Palatal evaluation and treatment in 22q11.2 deletion syndrome

Comparative Study of Pharyngeal Flap Outcomes between Children with 22q11.2 Deletion Syndrome and Nonsyndromic Cleft Lip and Palate

BACKGROUND

Management of velopharyngeal insufficiency (VPI) in 22q11.2 deletion syndrome is challenging. The authors compared pharyngeal flap outcomes in children with 22q11.2 deletion syndrome to those with nonsyndromic cleft lip and palate (CLP) to assess risk of poor speech outcomes and negative sequelae.

METHODS

Children with 22q11.2 deletion syndrome or CLP treated with pharyngeal flap through a multidisciplinary VPI clinic between 2009 and 2020 were retrospectively reviewed. Preoperative and postoperative speech assessments, perioperative characteristics, and complications were identified.

RESULTS

Thirty-six children with 22q11.2 deletion syndrome and 40 with CLP were included. Age at surgery ( P = 0.121), preoperative velopharyngeal competence score ( P = 0.702), and preoperative resonance ( P = 0.999) were similar between groups. Pharyngeal flaps were wider ( P = 0.038) and length of stay longer in the 22q11.2 deletion syndrome group ( P = 0.031). On short-term follow-up 4 months after surgery, similar speech outcomes were seen between groups. At long-term follow-up greater than 12 months after surgery, 86.7% of 22q11.2 deletion syndrome versus 100% of CLP ( P = 0.122) children had improvement in velopharyngeal function; however, fewer children with 22q11.2 deletion syndrome (60.0%) achieved a completely "competent" velopharyngeal competence score compared with those with CLP (92.6%) ( P = 0.016). Nasal regurgitation improved for both groups, with a greater improvement in those with 22q11.2 deletion syndrome ( P = 0.026). Revision rate ( P = 0.609) and new-onset obstructive sleep apnea ( P = 0.999) were similar between groups.

CONCLUSIONS

Children with 22q11.2 deletion syndrome have improved speech after pharyngeal flap, but they may be less likely to reach normal velopharyngeal function over the long term than those with CLP; however, negative sequelae do not differ. Improvement in nasal regurgitation is a uniquely positive outcome in this population.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Assessing Complication Risk of Pressure Equalizing Tube Placement in Children With Velocardiofacial Syndrome (22q11.2 Deletion Syndrome/DiGeorge Syndrome)

INTRODUCTION

Persistent tympanic membrane perforation is a known complication of pressure-equalizing (PE) tube insertion. Conductive hearing loss and otorrhea can necessitate surgical repair of these perforations. Long-term tympanostomy tube placement can increase the risk of these complications. Patients with velocardiofacial syndrome (VCFS) typically require prolonged PE tube placement and are thought to have higher risk of requiring additional otologic interventions after PE tube placement. To date, no work has established rates of post-PE tube complications requiring myringoplasty or tympanoplasty in patients with VCFS.

METHODS

A retrospective case review including all patients with VCFS at a single large children's hospital between the years 2000 and 2020 was performed. Number of PE tube insertions required and additional otologic interventions performed were the primary endpoints assessed.

RESULTS

Of 212 total patients with VCFS, 66 (31%) underwent PE tube placement. Of these children, 46 (70%) required 2 or more sets of PE tubes. A total of 53 patients (80.3%) required no otologic interventions apart from PE tube insertions. Of the 13 patients (19.7%) requiring additional otologic surgery, 6 (9.5%) underwent myringoplasty, and 9 patients (13.6%) required tympanoplasty. There was no significant difference in tympanoplasty (P > 1), myringoplasty (P > 1), or other surgical intervention rates (P = .7464) between VCFS patients with any type of cleft palate versus those with anatomically normal palates.

CONCLUSION

This work suggests that most VCFS patients that require tubes, require at least 2 sets of PE tubes, and that the rate of post-PE tube complications requiring further otologic surgery is an order of magnitude higher than the rate established at this institution. Counseling for PE tube placement in VCFS patients may require specific dialogue regarding the substantially increased risk of complications and effort to build appropriate expectations for surgical outcomes regardless of palatal status.

Sphincter Pharyngoplasty for Velopharyngeal Dysfunction: Impact of 22q11.2 Deletion Syndrome

OBJECTIVE

Patients with 22q11.2 deletion syndrome (22q11DelS) often present with velopharyngeal dysfunction (VPD). VPD in patients with 22q11DelS is multifactorial beyond velopharyngeal insufficiency (VPI) alone, and differences in surgical outcomes are poorly understood. Our objective was to determine whether patients with 22q11DelS have an increased risk for persistent VPI after sphincter pharyngoplasty compared to patients without 22q11DelS.

METHODS

We completed a retrospective cohort study of patients with 22q11DelS undergoing sphincter pharyngoplasty between 1995 and 2019 using a VPD clinic database. Patients with 22q11DelS were compared to a cohort of 2:1 frequency-matched (age, degree of velopharyngeal closure) patients without 22q11DelS. Variables included patient characteristics, surgical history, perceptual speech evaluation, and degree of closure on nasopharyngoscopic evaluations. Primary outcomes included postoperative VPI severity and hypernasality. Speech and nasopharyngoscopic characteristics were compared using Fisher's exact test. Postoperative VPI severity and hypernasality were compared between groups via relative risks (RR) from mixed effects Poisson regression models, with random effects of age and velopharyngeal closure.

RESULTS

134 patients (51 22q11DelS, 83 matched) were included, with mean age of 7.3 years (standard deviation 3.0) and 50% male. Cohorts had similar preoperative speech characteristics and nasopharyngoscopic findings. Patients with 22q11DelS had similar postoperative VP function as patients without 22q11DelS (RR 0.85, CI 0.46-1.57 for VPI severity, RR 0.83, CI 0.45-1.53 for hypernasality). Even after adjusting by preoperative variables, no differences were seen between both groups.

CONCLUSION

Matched for age and pre-operative velopharyngeal closure, patients with and without 22q11DelS and VPI had similar benefits after sphincter pharyngoplasty.

LEVEL OF EVIDENCE

Non-randomized controlled cohort study, 3 Laryngoscope, 133:2813-2820, 2023.

Identification of a new familial case of 3q29 deletion syndrome associated with cleft lip and palate via whole-exome sequencing

Many unbalanced large copy number variants reviewed in the paper are associated with syndromic orofacial clefts, including a 1.6 Mb deletion on chromosome 3q29. The current report presents a new family with this recurrent deletion identified via whole-exome sequencing and confirmed by array comparative genomic hybridization. The proband exhibited a more severe clinical phenotype than his affected mother, comprising right-sided cleft lip/alveolus and cleft palate, advanced dental caries, heart defect, hypospadias, psychomotor, and speech delay, and an intellectual disability. Data analysis from the 3q29 registry revealed that the 3q29 deletion increases the risk of clefting by nearly 30-fold. No additional rare and pathogenic nucleotide variants were identified that could explain the clefting phenotype and observed intrafamilial phenotypic heterogeneity. These data suggest that the 3q29 deletion may be the primary risk factor for clefting, with additional genomic variants located outside the coding sequences, methylation changes, or environmental exposure serving as modifiers of this risk. Additional studies, including whole-genome sequencing or methylation analyses, should be performed to identify genetic factors underlying the phenotypic variation associated with the recurrent 3q29 deletion.

Different Types of Deletions Created by Low-Copy Repeats Sequences Location in 22q11.2 Deletion Syndrome: Genotype-Phenotype Correlation

The most frequent microdeletion, 22q11.2 deletion syndrome (22q11.2DS), has a wide and variable phenotype that causes difficulties in diagnosis. 22q11.2DS is a contiguous gene syndrome, but due to the existence of several low-copy-number repeat sequences (LCR) it displays a high variety of deletion types: typical deletions LCR A-D-the most common (~90%), proximal deletions LCR A-B, central deletions (LCR B, C-D) and distal deletions (LCR D-E, F).

METHODS

We conducted a retrospective study of 59 22q11.2SD cases, with the aim of highlighting phenotype-genotype correlations. All cases were tested using MLPA combined kits: SALSA MLPA KIT P245 and P250 (MRC Holland).

RESULTS

most cases (76%) presented classic deletion LCR A-D with various severity and phenotypic findings. A total of 14 atypical new deletions were identified: 2 proximal deletions LCR A-B, 1 CES (Cat Eye Syndrome region) to LCR B deletion, 4 nested deletions LCR B-D and 1 LCR C-D, 3 LCR A-E deletions, 1 LCR D-E, and 2 small single gene deletions: delDGCR8 and delTOP3B.

CONCLUSIONS

This study emphasizes the wide phenotypic variety and incomplete penetrance of 22q11.2DS. Our findings contribute to the genotype-phenotype data regarding different types of 22q11.2 deletions and illustrate the usefulness of MLPA combined kits in 22q11.2DS diagnosis.

Craniofacial Phenotypes and Genetics of DiGeorge Syndrome

The 22q11.2 deletion is one of the most common genetic microdeletions, affecting approximately 1 in 4000 live births in humans. A 1.5 to 2.5 Mb hemizygous deletion of chromosome 22q11.2 causes DiGeorge syndrome (DGS) and velocardiofacial syndrome (VCFS). DGS/VCFS are associated with prevalent cardiac malformations, thymic and parathyroid hypoplasia, and craniofacial defects. Patients with DGS/VCFS manifest craniofacial anomalies involving the cranium, cranial base, jaws, pharyngeal muscles, ear-nose-throat, palate, teeth, and cervical spine. Most craniofacial phenotypes of DGS/VCFS are caused by proximal 1.5 Mb microdeletions, resulting in a hemizygosity of coding genes, microRNAs, and long noncoding RNAs. TBX1, located on chromosome 22q11.21, encodes a T-box transcription factor and is a candidate gene for DGS/VCFS. TBX1 regulates the fate of progenitor cells in the cranial and pharyngeal apparatus during embryogenesis. Tbx1-null mice exhibit the most clinical features of DGS/VCFS, including craniofacial phenotypes. Despite the frequency of DGS/VCFS, there has been a limited review of the craniofacial phenotypes of DGC/VCFS. This review focuses on these phenotypes and summarizes the current understanding of the genetic factors that impact DGS/VCFS-related phenotypes. We also review DGS/VCFS mouse models that have been designed to better understand the pathogenic processes of DGS/VCFS.

Clinical evaluation of patients with a neuropsychiatric risk copy number variant

Several copy number variants (CNVs) have been identified to confer high risk for a range of neuropsychiatric conditions. Because of advances in genetic testing within clinical settings, patients are increasingly receiving diagnoses of copy number variant genomic disorders. However, clinical guidelines surrounding assessment and management are limited. This review synthesises recent research and makes preliminary recommendations regarding the clinical evaluation of patients with neuropsychiatric risk CNVs. We recommend multi-system assessment beyond the initial referral reason, recognition of the potential need for co-ordinated multidisciplinary care, and that interventions take account of relevant multimorbidity. The frequently complex needs of patients with CNVs across the life-course pose challenges for many health care systems and may be best provided for by the establishment of specialist clinics.

Characteristics of velopharyngeal dysfunction in 22q11.2 deletion syndrome: a retrospective case-control study

Objective

To identify and describe the dynamic features of velopharyngeal dysfunction (VPD) in patients with 22q11.2 deletion syndrome relative to patients with non-syndromic cleft palates.

Study design

Retrospective case-control study.

Setting

Pediatric tertiary care center.

Subjects and methods

A total of 30 children (aged 9–16 years) with VPD were included in this study. Fifteen children with a definitive diagnosis of 22q11.2 deletion syndrome requiring surgical VPD repair were included in the 22q11.2 deletion syndrome group. Fifteen age- and sex-matched children with non-syndromic cleft palate requiring surgical VPD repair were included in the non-syndromic cleft palate group for comparison. Velar displacement, lateral pharyngeal wall displacement, and lateral pharyngeal wall motion pattern data were extracted from preoperative Multiview Videofluoroscopy imaging studies of all children and compared across groups.

Results

Lateral pharyngeal wall displacement was found to be reduced in the 22q11.2 deletion syndrome group (U = 29.50, p = .001, r = .63). However, measures of velar displacement were not observed to differ between groups. Similarly, lateral pharyngeal wall motion pattern distributions were not found to differ across these two groups.

Conclusions

Velopharyngeal dysfunction in patients with 22q11.2 deletion syndrome showed differences in dynamic velopharyngeal function when compared to non-syndromic cleft palate patients. The current findings provide initial insights into the unique aspects of velopharyngeal dysfunction for patients with 22q11.2 deletion syndrome. These findings may guide further efforts directed toward understanding the dynamic velopharyngeal characteristics of this population and potentially optimize surgical management and functional outcomes.

Candidate modifier genes for immune function in 22q11.2 deletion syndrome

Background

The 22q11.2 deletion syndrome (22q11.2DS) is the most common contiguous microdeletion affecting humans and exhibits extreme phenotypic heterogeneity. Patients can manifest any combination of comorbidities including congenital heart disease, hypoparathyroidism, cleft palate, kidney abnormalities, neurodevelopmental disorders, and immune dysfunction. Immunodeficiency is present in the majority of patients with 22q11.2DS and is the second leading cause of death in these patients. Knowing the genetic determinants of immune dysfunction will aid in prognostication and potentially novel treatments.

Methods

We performed exome sequencing and gene‐based variant association analysis on 31 deeply phenotyped individuals with the canonical 3Mb 22q11.2 deletion to identify what genes outside the 22q11.2 locus may be modifying the immune dysregulated phenotype. Immunophenotyping was performed using preexisting medical data and a novel scoring system developed from numerous clinical laboratory values including immunoglobulin levels, lymphocyte transformation to antigens (LTA), lymphocyte transformation to mitogens (LTM), and peripheral blood flow cytometry. Immunophenotypic scoring was validated against newborn screening T‐cell receptor excision circle (TREC) results.

Results

Rare DNA variants in transcriptional regulators involved in retinoic acid signaling (NCOR2, OMIM *600848 and EP300, OMIM *602700) were found to be associated with immunophenotype.

Conclusion

The expression of TBX1, which seems to confer the major phenotypic features of 22q11.2DS, is regulated via retinoic acid signaling, and alterations in retinoic acid signaling during embryonic development can lead to phenocopies of 22q11.2DS. These observations support the hypothesis that genetic modifiers outside the microdeletion locus may influence the immune function in 22q11.2DS patients.