper lip lesion present at birth presented with recurrent swelling and occasional erythema. Examination revealed a mildly swollen punctum at the right upper wet/dry vermillion with expressible serous drainage. There were no other phenotypic or cognitive concerns. The lesion was surgically excised using vertical wedge resection. The postoperative course showed well well-healed incision. The pathology report confirmed a lip pit. The family was referred to genetics for further evaluation. Van der Woude syndrome (VWS) is a genetic disorder associated with abnormal development of the paramedian lip. Most congenital lip pits are primarily found on the lower lips, with paramedian lip pits being the most common. Upper lateral lip pits with or without accompanying lip pits are considerably rarer. Though VWS is commonly associated with mutations in the interferon regulatory factor 6 or grainyhead-like protein 3 genes, ~25% of affected individuals lack an identified genetic etiology. A high index of suspicion for VWS is warranted if lip pits are present in the absence of other phenotypic abnormalities and should prompt genetic testing for interferon regulatory factor 6 and grainyhead-like protein 3 mutations. Multidisciplinary teams should consider patient self-esteem, quality of life, and potential family planning when deciding on surgical intervention for lip pits. Surgical management of pits should entail tissue-preserving techniques such as vertical wedge resection and inverted T-lip reduction to prevent whistle-lip deformity.

Congenital midline upper lip sinus in an infant

Congenital lip sinus is a rare entity with upper lip sinus being rarer than the lower lip sinus. It can be an isolated entity or associated with cleft lip, palate or Van der Woude syndrome. Syndromic association requires proper evaluation and aggressive surgical treatment. Preoperative delineation of the sinus tract with ultrasound sonography or MRI is mandatory. Simple excision is sufficient in cases of isolated sinuses. In this article, we report an infant with upper lip sinus managed successfully with simple excision and reviewed the literature.

Surgical Treatment of Lip Pits in Van der Woude Syndrome: A Preliminary Retrospective Study of 24 Patients

BACKGROUND

Van der Woude syndrome (VWS) is a rare congenital malformation characterized by lower lip pits among patients with a lip and/or palate cleft. It is transmitted by an autosomal dominant inheritance with variable expressivity.

METHODS

The study group consisted of 24 consecutive patients (13 males and 11 females) with VWS operated on at a single center between 2009 and 2022. They suffered from: bilateral cleft lip and palate - 6 patients; unilateral cleft lip and palate - 9 patients; cleft lip - 1 patient; and isolated cleft palate - 8 patients.

RESULTS

In 16 (66%) cases pits of lower lip occurred on both side of midline, while in 8 (34%) the pits were detected unilaterally. The primary cleft repairs were performed according to one-stage principle at the mean age of 8.6 months (SD 1.4, range 6-12). In all patients lower lip pits repairs were performed after the primary cleft repairs as a separate procedure at the mean age of 37 months (SD 11.3 range 14-85). The mean number of all primary repairs of the syndrome-both cleft defect and lower lip pits repairs-was 2.46. Nine patients (37.5%) required additional secondary corrections of the lower lip due to the poor aesthetic post-operative outcome.

CONCLUSIONS

The frequent need for secondary corrections of residual lower lip deformities indicates the considerable difficulties in obtaining a satisfactory outcome of the repairs to lip pits caused by VWS. The average number of the primary surgical interventions in evaluated material remained low.

Genetic Inheritance Models of Non-Syndromic Cleft Lip with or without Palate: From Monogenic to Polygenic

Non-syndromic cleft lip with or without palate (NSCL/P) is a prevalent birth defect that affects 1/500-1/1400 live births globally. The genetic basis of NSCL/P is intricate and involves both genetic and environmental factors. In the past few years, various genetic inheritance models have been proposed to elucidate the underlying mechanisms of NSCL/P. These models range from simple monogenic inheritance to more complex polygenic inheritance. Here, we present a comprehensive overview of the genetic inheritance model of NSCL/P exemplified by representative genes and regions from both monogenic and polygenic perspectives. We also summarize existing association studies and corresponding loci of NSCL/P within the Chinese population and highlight the potential of utilizing polygenic risk scores for risk stratification of NSCL/P. The potential application of polygenic models offers promising avenues for improved risk assessment and personalized approaches in the prevention and management of NSCL/P individuals.

Orofacial Clefts: Genetics of Cleft Lip and Palate

Orofacial clefting is considered one of the commonest birth defects worldwide. It presents as cleft lip only, isolated cleft palate or cleft lip and palate. The condition has a diverse genetic background influenced by gene-gene and gene-environment interaction, resulting in two main types, syndromic and nonsyndromic orofacial clefts. Orofacial clefts lead to significant physiological difficulties that affect feeding, speech and language development and other developmental aspects, which results in an increased social and financial burden on the affected individuals and their families. The management of cleft lip and palate is solely based on following a multidisciplinary team approach. In this narrative review article, we briefly summarize the different genetic causes of orofacial clefts and discuss some of the common syndromes and the approach to the management of orofacial clefts.

Van Der Woude Syndrome: A Case Series at Chu D' Treichville, Abidjan, Cote D' Ivoire

Background

Van der Woude syndrome (VWS), characterised mainly by lower lip pits and orofacial cleft (OFC), is the most common syndrome associated with an OFC. It is inherited as an autosomal dominant, high penetrance disorder with variable phenotypic expression and caused by the genetic mutation of the interferon regulatory factor 6 gene (IRF6). This study showcases the syndrome's variable phenotypic expressivity in six cases seen at Chu d' Treichvile, Abidjan, and Cote d'Ivoire.

Materials and Methods

A review of six cases at the above-named hospital. Data collected include age at presentation, gender, type of cleft, presence or absence of lip pits, and family history of VWS.

Results

Six cases of VWS were reviewed with an age range from 2 to 39 years and a male-to-female ratio of 1:2. Three of the patients had a bilateral cleft lip, one case of unilateral cleft lip and palate, another single case of cleft palate only while the sixth patient has no cleft deformity. All the patients have bilateral lower lip pits except one with a single median pit on the lower lip. There is a family history of VWS in three of the patients.

Conclusion

Our study demonstrates the variable expressivity of VWS as different forms of lower lip pits and OFC. The presence of lower lip pits should be a signal for examination of family members to identify other cases and those likely to have cleft babies. Genetic mapping to detect mutation of IRF6 genes will be of tremendous aid in the effective diagnosis of VWS.

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.

The genetic factors contributing to the risk of cleft lip-cleft palate and their clinical utility

Cleft lip and cleft palate (CL/P) are among the most common congenital malformations in neonates and have syndromic or nonsyndromic forms. Nonsyndromic forms of malformation are being reported to be associated with chromosomal DNA modification by teratogenic exposure and to complex genetic contributions of multiple genes. Syndromic forms are shown to be related to chromosomal aberrations or monogenic diseases. There is a growing body of data illustrating the association of several genes with risk of developing this malformation, including genetic defects in T-box transcription factor-22 (TBX22), interferon regulatory factor-6 (IRF6), and poliovirus receptor-like-1 (PVRL1), responsible for X-linked cleft palate, cleft lip/palate-ectodermal dysplasia syndrome, and Van der Woude and popliteal pterygium syndromes, respectively. Genetic variants in MTR, PCYT1A, ASS1, SLC 25A13, GSTM1, GSTT1, SUMO1 BHMT1, and BHMT2 are being reported to be linked with CL/P risk. The etiology of nonsyndromic CLP is still remained to be unknown, although mutations in candidate genes have been found. Here, we provide an overview about the potential variants to be associated with CL/P for identification of the relative risk of CLP with respect to the basis of genetic background and environmental factors (e.g., dietary factors, alcohol use).

Craniofacial characteristics in Van der Woude syndrome

AIM

To describe the particular craniofacial characteristics of Van der Woude syndrome(VWS) patients compared to patients with a non-syndromic cleft(CG1) and to a malocclusive healthy population(CG2).

MATERIAL AND METHODS

Retrospective case-control study. A sample of 110matched-patients was recruited(VWS(n=7),CG1(n=49),CG2(n=49)).Subsequently, 37 radiometric-variables were analysed and the dental-skeletal ages were determined. The intra/inter-observer method errors were quantified.Descriptive statistics were computed, and different inferential analysis tests were used depending on the normality of the data(Chi-square-test,Fisher-exact-test,paired-Student'sT-test,Mann-Whitney´s-test)(p-value<0.05).Pairwise comparisons were corrected by Bonferroni´s criteria.

RESULTS

VW-patients presented specific craniofacial characteristics and morphology. A marked tendency to the vertical growth pattern was found in VW-patients compared to CG1-CG2(p<0.001); at the sagittal level, skeletal class II caused by mandibular retrognathism, with a greatly increased ANB angle compared to CG1(p=0.042). Dental analysis showed that the lower incisor was more retruded and retroclined(p<0.05 in all cases)and the interincisal angulation was increased(p<0.001(CG2)).At the profile level, an open nasolabial angle(p=0.040;CG1) and a more protruding lower lip with respect to the Sn-Pg plane(p=0.040(CG1);p=0.044(CG2))were observed.

CONCLUSIONS

VW-patients present particular characteristics in the facial skeletal structures. There is a critical necessity to increase the evidence regarding specific clinical features and orofacial pathology of rare diseases such as VWS, which will help to these minorities to gain access in the future to a better quality of care with precise treatment and diagnostic necessities.

Mutations in Van Der Woude Families From Ethiopia

BACKGROUND

Van der Woude syndrome (VWS) is the most common syndromic orofacial cleft which accounts for approximately 2% of all cleft lip (CL) and/or palate cases. It is characterized by the presence of lower lip pits, in addition to CL, CL with or without cleft palate, cleft palate only, and hypodontia. It is inherited as an autosomal-dominant trait with almost complete penetrance but variable expressivity, and different variants in IRF6 gene have been reported in different populations around the world including African populations (Ethiopian, Ghanaian, and Nigerian).

METHODS AND FINDINGS

The authors investigated the role of IRF6 in Ethiopian families with VWS. The DNA of 7 families with VWS from Ethiopia were screened by Sanger sequencing. The authors screened all 9 exons of IRF6 and found a novel missense variant in exon 4 (p. Gly65Glu). This variant was predicted to be deleterious/probably damaging by Sift and PolyPhen, respectively. The IRF6 variant (p. Gly65Glu) segregates in the family since it was identified in the father and a sibling.

CONCLUSION

Several of the individuals with lower lip pits in this study did not seek treatment. This is due to lack of awareness about the significance of this minor looking deformity and its consequences, and availability of treatment for birth defects. Therefore, it is important to educate families. Finally, screening for novel variants in known genes has a role in counseling and prenatal diagnosis for high-risk families.

Lower lip pits with sinus tracts in Van der Woude syndrome: a case report and review of the literature

In Van der Woude syndrome (VWS), a rare congenital disease, lower lip pits (LLPs) can cause an aesthetically significant deformity. Surgical treatment of LLPs is necessary if they cause recurrent inflammation or aesthetic problems. Intraoperatively, surgeons should keep in mind the possibility of deep extension of the sinus tract and the relative deficiency of the midline in VWS, which increases the risk of lip disfigurement. Herein, we emphasize the importance of using a tissue-preserving technique to improve aesthetic results in VWS patients with a sinus tract.

Taurodontism in the first permanent molars in Van der Woude syndrome compared to isolated cleft palate

OBJECTIVES

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.

MATERIALS AND METHODS

One hundred and seventy-eight dental panoramic tomographs (DPTs) (105 girls and 73 boys) consisting of 42 VWS patients (x¯=8.55±1.02 years), 42 NSCP patients (x¯=8.59±1.02 years), and 94 normative non-cleft children (x¯=8.79±1.16 years) 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.

RESULTS

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.

CONCLUSION

This study shows a higher prevalence of taurodontism in VWS and NSCP. Most taurodontic molars are hypotaurodontic and most occur bilaterally.

Clinical Findings and Outcomes of Palatal Repair in 9 Patients With Van der Woude Syndrome

INTRODUCTION

Van der Woude syndrome (VWS), an autosomal dominant condition associated with clefts of the lip and/or palate and lower lip pits, is caused by mutations in interferon regulatory factor 6 gene. It is reported to be the most common syndromic cleft worldwide. This case series presents the phenotypic characteristics and treatment outcomes in a group of 9 patients diagnosed with VWS.

METHODS

A retrospective review was performed on records of patients given a diagnosis of VWS presenting to the Department of Plastic Surgery of Sohag University between July 2009 and November 2019. Data analyses included age and sex of affected patients, type of the cleft, associated anomalies, presence of lower lip pits, and history of lower lip pits/cleft in the family and treatment outcomes.

RESULTS

The study identified 9 patients (male = 2, female = 7). Age at first presentation ranged between 1 week and 7 years (mean = 1.3 years). Four patients had bilateral cleft lip and palate and 1 patient had unilateral cleft lip and palate (UCLP), whereas 4 patients had isolated cleft palate. Bilateral lower lip pits were presented in 8 patients, whereas the ninth patient has unilateral pit. Family history was positive in 3 patients. Most patients in this study developed after palatal repair speech problems with an increased rate of secondary surgical procedures needed for correction of velopharyngeal insufficiency.

CONCLUSIONS

All reviewed cases of VWS presented with lower lip pits and cleft palate with or without cleft lip. A positive family history of similar conditions was demonstrated in 33.3% of our patients. This study suggests an increased incidence of secondary palatal surgeries for velopharyngeal insufficiency in patients with VWS; this warrant further studies including control group of nonsyndromic cleft patients.

Congenital Cheek Fistula: A Rare Case of Developmental Abnormality in the Buccal Area

A congenital cheek fistula is a rare malformation in the buccal area. Here, we report the case of a congenital cheek fistula in a 50-year-old woman who visited our clinic with complaints of swelling and pain in her left cheek. Physical examination revealed a small hole in the left corner of the mouth present since birth. She had no other congenital malformations in the maxillofacial region such as an accessory ear and cleft lip. Manual compression of the cheek mass induced serous discharge from the hole. Magnetic resonance imaging (MRI) showed a cystic lesion in the left cheek and a fistula within the orbicularis oris muscle that opened into the small hole. After immediate incision and drainage of the cyst, both the cyst and fistula were surgically resected. The cystic lesion was completely delineated from the boundary of the parotid gland. The orbicularis oris muscle was partially incised to remove the fistula and the surrounding scar tissue. Histopathological examination of the resected specimen revealed a cavity consisting of epithelium inside the fistula. The postoperative course was insignificant. No recurrence of the cyst was observed six months postoperatively. The operative and pathological findings demonstrated that the ectoderm-derived epithelial tissue was enclosed by the mesoderm-derived muscle tissue. The mixture of different germ layer-derived tissues suggested that the fistula was a type of congenital transverse facial cleft induced by malfusion of the mandibular and maxillary prominences during embryonic development. The differential diagnoses of the congenital cheek fistula included orocutaneous fistulas and salivary fistulas. MRI was useful in delineating the border between the lesion and the surrounding tissue.

Dental age, agenesis, and morphological anomalies in individuals with Van der Woude syndrome and isolated cleft palate

OBJECTIVES

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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: REPORT OF TWO CASES”

Van Der Woude syndrome is a rare autosomal dominant condition which is associated with developmental malformations involving lips, palate. This syndrome can be a genetic origin due to Microdeletion of chromosome bands 1q32-q41 and also mutation of Interferon regulatory factor 6 (IRF-6) can be a pathogenic cause. We report two interesting cases of Van Der Woude syndrome with lip pits and orofacial features.

Altered regulation of cell migration in IRF6-mutated orofacial cleft patients-derived primary cells reveals a novel role of Rho GTPases in cleft/lip palate development

Orofacial clefts are the most common congenital craniofacial birth defects. They occur from a failure in cell proliferation and fusion of neural crest cells of the lip buds and/or palatal shelves. In this study, we investigate the genetic basis and molecular mechanisms in primary cells derived from a cleft and lip palate patient presenting van der Woude syndrome (VWS). Since mutations in the integrin genes are widely correlated with VWS, Interferon Regulatory Factor 6 (IRF6) screening was conducted in a cohort of 200 participants presenting with orofacial anomalies. Primary fibroblastic cells derived from the upper right gingiva and palatal regions were isolated and two cellular populations from two participants were obtained: a control with no cleft phenotype and a patient with a cleft phenotype typical of van der Woude syndrome (VWS). IRF6 targeted sequencing revealed mutations in two distinct families. Our results showed no alteration in the viability of the CLP/VWS patient cells, suggesting the phenotype associate with the disease is not secondary to a defect in cell proliferation. We did however detect a significant decrease in the migratory ability of the CLP with Van der Woude syndrome (CLP/VWS) patient cells, which could account for the phenotype. When compared to normal cells, patient cells showed a lack of polarization, which would account for their lack of mobility. Patient cells showed protrusions all around the cells and a lack of defined leading edge. This was reflected with actin staining, WAVE2 and Arp2 around the cell, and correlated with an increase in Rac1 activation. Consistently with the increase in Rac1 activation, patient cells showed a loss in the maturation of focal adhesions needed for contractility, which also accounts for the lack in cell migration. Our findings give increased understanding of the molecular mechanisms of VWS and expands the knowledge of van der Woude syndrome (VWS) occurrence by providing a strong molecular evidence that CLP with Van der Woude syndrome (CLP/VWS) phenotype is caused by a defect in normal physiological processes of cells.

Orofacial clefts embryology, classification, epidemiology, and genetics

Orofacial clefts (OFCs) rank as the second most common congenital birth defect in the United States after Down syndrome and are the most common head and neck congenital malformations. They are classified as cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO). OFCs have significant psychological and socio-economic impact on patients and their families and require a multidisciplinary approach for management and counseling. A complex interaction between genetic and environmental factors contributes to the incidence and clinical presentation of OFCs. In this comprehensive review, the embryology, classification, epidemiology and etiology of clefts are thoroughly discussed and a "state-of-the-art" snapshot of the recent advances in the genetics of OFCs is presented.

Screening of IRF6 Variants in Patients Subjected to Genetic Association Studies for Nonsyndromic Cleft Lip/Palate

OBJECTIVE

To screen for interferon regulatory factor 6 (IRF6) pathogenic variants in patients clinically diagnosed with nonsyndromic cleft lip palate (NSCL/P) and establish the proportion of misdiagnosed Van der Woude syndrome (VWS) cases, which could have biased previous NSCL/P case-control association studies.

DESIGN

Retrospective case series.

SETTING

Tertiary care children's hospital.

PARTICIPANTS

One hundred seventy-two unrelated Mexican patients with NSCL/P, 128 of whom had previously been included in a NSCL/P case-control association study.

MAIN OUTCOMES MEASUREMENTS

Sanger sequencing of the 9 IRF6 exons were performed, all variants respect with sequence reference were reported and classified for their pathogenic significance according to the American College of Medical Genetics and Genomics guidelines.

RESULTS

Seven percent of cases were familial. No pathogenic variant was identified in IRF6. We identified 12 previously reported benign variants; their frequencies did not significantly differ from those reported for individuals of Mexican ancestry. Three of them were uncommon intronic variants not reported in ClinVar. The rs2235371 and rs2235375 variants, which were previously analyzed in a NSCL/P case-control association study (containing 132 patients, 128 of whom were analyzed herein) did not show discordant association results comparing to the 370 controls from the previous study.

CONCLUSIONS

The misdiagnosis of IRF6-related VWS as NSCL/P appears to be infrequent in our sample, suggesting that mutational screening of IRF6 would have a low diagnostic yield in patients with NSCL/P. The absence of IRF6 pathogenic alleles could be related to the application of an exhaustive clinical evaluation that discarded the syndromic forms and/or the low proportion of familial cases included.

A Novel Van der Woude Syndrome-Causing IRF6 Variant Is Subject to Incomplete Non-sense-Mediated mRNA Decay Affecting the Phenotype of Keratinocytes

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.

Clinical Evaluation and Anatomic Variation of the Oral Cavity

Clinicians should be knowledgeable about the anatomy of the oral cavity and variations of normal because of oral and systemic health connections. This article presents an overview of normal and variations of normal anatomy of the oral cavity.

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.

A cleft lip and palate gene, Irf6, is involved in osteoblast differentiation of craniofacial bone

BACKGROUND

Interferon regulatory factor 6 (IRF6) plays a critical role in embryonic tissue development, including differentiation of epithelial cells. Besides orofacial clefting due to haploinsufficiency of IRF6, recent human genetic studies indicated that mutations in IRF6 are linked to small mandible and digit abnormalities. The function of IRF6 has been well studied in oral epithelium; however, its role in craniofacial skeletal formation remains unknown. In this study, we investigated the role of Irf6 in craniofacial bone development using comparative analyses between wild-type (WT) and Irf6-null littermate mice.

RESULTS

Immunostaining revealed the expression of IRF6 in hypertrophic chondrocytes, osteocytes, and bone matrix of craniofacial tissues. Histological analysis of Irf6-null mice showed a remarkable reduction in the number of lacunae, embedded osteocytes in matrices, and a reduction in mineralization during bone formation. These abnormalities may explain the decreased craniofacial bone density detected by micro-CT, loss of incisors, and mandibular bone abnormality of Irf6-null mice. To validate the autonomous role of IRF6 in bone, extracted primary osteoblasts from calvarial bone of WT and Irf6-null pups showed no effect on osteoblastic viability and proliferation. However, a reduction in mineralization was detected in Irf6-null cells.

CONCLUSIONS

Altogether, these findings suggest an autonomous role of Irf6 in regulating bone differentiation and mineralization. Developmental Dynamics 248:221-232, 2019. © 2019 Wiley Periodicals, Inc.

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.

IRF6 rs2235375 single nucleotide polymorphism is associated with isolated non-syndromic cleft palate but not with cleft lip with or without palate in South Indian population

Introduction

Transcription factors are very diverse family of proteins involved in activating or repressing the transcription of a gene at a given time. Several studies using animal models demonstrated the role of transcription factor genes in craniofacial development.

Objective

We aimed to investigate the association of IRF6 intron-6 polymorphism in the non-syndromic cleft lip with or without palate in a South Indian population.

Methods

173 unrelated nonsyndromic cleft lip with or without cleft palate patients and 176 controls without clefts patients were genotyped for IRF6 rs2235375 variant by allele-specific amplification using the KASPar single nucleotide polymorphism genotyping system. The association between interferon regulatory factor-6 gene intron-6 dbSNP208032210:g.G>C (rs2235375) single nucleotide polymorphism and non-syndromic cleft lip with or without palate risk was investigated by chi-square test.

Results

There were significant differences in genotype or allele frequencies of rs2235375 single nucleotide polymorphism between controls and cases with non-syndromic cleft lip with or without palate. IRF6 rs2235375 variant was significantly associated with increased risk of non-syndromic cleft lip with or without palate in co-dominant, dominant (OR: 1.19; 95% CI 1.03–2.51; p = 0.034) and allelic models (OR: 1.40; 95% CI 1.04–1.90; p = 0.028). When subset analysis was applied significantly increased risk was observed in cleft palate only group (OR dominant: 4.33; 95% CI 1.44–12.97; p = 0.005).

Conclusion

These results suggest that IRF6 rs2235375 SNP play a major role in the pathogenesis and risk of developing non-syndromic cleft lip with or without palate.

MR Imaging of the Fetal Face: Comprehensive Review

The human face is a complex anatomic structure with an equally complex embryologic development. Derangement of the developmental process can result in various structural anomalies, which range from a mainly cosmetic deformity, such as cleft lip, to potentially life-threatening conditions such as arhinia. These anomalies (a) can occur as isolated anomalies; (b) can be associated with intracranial, spinal, or dental anomalies; or (c) can be a part of various syndromes, thus serving as diagnostic clues in such cases. Proper evaluation of fetal facial deformities can help in prognostication, family counseling, and prenatal or early postnatal intervention. Ultrasonography (US) is the first line of investigation in these cases. However, when US does not allow complete evaluation of these anomalies owing to its inherent limitations, magnetic resonance (MR) imaging allows comprehensive evaluation of the anomaly itself and also evaluation of various associations and the treatment approach. The embryology of the fetal facial structures is considered with regard to the MR imaging technique and the MR imaging anatomy. The MR imaging features of various structural anomalies are described and classified into six groups, namely, orofacial clefts, orbital anomalies, nasal anomalies, facial masses, external ear anomalies, and abnormal face shape or profile. Also, the key associations and relevant treatment implications are reviewed. The article provides a "one-stop shop" review of these unique disorders-from basic understanding of the embryology to applying the knowledge in clinical practice, helping the interprofessional team and the patients alike. ^©RSNA, 2018.

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.

Diseases of the lips

Heath care providers should be comfortable with normal as well as pathologic findings in the lips, because the lips are highly visible and may display clinical manifestations of local, as well as systemic inflammatory, allergic, irritant, and neoplastic alterations. Fortunately, the lips are easily accessible. The evaluation should include a careful history and physical examination, including visual inspection, as well as palpation of the lips and an examination of associated cervical, submandibular, and submental nodes. Pathologic and microscopic studies, as well as a review of medications, allergies, and habits, may further highlight possible etiologies. Many lip conditions, including premalignant changes, are relatively easy to treat, when the abnormalities are detected early; however, advanced disease and malignancies are challenging for both the patient and clinician. Treatment should be focused on eliminating potential irritants or allergens and treatment of the primary dermatosis. In this paper we review physiologic variants as well as pathologic conditions of the lips.

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.

Grainyhead-like Transcription Factors in Craniofacial Development

Craniofacial development in vertebrates involves the coordinated growth, migration, and fusion of several facial prominences during embryogenesis, processes governed by strict genetic and molecular controls. A failure in any of the precise spatiotemporal sequences of events leading to prominence fusion often leads to anomalous facial, skull, and jaw formation-conditions termed craniofacial defects (CFDs). Affecting approximately 0.1% to 0.3% of live births, CFDs are a highly heterogeneous class of developmental anomalies, which are often underpinned by genetic mutations. Therefore, identifying novel disease-causing mutations in genes that regulate craniofacial development is a critical prerequisite to develop new preventive or therapeutic measures. The Grainyhead-like ( GRHL) transcription factors are one such gene family, performing evolutionarily conserved roles in craniofacial patterning. The antecedent member of this family, Drosophila grainyhead ( grh), is required for head skeleton development in fruit flies, loss or mutation of Grhl family members in mouse and zebrafish models leads to defects of both maxilla and mandible, and recently, mutations in human GRHL3 have been shown to cause or contribute to both syndromic (Van Der Woude syndrome) and nonsyndromic palatal clefts. In this review, we summarize the current knowledge regarding the craniofacial-specific function of the Grainyhead-like family in multiple model species, identify some of the major target genes regulated by the Grhl transcription factors in craniofacial patterning, and, by examining animal models, draw inferences as to how these data will inform the likely roles of GRHL factors in human CFDs comprising palatal clefting. By understanding the molecular networks regulated by Grhl2 and Grhl3 target genes in other systems, we can propose likely pathways that mediate the effects of these transcription factors in human palatogenesis.

Multidisciplinary management of a patient with van der Woude syndrome: A case report

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We described the orthodontic treatment of a girl diagnosed with VWS.

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Multidisciplinary techniques resulted in satisfactory outcomes.

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Genetic testing determined a known putative splice site mutation.

Introduction

Van der Woude syndrome (VWS) is the most frequent form of syndromic cleft lip and palate (SCLP) accounting for 2% of all patients with CLP.

Case presentation

We describe the orthodontic treatment of a girl diagnosed with VWS referred by her family dentist for her cosmetic concerns.

Discussion

Comprehensive orthodontic treatment, secondary bone graft, distraction osteogenesis (for a deficient maxilla), secondary palatoplasty and excision of lower lip pits, as well as orthodontic and prosthetic procedures may provide a satisfactory outcome. Genetic testing showed a known putative splice site mutation (c.174 + 1 G/A) as the prime cause of VWS in our patient and her family.

Conclusion

SCLP has significant effects on facial aesthetics and the psychosocial status. Parents should be assessed and counseled appropriately. This condition is treatable in the absence of life threatening systemic anomalies. An interdisciplinary team approach is advocated.

Association between IRF6 and 8q24 polymorphisms and nonsyndromic cleft lip with or without cleft palate: Systematic review and meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis of interferon regulatory factor 6 and 8q24 polymorphisms with nonsyndromic cleft lip with/without cleft palate (NSCL/P).

METHODS

Data extraction was independently performed by two reviewers. Genotypic effects of four polymorphisms from 31 studies were pooled separately by ethnicity using a mixed-effect logit model with accounting for heterogeneity.

RESULTS

For rs2235371, AA and GA carried, respectively, 51% (95% confidence interval [CI], 37%-61%) and 42% (95% CI, 32%-50%) lower risks of NSCL/P than GG genotypes in Asians, but these genotypes were not significant in Caucasians. For rs2013162, only AA was significant, that is, carried 0.65 (95% CI, 0.52-0.82) times lower odds than CC in Caucasians but not for Asians. For rs642961, AA and GA genotypes, respectively, carried 2.47 (95% CI, 1.41-4.35) and 1.40 (95% CI, 1.12-1.75) times higher odds in Asian, and 2.03 (95% CI, 1.52-2.71) and 1.58 (95% CI, 1.37-1.82) times higher odds in Caucasians compare with GG genotypes. For rs987525, AA and CA genotypes carried 2.27 (95% CI, 1.43-3.60) and 1.34 (95% CI, 1.02-1.77) times higher odds in Asian, and 5.25 (95% CI, 3.98-6.91) and 2.13 (95% CI-1.82, 2.49) times higher odds in Caucasians, and 1.42 (95% CI, 1.10-1.82) and 1.28 (95% CI, 1.09-1.50) times higher odds in mixed ethnicities compared with CC genotypes. These variant effects remained significant based on applying Bonferroni corrected-thresholds, except in the mixed ethnicity.

CONCLUSION

We show robust variant effects in NSCL/P. Considering them with other genes and risk factors might be useful to improve prediction of NSCL/P occurrence. Birth Defects Research (Part A) 106:773-788, 2016. © 2016 The Authors Birth Defects Research Part A: Clinical and Molecular Teratology Published by Wiley Periodicals, Inc.

Management of Lip Pits in Van der Woude Syndrome: A Clinical Classification With Difficulty Index

PURPOSE

Numerous case reports have been published on lip pits in Van der Woude syndrome explaining the morphology and genetics in detail; however, thus far, no article has focused on the classification of lip pits as an aid in surgical management. Although the procedure for lip pits in Van der Woude syndrome appears straightforward, even in the best of hands, the excision can be very challenging with no guarantee of esthetically desirable results. Therefore, we have devised a classification based on a difficulty index in the management of lower lip pits to assist in predicting the treatment outcome before surgery, as well as to offer the choice of a particular technique in a specific situation.

MATERIALS AND METHODS

We reviewed 19 cases of Van der Woude syndrome having lower lip pits that were operated on at our unit from May 2005 to June 2015 with a minimum follow-up of at least 6 months. The data analyzed included the patient's age and gender, location of the lip pits with regard to their proximity to the white skin roll, number of lip pits, presurgical depth of the lip pits, and discharge of mucous secretion from the pits, as well as timing of lip pit excision. Four techniques of excision were performed via routine excision, modified routine excision, vertical wedge excision, and inverted-T lip reduction. The data were tabulated and analyzed. On the basis of our experience in managing lip pits, a clinically relevant classification with a difficulty index was then proposed.

RESULTS

Among the 12 patients having preoperative involvement of the white skin roll, 8 had distortion of the white skin roll when operated on by either routine excision (n = 2), modified routine excision (n = 3), or inverted-T lip reduction (n = 3). The remaining 4 patients had no distortion of the white skin roll after surgery when the vertical wedge excision technique was performed. The 7 patients who had no distortion of the white skin roll preoperatively presented with esthetic results when operated on by either the routine excision, modified routine excision, or inverted-T lip reduction technique. In 2 patients with a presurgical pit depth greater than 6 mm, mucocele formation was observed after surgery. Using the data obtained, we proposed a classification based on 2 parameters: involvement of the white skin roll and presurgical depth. A difficulty index also was proposed using these same variables.

CONCLUSIONS

Classification and evaluation of the difficulty of lip pit excision are essential in planning the surgical treatment to give improved esthetic results. This proposed classification and difficulty index will provide the operating surgeon with a standardized scheme to evaluate the difficulty of the excision as well as to predict the overall outcome of the procedure before surgery.

Prenatal diagnosis and management of Van der Woude syndrome

We report the postnatal diagnosis of Van der Woude syndrome (VWS) in a foetus found to have an isolated right cleft lip and palate by ultrasound examination. After prenatal genetic counselling, the parents declined further evaluation by amniocentesis. At delivery, the infant was also found to have labial pits in the lower lip in addition to the cleft lip and palate identified by ultrasound consistent with VWS. Although VWS is rare, its autosomal dominant inheritance and variable penetrance should prompt additional modalities to more thoroughly evaluate the extent of other organ system and more extensive craniofacial anomalies.

Recognizable syndromes in the newborn period

Making the diagnosis of genetic syndromes in the neonatal period can be challenging, as limited information concerning growth and development is available. The pattern of dysmorphic features and malformations is, therefore, correspondingly more important in syndrome recognition. The authors provide specific examples of the differences in the presentation for selected syndromes between the newborn period and later childhood. The purpose is to describe the variation in presentation that can occur with chronologic age and to aid in the early diagnosis of these conditions.