Van der woude syndrome with short review of 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.

DNA methylation effects on Van der Woude Syndrome phenotypic variability

OBJECTIVE

Van der Woude Syndrome (VWS) classically presents with combinations of lip pits (LP) and orofacial clefts, with marked phenotypic discordance even amongst individuals carrying the same mutation. Such discordance suggests a possible role for epigenetic factors as phenotypic modifiers. Both IRF6 , causal for 70% of VWS cases, and TP63 interact in a regulatory loop to coordinate epithelial proliferation and differentiation for palatogenesis. We hypothesize that differential DNA methylation (DNAm) in CpG sites within regulatory regions of IRF6 and TP63 are associated with VWS phenotypic discordance.

METHODS

We measured DNAm levels of CpG sites located in the promoter regions of IRF6 and TP63 and in an IRF6 enhancer element (MCS9.7) in 83 individuals with VWS grouped within 5 phenotypes for primary analysis: 1=CL+/-P+LP, 2=CL+/-P, 3=CP+LP, 4=CP, 5=LP and 2 phenotypes for secondary analysis: 1=any cleft and LP, 2= any cleft without LP. DNA samples were bisulfite converted and pyrosequenced with target-specific primers. Methylation levels were compared amongst phenotypes.

RESULTS

CpG sites in the IRF6 promoter showed statistically significant differences in methylation among phenotypic groups in both analyses (P<0.05). Individuals with any form of cleft (Groups 1-4) had significantly higher methylation levels than individuals with lip pits only (Group 5). In the secondary analysis, individuals in Group 1 (cleft+LP) had significantly higher methylation than Group 2 (cleft only).

CONCLUSION

Results indicated that hypermethylation of the IRF6 promoter is associated with more severe phenotypes (any cleft +/- lip pits); thus, possibly impacting an already genetically weakened IRF6 protein and leading to a more severe phenotype.

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.

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.