Clinical, cytogenetic, and molecular outcomes in a series of 66 patients with Pierre Robin sequence and literature review: 22q11.2 deletion is less common than other chromosomal anomalies

Global birth prevalence of Robin sequence in live-born infants: a systematic review and meta-analysis

Robin sequence (RS), a congenital disorder of jaw maldevelopment and glossoptosis, poses a substantial healthcare burden and has long-term health implications if airway obstruction is suboptimally treated. This study describes the global birth prevalence of RS and investigates whether prevalence estimates differ by geographical location, ethnicity or study data source (registry versus non-registry data). The protocol was prospectively registered with PROSPERO.Databases were searched using keywords and subject terms for "Robin sequence", "epidemiology", "incidence" and "birth prevalence". Meta-analysis was performed fitting random effects models with arcsine transformation.From 34 eligible studies (n=2722 RS cases), pooled birth prevalence was 9.5 per 100 000 live births (95% CI 7.1-12.1) with statistical heterogeneity. One third of studies provided a case definition for RS and numerous definitions were used. A total of 22 countries were represented, predominantly from European populations (53% of studies). There was a trend towards higher birth prevalence in European populations and lower prevalence from registry-based studies. Only two studies reported ethnicity.This study indicates that RS occurs globally. To investigate geographical differences in prevalence, additional studies from non-European populations and reporting of ethnicity are needed. Heterogeneity of estimates may be due to variable diagnostic criteria and ascertainment methods. Recently published consensus diagnostic criteria may reduce heterogeneity among future studies.

Epidemiology of Robin sequence in the UK and Ireland: an active surveillance study

BACKGROUND

Birth prevalence of Robin sequence (RS) is commonly reported as 1 case per 8000-14 000 live births. These estimates are based on single-source case ascertainment and may miss infants who did not require hospital admission or those without overt upper airway obstruction at birth.

OBJECTIVES

To identify the true birth prevalence of RS with cleft palate in the UK and Ireland from a population-based birth cohort with high case ascertainment.

METHODS

Active surveillance of RS with cleft palate was carried out in the UK/Ireland using dual sources of case ascertainment: British Paediatric Surveillance Unit (BPSU) reporting card and nationally commissioned cleft services. Clinical data were collected from notifying clinicians at two time points.

RESULTS

173 live-born infants met the surveillance case definition, giving a birth prevalence of 1 case per 5250 live births (19.1 per 100 000 (95% CI 16.2 to 21.9)), and 1:2690 in Scotland. 47% had non-isolated RS, with Stickler syndrome the most common genetic diagnosis (12% RS cases). Birth prevalence derived from the combined data sources was significantly higher than from BPSU surveillance alone.

CONCLUSIONS

Birth prevalence of RS in the UK/Ireland derived from active surveillance is higher than reported by epidemiological studies from several other countries, and from UK-based anomaly registries, but consistent with published retrospective data from Scotland. Dual case ascertainment sources enabled identification of cases with mild or late-onset airway obstruction that were managed without hospital admission. Studies of aetiology and equivalent well-designed epidemiological studies from other populations are needed to investigate the identified geographical variability in birth prevalence.

Associated anomalies in Pierre Robin sequence

Pierre Robin sequence (PRS) is frequently co-occurring with other non-PRS congenital anomalies. The types and the prevalence of anomalies co-occurring with PRS vary in the reported studies. The aims of this report was to study the types and the prevalence of the anomalies co-occurring with PRS in a well-studied population northeastern France. The types and the prevalence of anomalies co-occurring in cases with PRS were ascertained in all terminations of pregnancy, stillbirths and live births in 387,067 births occurring consecutively during the period 1979-2007 in the area covered by our registry of congenital anomalies which is population-based, 89 cases of PRS were registered during the study period with a prevalence of 2.29 per 10,000 births, 69.7% of the cases had associated non-PRS anomalies. Chromosomal abnormalities were present in 10 (11.2%) cases including three 22 q11.2 deletion. Non-chromosomal recognizable conditions were diagnosed in 27 cases (30.3%) including 10 Stickler syndrome, 8 Treacher Collins syndrome, 3 cases with short stature and 6 other syndromes. Multiple congenital anomalies (MCA) were present in 25 cases (28.1%). The most frequent MCA were in the ear, face and neck (35 out of 98 anomalies, 35.7%), cardiovascular (18 anomalies, 18.4%), musculoskeletal (11 anomalies, 11.2%), central nervous (7 anomalies, 7.1%), urinary (6 anomalies, 6.1%), and eye (6 anomalies, 6.1%) system. The high prevalence of associated anomalies justifies a thorough screening for other congenital anomalies in cases with PRS.

Syndromes associated with Robin sequence: a national prospective cohort study

OBJECTIVES

To determine the prevalence of syndromic Robin sequence (RS) in the UK and if this group of patients had an increased need for airway and feeding management compared with a non-syndromic RS cohort.

DESIGN

A prospective national multicentre study of cases submitted to the Cleft Collective cohort studies.

SETTING

Specialist cleft services in the UK.

PATIENTS

259 participants who fulfilled the diagnosis of RS. This group was compared with 548 participants with cleft palate only (CPO).

MAIN OUTCOME MEASURES

The primary outcome measure was the presence of a syndrome in patients with RS and CPO. Secondary outcome measures included the use of airway and feeding adjuncts.

RESULTS

An associated syndrome was seen in 28% of patients with RS and 14% of patients with CPO. The most common syndrome for the RS group was Stickler syndrome (27%). Syndromic status was significantly higher among patients with RS compared with those with CPO (OR 2.36, 95% CI 1.65 to 3.39; p<0.001). Patients with syndromic RS have an increased reliance on airway adjuncts compared with the patients without syndromic RS (OR 2.02, 95% CI 1.13 to 3.64; p=0.018). There was no evidence of a difference in the use of feeding adjuncts between syndromic and non-syndromic RS groups (OR 2.43, 95% CI 0.78 to 7.58; p=0.126).

CONCLUSION

The presence of a syndrome has implications for management of patients with RS. Early identification of a syndrome may help prevent the consequences of a missed syndromic diagnosis. Routine ophthalmological and genetic screening for Stickler syndrome should be mandatory for all patients with RS.

Disrupted tenogenesis in masseter as a potential cause of micrognathia

Micrognathia is a severe craniofacial deformity affecting appearance and survival. Previous studies revealed that multiple factors involved in the osteogenesis of mandibular bone have contributed to micrognathia, but concerned little on factors other than osteogenesis. In the current study, we found that ectopic activation of Fgf8 by Osr2-cre in the presumptive mesenchyme for masseter tendon in mice led to micrognathia, masseter regression, and the disrupted patterning and differentiation of masseter tendon. Since Myf5-cre;Rosa26R-Fgf8 mice exhibited the normal masseter and mandibular bone, the possibility that the micrognathia and masseter regression resulted directly from the over-expressed Fgf8 was excluded. Further investigation disclosed that a series of chondrogenic markers were ectopically activated in the developing Osr2-cre;Rosa26R-Fgf8 masseter tendon, while the mechanical sensing in the masseter and mandibular bone was obviously reduced. Thus, it suggested that the micrognathia in Osr2-cre;Rosa26R-Fgf8 mice resulted secondarily from the reduced mechanical force transmitted to mandibular bone. Consistently, when tenogenic or myogenic components were deleted from the developing mandibles, both the micrognathia and masseter degeneration took place with the decreased mechanical sensing in mandibular bone, which verified that the loss of mechanical force transmitted by masseter tendon could result in micrognathia. Furthermore, it appeared that the micrognathia resulting from the disrupted tenogenesis was attributed to the impaired osteogenic specification, instead of the differentiation in the periosteal progenitors. Our findings disclose a novel mechanism for mandibular morphogenesis, and shed light on the prevention and treatment for micrognathia.

Next Generation Sequencing and Cytogenetic Based Evaluation of Indian Pierre Robin Sequence Families Reveals CNV Regions of Modest Effect and a Novel LOXL3 Mutation

BACKGROUND

Pierre Robin Sequence (PRS) affects approximately 1 per 8500 to 14000 new-borns worldwide. Although the clinical entity is well defined, the pathogenesis of PRS is debated. The present study aims to understand the contribution of genomic imbalances and genetic variants in patients clinically diagnosed of PRS.

METHODOLOGY

A total of 7 independent patients with nonsyndromic PRS thoroughly evaluated by a medical geneticist at a tertiary care hospital, were included in the study. Blood samples were collected from these patients and their family members. Array CGH was performed on all 7 patients and their respective family members for detection of underlying cytogenetic defects. Whole exome sequencing (WES) was performed for 5 families to capture single nucleotide variants or small indels.

RESULTS

Cytogenetic analyses did not detect any previously reported gross chromosomal aberrations for PRS in the patient cohort. However, copy number variations (CNVs) of size <1 Mb were detected in patients which may have implications in PRS. The present study provided evidence for the occurrence of de novo deletions at 7p14.1 locus in PRS patients: further validating the candidate loci susceptibility in oral clefts. WES data identified LOXL3 as candidate gene, carrying novel deleterious variant, which is suggestive of the role of point mutations in the pathogenesis of PRS.

CONCLUSION

The present study offered considerable insight into the contribution of cytogenetic defects and novel point mutation in the etiology of nonsyndromic PRS. Studies comprising large number of cases are required to fully elucidate the genetic mechanisms underlying the PRS phenotype.

Robin sequence without cleft palate: Genetic diagnoses and management implications

Robin sequence (RS), the triad of micrognathia, glossoptosis, and airway obstruction, is a major cause of respiratory distress and feeding difficulties in neonates. Robin sequence can be associated with other medical or developmental comorbidities in ~50% of cases ("syndromic" RS). As well, RS is variably associated with cleft palate (CP). Previous studies have not investigated differences in clinical characteristics of children with RS based on presence or absence of CP. We retrospectively reviewed 175 children with RS and compared genetic diagnoses, medical and developmental comorbidities, severity of airway obstruction, and feeding outcomes between those with and without CP. Strikingly, 45 of 45 (100%) children with RS without CP were classified as syndromic due to presence of comorbidities unrelated to RS, while 83 of 130 (64%) children with RS with CP were classified as syndromic. Among 128 children with syndromic RS, there were no differences in severity of airway obstruction, surgical intervention rate or type, or feeding outcome at 12 months based on CP status. Our findings support the conclusion that the pathogenesis of RS without CP is distinct from RS with CP and more likely to cause additional medical or developmental problems. Alternatively, children with RS without CP and without additional anomalies present may be under recognized.

Predictors of Success After Furlow Palatoplasty for Repair of Cleft Palate: Does Syndrome Matter?

OBJECTIVE

To determine predictors of success following Veau 1 and 2 cleft palate repair in patients with and without syndromes.

STUDY DESIGN

Retrospective review of prospectively collected data.

SETTING

Tertiary care children's hospital.

METHODS

All children <18 months of age undergoing Furlow palatoplasty for Veau 1 and 2 cleft repair between 2000 and 2014 with postoperative perceptual speech assessment (PSA).

RESULTS

In total, 368 consecutive patients were identified; 95 were excluded, resulting in 273 patients. Median age at surgery was 13.0 months (interquartile range [IQR], 11-15 months) with postoperative PSA at a median of 32.3 months (IQR, 26.3-44.5 months). Fifty patients (18.3%) had syndrome diagnosis; 59 patients (21.6%) had nonsyndromic Robin sequence. Velopharyngeal insufficiency (VPI) occurred in 27 patients (10.5%); 13 underwent secondary speech surgery. Cleft-related speech errors occurred in 46 patients (17.6%). Non-cleft-related speech errors occurred in 155 patients (59.6%) and reduced intelligibility in 127 patients (47.9%). Oronasal fistula occurred in 23 patients (8.8%) and was exclusive to Veau 2 clefts. In multivariate analysis, age >13 months at palatoplasty demonstrated a 6-fold higher rate of VPI (hazard ratio [HR], 6.64; P < .01), worse speech outcomes (HR, 6.04; P < .01; HR, 1.60; P < .01; HR, 1.57; P = .02), and greater speech therapy utilization (HR, 2.18; P < .01).

CONCLUSION

VPI occurred in 10% of patients undergoing Furlow palatoplasty repair of Veau 1 or 2 clefts. Age <13 months at palatoplasty was associated with improved speech outcomes and lower VPI incidence (2.8% vs 16.2%). Syndromic diagnosis was associated with noncleft speech errors and reduced intelligibility on univariate analysis but not velopharyngeal function after palatoplasty.

Incidence of mandibular distraction osteogenesis in Stickler Syndrome: Variation due to COL2A1 and COL11A1

OBJECTIVE

To determine whether the two most common genetic mutations seen in Stickler Syndrome (SS) (COL2A1 and COL11A1) affect the incidence of mandibular distraction osteogenesis (MDO) and what impact Robin sequence (RS) has on diagnosis. SS is an autosomal dominant connective tissue disorder characterized by almost complete penetrance. COL2A1 and COL11A1 are the two most common mutations seen in SS patients. SS often presents at birth with RS, which is characterized by the triad of micrognathia, glossoptosis, and tongue-based airway obstruction. MDO is one surgical intervention that has been shown to be successful in relieving tongue base obstruction and is the surgical intervention of choice for this condition.

METHODS

A retrospective chart review was performed on all patients with a diagnosis of SS at a tertiary pediatric hospital between January 1, 2003 and December 31, 2018. The included patient charts were reviewed for demographic information, SS mutation, and history of MDO. Forty-six patients had a clinical diagnosis of SS. Of those, 31 met inclusion criteria which involved having a molecular diagnosis of SS and sufficient follow up information to determine if MDO was indicated or performed. Twenty-two of the 31 included patients had a diagnosis of RS (70.96%). Thirteen of the 31 patients (41.94%) included in this study required MDO as a neonate.

RESULTS

Fifty-percent of patients with type I (COL2A1) required MDO as a neonate compared to only 31% of patients with type II (COL11A1), though the difference between the two groups was not statistically significant.

CONCLUSION

The findings of this study suggest that patients with type I mutation may have a higher incidence of MDO than patients with a type II mutation, though further research with larger sample sizes is needed. This information is helpful in counseling those with SS or family history of SS about what they can expect related to RS and need for MDO based on genetic findings.

LEVEL OF EVIDENCE

3.

Long-term Speech Outcomes of Cleft Palate Repair in Robin Sequence versus Isolated Cleft Palate

Supplemental Digital Content is available in the text.

Whether treatment of cleft palate (CP) associated with Robin sequence (RS) should attain outcomes similar to those of isolated cleft palate (ICP) remains unknown. This study compares treatment and outcomes in both conditions and delineates predictors of long-term outcome.

Phenotypes, Developmental Basis, and Genetics of Pierre Robin Complex

The phenotype currently accepted as Pierre Robin syndrome/sequence/anomalad/complex (PR) is characterized by mandibular dysmorphology, glossoptosis, respiratory obstruction, and in some cases, cleft palate. A causative sequence of developmental events is hypothesized for PR, but few clear causal relationships between discovered genetic variants, dysregulated gene expression, precise cellular processes, pathogenesis, and PR-associated anomalies are documented. This review presents the current understanding of PR phenotypes, the proposed pathogenetic processes underlying them, select genes associated with PR, and available animal models that could be used to better understand the genetic basis and phenotypic variation of PR.

Oral Manifestations of Wolf-Hirschhorn Syndrome: Genotype-Phenotype Correlation Analysis

Background: Wolf-Hirschhorn syndrome (WHS) is a rare disease caused by deletion in the distal moiety of the short arm of chromosome 4. The objectives of this study were to report the most representative oral findings of WHS, relate them with other clinical characteristics of the disease, and establish possible phenotype-genotype correlation. Methods: The study was conducted at 6 reference centers distributed throughout Spain during 2018–2019. The study group consisted of 31 patients with WHS who underwent a standardized oral examination. Due to behavioral reasons, imaging studies were performed on only 11 of the children 6 years of age or older. All participants had previously undergone a specific medical examination for WHS, during which anatomical, functional, epilepsy-related, and genetic variables were recorded. Results: The most prevalent oral manifestations were delayed tooth eruption (74.1%), bruxism (64.5%), dental agenesis (63.6%), micrognathia (60.0%), oligodontia (45.5%), and downturned corners of the mouth (32.3%). We detected strong correlation between psychomotor delay and oligodontia (p = 0.008; Cramér’s V coefficient, 0.75). The size of the deletion was correlated in a statistically significant manner with the presence of oligodontia (p = 0.009; point-biserial correlation coefficient, 0.75). Conclusion: Certain oral manifestations prevalent in WHS can form part of the syndrome’s phenotypic variability. A number of the characteristics of WHS, such as psychomotor delay and epilepsy, are correlated with oral findings such as oligodontia and bruxism. Although most genotype-phenotype correlations are currently unknown, most of them seem to be associated with larger deletions, suggesting that some oral-facial candidate genes might be outside the critical WHS region, indicating that WHS is a contiguous gene syndrome.

Further Clinical Delineation of Chromosome 1q21Microduplication Syndrome: Robin Sequence as an Under-Recognized Association in Chromosomal Microdeletions and Duplications

Robin sequence (RS) has been reported in association with single gene disorders and chromosomal abnormalities; however, it has not previously been described in connection with chromosome 1q21 microduplication. We present the first known case of a neonate diagnosed with chromosome 1q21.1 microduplication syndrome and RS requiring surgical airway intervention. This case demonstrates the value of genetic testing in cases of RS presenting with other congenital anomalies.

Weight Gain in Infants With Pierre Robin Sequence in the First Year of Life

OBJECTIVE

To compare growth trends among infants with Pierre Robin sequence (PRS) to normal World Health Organization (WHO) growth standards.

STUDY DESIGN

Case series with chart review.

SUBJECTS AND METHODS

Twenty-four infants with syndromic and nonsyndromic PRS (54% male) treated at an urban academic medical center between 2009 and 2017 were included. Infants with symptomatic hypoventilation underwent mandibular distraction osteogenesis (71%). Weights were recorded at roughly 1- to 3-month intervals from birth to 12 months, with ages adjusted for prematurity. The 50th percentile (P50) for this cohort was calculated and compared to WHO standards.

RESULTS

In total, 135 weight entries for 24 subjects were included. The birth weight P50 was similar to the WHO standard (females: 0.09 kg above WHO [95% CI, -0.25 to +0.43; z score = 0.19]; males: 0.38 kg below WHO [95% CI, -0.77 to 0.00; z score = -0.79]). A slower growth rate was noted among female and male infants with PRS: in month 5, the PRS P50 among females was 1.42 kg below the WHO standard (95% CI, -1.77 to -1.07; z score = -1.64). Among males in month 3, the PRS P50 was 1.68 kg below the WHO standard (95% CI, -2.12 to -1.24; z score = -2.19). By month 12, weight deficiencies had resolved in both groups.

CONCLUSION

Newborns with and without PRS may have similar birth weights, but the growth rate among male and female infants with PRS may lag behind that of unaffected infants, even when upper airway obstruction has been addressed in early infancy.

Associated syndromes in patients with Pierre Robin Sequence

OBJECTIVES

Classically, Pierre Robin Sequence (PRS) is a triad of micrognathia, glossoptosis, and airway obstruction, although frequently associated with cleft palate. Current literature reports that Stickler syndrome is the most common syndrome associated with PRS, and 22q11 deletion syndrome (22q11 DS) as the second most common. This study identifies associations between PRS and genetic syndromes.

METHODS

A retrospective chart review was performed to identify patients diagnosed with PRS over a 10-year period from 4/1/2007 to 4/1/2017 at a tertiary children's hospital.

RESULTS

4,052 consecutive charts were reviewed and 234 patients had a diagnosis of PRS confirmed with the triad of micrognathia, glossoptosis, and airway obstruction. Of note, all of these patients had cleft palate. Of the 234 patients with PRS, 65 patients had syndromic diagnoses (28%). One patient had 22q11 DS (0.43%), and 31 patients had Stickler syndrome (13.2%). Additionally, 3 patients had central hypoventilation syndrome, 3 patients had Duane syndrome, 2 patients had Cornelia de Lange syndrome, 2 patients had Emanuel syndrome, 2 patients had Gordon syndrome, 2 patients had Mobius syndrome, 2 patients had Nager syndrome. Multiple other syndromes were identified, but occurred in isolated cases.

CONCLUSION

This study supports literature that PRS is most commonly associated with Stickler Syndrome but rarely associated with 22q11 DS given that only 1 patient had both PRS and 22q11 DS.

Clinical and genetic characterization of patients with Pierre Robin sequence and spinal disease: review of the literature and novel terminal 10q deletion

INTRODUCTION

The Pierre-Robin sequence (PRS) is a pattern of congenital facial abnormalities comprising micrognathia, glossoptosis, and airway obstruction. Associated spinal pathologies have rarely been reported with PRS.

METHODS

We explore the molecular genetic basis of this association through a systematic review of spinal disease in patients with PRS. We also present an illustrative case of a PRS patient with tethered cord in the setting of chromosome 10q terminal deletion.

RESULTS

Our systematic literature review of spinal disease in patients with PRS revealed several patterns in the underlying genetic syndromes causing these conditions to co-occur. These principles are illustrated in the case of a 6-month-old female with PRS and a 14.34-Mb terminal deletion of chromosome 10q, who was found to have a sacral dimple during a routine outpatient checkup. Magnetic resonance imaging of the spine revealed a lumbar syrinx associated with tethered spinal cord. Surgical de-tethering was undertaken, with subsequent improvement in motor function and decrease in the size of the syrinx. The deletion of chromosome 10q in our patient had not previously been described in association with tethered cord or PRS.

CONCLUSION

Spinal pathologies are understudied contributors to disease burden in patients with PRS. The range of predisposing syndromes and mutations in patients with both PRS and spinal disorders remains poorly characterized but may be more defined than previously conceived. Clinical screening is most critical during neonatal and adolescent developmental periods with continued neurological assessment. This study emphasizes the need for early genetic testing and counseling in this patient population, in parallel with research efforts to develop molecular classifications to guide clinical management.

The ontogeny of Robin sequence

The triad of micrognathia, glossoptosis, and concomitant airway obstruction defined as "Robin sequence" (RS) is caused by oropharyngeal developmental events constrained by a reduced stomadeal space. This sequence of abnormal embryonic development also results in an anatomical configuration that might predispose the fetus to a cleft palate. RS is heterogeneous and many different etiologies have been described including syndromic, RS-plus, and isolated forms. For an optimal diagnosis, subsequent treatment and prognosis, a thorough understanding of the embryology and pathogenesis is necessary. This manuscript provides an update about our current understanding of the development of the mandible, tongue, and palate and possible mechanisms involved in the development of RS. Additionally, we provide the reader with an up-to-date summary of the different etiologies of this phenotype and link this to the embryologic, developmental, and genetic mechanisms.

Robin sequence: what the multidisciplinary approach can do

Robin sequence (RS) is a commonly encountered triad of micrognathia, glossoptosis, and airway obstruction, with or without a cleft palate. The management of airway obstruction is of paramount importance, and multiple reviews and retrospective series outline the diagnosis and treatment of RS. This article focuses on the multidisciplinary nature of RS and the specialists’ contributions and thought processes regarding the management of the RS child from birth to skeletal maturity. This review demonstrates that the care of these children extends far beyond the acute airway obstruction and that thorough monitoring and appropriate intervention are required to help them achieve optimal outcomes.

Clinical and Molecular Characterisation of Children with Pierre Robin Sequence and Additional Anomalies

Pierre Robin Sequence (PRS) is usually classified into syndromic and nonsyndromic groups, with a further subclassification of the nonsyndromic group into isolated PRS and PRS with additional anomalies (PRS-Plus). The aim of this research is to provide an accurate phenotypic characterisation of nonsyndromic PRS, specifically the PRS-Plus subgroup. We sought to examine the frequency of sequence variants in previously defined conserved noncoding elements (CNEs) in the putative enhancer region upstream of SOX9, the regulation of which has been associated with PRS phenotypes. We identified 141 children with nonsyndromic PRS at the Royal Children's Hospital, Melbourne from 1985 to 2012 using 2 databases. Clinical and demographic data were extracted by file review and children categorized as 'isolated PRS' or 'PRS-Plus'. A subset of children with PRS-Plus was selected for detailed phenotyping and DNA sequencing of the upstream SOX9 CNEs. We found 83 children with isolated PRS and 58 with PRS-Plus. The most common PRS-Plus malformations involved the musculoskeletal and ocular systems. The most common coexisting craniofacial malformation was choanal stenosis/atresia. We identified 10 children with a family history of PRS or cleft palate. We found a single nucleotide substitution in a putative GATA1-binding site in one patient, but it was inherited from his phenotypically unaffected mother. PRS-Plus represents a broad phenotypic spectrum with uncertain pathogenesis. Dysmorphology assessment by a clinical geneticist is recommended. SOX9 CNE sequence variants are rare in our cohort and are unlikely to play a significant role in the pathogenesis of PRS-Plus.