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

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.

Cleft Lip and Palate in Ectodermal Dysplasia

OBJECTIVE

Ectodermal dysplasia (ED) comprises multiple syndromes that affect skin, hair, nails, and teeth, and sometimes are associated with orofacial clefting. The purpose of this study is to (1) identify the prevalence and characteristics of cleft lip and/or palate (CL/P) in patients with ED and (2) describe the management and outcomes.

DESIGN

Retrospective review from 1990 to 2019.

PATIENTS

All patients with ED treated at Boston Children's Hospital.

MAIN OUTCOMES MEASURES

Prevalence of CL/P was calculated and clinical details recorded: phenotypic anomalies, cleft type, operative treatment, and results of repair.

RESULTS

Of 170 patients with a purported diagnosis of ED, 24 (14%) had CL/P. Anatomic categories were bilateral CL/P (67%), unilateral CL/P (8%), and cleft palate only (25%). The most common ED syndrome (37%) was ectrodactyly, ectodermal dysplasia, and cleft lip/palate (EEC). Pathogenic variants in TP63 were the most frequent finding in the 11 patients who had genetic testing. Aberrations from a typical clinical course included failure of presurgical dentofacial orthopedics, dehiscence of nasolabial adhesion, and total palatal absence requiring free-flap construction. Two patients had prolonged postoperative admission for respiratory infection. High fistula (8%) and velopharyngeal insufficiency (33%) rates reflected the predominance of bilateral complete forms.

CONCLUSIONS

As in other types of syndromic CL/P, cleft phenotypic expression in ED is more severe than the general cleft population. Further studies are needed to correlate genotype and phenotype for the distinct syndromes included in the ED spectrum.

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.

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.