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

Effect of Veau Class on Levator Veli Palatini Muscle Composition

OBJECTIVE

To examine levator veli palatini muscle composition in patients with nonsyndromic cleft palate and investigate the impact of Veau class.

DESIGN

Prospective cohort study.

SETTING

Tertiary care academic hospital.

PATIENTS/PARTICIPANTS

Thirteen patients with nonsyndromic cleft palate were recruited.

INTERVENTIONS

During primary palatoplasty, a sample of levator veli palatini muscle was excised and prepared for histological analysis.

MAIN OUTCOME MEASURES

Fat and collagen content were determined utilizing Oil Red and Sirius red stains, respectively, while muscle fiber cross-sectional areas were calculated from H&E-stained samples, with analysis using histomorphometric methods. Immunofluorescent staining of myosin heavy chain isoforms was performed.

RESULTS

Patients underwent repair at 10.8 months of age (interquartile range [IQR] 10.2-12.9). Fat content of the levator veli palatini muscle was low in both groups, ranging from 0% to 5.2%. Collagen content ranged from 8.5% to 39.8%; neither fat nor collagen content showed an association with Veau classes. Mean muscle fiber cross-sectional area decreased with increasing Veau class, from 808 µm2 (range 692-995 µm2) in Veau II to 651 µm2 (range 232-750 µm2) in Veau III (P = .02). There was also a nonsignificant decrease in proportion of type I muscle fibers with increasing Veau class (44.3% [range 31.4%-84.4%] in Veau II vs 35.3% [range 17.4%-61.3%] in Veau III).

CONCLUSIONS

Muscle fiber area in levator veli palatini muscles decreases in Veau III clefts in comparison to Veau II. The impact of these differences in velopharyngeal dysfunction requires further analysis of a larger cohort.

DNA methylation differences in monozygotic twins with Van der Woude syndrome

Introduction

Van der Woude Syndrome (VWS) is an autosomal dominant disorder responsible for 2% of all syndromic orofacial clefts (OFCs) with IRF6 being the primary causal gene (70%). Cases may present with lip pits and either cleft lip, cleft lip with cleft palate, or cleft palate, with marked phenotypic discordance even among individuals carrying the same mutation. This suggests that genetic or epigenetic modifiers may play additional roles in the syndrome's etiology and variability in expression. We report the first DNA methylation profiling of 2 pairs of monozygotic twins with VWS. Our goal is to explore epigenetic contributions to VWS etiology and variable phenotypic expressivity by comparing DNAm profiles in both twin pairs. While the mutations that cause VWS in these twins are known, the additional mechanism behind their phenotypic risk and variability in expression remains unclear.

Methods

We generated whole genome DNAm data for both twin pairs. Differentially methylated positions (DMPs) were selected based on: (1) a coefficient of variation in DNAm levels in unaffected individuals < 20%, and (2) intra-twin pair absolute difference in DNAm levels >5% (delta beta > | 0.05|). We then divided the DMPs in two subgroups for each twin pair for further analysis: (1) higher methylation levels in twin A (Twin A > Twin B); and (2) higher methylation levels in twin B (Twin B >Twin A).

Results and Discussion

Gene ontology analysis revealed a list of enriched genes that showed significant differential DNAm, including clef-associated genes. Among the cleft-associated genes, TP63 was the most significant hit (p=7.82E-12). Both twin pairs presented differential DNAm levels in CpG sites in/near TP63 (Twin 1A > Twin 1B and Twin 2A < Twin 2B). The genes TP63 and IRF6 function in a biological regulatory loop to coordinate epithelial proliferation and differentiation in a process that is critical for palatal fusion. The effects of the causal mutations in IRF6 can be further impacted by epigenetic dysregulation of IRF6 itself, or genes in its pathway. Our data shows evidence that changes in DNAm is a plausible mechanism that can lead to markedly distinct phenotypes, even among individuals carrying the same mutation.

Novel de novo missense mutation in the interferon regulatory factor 6 gene in an Italian infant with IRF6-related disorder

Background

Congenital maxillomandibular syngnathia is a rare craniofacial anomaly leading to difficulties in feeding, breathing and ability to thrive. The fusion may consist of soft tissue union (synechiae) to hard tissue union. Isolated cases of maxillomandibular fusion are extremely rare, it is most often syndromic in etiology.

Case presentation

Clinical management of a female newborn with oromaxillofacial abnormities (synechiae, cleft palate, craniofacial dysmorphisms, dental anomaly) and extraoral malformations (skinfold overlying the nails of both halluces, syndactyly, abnormal external genitalia) is presented. The associated malformations addressed to molecular genetic investigations revealing an interferon regulatory factor 6 (IRF6)-related disorder (van der Woude syndrome/popliteal pterygium syndrome). A novel de novo heterozygous mutation in exon 4 of IRF6 gene on chromosome 1q32.2, precisely c.262A > G (p.Asn88Asp), was found. Similarities are discussed with known asparagine missense mutations in the same codon, which may alter IRF6 gene function by reduced DNA-binding ability. A concomitant maternal Xp11.22 duplication involving two microRNA genes could contribute to possible epigenetic effects.

Conclusions

Our reported case carrying a novel mutation can contribute to expand understandings of molecular mechanisms underlying synechiae and orofacial clefting and to correct diagnosing of incomplete or overlapping features in IRF6-related disorders. Additional multidisciplinary evaluations to establish the phenotypical extent of the IRF6-related disorder and to address family counseling should not only be focused on the surgical corrections of syngnathia and cleft palate, but also involve comprehensive otolaryngologic, audiologic, logopedic, dental, orthopedic, urological and psychological evaluations.

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.

Benchmarking Speech, Velopharyngeal Function Outcomes and Surgical Characteristics Following the Sommerlad Protocol and Palate Repair Technique

Objective:

To report speech and velopharyngeal function (VPF) outcomes, and surgical characteristics, at age 5 following early complete palate closure using the Sommerlad protocol.

Design:

A retrospective, descriptive, cross-sectional consecutive series.

Setting:

A regional twin site center; a district general hospital and tertiary children’s hospital.

Participants:

Between 1993 and 2006, 877 participants underwent surgery; 712 (81%) were eligible for inclusion; 391 (55%) were included, 321 (45%) excluded. Thirteen percent had bilateral cleft lip and palate (CLP), 40% unilateral CLP, and 47% isolated cleft palate.

Intervention:

Lip and vomerine flap repair at 3 months of age (BCLP, UCLP) with soft palate closure using radical muscle dissection and retropositioning at a mean age of 6.6 months, range 4 to 23 months, as described and undertaken by Sommerlad.

Outcome Measures:

Velopharyngeal Composite (VPC) CAPS-A and articulation summary scores derived from analysis using the Cleft Audit Protocol for Speech-Augmented.

Results:

A VPC-SUM CAPS-A score of “0” was found in 97% reflecting adequate VPF; 73% had no cleft articulation difficulties. The BCLP group had the poorest articulation. Secondary speech surgery rate was 2.6% and 10.7% had fistula repair. Levator muscle quality and degree of retropositioning was associated with speech outcomes related to VPF. 2.6% had current features of VPI.

Conclusions:

Complete palate closure by around 6 months of age by the surgeon who described the technique led to excellent perceived VPF and very good speech outcomes at age 5, with less speech therapy and secondary speech surgery than commonly reported. These findings serve as a benchmark for the Sommerlad protocol and technique.