Radiographic study of the upper cervical spine in the 22q11.2 deletion syndrome

A regulatory variant impacting TBX1 expression contributes to basicranial morphology in Homo sapiens

Changes in gene regulatory elements play critical roles in human phenotypic divergence. However, identifying the base-pair changes responsible for the distinctive morphology of Homo sapiens remains challenging. Here, we report a noncoding single-nucleotide polymorphism (SNP), rs41298798, as a potential causal variant contributing to the morphology of the skull base and vertebral structures found in Homo sapiens. Screening for differentially regulated genes between Homo sapiens and extinct relatives revealed 13 candidate genes associated with basicranial development, with TBX1, implicated in DiGeorge syndrome, playing a pivotal role. Epigenetic markers and in silico analyses prioritized rs41298798 within a TBX1 intron for functional validation. CRISPR editing revealed that the 41-base-pair region surrounding rs41298798 modulates gene expression at 22q11.21. The derived allele of rs41298798 acts as an allele-specific enhancer mediated by E2F1, resulting in increased TBX1 expression levels compared to the ancestral allele. Tbx1-knockout mice exhibited skull base and vertebral abnormalities similar to those seen in DiGeorge syndrome. Phenotypic differences associated with TBX1 deficiency are observed between Homo sapiens and Neanderthals (Homo neanderthalensis). In conclusion, the regulatory divergence of TBX1 contributes to the formation of skull base and vertebral structures found in Homo sapiens.

Musculoskeletal phenotypes in 3q29 deletion syndrome

3q29 deletion syndrome (3q29del) is a rare genomic disorder caused by a 1.6 Mb deletion (hg19, chr3:195725000-197350000). 3q29del is associated with neurodevelopmental and psychiatric phenotypes, including an astonishing >40-fold increased risk for schizophrenia, but medical phenotypes are less well-described. We used the online 3q29 registry of 206 individuals (3q29deletion.org) to recruit 57 individuals with 3q29del (56.14% male) and requested information about musculoskeletal phenotypes with a custom questionnaire. 85.96% of participants with 3q29del reported at least one musculoskeletal phenotype. Congenital anomalies were most common (70.18%), with pes planus (40.35%), pectus excavatum (22.81%), and pectus carinatum (5.26%) significantly elevated relative to the pediatric general population. 49.12% of participants reported fatigue after 30 min or less of activity. Bone fractures (8.77%) were significantly elevated relative to the pediatric general population. Participants commonly report receiving medical care for musculoskeletal complaints (71.93%), indicating that these phenotypes impact quality of life for individuals with 3q29del. This is the most comprehensive description of musculoskeletal phenotypes in 3q29del to date, suggests ideas for clinical evaluation, and expands our understanding of the phenotypic spectrum of this syndrome.

Musculoskeletal phenotypes in 3q29 deletion syndrome

3q29 deletion syndrome (3q29del) is a rare genomic disorder caused by a 1.6 Mb deletion (hg19, chr3:195725000â€"197350000). 3q29del is associated with neurodevelopmental and psychiatric phenotypes, including an astonishing >40-fold increased risk for schizophrenia, but medical phenotypes are less well-described. We used the online 3q29 registry ( 3q29deletion.org ) to recruit 57 individuals with 3q29del (56.14% male) and requested information about musculoskeletal phenotypes with a custom questionnaire. 85.96% of participants with 3q29del reported at least one musculoskeletal phenotype. Congenital anomalies were most common (70.18%), with pes planus (40.35%), pectus excavatum (22.81%), and pectus carinatum (5.26%) significantly elevated relative to the pediatric general population. 49.12% of participants reported fatigue after 30 minutes or less of activity. Bone fractures (8.77%) were significantly elevated relative to the pediatric general population, suggesting 3q29del impacts bone strength. Participants commonly report receiving medical care for musculoskeletal complaints (71.93%), indicating that these phenotypes impact quality of life for individuals with 3q29del. This is the most comprehensive description of musculoskeletal phenotypes in 3q29del to date, suggests ideas for clinical evaluation, and expands our understanding of the phenotypic spectrum of this syndrome.

Updated clinical practice recommendations for managing children with 22q11.2 deletion syndrome

This review aimed to update the clinical practice guidelines for managing children and adolescents with 22q11.2 deletion syndrome (22q11.2DS). The 22q11.2 Society, the international scientific organization studying chromosome 22q11.2 differences and related conditions, recruited expert clinicians worldwide to revise the original 2011 pediatric clinical practice guidelines in a stepwise process: (1) a systematic literature search (1992-2021), (2) study selection and data extraction by clinical experts from 9 different countries, covering 24 subspecialties, and (3) creation of a draft consensus document based on the literature and expert opinion, which was further shaped by survey results from family support organizations regarding perceived needs. Of 2441 22q11.2DS-relevant publications initially identified, 2344 received full-text reviews, including 1545 meeting criteria for potential relevance to clinical care of children and adolescents. Informed by the available literature, recommendations were formulated. Given evidence base limitations, multidisciplinary recommendations represent consensus statements of good practice for this evolving field. These recommendations provide contemporary guidance for evaluation, surveillance, and management of the many 22q11.2DS-associated physical, cognitive, behavioral, and psychiatric morbidities while addressing important genetic counseling and psychosocial issues.

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.

Differences in craniofacial morphology between platybasic and nonplatybasic patients with velopharyngeal dysfunction and control subjects

INTRODUCTION

This study aimed to identify the characteristics of cranial-base morphology in platybasic and nonplatybasic patients with palatal anomalies and velopharyngeal dysfunction (VPD) compared with control subjects to investigate structural factors related to craniofacial morphology that affect the nasopharyngeal space and may influence velopharyngeal function, and to develop precise treatments for specific patients with VPD.

METHODS

Three hundred eighty-six patients with VPD and various palatal anomalies were studied retrospectively. The control group included 126 healthy patients with normal speech. Lateral cephalometric images assessed craniofacial morphology.

RESULTS

Nonplatybasic patients and control subjects had larger SNA, S-Ba-Ptm, and N-Ba-PP angles (in the craniomaxillary complex), and platybasic patients had larger nasopharyngeal ANS-Ptm-Ve and Ba-S-Ptm angles and longer Ve-T and Ve-Ba distances than the nonplatybasic patients. All study patients had larger ANB, Gn-Go-Ar, and PP-MP angles (in the craniomandibular complex). Nonplatybasic patients had smaller Ba-SN angles than platybasic patients and controls because of more acute N-S-Ptm angle. Among the nonplatybasic patients, Ve-T length tended to be shorter (with no significant difference between groups) and located more inferiorly (because of the smallest ANS-Ptm-Ve angle) in relation to the maxilla. Thus, the nasopharynx was narrower horizontally but longer vertically than in patients with platybasia.

CONCLUSIONS

Cranial-base flexure influences the shape of the skull base and facial-skeletal structure and may alter the pharyngeal space between them. This finding should help improve preoperative planning regarding the effect of the pharyngeal flap height relative to the nasopharynx and oropharynx ratio that affects surgical outcomes, such as resonance and residual VPD. In patients with Class III malocclusion and maxillary constriction, careful planning of presurgical orthodontic treatment is needed in maxillary advancement procedures. Orthodontic and surgical collaboration can help prevent postoperative VPD, especially in platybasic patients.

Neurosurgical Evaluation and Management of Patients with Chromosomal Abnormalities

Patients with chromosomal abnormalities are at risk for numerous neurosurgical pathologies, given the broad impact and multisystem involvement of these disorders. Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), Patau syndrome (trisomy 13), Klinefelter syndrome (47,XXY), and velocardiofacial or DiGeorge syndrome (22q11.2 deletion) are particularly associated with neurosurgical concerns. Given the heterogeneity of concerns and presentations, these patients benefit from multidisciplinary care provided by teams familiar with their specific syndrome.

Velopharyngeal Incompetence in Children With 22q11.2 Deletion Syndrome: Velar and Pharyngeal Dimensions

ABSTRACT

The surgical management of velopharyngeal incompetence (VPI) in children with 22q11.2 deletion syndrome (22q11.2 DS) is challenging. There are numerous approaches and children often undergo more than one operation. Our aim was to develop a method using images from routine lateral videofluoroscopy to study the dimensions of the velopharynx in this cohort.We analyzed 22 pre-operative lateral videofluoroscopy recordings of children with 22q11.2 DS and VPI. Fourteen had a submucous cleft palate (SMCP) and 8 had no obvious palatal abnormality but who were subsequently labelled as having an occult submucous cleft palate (OSMCP). The control data were 10 historic records of children with cleft lip and an intact palate. The authors identified key points on radiographs of the velum at rest and when elevated to measure the total velar length, functional velar length and pharyngeal depth and compared them ratiometrically.The intra-observer reliability was > 0.9 whereas the inter-observer reliability was > 0.74. The velopharyngeal depth/total velar length was significantly greater in 22q11.2 DS than the control group P < 0.001. There was no difference between SMCP and OSMCP patients, P = 0.556. There was no difference in the functional velar length/total velar length between 22q11.2 DS and controls (P = 0.763).In this study, the authors demonstrate a reliable method to gain useful ratiometric measurements of the velopharynx. This may help with treatment planning. Children with 22q11.2 DS and VPI have a larger velopharyngeal depth/total velar length ratio that may explain some of the difficulty in management.

Magnetic resonance angiography (MRA) in preoperative planning for patients with 22q11.2 deletion syndrome undergoing craniofacial and otorhinolaryngologic procedures

INTRODUCTION

Patients with 22q11.2 deletion syndrome (22q11.2DS) have a variety of anatomic anomalies. For surgeons operating in proximity to the retropharynx, the most pertinent is medial displacement of the internal carotid arteries. The purpose of this study is to describe the preoperative use of magnetic resonance angiography (MRA) in surgical planning and update the incidence rate of medial carotid displacement in patients with 22q11.2DS.

METHODS

This is a retrospective cohort study of patients with a confirmed diagnosis of 22q11.2 deletion and preoperative MRA <18 years old who underwent tonsillectomy, adenoidectomy, Furlow palatoplasty (FPP), posterior pharyngeal flap (PPF), sphincter pharyngoplasty (SPP), or submucosal cleft palate (SMCP) repair between January 1st, 2008 and December 31st, 2019.

RESULTS

Ninety patients who met the inclusion criteria underwent 133 procedures. The majority identified as Caucasian (84.4%); 52.2% were female. Cervical MRA was more likely to be ordered before a PPF (80.9%) and tonsillectomy (72.7%) over a FPP (47.6%) or adenoidectomy (11.1%). Carotid medialization was visualized in 23 patients (25.6%) and was mild in 11 cases, moderate in 7 cases, and significant in 5 cases. There was no association between sex, race/ethnicity, or genetic diagnosis with carotid medialization. Flap shortening was necessary in 20% of PPF cases to avoid injuring the medialized vessel.

CONCLUSION

Patients with 22q11.2DS may have higher rates of medialization of the carotid arteries than previously thought. Given the risk for complications in these patients during pharyngeal operations, there may be a critical place for MRA in surgical planning for patients with 22q11.2DS.

The Clinical Utility of Flexion-extension Cervical Spine MRI in 22q11.2 Deletion Syndrome

BACKGROUND

Our goal is to correlate the findings on flexion and extension radiographs with dynamic magnetic resonance imaging (MRI), and the clinical history, in a nonrandomly selected cohort of patients with 22q11.2 deletion syndrome (22q).

METHODS

All patients with the 22q who had a dynamic MRI from January 2004 to March 2015 were included. We analyzed multiple radiographic measurements on both the dynamic plain films and the MRIs, and correlated these findings with a review of each patient's medical record.

RESULTS

Multiple congenital anomalies were identified as noted in previous studies, and 61% of the patients had a failure of fusion of the anterior (n=2, 9%), posterior (n=2, 9%), or anterior and posterior arches (n=10, 43%). Quantitative measurements were impossible to report with certainty because of the upper cervical anomalies, and no cases of instability were identified using a qualitative assessment. We identified spinal cord encroachment (30%) and impingement (18%); however, none of the patients had any signal change in their spinal cord. None of these findings could be definitively correlated with any clinical symptoms. A single patient was diagnosed with a Chiari I malformation, while another had cerebellar ectopia.

CONCLUSIONS

Although the upper cervical anomalies are extremely common in 22q, we did not identify cases of instability on dynamic plain radiographs and MRI. Although our findings do not support routine screening with flexion and extension MRI, this study may be required in patients with neurological symptoms and/or findings or abnormalities on dynamic plain radiographs.

LEVEL OF EVIDENCE

Level III.

Palatal evaluation and treatment in 22q11.2 deletion syndrome

Palatal involvement occurs commonly in patients with 22q11.2 Deletion Syndrome (22qDS), and includes palatal clefting and velopharyngeal dysfunction in the absence of overt or submucous clefts. The reported incidence and distribution of palatal abnormalities vary in the literature. The aim of this article is to revisit the incidence and presenting features of palatal abnormalities in a large cohort of patients with 22qDS, summarize the surgical treatments performed in this cohort, and provide an overview of surgical treatment protocols and management guidelines for palatal abnormalities in this syndrome. Charts of 1,121 patients seen through the 22q and You Center at the Children's Hospital of Philadelphia were reviewed for palatal status, demographic factors, deletion size, and corrective surgical procedures. Statistical analysis was performed using Pearson's chi-squared test to identify differences between gender, deletion size, and palatal abnormality. Of the patients with complete evaluations, 67% were found to have a palatal abnormality. The most common finding was velopharyngeal dysfunction in 55.2% of patients, and in 33.3% of patients, this occurred in the absence of palatal clefting. There was no significant difference in the incidence of palatal abnormalities by gender; however, a difference was noted among race (p < 0.01) and deletion sizes (p < 0.01). For example, Caucasian and Asian patients presented with a much higher prevalence of palatal abnormalities, and conversely those with nested deletions presented with a much lower rate of palatal defects. Overall, 26.9% of patients underwent palatal surgery, and the most common indication was velopharyngeal dysfunction. Palatal abnormalities are a hallmark feature of 22q11.2 Deletion Syndrome; understanding the incidence, presenting features, and treatment protocols are essential for practitioners counseling and treating families affected with this disorder.

Management of velopharyngeal dysfunction in patients with 22q11.2 deletion syndrome: A survey of practice patterns

OBJECTIVE

To determine demographics and practice patterns of surgeons treating velopharyngeal dysfunction (VPD) in patients with 22q11.2 deletion syndrome (22q11.2DS).

METHODS

An anonymous electronic survey study was administered to the surgical membership of the American Cleft Palate-Craniofacial Association and the Society for Ear Nose and Throat Advances in Children. The survey queried surgeon demographics and differences in management practices for submucous cleft palate (SMCP), pharyngoplasty algorithms, and self-reported complications for nonsyndromic versus 22q11.2DS patients.

RESULTS

126 surveys were returned from 9 international regions with the majority from the United States (73%), followed by Western Europe (9.5%) and Canada (7.9%). Plastic surgery was the most common specialty (61.9%), followed by otolaryngology (27.8%). 88.1% reported fellowship training, and 33% completed multiple fellowships. Prior to proceeding with pharyngoplasty in 22q11.2DS patients, surgeons required the following assessments: speech evaluation (79.4%), velopharyngeal imaging (51.6%), cardiac evaluation (50.0%), carotid artery MRI (29.4%), and cervical spine x-rays (11.1%). Nasoendoscopy was the most common modality used for imaging the velopharynx. Overall, providers managed patients with 22q11.2DS similarly to nonsyndromic patients, with several significant exceptions including that they were more likely to perform SMCP repair alone as a first approach in nonsyndromic patients (p = 0.031) and posterior pharyngeal flap without SMCP repair in those with 22q11.2DS (p = 0.017).

CONCLUSIONS

Practice patterns for the management of VPD in patients with 22q11.2DS vary across providers. Further collaborative studies are needed to develop optimal treatment paradigms for VPD in patients with 22q11.2 DS.

Sleep Disturbances in 22q11.2 Deletion Syndrome: A Case with Obstructive and Central Sleep Apnea

The 22q11.2 deletion syndrome is characterized by wide phenotypic variability, frequently involving characteristic craniofacial features, cardiac malformations, and learning difficulties. Skeletal anomalies are also common and include an obtuse angle of the cranial base, retrognathia, and cervical spine abnormalities. Despite these anomalies, sleep-disturbed breathing is not reported frequently in patients with 22q11.2 deletion syndrome. We describe a patient with an obstructive sleep disturbance that was successfully treated with a tonsillectomy followed by mandibular distraction osteogenesis. She also had central sleep apnea, initially attributed to spinal cord impingement from cervical instability. Posterior cervical fusion was associated with a decrease in the number of central apneic events.

Cervical Instability in Pierre Robin Sequence: An Addition to the Algorithm

Many patients with Pierre Robin sequence (PRS) have associated birth defects, most commonly in association with abnormalities in bone or cartilage formation. Depending on severity, treatment of PRS ranges from nonoperative management with prone positioning to surgical intervention such as distraction osteogenesis. Generally, if a surgical approach is needed, these patients undergo nasal endoscopy or direct laryngoscopy with their intubation, which puts the cervical spine in a position of extreme extension. The authors present a patient with syndromic PRS secondary to Sticklers syndrome, with a cervical abnormality diagnosed with three-dimensional computed tomography and further evaluated with dynamic lateral plain x-rays to assess cervical instability. The goal of this report is to highlight the need to include cervical spine evaluation in the preoperation workup of patients with PRS, especially those with suspected abnormalities in bone or collagen formation.

Genetics of Cleft Palate and Velopharyngeal Insufficiency

Velopharyngeal insufficiency (VPI) can occur in the setting of an unrepaired or repaired cleft lip and palate. The rate of VPI has been documented as high as 33% in some studies with higher rates of recurrences following surgery associated with genetic syndromes such as 22q11.2 deletions. The primary cause of VPI in these groups is still identified as the anatomic abnormalities of the velum. In this review, the anatomy and physiology of the velum are discussed along with genetic mutations associated with VPI.

22q11.2 deletion syndrome

22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion disorder, estimated to result mainly from de novo non-homologous meiotic recombination events occurring in approximately 1 in every 1,000 fetuses. The first description in the English language of the constellation of findings now known to be due to this chromosomal difference was made in the 1960s in children with DiGeorge syndrome, who presented with the clinical triad of immunodeficiency, hypoparathyroidism and congenital heart disease. The syndrome is now known to have a heterogeneous presentation that includes multiple additional congenital anomalies and later-onset conditions, such as palatal, gastrointestinal and renal abnormalities, autoimmune disease, variable cognitive delays, behavioural phenotypes and psychiatric illness - all far extending the original description of DiGeorge syndrome. Management requires a multidisciplinary approach involving paediatrics, general medicine, surgery, psychiatry, psychology, interventional therapies (physical, occupational, speech, language and behavioural) and genetic counselling. Although common, lack of recognition of the condition and/or lack of familiarity with genetic testing methods, together with the wide variability of clinical presentation, delays diagnosis. Early diagnosis, preferably prenatally or neonatally, could improve outcomes, thus stressing the importance of universal screening. Equally important, 22q11.2DS has become a model for understanding rare and frequent congenital anomalies, medical conditions, psychiatric and developmental disorders, and may provide a platform to better understand these disorders while affording opportunities for translational strategies across the lifespan for both patients with 22q11.2DS and those with these associated features in the general population.

Platybasia in 22q11.2 deletion syndrome is not correlated with speech resonance

BACKGROUND

An abnormally obtuse cranial base angle, also known as platybasia, is a common finding in patients with 22q11.2 deletion syndrome (22q11DS). Platybasia increases the depth of the velopharynx and is therefore postulated to contribute to velopharyngeal dysfunction. Our objective was to determine the clinical significance of platybasia in 22q11DS by exploring the relationship between cranial base angles and speech resonance.

METHODS

In this retrospective chart review at a tertiary hospital, 24 children (age, 4.0-13.1 years) with 22q11.2DS underwent speech assessments and lateral cephalograms, which allowed for the measurement of the cranial base angles.

RESULTS

One patient (4%) had hyponasal resonance, 8 (33%) had normal resonance, 10 (42%) had hypernasal resonance on vowels only, and 5 (21%) had hypernasal resonance on both vowels and consonants. The mean cranial base angle was 136.5° (standard deviation, 5.3°; range, 122.3-144.8°). The Kruskal-Wallis test showed no significant relationship between the resonance ratings and cranial base angles (P=0.242). Cranial base angles and speech ratings were not correlated (Spearman correlation=0.321, P=0.126). The group with hypernasal resonance had a significantly more obtuse mean cranial base angle (138° vs. 134°, P=0.049) but did not have a greater prevalence of platybasia (73% vs. 56%, P=0.412).

CONCLUSIONS

In this retrospective chart review of patients with 22q11DS, cranial base angles were not correlated with speech resonance. The clinical significance of platybasia remains unknown.

Perioperative risk factors in patients with 22q11.2 deletion syndrome requiring surgery for velopharyngeal dysfunction

Objective : To determine the prevalence of cardiac, cervical spine, and carotid artery abnormalities in patients with 22q11.2 deletion syndrome (22q11.2DS) undergoing surgery for velopharyngeal dysfunction (VPD), associations between the presence of these abnormalities, and whether these abnormalities caused changes in surgical management or perioperative complications. Design : Retrospective review. Setting : Tertiary pediatric hospital. Patients : Seventy patients with 22q11.2DS with complete preoperative cervical vascular and spine imaging and cardiac evaluation between 1998 and 2011. Main Outcome Measures : Incidence of cardiac, cervical spine, and vascular abnormalities; related perioperative complications; and resulting changes in surgical, anesthetic, or perioperative management plan. Results : Cardiac abnormalities occurred in 45 patients (64.3%), and 8 patients required cardiac anesthesia. Thirty-eight patients (54.3%) had at least one vascular abnormality of the neck, and 14% had medial deviation of the internal carotid artery. Surgery was not performed in one patient, and the surgical plan was altered in three patients because of carotid anomalies. Cervical spine abnormalities were found in 24 patients (34.3%); 8 patients demonstrated radiographic evidence of cervical instability and were treated with spinal precautions during surgery. The presence of one anomaly was not predictive of any other finding, and there were no complications related to the heart, cervical spine, or carotid arteries. Conclusions : Anomalies of the heart, cervical spine, and cervical vasculature occur frequently in 22q11.2DS, vary drastically in severity, and are impossible to predict based on other features of the syndrome. Preoperative diagnosis of these comorbidities with routine imaging can minimize the risk of avoidable surgical complications.

Imaging of the craniovertebral junction anomalies in children

The craniovertebral junction (CVJ) is interposed between the unsegmented skull and the segmented spine; it is functionally unique as it allows the complex motion of the head. Because of its unique anatomy, numerous craniometric indices have been devised. Because of its complex embryology, different from that of the adjacent skull and spine, it is commonly the seat of malformations. Because of the mobility of the head, and its relative weight, the craniovertebral junction is vulnerable to trauma. Like the rest of the axial skeleton, it may be affected by many varieties of dysplasia. In addition, the bony craniovertebral junction contains the neural craniovertebral junction and its surrounding CSF: any bony instability or loss of the normal anatomic relationships may therefore compromise the neural axis. In addition, the obstruction of the meningeal spaces at this level can compromise the normal dynamics of the CSF and result in hydrocephalus and/or syringohydromyelia. To image the CVJ, plain X-rays are essentially useless. MR is optimal in depicting the soft tissues (including the neural axis) and the joints, as well as the bone itself. CT still may be important to better demonstrate the bony abnormalities.

Towards a safety net for management of 22q11.2 deletion syndrome: guidelines for our times

The commonest autosomal deletion, 22q11.2 deletion syndrome (22q11DS) is a multisystem disorder varying greatly in severity and age of identification between affected individuals. Holistic care is best served by a multidisciplinary team, with an anticipatory approach. Priorities tend to change with age, from feeding difficulties, infections and surgery of congenital abnormalities particularly of the heart and velopharynx in infancy and early childhood to longer-term communication, learning, behavioural and mental health difficulties best served by evaluation at intervals to consider and initiate management. Regular monitoring of growth, endocrine status, haematological and immune function to enable early intervention helps in maintaining health.

CONCLUSION

Guidelines to best practice management of 22q11DS based on a literature review and consensus have been developed by a national group of professionals with consideration of the limitations of available medical and educational resources.

Cervical spine abnormalities in 22q11.2 deletion syndrome

OBJECTIVE

The 22q11.2 deletion syndrome is among the most common head-and-neck-related syndromes. The literature has examined many of the phenotypic features of 22q11.2 deletion syndrome; however, few studies have explored the manifestation of cervical spine abnormalities. In this study, we compared the cervical spines of individuals with and without 22q11.2 deletion syndrome using diagnostic imaging.

DESIGN

A retrospective case-control study, with age- and sex-matched control participants who underwent flexion/extension x-rays and either a computed tomography or MRI scan.

SETTING

PARTICIPANTS presented to the velopharyngeal insufficiency clinic at Victoria Hospital in London, Ontario, Canada, a tertiary care center.

PARTICIPANTS

Sixteen pediatric patients (<age 18 at presentation) who had genetically confirmed 22q11.2 deletion syndrome were age- and sex-matched to 16 patients who presented with head and neck trauma without radiographic evidence of injury to the cervical spine. The mean age was 11.7 years (range, 2 to 21 years).

MAIN OUTCOME MEASURE

Radiographic evidence of cervical spine abnormalities ± evidence of instability.

RESULTS

Patients with 22q11.2 deletion syndrome were significantly more likely to have an open posterior arch of C1 (P < .0001), anterior arch cleft of C1 (P < .0001), and platybasia (P = .001). There was also a positive trend for fusion of the C2-C3 vertebrae (P = .051).

CONCLUSION

Significant differences in radiographic cervical spine measurements were found between 22q11.2 deletion syndrome patients and controls. Cervical spine abnormalities are common phenotypic features of 22q11.2 deletion syndrome, but the clinical consequences are poorly understood. Further investigation is necessary to understand the possible ramifications of these abnormalities, including precautions during medically necessary interventions, and lifestyle limitations for these individuals.

Velopharyngeal Dysfunction and 22q11.2 Deletion Syndrome: A Longitudinal Study of Functional Outcome and Preoperative Prognostic Factors

Objective

To describe the effect of time after velopharyngoplasty on outcome and to search for preoperative prognostic factors for residual hypernasality in patients with 22q11.2 deletion syndrome.

Design

Retrospective chart review.

Setting

Tertiary hospital.

Patients

Patients with 22q11.2 deletion syndrome and velopharyngeal dysfunction who underwent a primary (modified) Honig velopharyngoplasty between 1989 and 2009.

Main Outcome Measures

Clinically obtained perceptual and instrumental measurements of resonance, nasalance, and understandability before and after velopharyngoplasty.

Results

Data were available for 44 of 54 patients (81% follow-up), with a mean follow-up time of 7.0 years (range, 1.0 to 19.4 years). During follow-up, 24 (55%) patients attained normal resonance and 20 (45%) had residual hypernasality or underwent revision surgery. Mean postoperative nasalance and understandability scores were closer to the norm than mean preoperative scores were (2.0 versus 5.5 standard deviations for the normal passage, 1.3 versus 8.1 standard deviations for the nonnasal passage, and score 2.3 versus 4.1 understandability). Serial measurements revealed that hypernasality only resolved an average of 5 years after surgery, and three patients whose resonance initially normalized later relapsed to hypernasality. Gender, age at surgery, lateral pharyngeal wall adduction, velar elevation, presence of a palatal defect, previous intravelar veloplasty, nasalance, understandability, adenoidectomy, hearing loss, and IQ were not able to predict poor outcome following primary velopharyngoplasty (all p > .05).

Conclusions

In this chart review of patients with 22q11.2 deletion syndrome and velopharyngeal dysfunction, residual hypernasality persisted in many patients after velopharyngoplasty. None of the preoperative factors that were studied had prognostic value for the outcome.

Spine segmentation and enumeration and normal variants

This article provides a comprehensive review of spine segmentation and enumeration. This important and relatively underappreciated issue, when neglected, frequently results in confusion in vertebral numbering and ultimately may result in wrong segment interventions. The authors supplement this topic with a discussion of normal variants.

Review of cervical spine anomalies in genetic syndromes

STUDY DESIGN

Focused review of the literature.

OBJECTIVE

Assist spine specialists in diagnosis and treatment of cervical spine anomalies found in selected genetic syndromes.

SUMMARY OF BACKGROUND DATA

Cervical spine instability and/or stenosis are potentially debilitating problems in many genetic syndromes. These problems can be overlooked among the other systemic issues more familiar to clinicians and radiologists evaluating these syndromes. It is imperative that spine specialists understand the relevant issues associated with these particular syndromes.

METHODS

The literature was reviewed for cervical spine issues in 10 specific syndromes. The information is presented in the following order: First, the identification and treatment of midcervical kyphosis in Larsen syndrome and diastrophic dysplasia (DD). Next, the upper cervical abnormalities seen in Down syndrome, 22q11.2 Deletion syndrome, pseudoachondroplasia, Morquio syndrome, Goldenhar syndrome, spondyloepiphyseal dysplasia congenita, and Kniest dysplasia. Finally, the chin-on-chest deformity of fibrodysplasia ossificans progressiva.

RESULTS

Midcervical kyphosis in patients with Larsen syndrome and DD needs to be evaluated and imaged often to track deformity progression. Upper cervical spine instability in Down syndrome is most commonly caused by ligamentous laxity at C1 to C2 and occiput-C1 levels. Nearly 100% of patients with 22q11.2 deletion syndrome have cervical spine abnormalities, but few are symptomatic. Patients with pseudoachondroplasia and Morquio syndrome have C1 to C2 instability related to odontoid dysplasia (hypoplasia and os odontoideum). Morquio patients also have soft tissue glycosaminoglycan deposits, which cause stenosis and lead to myelopathy. Severely affected patients with spondyloepiphyseal dysplasia congenita are at high risk of myelopathy because of atlantoaxial instability in addition to underlying stenosis. Kniest syndrome is associated with atlantoaxial instability. Cervical spine anomalies in Goldenhar syndrome are varied and can be severe. Fibrodysplasia ossificans progressiva features severe, deforming heterotopic ossification that can become life-threatening.

CONCLUSION

It is important to be vigilant in the diagnosis and treatment of cervical spine anomalies in patients with genetic syndromes.

MR imaging features of common variant spinal anatomy

The spine is one of the most commonly imaged body parts for all age groups, with indications ranging from congenital abnormalities at birth to degenerative pathology toward the end of life. Because of the importance of softtissue contrast when imaging the spine, MR imaging has become the most important modality in its evaluation. One of the key challenges in the clinical analysis of spinal MR imaging lies in the wide range of so-called normal variability. The goal of this article is not to provide the reader with an exhaustive atlas detailing the appearance of every known variant. Instead, the authors review the MR appearance of the most important variants and provide a logical and, they hope, memorable framework for assimilating this information into practice. To understand why these variations occur, the authors examine the aberrant pathways of embryology, growth, and development that lead to their formation.

[Cephalometric study of the velocardiofacial syndrome: Impact of dysmorphosis on phonation]

INTRODUCTION

Velopharyngeal insufficiency is a frequent sign of the velocardiofacial syndrome (VCFS) but its origins are not well-documented. Our aim was to establish a correlation between this functional disorder and regional morphological anomalies.

PATIENTS AND METHODS

Twenty-seven of 36 patients presenting with VCFS could be included retrospectively. We measured cavum depth and velum length on lateral orthodontic X-rays, and assessed the relationship between these two measures. We compared these measures to those of reference populations. Postoperative phonation was assessed with an aerophonoscope.

RESULTS

The patients presented with a short velum and a deep cavum. Cranium base and upper cervical spine were malformed in 22 of the 27 patients. Seventeen of the 23 assessed patients (66%) improved their phonation after surgery.

DISCUSSION

Our data suggests that velopharyngeal insufficiency in VCFS could be the result of a more global craniospinal growth disorder the functional consequences of which remain unclear. The frequent association of morphological anomalies with mental retardation is probably responsible for the failure to normalize phonation.

Chromosome 22q11.2 deletion syndrome (DiGeorge syndrome/velocardiofacial syndrome)

Chromosome 22q11.2 deletion syndrome is a common syndrome also known as DiGeorge syndrome and velocardiofacial syndrome. It occurs in approximately 1:4000 births, and the incidence is increasing due to affected parents bearing their own affected children. The manifestations of this syndrome cross all medical specialties, and care of the children and adults can be complex. Many patients have a mild to moderate immune deficiency, and the majority of patients have a cardiac anomaly. Additional features include renal anomalies, eye anomalies, hypoparathyroidism, skeletal defects, and developmental delay. Each child's needs must be tailored to his or her specific medical problems, and as the child transitions to adulthood, additional issues will arise. A holistic approach, addressing medical and behavioral needs, can be very helpful.

Lack of the mesodermal homeodomain protein MEOX1 disrupts sclerotome polarity and leads to a remodeling of the cranio-cervical joints of the axial skeleton

Meox1 and Meox2 are two related homeodomain transcription factor genes that together are essential for the development of all somite compartments. Here we show that mice homozygous for Meox1 mutations alone have abnormalities that are restricted to the sclerotome and its derivatives. A prominent and consistent phenotype of these mutations is a remodeling of the cranio-cervical joints whose major feature is the assimilation of the atlas into the basioccipital bone so that the skull rests on the axis. These abnormalities can be traced back to changes in the relative rates of cell proliferation in the rostral and caudal sclerotome compartments, and they are associated with alterations in the expression of at least three transcription factor genes, Tbx18, Uncx, and Bapx1. As previously observed for Bapx1, MEOX1 protein occupies evolutionarily conserved promoter regions of Tbx18 and Uncx, suggesting that Meox1 regulates these genes at least in part directly. Hence, Meox1 is part of a regulatory circuit that serves an essential, non-redundant function in the maintenance of rostro-caudal sclerotome polarity and axial skeleton formation.

Vertebral fusion in a patient with supernumerary-der(22)t(11;22) syndrome

A patient with a 47,XX,+der(22)t(11;22)(q23.3;q11.2) karyotype exhibited brisk tendon reflex and Babinski sign with suggested pyramidal sign. A three-dimensional computed tomographic reconstruction revealed a T1-T2 vertebral fusion without hemivertebrae. Sagittal magnetic resonance imaging revealed degenerative disk changes, mild disk herniation, and mild spinal cord compression. Congenital vertebral fusion may be one of the anomalies in supernumerary-der(22)t(11;22) syndrome. Once clinical diagnosis of this chromosome aberration is established, radiologic evaluation of vertebrae and spinal neuroimaging should be performed.

The facial phenotype of the velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) is a genetic disorder that is common but often variable in its expression. Several key organ systems are most often affected, including the craniofacial skeleton and soft tissues. Identification of the associated facial features will aid in the improved detection of patients. This review aims to highlight the approaches to facial analysis that are essential to the detection of the facial dysmorphisms in velo-cardio-facial syndrome, many of which may be subtle.

Advanced imaging of the cervical spine and spinal cord in 22q11.2 deletion syndrome: age-matched, double-cohort, controlled study

PURPOSE

The 22q11.2 deletion syndrome is a common genetic syndrome with a wide spectrum of abnormalities. We have previously described multiple anomalies of the upper cervical spine in this disorder. The objective of this study was to use advanced imaging to further define the morphology of the cervical spine and spinal cord in the 22q11.2 deletion syndrome, with a comparison to age-matched controls.

METHODS

A total of 32 patients with a 22q11.2 deletion underwent advanced imaging (computed tomography/magnetic resonance imaging; CT/MRI) of the cervical spine. In 27 patients, space available for the cord (SAC); the sagittal diameter of the vertebral body, spinal canal, cerebrospinal fluid (CSF), and spinal cord; and the cross sectional area of the spinal canal, CSF, and spinal cord were measured at each cervical level and compared to 29 age-matched controls. Statistical analysis was performed and potential implications were hypothesized.

RESULTS

In 22q11.2 patients, advanced imaging identified 40 pathologies not evident on plain radiographs with potential mechanical and/or neurological implications. These patients also had significantly smaller values (P </= 0.05) of the following parameters at one or more cervical levels, relative to age-matched controls: width of the vertebral body, spinal canal, CSF, and spinal cord; area of the spinal canal, CSF, and spinal cord. Neurologic symptoms were observed in 4/32 patients, with one patient requiring surgical intervention.

CONCLUSIONS

Advanced imaging of the cervical spine can detect findings not evident on plain radiographs in the 22q11.2 deletion syndrome. CT and/or MRI may be indicated when there is a high index of suspicion for clinical instability or neurologic compromise in order to rule out dynamic encroachment or impending neurologic sequelae. Spinal canal and spinal cord dimensions are reduced in these patients relative to controls with currently unknown clinical significance.

C1-2 vertebral anomalies in 22q11.2 microdeletion syndrome

BACKGROUND

Chromosome 22q11.2 microdeletion syndrome (22q11DS) is characterized by cleft palate, cardiac anomalies, characteristic facies, high prevalence of skeletal anomalies and learning disability.

OBJECTIVE

To evaluate the prevalence of craniovertebral junction anomalies in children with 22q11DS and compare these findings to those in nonsyndromic children with velopharyngeal insufficiency (VPI).

MATERIALS AND METHODS

Sequential CT scans performed for presurgical carotid assessment in 76 children (45 children positive for chromosome 22q11.2 deletion and 31 negative for the deletion) with VPI were retrospectively evaluated for assessment of C1-2 anomalies.

RESULTS

C1-2 vertebral anomalies, specifically midline C1 defects, uptilted or upswept posterior elements of C2 and fusions of C2-3, were nearly universal in our cohort of 22q11DS patients with VPI. They were strikingly absent in the majority of non-22q11DS patients with VPI.

CONCLUSION

C1-2 vertebral anomalies, particularly those listed above, are important radiographic markers for 22q11DS.

Expanding the phenotype of 22q11 deletion syndrome: the MURCS association

The MURCS association [Müllerian Duct aplasia or hypoplasia (M), unilateral renal agenesis (UR) and cervicothoracic somite dysplasia (CS)] manifests itself as Müllerian Duct aplasia or hypoplasia, unilateral renal agenesis and cervicothoracic somite dysplasia. We report on a 22-year-old woman with bicornuate uterus, right renal agenesis, C2-C3 vertebral fusion (MURCS association) and 22q11.2 deletion. Angio-MRI revealed the aberrant origin of arch arteries. Hashimoto thyroiditis, micropolycystic ovaries with a dermoid cyst in the right ovary and mild osteoporosis were also diagnosed. Accurate revision of radiographs enabled us also to identify thoracolumbar and lumbosacral vertebral-differentiation defects. Audiometry and echocardiogram were normal. Bone densitometry showed osteoporosis. As per our evaluation, the patient had short stature, obesity (BMI 30.7) and facial features suggestive of the 22q11 deletion syndrome. Multiplex ligation-dependent probe amplification analysis showed a de-novo 22q11.2 deletion confirmed by array-comparative genomic hybridization analysis. We discuss whether this is a casual association or whether it is an additional syndrome owing to the well known phenotype extensive variability of the 22q11 deletion syndrome.

Congenital osseous anomalies of the upper cervical spine

BACKGROUND

The developmental anatomy and biomechanics of the upper cervical spine are unique in children. Congenital osseous anomalies in this region may be associated with an increased risk for subsequent neurological compromise from instability and/or spinal cord encroachment. We performed a double-cohort study evaluating congenital osseous anomalies of the upper cervical spine in children who presented with one or more clinical problems, and we attempted to outline the risk of possible neurological compromise.

METHODS

We reviewed the medical records and imaging studies of all children seen and treated for osseous anomalies of the upper cervical spine at our institution between 1988 and 2003. Patients were divided into two cohorts on the basis of the presence or absence of associated syndromes. Parameters reviewed included demographic data, clinical presentation, and imaging features. All anomalies involving the central nervous system, the occipitocervical junction, and the upper cervical osseous canal were included. Complicating sequelae such as canal stenosis, segmental instability, and other anomalies of the central nervous system and spine were identified.

RESULTS

Sixty-eight consecutive children were identified. Twenty-one patients had an underlying described syndrome. There were 234 osseous anomalies (average, 3.4 per patient). Three or more anomalies were noted in 79% of the patients. There was no significant difference in the mean number of anomalies (p = 0.80) or in the frequency of any specific anomaly (p > 0.20 for all) between syndromic and nonsyndromic patients. The variety of clinical presentations included neck pain (twenty-six patients), neurological changes (twenty-one patients), and torticollis and/or stiffness (twenty-one patients). Twenty-three patients had more than one complaint. Six patients had isolated spinal instability, twenty-eight had isolated spinal cord encroachment, and six had a combination of both. Forty-four (65%) of the sixty-eight patients underwent surgical decompression and/or arthrodesis principally focused from the foramen magnum to the second cervical vertebra.

CONCLUSIONS

As a result of these findings, we recommend a thorough evaluation and advanced imaging of the upper cervical spine in all children who present with symptoms related to the upper cervical spine, to identify associated anomalies and further define the nature of canal encroachment including any potential for neurologic compromise.

Velo-cardio-facial syndrome: 30 Years of study

Velo-cardio-facial syndrome is one of the names that has been attached to one of the most common multiple anomaly syndromes in humans. The labels DiGeorge sequence, 22q11 deletion syndrome, conotruncal anomalies face syndrome, CATCH 22, and Sedlacková syndrome have all been attached to the same disorder. Velo-cardio-facial syndrome has an expansive phenotype with more than 180 clinical features described that involve essentially every organ and system. The syndrome has drawn considerable attention because a number of common psychiatric illnesses are phenotypic features including attention deficit disorder, schizophrenia, and bipolar disorder. The expression is highly variable with some individuals being essentially normal at the mildest end of the spectrum, and the most severe cases having life-threatening and life-impairing problems. The syndrome is caused by a microdeletion from chromosome 22 at the q11.2 band. Although the large majority of affected individuals have identical 3 megabase deletions, less than 10% of cases have smaller deletions of 1.5 or 2.0 megabases. The 3 megabase deletion encompasses a region containing 40 genes. The syndrome has a population prevalence of approximately 1:2,000 in the United States, although incidence is higher. Although initially a clinical diagnosis, today velo-cardio-facial syndrome can be diagnosed with extremely high accuracy by fluorescence in situ hybridization and several other laboratory techniques. Clinical management is age dependent with acute medical problems such as congenital heart disease, immune disorders, feeding problems, cleft palate, and developmental disorders occupying management in infancy and preschool years. Management shifts to cognitive, behavioral, and learning disorders during school years, and then to the potential for psychiatric disorders including psychosis in late adolescence and adult years. Although the majority of people with velo-cardio-facial syndrome do not develop psychosis, the risk for severe psychiatric illness is 25 times higher for people affected with velo-cardio-facial syndrome than that of the general population. Therefore, interest in understanding the nature of psychiatric illness in the syndrome remains strong.

Occipitalization of the atlas in children. Morphologic classification, associations, and clinical relevance

BACKGROUND

Occipitalization is defined as a congenital fusion of the atlas to the base of the occiput. We are not aware of any previous studies addressing the morphologic patterns of occipitalization or the implications of occipitalization in children. We present data on what we believe is the largest reported series of children with occipitalization studied with computed tomography and/or magnetic resonance imaging, and we provide a description of their clinical characteristics.

METHODS

We retrospectively reviewed all cases of occipitalization in children included in our spine database. Patient charts and imaging studies were reviewed. A new morphologic classification of occipitalization was developed from the two-dimensional sagittal and coronal reformatted computed tomographic reconstructions and/or magnetic resonance images. The classification includes four patterns according to the anatomic site of occipitalization (Zones 1, 2, and 3 and a combination of those zones), and it was applied to this group of patients. Imaging studies were also reviewed for evidence of cervical instability and for other anomalies of the craniovertebral junction.

RESULTS

Thirty patients with occipitalization were identified. There were twenty-four boys and six girls with a mean age of 6.5 years. The morphologic categorization was Zone 1 (a fused anterior arch) in six patients, Zone 2 (fused lateral masses) in five, Zone 3 (a fused posterior arch) in four, and a combination of fused zones in fifteen. Seventeen patients (57%) had atlantoaxial instability, and eight of them had an associated C2-C3 fusion. Eleven patients (37%) had spinal canal encroachment, and five of them had clinical findings of myelopathy. The highest prevalence of spinal canal encroachment (63%) was noted in patients with occipitalization in Zone 2.

CONCLUSIONS

Occipitalization is associated with abnormalities that lead to narrowing of the space available for the spinal cord or brainstem. The risk of atlantoaxial instability developing is particularly high when there is an associated congenital C2-C3 fusion. Two-dimensional sagittal and coronal reformatted computed tomographic reconstructions and/or magnetic resonance images can help to establish the diagnosis and permit categorization of occipitalization in three zones, each of which may have a different prognostic implication.

Three sisters with Chiari I malformation with and without associated syringomyelia

Two daughters of non-consanguineous Ashkenazi Jewish parentage presented with occipital headaches in the second decade of life. Each had a symptomatic Chiari I malformation (CMI) and a large cervicothoracic syrinx. A third sister was diagnosed as having CMI without syrinx after MR screening of first-degree relatives. A fourth (the eldest) sister was asymptomatic and did not have CMI or syrinx. The girls' mother had platybasia on screening MR and a history of cough headaches. All four sisters also had demonstrable platybasic features on MR. The girls' father was asymptomatic and radiologically normal. This family represents the first reported case of three siblings in one family with confirmed CMI with or without syrinx. We discuss the possible genetic and mechanical mechanisms for the development of these abnormalities in this family.

Velo-cardio-facial syndrome: the pediatric otolaryngologist's perspective

PURPOSE OF REVIEW

The understanding of velo-cardio-facial syndrome has grown markedly since the initial descriptions of this common genetic disorder nearly 30 years ago. Our knowledge of the syndrome has advanced in part from opportunities to monitor many patients into adulthood because of advances in the fields of cardiothoracic surgery and immunology. Longitudinal study has brought to light psychiatric and behavioral features of the syndrome that are often not apparent until late adolescence or the early adult years. Certain endocrine and immunologic features of the syndrome thought to be resolved in childhood are now witnessed in older patients. Variable expression and lack of disease awareness are two major factors that contribute to the delays in diagnosis in many cases. To address this, there has been a call to delineate screening parameters for patients at risk of carrying the deletion.

RECENT FINDINGS

Several areas are highlighted in this review, reflecting the focus of scholarly work on velo-cardio-facial syndrome in the past year. Molecular genetics has shown smaller deletions in many families with the syndrome. The gene TBX1 has been found to be important to the phenotype. Surgical outcomes data reveal the greater challenges involved in correcting velopharyngeal insufficiency.

SUMMARY

Defining the genetic basis of velo-cardio-facial syndrome will allow clinicians and basic scientists to make further inroads into understanding the variable expressivity of this syndrome. It is also important to be aware of the continued diagnostic challenges encountered by clinicians in attempts to improve the detection of patients with this syndrome.