Defining the clinical spectrum of deletion 22q11.2

Tbx1 haploinsufficiency leads to local skull deformity, paraflocculus and flocculus dysplasia, and motor-learning deficit in 22q11.2 deletion syndrome

Neurodevelopmental disorders are thought to arise from intrinsic brain abnormalities. Alternatively, they may arise from disrupted crosstalk among tissues. Here we show the local reduction of two vestibulo-cerebellar lobules, the paraflocculus and flocculus, in mouse models and humans with 22q11.2 deletion syndrome (22q11DS). In mice, this paraflocculus/flocculus dysplasia is associated with haploinsufficiency of the Tbx1 gene. Tbx1 haploinsufficiency also leads to impaired cerebellar synaptic plasticity and motor learning. However, neural cell compositions and neurogenesis are not altered in the dysplastic paraflocculus/flocculus. Interestingly, 22q11DS and Tbx1+/- mice have malformations of the subarcuate fossa, a part of the petrous temporal bone, which encapsulates the paraflocculus/flocculus. Single-nuclei RNA sequencing reveals that Tbx1 haploinsufficiency leads to precocious differentiation of chondrocytes to osteoblasts in the petrous temporal bone autonomous to paraflocculus/flocculus cell populations. These findings suggest a previously unrecognized pathogenic structure/function relation in 22q11DS in which local skeletal deformity and cerebellar dysplasia result in behavioral deficiencies.

Comparison of the Accuracy in Provisional Diagnosis of 22q11.2 Deletion and Williams Syndromes by Facial Photos in Thai Population Between De-Identified Facial Program and Clinicians

Introduction

There are more than 6000 genetic syndromes, therefore the recognition of facial patterns may present a challenge for clinicians. The 22q11.2 deletion syndrome (22q11.2 DS) and Williams syndrome (WS) are two different genetic syndromes but share some common phenotypic traits and subtle facial dysmorphisms. Therefore, any tool that would help clinicians recognize genetic syndromes would likely result in a more accurate diagnosis.

Methods

The syndrome identification accuracy was compared between 2 different facial analysis algorithms (DeepGestalt and GestaltMatcher) of the Face2Gene (F2G) tool and a group of 9 clinicians with different levels of expertise before and after using F2G for a cohort of 64 Thai participants' frontal facial photos divided into 3 groups of 22q11.2 DS, WS and unaffected controls.

Results

The higher accuracy from the DeepGestalt algorithm than from clinicians was demonstrated, especially when comparing between the two syndromes. The accuracy was highest when clinicians use the tool combined with their own decision-making process. The tool's second algorithm, GestaltMatcher revealed clear separation among these three groups of photos.

Discussion

The result of F2G outperforming clinicians was not surprising. However, the highest increase in accuracy was with nondysmorphology clinicians using F2G.

Conclusion

Face2Gene would be a useful tool to help clinicians in facial recognition of genetic syndromes, before ordering specific tests to confirm the definite diagnosis.

Next-generation sequencing profiling of miRNAs in individuals with 22q11.2 deletion syndrome revealed altered expression of miR-185-5p

BACKGROUND

The 22q11.2 deletion syndrome (22q11.2DS) is a microdeletion syndrome with highly variable phenotypic manifestations, even though most patients present the typical 3 Mb microdeletion, usually affecting the same ~ 106 genes. One of the genes affected by this deletion is DGCR8, which plays a crucial role in miRNA biogenesis. Therefore, the haploinsufficiency of DGCR8 due to this microdeletion can alter the modulation of the expression of several miRNAs involved in a range of biological processes.

RESULTS

In this study, we used next-generation sequencing to evaluate the miRNAs profiles in the peripheral blood of 12 individuals with typical 22q11DS compared to 12 healthy matched controls. We used the DESeq2 package for differential gene expression analysis and the DIANA-miTED dataset to verify the expression of differentially expressed miRNAs in other tissues. We used miRWalk to predict the target genes of differentially expressed miRNAs. Here, we described two differentially expressed miRNAs in patients compared to controls: hsa-miR-1304-3p, located outside the 22q11.2 region, upregulated in patients, and hsa-miR-185-5p, located in the 22q11.2 region, which showed downregulation. Expression of miR-185-5p is observed in tissues frequently affected in patients with 22q11DS, and previous studies have reported its downregulation in individuals with 22q11DS. hsa-miR-1304-3p has low expression in blood and, thus, needs more validation, though using a sensitive technology allowed us to identify differences in expression between patients and controls.

CONCLUSIONS

Thus, lower expression of miR-185-5p can be related to the 22q11.2 deletion and DGCR8 haploinsufficiency, leading to phenotypic consequences in 22q11.2DS patients, while higher expression of hsa-miR-1304-3p might be related to individual genomic variances due to the heterogeneous background of the Brazilian population.

Thalamocortical organoids enable in vitro modeling of 22q11.2 microdeletion associated with neuropsychiatric disorders

Thalamic dysfunction has been implicated in multiple psychiatric disorders. We sought to study the mechanisms by which abnormalities emerge in the context of the 22q11.2 microdeletion, which confers significant genetic risk for psychiatric disorders. We investigated early stages of human thalamus development using human pluripotent stem cell-derived organoids and show that the 22q11.2 microdeletion underlies widespread transcriptional dysregulation associated with psychiatric disorders in thalamic neurons and glia, including elevated expression of FOXP2. Using an organoid co-culture model, we demonstrate that the 22q11.2 microdeletion mediates an overgrowth of thalamic axons in a FOXP2-dependent manner. Finally, we identify ROBO2 as a candidate molecular mediator of the effects of FOXP2 overexpression on thalamic axon overgrowth. Together, our study suggests that early steps in thalamic development are dysregulated in a model of genetic risk for schizophrenia and contribute to neural phenotypes in 22q11.2 deletion syndrome.

Understanding the Variability of 22q11.2 Deletion Syndrome: The Role of Epigenetic Factors

Initially described as a triad of immunodeficiency, congenital heart defects and hypoparathyroidism, 22q11.2 deletion syndrome (22q11.2DS) now encompasses a great amount of abnormalities involving different systems. Approximately 85% of patients share a 3 Mb 22q11.2 region of hemizygous deletion in which 46 protein-coding genes are included. However, the hemizygosity of the genes of this region cannot fully explain the clinical phenotype and the phenotypic variability observed among patients. Additional mutations in genes located outside the deleted region, leading to "dual diagnosis", have been described in 1% of patients. In some cases, the hemizygosity of the 22q11.2 region unmasks autosomal recessive conditions due to additional mutations on the non-deleted allele. Some of the deleted genes play a crucial role in gene expression regulation pathways, involving the whole genome. Typical miRNA expression patterns have been identified in 22q11.2DS, due to an alteration in miRNA biogenesis, affecting the expression of several target genes. Also, a methylation epi-signature in CpG islands differentiating patients from controls has been defined. Herein, we summarize the evidence on the genetic and epigenetic mechanisms implicated in the pathogenesis of the clinical manifestations of 22q11.2 DS. The review of the literature confirms the hypothesis that the 22q11.2DS phenotype results from a network of interactions between deleted protein-coding genes and altered epigenetic regulation.

Multivariate patterns of disrupted sleep longitudinally predict affective vulnerability to psychosis in 22q11.2 Deletion Syndrome

22q11.2 deletion syndrome (22q11DS) contributes dramatically to increased genetic risk for psychopathology, and in particular schizophrenia. Sleep disorders, including obstructive sleep apnea (OSA), are also highly prevalent, making 22q11DS a unique model to explore their impact on psychosis vulnerability. Still, the contribution of sleep disturbances to psychosis vulnerability remains unclear. We characterized the sleep phenotype of 69 individuals with 22q11DS and 38 healthy controls with actigraphy and sleep questionnaires. Psychiatric symptoms were measured concomitantly with the baseline sleep assessment and at longitudinal follow-up, 3.58±0.85 years later. We used a novel multivariate partial-least-square-correlation (PLSC) approach to identify sleep patterns combining objective and subjective variables, which correlated with psychiatric symptoms. We dissected longitudinal pathways linking sleep disturbances to psychosis, using multi-layer-network-analysis. 22q11DS was characterized by a non-restorative sleep pattern, combining increased daytime fatigue despite longer sleep duration. Non-restorative sleep combined with OSA symptoms correlated with both emotional and psychotic symptoms. Moreover, a sleep pattern evocative of OSA predicted longitudinal worsening of positive and negative symptoms, by accentuating the effects of emotional dysregulation. These results suggest that sleep disturbances could significantly increase psychosis risk, along an affective pathway. If confirmed, this suggests that systematic screening of sleep quality could mitigate psychosis vulnerability in 22q11DS.

A comprehensive list of human microdeletion and microduplication syndromes

OBJECTIVE

The phenotypic spectrum of human microdeletion and microduplication syndromes (MMS) is heterogeneous but often involves intellectual disability, autism spectrum disorders, dysmorphic features and/or multiple congenital anomalies. While the common recurrent copy number variants (CNVs) which underlie these MMS have been well-studied, the expansion of clinical genomic testing has led to the identification of many rare non-recurrent MMS. To date, hundreds of unique MMS have been reported in the medical literature, and no single resource exists which compiles all these MMS in one location. This comprehensive list of MMS will aid further study of CNV disorders as well as serve as a resource for clinical laboratories performing diagnostic CNV testing.

DATA DESCRIPTION

Here we provide a comprehensive list of MMS which have been reported in the medical literature to date. This list is sorted by genomic location, and for each MMS, we provide a list of publications for referral, as well as the consensus coordinates, representative region, shortest regions of overlap (SRO), and/or subregions where applicable.

Transcriptional coregulator Ess2 controls survival of post-thymic CD4+ T cells through the Myc and IL-7 signaling pathways

Ess2, also known as Dgcr14, is a transcriptional co-regulator of CD4+ T cells. Ess2 is located in a chromosomal region, the loss of which has been associated with 22q11.2 deletion syndrome (22q11DS), which causes heart defects, skeletal abnormalities, and immunodeficiency. However, the specific association of Ess2 with 22q11DS remains unclear. To elucidate the role of Ess2 in T-cell development, we generated Ess2 floxed (Ess2fl/fl) and CD4+ T cell-specific Ess2 KO (Ess2ΔCD4/ΔCD4) mice using the Cre/loxP system. Interestingly, Ess2ΔCD4/ΔCD4 mice exhibited reduced naïve T-cell numbers in the spleen, while the number of thymocytes (CD4-CD8-, CD4+CD8+, CD4+CD8-, and CD4-CD8+) in the thymus remained unchanged. Furthermore, Ess2ΔCD4/ΔCD4 mice had decreased NKT cells and increased γδT cells in the thymus and spleen. A genome-wide expression analysis using RNA-seq revealed that Ess2 deletion alters the expression of many genes in CD4 single-positive thymocytes, including genes related to the immune system and Myc target genes. In addition, Ess2 enhanced the transcriptional activity of c-Myc. Some genes identified as Ess2 targets in mice show expressional correlation with ESS2 in human immune cells. Moreover, Ess2ΔCD4/ΔCD4 naïve CD4+ T cells did not maintain survival in response to IL-7. Our results suggest that Ess2 plays a critical role in post-thymic T-cell survival through the Myc and IL-7 signaling pathways.

New Phenotypic Feature in a Patient With a Rare Triplication of the 22q11.2 Region Presenting With Peters Anomaly, Congenital Heart Disease, and Global Developmental Delay: A Case Report and Literature Review

The vulnerability of chromosome 22q11.2 region to rearrangement is due to several low copy repeat (LCR) sequences. These rearrangements are involved in syndromes that share similar phenotypic features. The rearrangements of the 22q11.2 chromosomal region are common, specifically, duplications and deletions associated with congenital anomalies and developmental disabilities disorders. However, the features associated with this chromosomal rearrangement remain largely unknown. We present, to the best of our knowledge, the third patient affected by triplication of the 22q11.2 chromosome region, who presents with Peters anomaly, global developmental delay, patent ductus arteriosus, and subaortic stenosis. This case highlights a new phenotypic feature associated with triplication of this genomic region.

Late maternal diagnosis of DiGeorge syndrome with congenital hypoparathyroidism following antenatal detection of the same 22q11.2 microdeletion syndrome in the fetus

Genetic causes of hypocalcaemia can be overlooked in patients who present without apparent syndromic features. One relatively common but under-recognised genetic disorder is DiGeorge syndrome, which is often diagnosed in childhood but rarely in adulthood. Its enigmatic diagnosis can be attributed to its broad heterogeneous clinical presentation, such as the absence of cardiac abnormalities with only subtly abnormal facies. The presence of hypoparathyroidism-related hypocalcaemia may be the first early sign. We describe a young female adult with childhood-onset hypocalcaemia who was diagnosed with DiGeorge syndrome during her pregnancy when the fetus was found to have the same condition on antenatal screening and autopsy. This case reminds clinicians to consider the genetic causes of hypoparathyroidism-induced hypocalcaemia early on in childhood, while acknowledging the possibility of a late diagnosis in adulthood. We also highlight the risks of severe hypocalcaemia in pregnancy and outline a systematic approach to the evaluation of chronic hypocalcaemia.

Social Cognition Impairments in 22q11.2DS Individuals With and Without Psychosis: A Comparison Study With a Large Population of Patients With Schizophrenia

Background

22q11.2 Deletion Syndrome (22q11DS) represents one of the most important genetic risk factors for schizophrenia (SCZ) and a reliable biological model to study endophenotypic characters of SCZ. The aim of the study was to investigate Social Cognition impairments in subjects with 22q11.2DS compared to a considerable sample of schizophrenic patients.

Methods

Forty-four individuals with 22q11.2DS (DEL) and 18 patients with 22q11.2DS and psychosis (DEL_SCZ) were enrolled; these groups were compared to 887 patients with schizophrenia (SCZ) and 780 healthy controls (HCs); the latter groups were recruited by the Italian Network for Research on Psychoses (NIRP) to which our Centre took part. Social cognition was evaluated through The Awareness of Social Inference Test (TASIT). A resampling procedure was employed to balance differences in samples size.

Results

All clinical groups (DEL; DEL_SCZ; and SCZ) showed worse performance on TASIT than HCs, except in Sincere scale. No differences between-clinical groups were found, except for Simple Sarcasm, Paradoxical Sarcasm and Enriched Sarcasm scales.

Conclusions

SC was impaired in individuals with 22q11.2DS regardless of psychotic symptomatology, similarly to people with SCZ. Therefore, SC deficits may represent potential endophenotypes of SCZ contributing to the vulnerability to psychosis.

Clinical Features of Aberrations Chromosome 22q: A Pilot Study

Objective  A significant number of genetic variations have been identified in chromosome 22, using molecular genetic techniques. Various genomic disorders on chromosome 22, including cat's eye syndrome caused by extra copies of the proximal region of the 22q chromosome, are now well-defined. Our aim in the study was to show phenotypic variability associated with rearrangements of the 22q chromosomal region.

Methods  We focused our study on clinical aspects of these disorders, including genetic testing, genotype-phenotype correlation, and potential treatments. A total of 998 patients were referred for genetic analysis (Karyotyping, MLPA, array-CGH) during January 2015 to February 2020 because of intellectual deficiency, behavior issues, and/or multiple congenital abnormalities in several genetics departments. Informed consent was obtained from all the patients and/or their parents.

Results  22q11.21 or 22q13.33 microdeletions and 22q11.22-q11.23 microduplication were identified in 31 patients out of referrals. The 22q aberrations were detected in 31/998 patients, giving a prevalence of 3.1%. In this study, 18 patients with 22q11.2 (LCR22A-H) deletion, three patients with 22q13.31 deletion, 9 patients with 22q11.2 duplication and one patient with 22q13.31 duplication were identified. We report on the clinical and molecular characterization of 31 individuals with distal deletions and duplications of chromosome 22q.

Conclusions  The current study demonstrated in the largest postnatal case series reporting the whole spectrum of atypical phenotypic and genotypic variations at 22q. We believe that when all the phenotypic differences are taken into account, various anomalies including developmental delay and intellectual disability might be considered as an indication to search for aberrations of 22q along with congenital heart diseases.

Medical and dental characteristics of children with chromosome 22q11.2 deletion syndrome at the Royal Children's Hospital, Melbourne

BACKGROUND

Chromosome 22q11.2 deletion syndrome (22q11.2DS) is a multifaceted syndrome with a variable phenotype. Few studies have described the associated dental characteristics and their relationship with medical co-morbidities; and no Australian data exist.

AIM

To determine the clinical manifestations and correlations between oral and medical conditions in children with 22q11.2DS.

DESIGN

A retrospective observational study. Children genetically diagnosed with 22q11.2DS at the Royal Children's Hospital Melbourne were selected; their medical and dental characteristics were collated and analysed.

RESULTS

The study population (n = 57; mean age 11.5 years, range 2-27 years) experienced a range of medical conditions involving multiple medical systems; of whom 44 (77.2%) had caries experience, 7 (12.3%) developmentally missing teeth, and 31 (54.4%) developmental defects of enamel (DDE). Smaller proportions of primary teeth were affected by DDE in children with congenital heart disease (2.2% vs 9.7%; P = .02), and cardiac surgery (0.2% vs 9%; P = .001). Conversely, children with hypoparathyroidism (n = 2) had significantly higher proportions of primary teeth affected by DDE (27.5% vs 4%; P = .02).

CONCLUSIONS

Significant associations existed between medical conditions (congenital heart disease, history of cardiac surgery, and hypoparathyroidism) and primary dentition DDE in children with 22q11.2 DS.

Total Anomalous Pulmonary Venous Connection in Mother and Son with a Central 22q11.2 Microdeletion

In this clinical report, we describe a male infant and his mother, who had similar congenital heart defects. They were both diagnosed neonatally with total anomalous pulmonary venous connection (TAPVC) in combination with other heart defects. Neither of the two had any other organ malformations or dysmorphic facial features. SNP-array identified a central 22q11.2 microdeletion in the male infant and his mother as well as in the maternal grandmother and maternal aunt. The mother and the maternal aunt additionally harbored a 15q11.2 BP1-BP2 microdeletion. The maternal grandmother was unaffected by heart disease. However, heart computed tomography scan of the maternal aunt revealed a quadricuspid aortic valve. Additionally, the maternal grandmother and the maternal aunt both had significant learning disabilities. Rarely, TAPVC has been described in patients with the common 22q11.2 microdeletions. However, to the best of our knowledge, TAPVC has not previously been reported in patients with this small central 22q11.2 microdeletion. Haploinsufficiency of TBX1 was originally thought to be the main cause of the 22q11.2 microdeletion syndrome phenotype, but TBX1 is not included in the atypical central 22q11.2 microdeletion. Previous reports have suggested an association between TAPVC and the 15q11.2 BP1-BP2 microdeletion. Our report does not support this association as the maternal aunt, who harbors both microdeletions, is unaffected by TAPVC, and the male infant affected by TAPVC does not harbor the 15q11.2 BP1-BP2 microdeletion. Our findings support that genes located in the central 22q11.2 region are important for heart development and that haploinsufficiency of these genes plays a crucial role in the development of the rare heart defect TAPVC.

Screening of 22q11.2DS Using Multiplex Ligation-Dependent Probe Amplification as an Alternative Diagnostic Method

Background

The 22q11.2 deletion syndrome (22q11.2DS) is the most common form of deletion disorder in humans. Low copy repeats flanking the 22q11.2 region confers a substrate for nonallelic homologous recombination (NAHR) events leading to rearrangements which have been reported to be associated with highly variable and expansive phenotypes. The 22q11.2DS is reported as the most common genetic cause of congenital heart defects (CHDs).

Methods

A total of 42 patients with congenital heart defects, as confirmed by echocardiography, were recruited. Genetic molecular analysis using a fluorescence in situ hybridization (FISH) technique was conducted as part of routine 22q11.2DS screening, followed by multiplex ligation-dependent probe amplification (MLPA), which serves as a confirmatory test.

Results

Two of the 42 CHD cases (4.76%) indicated the presence of 22q11.2DS, and interestingly, both cases have conotruncal heart defects. In terms of concordance of techniques used, MLPA is superior since it can detect deletions within the 22q11.2 locus and outside of the typically deleted region (TDR) as well as duplications.

Conclusion

The incidence of 22q11.2DS among patients with CHD in the east coast of Malaysia is 0.047. MLPA is a scalable and affordable alternative molecular diagnostic method in the screening of 22q11.2DS and can be routinely applied for the diagnosis of deletion syndromes.

From Learning to Memory: A Comparison Between Verbal and Non-verbal Skills in 22q11.2 Deletion Syndrome

Background: Previous studies on possible memory deficits in 22q11DS often focused on quantifying the information memorized, whereas learning processes have been mostly overlooked. Furthermore, methodological differences in task design have made verbal and non-verbal comparison challenging and mixed results have been observed depending on chosen stimuli. Method: 135 participants (78 with 22q11DS) completed a multi-trial memory task modeled after the Rey Auditory Verbal Learning Task, comparing verbal and non-verbal learning as well as retention over time. Performance in the 22q11DS group were compared to controls and learning curves were analyzed. Results: In 22q11DS, slower acquisition of non-verbal material and higher rates of errors in both verbal and non-verbal tasks was observed. After 30 min, free recall performance, when corrected for initial learning rate, was similar between 22q11DS and controls. Conversely, recognition performance was overall weaker for 22q11DS in both modalities (verbal and non-verbal). Conclusion: This study examined how information is acquired, retained in memory over time and how different recall modalities (free recall vs. recognition) could yield different performances. Clinical implications of the findings are discussed.

A case of aberrant CD8 T cell-restricted IL-7 signaling with a Janus kinase 3 defect-associated atypical severe combined immunodeficiency

Severe combined immunodeficiency (SCID) disorders compromise lymphocyte numbers and/or function. One subset of SCID typically affects T cell and Natural Killer (NK) cell development in tandem (T^-B⁺NK^-) due to mutations arising in the genes encoding the common γ chain or Janus Kinase 3 (JAK3). In rare circumstances, mutations in the JAK3 gene have been reported to cause atypical SCID that selectively affects T cells (T^-B⁺NK⁺). Here we describe a case involving a female infant who was referred to our institution on day nine of life following an abnormal newborn screen result for T^-SCID. Immunological assessments revealed a T^-B⁺NK⁺ phenotype and molecular analyses, including whole exome sequencing, identified compound heterozygous JAK3 variants (R117C and E658K). Pre-transplant phosflow analyses revealed a persistent IL-7 signaling defect, based on phospho-STAT5 measurements, only in CD8 but not CD4 T cells. Intriguingly, phospho-STAT5 signals in response to IL-2 stimulation were not affected in either CD4 or CD8 T cells. The pre-transplant clinical course was unremarkable, and the patient received a cord-blood stem cell transplant on day 716 of life. Post-transplant monitoring revealed that despite normalization of lymphocyte counts, the CD8 T cell-restricted IL-7 signaling defect was still evident at day 627 post-transplant (phospho-STAT5 signal in CD8 T cells was > 60% reduced compared with CD4 T cells). The post-transplant clinical course has also been complicated by identification of autoimmune responses and likely GVHD-induced ichthyosis. To the best of our knowledge, this report represents the third case of JAK3-associated atypical SCID reported in the literature.

Clinical Features to Predict 22q11.2 Deletion Syndrome Proven by Molecular Genetic Testing

The 22q11.2 deletion syndrome (22q11.2 DS) is the most common microdeletion syndrome with a wide variety of clinical features. However, as there are no clinical criteria for diagnosis, confirmation is solely done by genetic tests if clinicians recognize the syndrome. Therefore, we aimed to identify clinical features that may help clinicians recognize 22q11.2 DS. Participants with at least two anomalies were enrolled, complete patient history and physical examinations were performed, then multiplex ligation-dependent probe amplification (MLPA) analysis for 22q11.2 DS was utilized. We identified 11/48 (23%) cases with 22q11.2 DS. Palatal anomalies, hypocalcemia, and ≥3 affected body systems were highly significant presentations in the 22q11.2 DS group versus the group without deletion ( p  < 0.05). Therefore, a comprehensive physical examination is crucial at identifying any subtle features which may lead to testing and a definite diagnosis.

Prenatal diagnosis of 22q11.2 copy number abnormalities in fetuses via single nucleotide polymorphism array

The q11.2 region on chromosome 22 contains numerous low-copy repeats that lead to deleted or duplicated regions in the chromosome, thereby resulting in different syndromes characterized by intellectual disabilities or congenital anomalies. The association between patient phenotypes and 22q11.2 copy number abnormalities has been previously described in postnatal cases; however, these features have not been systematically evaluated in prenatal cases because of limitations in phenotypic identification in prenatal testing. In this study, we investigated the detection rate of 22q11.2 copy number abnormalities in 2500 fetuses using single nucleotide polymorphism (SNP) array and determined the common abnormal ultrasound findings in fetuses carrying the 22q11.2 copy number abnormalities. The 22q11.2 copy number abnormalities were identified in 13 fetuses with cardiovascular malformations (6/13), kidney malformations (3/13), isolated ultrasound markers (3/13), or high-risk Down syndrome based on maternal serum screening (1/13). Approximately 0.5% (13/2500) of the fetuses harbored 22q11.2 copy number abnormalities. The most frequent ultrasound findings in fetuses with these abnormalities were cardiovascular malformations, followed by kidney malformations and isolated ultrasound markers. Prenatal diagnosis of these genetic abnormalities allows for the delineation of differential diagnoses, characterization of a wide spectrum of associated malformations, and determination of associations that exist between prenatal diagnosis and obstetrical outcomes.

Neuroimaging Phenotypes Associated With Risk and Resilience for Psychosis and Autism Spectrum Disorders in 22q11.2 Microdeletion Syndrome

Identification of biological risk factors that contribute to the development of complex neuropsychiatric disorders such as psychosis and autism spectrum disorder (ASD) is key for early intervention and detection. Furthermore, parsing the biological heterogeneity associated with these neuropsychiatric syndromes will help us understand the neural mechanisms underlying psychiatric symptom development. The 22q11.2 microdeletion syndrome (22q11DS) is caused by a recurrent genetic mutation that carries significantly increased risk for developing psychosis and/or ASD. In this review, I provide an brief introduction to 22q11DS and discuss common phenotyping strategies that are used to assess psychosis and ASD in this population. I then summarize neuroimaging phenotypes associated with psychosis and ASD in 22q11.DS. Next, I discuss challenges within the field and provide practical suggestions to overcome these obstacles. Finally, I discuss future directions for moving 22q11DS risk and resilience research forward.

Schizophrenia-related microdeletion causes defective ciliary motility and brain ventricle enlargement via microRNA-dependent mechanisms in mice

Progressive ventricular enlargement, a key feature of several neurologic and psychiatric diseases, is mediated by unknown mechanisms. Here, using murine models of 22q11-deletion syndrome (22q11DS), which is associated with schizophrenia in humans, we found progressive enlargement of lateral and third ventricles and deceleration of ciliary beating on ependymal cells lining the ventricular walls. The cilia-beating deficit observed in brain slices and in vivo is caused by elevated levels of dopamine receptors (Drd1), which are expressed in motile cilia. Haploinsufficiency of the microRNA-processing gene Dgcr8 results in Drd1 elevation, which is brought about by a reduction in Drd1-targeting microRNAs miR-382-3p and miR-674-3p. Replenishing either microRNA in 22q11DS mice normalizes ciliary beating and ventricular size. Knocking down the microRNAs or deleting their seed sites on Drd1 mimicked the cilia-beating and ventricular deficits. These results suggest that the Dgcr8-miR-382-3p/miR-674-3p-Drd1 mechanism contributes to deceleration of ciliary motility and age-dependent ventricular enlargement in 22q11DS.

Inability to Mask Ventilate During Myringotomy Tube Replacement: A Case Report

We present the case of a 3-year-old female with multiple congenital anomalies, including postprandial otorrhea, who developed the inability to be mask ventilated secondary to a combination of velopharyngeal insufficiency and tympanic membrane perforation. When applied by mask, positive pressure ventilation was observed to preferentially escape the patient's left ear, resulting in significant air leak, insufficient tidal volumes, hypoventilation, and severe hypoxemia. The problem was remedied by the insertion of a finger into the patient's external auditory meatus, which controlled the air leak until the surgical team could provide definitive surgical correction of the velopharyngeal insufficiency and nasopharyngeal reflux.

Differences in the Tensor Veli Palatini Muscle and Hearing Status in Children With and Without 22q11.2 Deletion Syndrome

PURPOSE

To investigate the dimensions of the tensor veli palatini (TVP) muscle using high image resolution 3-dimensional magnetic resonance imaging (MRI) of the soft palate among children with normal velopharyngeal and craniofacial anatomy and to compare values to individuals with a diagnosis of 22q11.2 deletion syndrome (22q11DS). We also sought to determine whether there is a relationship between hypoplasia of the TVP and severity of middle ear dysfunction and hearing loss.

METHODS

Three-dimensional MRI were used to collect and analyze data obtained across 53 children between 4 and 12 years of age, including 40 children with normal velopharyngeal and craniofacial anatomy and 13 children with a diagnosis of 22q11.2 DS. Tensor veli palatini muscle length, thickness, and volume as well as bihamular distance were compared among participant groups.

RESULTS

A Welch's t-test revealed that the TVP in participants with 22q11DS is significantly shorter (P = .005, 17.3 vs 19.0 mm), thinner (P < .001, 1.1 vs 1.8 mm), and less voluminous (P < .001, 457.5 vs 667.3 mm³) than participants without 22q11DS. Participants with 22q11DS also had a greater (P = .006, 27.7 vs 24.7 mm) bihamular distance than participants without 22q11DS. There was an inverse relationship between TVP abnormalities noted above and the severity of audiologic and otologic histories.

CONCLUSION

The TVP muscle is substantially reduced in volume, length, and thickness in children with 22q11DS. These findings serve as preliminary support for the association of patient hearing and otologic severity and TVP dysmorphology.

In the line-up: deleted genes associated with DiGeorge/22q11.2 deletion syndrome: are they all suspects?

BACKGROUND

22q11.2 deletion syndrome (22q11DS), a copy number variation (CNV) disorder, occurs in approximately 1:4000 live births due to a heterozygous microdeletion at position 11.2 (proximal) on the q arm of human chromosome 22 (hChr22) (McDonald-McGinn and Sullivan, Medicine 90:1-18, 2011). This disorder was known as DiGeorge syndrome, Velo-cardio-facial syndrome (VCFS) or conotruncal anomaly face syndrome (CTAF) based upon diagnostic cardiovascular, pharyngeal, and craniofacial anomalies (McDonald-McGinn and Sullivan, Medicine 90:1-18, 2011; Burn et al., J Med Genet 30:822-4, 1993) before this phenotypic spectrum was associated with 22q11.2 CNVs. Subsequently, 22q11.2 deletion emerged as a major genomic lesion associated with vulnerability for several clinically defined behavioral deficits common to a number of neurodevelopmental disorders (Fernandez et al., Principles of Developmental Genetics, 2015; Robin and Shprintzen, J Pediatr 147:90-6, 2005; Schneider et al., Am J Psychiatry 171:627-39, 2014).

RESULTS

The mechanistic relationships between heterozygously deleted 22q11.2 genes and 22q11DS phenotypes are still unknown. We assembled a comprehensive "line-up" of the 36 protein coding loci in the 1.5 Mb minimal critical deleted region on hChr22q11.2, plus 20 protein coding loci in the distal 1.5 Mb that defines the 3 Mb typical 22q11DS deletion. We categorized candidates based upon apparent primary cell biological functions. We analyzed 41 of these genes that encode known proteins to determine whether haploinsufficiency of any single 22q11.2 gene-a one gene to one phenotype correspondence due to heterozygous deletion restricted to that locus-versus complex multigenic interactions can account for single or multiple 22q11DS phenotypes.

CONCLUSIONS

Our 22q11.2 functional genomic assessment does not support current theories of single gene haploinsufficiency for one or all 22q11DS phenotypes. Shared molecular functions, convergence on fundamental cell biological processes, and related consequences of individual 22q11.2 genes point to a matrix of multigenic interactions due to diminished 22q11.2 gene dosage. These interactions target fundamental cellular mechanisms essential for development, maturation, or homeostasis at subsets of 22q11DS phenotypic sites.

Surgical Outcomes for the Treatment of Velopharyngeal Insufficiency in 22q11.2 Deletion Syndrome

This study aimed to compare outcomes of concomitant palatoplasty and sphincter pharyngoplasty with pharyngeal flap and sphincter pharyngoplasty alone for the treatment of velopharyngeal insufficiency in patients with 22q11.2 deletion syndrome. Thirty-one cases were identified for inclusion in the study. Patients were separated into 3 surgical groups: combined palatoplasty and sphincter pharyngoplasty (n = 11), pharyngeal flap (n = 7), and sphincter pharyngoplasty (n = 13). Outcome measures included perceptual speech analyses, surgical complications, and revision rates. There were no differences in preoperative speech analysis scores ( P = .31). The combined palatoplasty and sphincter pharyngoplasty procedure had similar speech outcomes compared to pharyngeal flap, and both were significantly better than sphincter pharyngoplasty alone. Complication rates ( P = .61) and the need for revision surgery ( P = .25) were similar among all 3 groups. Concomitant palatoplasty and sphincter pharyngoplasty may be an alternative treatment for velopharyngeal insufficiency in children with 22q11.2 deletion syndrome.

Individuals with 22q11.2 deletion syndrome show intact prediction but reduced adaptation in responses to repeated sounds: Evidence from Bayesian mapping

One of the most common copy number variants, the 22q11.2 microdeletion, confers an increased risk for schizophrenia. Since schizophrenia has been associated with an aberrant neural response to repeated stimuli through both reduced adaptation and prediction, we here hypothesized that this may also be the case in nonpsychotic individuals with a 22q11.2 deletion. We recorded high-density EEG from 19 individuals with 22q11.2 deletion syndrome (12-25 years), as well as 27 healthy volunteers with comparable age and sex distribution, while they listened to a sequence of sounds arranged in a roving oddball paradigm. Using posterior probability maps and dynamic causal modelling we tested three different models accounting for repetition dependent changes in cortical responses as well as in effective connectivity; namely an adaptation model, a prediction model, and a model including both adaptation and prediction. Repetition-dependent changes were parametrically modulated by a combination of adaptation and prediction and were apparent in both cortical responses and in the underlying effective connectivity. This effect was reduced in individuals with a 22q11.2 deletion and was negatively correlated with negative symptom severity. Follow-up analysis showed that the reduced effect of the combined adaptation and prediction model seen in individuals with 22q11.2 deletion was driven by reduced adaptation rather than prediction failure. Our findings suggest that adaptation is reduced in individuals with a 22q11.2 deletion, which can be interpreted in light of the framework of predictive coding as a failure to suppress prediction errors.

Hemizygosity for the gene encoding glycoprotein Ibβ is not responsible for macrothrombocytopenia and bleeding in patients with 22q11 deletion syndrome

Essentials How thrombocytopenia relates to bleeding in 22q11 deletion syndrome (22q11DS) is not clear. Bleeding severity, platelet count and volume, and GPIBB were examined in patients with 22q11DS. Macrothrombocytopenia and bleeding typified imperfectly overlapping subsets of 22q11DS patients. GPIBB hemizygosity does not cause macrothrombocytopenia or bleeding in patients with 22q11DS. SUMMARY: Background and objectives Macrothrombocytopenia and bleeding are frequently associated with 22q11 deletion syndrome (22q11DS). GPIBB, which encodes the glycoprotein (GP) Ibβ subunit of GPIb-IX-V, is commonly deleted in patients with 22q11DS. Absence of functional GPIb-IX-V causes Bernard-Soulier syndrome, which is a severe bleeding disorder characterized by macrothrombocytopenia. Patients with 22q11DS are often obligate hemizygotes for GPIBB, and those with only a pathogenically disrupted copy of GPIBB present with Bernard-Soulier syndrome. The objective of this study was to determine how GPIBB hemizygosity and sequence variation relate to macrothrombocytopenia and bleeding in patients with 22q11DS who do not have Bernard-Soulier syndrome. Patients/methods We thoroughly characterized bleeding severity, mean platelet volume, platelet count and GPIBB copy number and sequence in patients with 22q11DS. Results and conclusions Macrothrombocytopenia and mild bleeding were observed in incompletely overlapping subsets of patients, and GPIBB copy number and sequence variation did not correlate with either macrothrombocytopenia or bleeding in patients with 22q11DS. These findings indicate that GPIBB hemizygosity does not result in either macrothrombocytopenia or bleeding in these patients. Alternative genetic causes of macrothrombocytopenia, potential causes of acquired thrombocytopenia and bleeding and ways in which platelet size, platelet count and GPIBB sequence information can be used to aid in the diagnosis and management of patients with 22q11DS are discussed.

Downregulation of genes outside the deleted region in individuals with 22q11.2 deletion syndrome

The 22q11.2 deletion syndrome (22q11.2DS) is caused by recurrent hemizygous deletions of chromosome 22q11.2. The phenotype of the syndrome is complex and varies widely among individuals. Little is known about the role of the different genes located in 22q11.2, and we hypothesized that genetic risk factors lying elsewhere in the genome might contribute to the phenotype. Here, we present the whole-genome gene expression data of 11 patients with approximately 3 Mb deletions. Apart from the hemizygous genes mapped to the 22q11.2 region, the TUBA8 and GNAZ genes, neighboring the deleted interval but in normal copy number, showed altered expression. When genes mapped to other chromosomes were considered in the gene expression analysis, a genome-wide dysregulation was observed, with increased or decreased expression levels. The enriched pathways of these genes were related to immune response, a deficiency that is frequently observed in 22q11.2DS patients. We also used the hypothesis-free weighted gene co-expression network analysis (WGCNA), which revealed the co-expression gene network modules with clear connection to mechanisms associated with 22q11.2DS such as immune response and schizophrenia. These findings, combined with the traditional gene expression profile, can be used for the identification of potential pathways and genes not previously considered to be related to the 22q11.2 deletion syndrome.

Numerical Processing Impairment in 22q11.2 (LCR22-4 to LCR22-5) Microdeletion: A Cognitive-Neuropsychological Case Study

Although progress has been made, the cognitive, biological and, particularly, the genetic underpinnings of math learning difficulties (MD) remain largely unknown. This difficulty stems from the heterogeneity of MD and from the large contribution of environmental factors to its etiology. Understanding endophenotypes, e.g., the role of the Approximate Number System (ANS), may help understanding the nature of MD. MD associated with ANS impairments has been described in some genetic conditions, e.g., 22q11.2 deletion syndrome (22q11.2DS or Velocardiofacial syndrome, VCFS). Recently, a girl with MD was identified in a school population screening. She has a new syndrome resulting from a microdeletion in 22q11.2 (LCR22-4 to LCR22-5), a region adjacent to but not overlapping with region 22q11.2 (LCR22-2 to LCR22-4), typically deleted in VCFS. Here, we describe her cognitive-neuropsychological and numerical-cognitive profiles. The girl was assessed twice, at 8 and 11 years. Her numerical-cognitive performance at both times was compared to demographically similar girls with normal intelligence in a single-case, quasi-experimental study. Neuropsychological assessment was normal, except for relatively minor impairments in executive functions. She presented severe and persistent difficulties in the simplest single-digit calculations. Difficulties in commutative operations improved from the first to the second assessment. Difficulties in subtraction persisted and were severe. No difficulties were observed in Arabic number writing. Difficulties in single-digit calculation co-occurred with basic numerical processing impairments in symbolic and non-symbolic (single-digit comparison, dot sets size comparison and estimation) tasks. Her difficulties suggest ANS impairment. No difficulties were detected in visuospatial/visuoconstructional and in phonological processing tasks. The main contributions of the present study are: (a) this is the first characterization of the neuropsychological phenotype in 22q11.2DS (LCR22-4 to LCR22.5) with normal intelligence; (b) mild forms of specific genetic conditions contribute to persistent MD in otherwise typical persons; (c) heterogeneity of neurogenetic underpinnings of MD is suggested by poor performance in non-symbolic numerical processing, dissociated from visuospatial/visuoconstructional and phonological impairments; (d) similar to what happens in 22q11.2DS (LCR22-2 to LCR22-4), ANS impairments may also characterize 22q11.2DS (LCR22-4 to LCR22-5).

A loss-of-function mutation p.T52S in RIPPLY3 is a potential predisposing genetic risk factor for Chinese Han conotruncal heart defect patients without the 22q11.2 deletion/duplication

Background

Conotruncal heart defect (CTD) is a complex congenital heart disease with a complex and poorly understood etiology. The transcriptional corepressor RIPPLY3 plays a pivotal role in heart development as a negative regulator of the key cardiac transcription factor TBX1. A previous study showed that RIPPLY3 contribute to cardiac outflow tract development in mice, however, the relationship between RIPPLY3 and human cardiac malformation has not been reported.

Methods

615 unrelated CTD Chinese Han patients were enrolled, we excluded the 22q11.2 deletion/duplication using a modified multiplex ligation-dependent probe amplification method—CNVplex^®, and investigated the variants of RIPPLY3 in 577 patients without the 22q11.2 deletion/duplication by target sequencing. Functional assays were performed to testify the potential pathogenicity of nonsynonymous variants found in these CTD patients.

Results

Four rare heterozygous nonsynonymous variants (p.P30L, p.T52S, p.D113N and p.V179D) were identified in four CTD patients, the variant NM_018962.2:c.155C>G (p.T52S) is referred as rs745539198, and the variant NM_018962.2:c.337G>A (p.D113N) is referred as rs747419773. However, variants p.P30L and p.V179D were not found in multiple online human gene variation databases. Western blot analysis and immunofluorescence showed that there were no significant difference between wild type RIPPLY3 and these four variants. Luciferase assays revealed that the p.T52S variant altered the inhibition of TBX1 transcriptional activity in vitro, and co-immunoprecipitation assays showed that the p.T52S variant reduced the physical interaction of RIPPLY3 with TBX1. In addition to the results from pathogenicity prediction tools and evolutionary protein conservation, the p.T52S variant was thought to be a potentially deleterious variant.

Conclusion

Our results provide evidence that deleterious variants in RIPPLY3 are potential molecular mechanisms involved in the pathogenesis of human CTD.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1633-1) contains supplementary material, which is available to authorized users.

Antenatal Diagnosis of Fetal Retinoid Syndrome at 20 Weeks of Gestation: A Case Report

INTRODUCTION

Isotretinoin, a synthetic derivative of vitamin A, is one of the most potent human teratogens, and is mainly utilized for the treatment of severe recalcitrant nodular acne. Retinoic acid embryopathy is well defined in the literature.

CASE REPORT

The mother was referred for a fetal posterior fossa abnormality, first detected at 20 weeks of gestation. The mother used isotretinoin until 18 weeks gestation. Ultrasound examination revealed hypertelorism, cerebellar hypoplasia, vermian agenesis, truncus arteriosus, anotia, thymic aplasia, corpus callosum hypoplasia. An intrauterine diagnosis of fetal retinoid syndrome was confirmed by fetopsy after termination of pregnancy.

CONCLUSION

The typical findings of fetal retinoid syndrome can be visualized with ultrasound in early second trimester.

Altered auditory processing and effective connectivity in 22q11.2 deletion syndrome

22q11.2 deletion syndrome (22q11.2DS) is one of the most common copy number variants and confers a markedly increased risk for schizophrenia. As such, 22q11.2DS is a homogeneous genetic liability model which enables studies to delineate functional abnormalities that may precede disease onset. Mismatch negativity (MMN), a brain marker of change detection, is reduced in people with schizophrenia compared to healthy controls. Using dynamic causal modelling (DCM), previous studies showed that top-down effective connectivity linking the frontal and temporal cortex is reduced in schizophrenia relative to healthy controls in MMN tasks. In the search for early risk-markers for schizophrenia we investigated the neural basis of change detection in a group with 22q11.2DS. We recorded high-density EEG from 19 young non-psychotic 22q11.2 deletion carriers, as well as from 27 healthy non-carriers with comparable age distribution and sex ratio, while they listened to a sequence of sounds arranged in a roving oddball paradigm. Despite finding no significant reduction in the MMN responses, whole-scalp spatiotemporal analysis of responses to the tones revealed a greater fronto-temporal N1 component in the 22q11.2 deletion carriers. DCM showed reduced intrinsic connection within right primary auditory cortex as well as in the top-down, connection from the right inferior frontal gyrus to right superior temporal gyrus for 22q11.2 deletion carriers although not surviving correction for multiple comparison. We discuss these findings in terms of reduced adaptation and a general increased sensitivity to tones in 22q11.2DS.

22q11.2 Deletion Syndrome in Colombian Patients With Syndromic Cleft Lip and/or Palate

The objective of this work was to identify 22q11.2 chromosomal deletion in patients with cleft lip and/or cleft palate and suggestive syndromic phenotype in Colombian patients. We studied 49 patients with cleft lip and/or cleft palate, exhibiting additional clinical findings linked to 22q11.2 deletion syndrome. All patients underwent high-resolution G-banded karyotyping, multiplex ligation-dependent probe amplification, and clinical evaluation by a geneticist. Seven patients presented 22q11.2 deletion and 2 patients had other chromosomal abnormalities. In conclusion, this study contributes with new data for genetic etiology in syndromic conditions of oral fissures.

Anatomic Malformations of the Middle and Inner Ear in 22q11.2 Deletion Syndrome: Case Series and Literature Review

BACKGROUND AND PURPOSE

The 22q11.2 deletion syndrome is characterized by a heterogenic phenotype, including hearing loss. The underlying cause of hearing loss, especially sensorineural hearing loss, is not yet clear. Therefore, our objective was to describe anatomic malformations in the middle and inner ear in patients with 22q11.2 deletion syndrome.

MATERIALS AND METHODS

A retrospective case series was conducted in 2 tertiary referral centers. All patients with 22q11.2 deletion syndrome who had undergone CT or MR imaging of the temporal bones were included. Radiologic images were evaluated on predetermined parameters, including abnormalities of the ossicular chain, cochlea, semicircular canals, and vestibule.

RESULTS

There were 26 patients (52 ears) with a CT or MR imaging scan available. A dense stapes superstructure was found in 18 ears (36%), an incomplete partition type II was suspected in 12 cochleas (23%), the lateral semicircular canal was malformed with a small bony island in 17 ears (33%), and the lateral semicircular canal and vestibule were fused to a single cavity in 15 ears (29%).

CONCLUSIONS

Middle and inner ear abnormalities were frequently encountered in our cohort, including malformations of the lateral semicircular canal.

Duplication and Deletion of 22q11 Associated with Anomalous Pulmonary Venous Connection

Anomalous pulmonary venous connection (APVC) is an uncommon congenital anomaly in which pulmonary venous blood flows directly into the right side of the heart or into the systemic veins. To identify whether there is any association between 22q11 CNVs and APVC, we analyzed the clinical data of 86 APVC patients and then studied the CNVs of 22q11 in 86 sporadic APVC patients by multiplex ligation-dependent probe amplification. The results showed that two patients carried the CNVs of 22q11, one patient had the deletion of 22q11 and the other had the duplication of 22q11. The incidence was significantly higher than that in the normal population (P < 0.01) that suggests a possible etiologic association between the duplication or deletion of 22q11 and the APVC in our patients.

22q11.2 Deletion Syndrome Is Associated With Impaired Auditory Steady-State Gamma Response

BACKGROUND

The 22q11.2 deletion syndrome confers a markedly increased risk for schizophrenia. 22q11.2 deletion carriers without manifest psychotic disorder offer the possibility to identify functional abnormalities that precede clinical onset. Since schizophrenia is associated with a reduced cortical gamma response to auditory stimulation at 40 Hz, we hypothesized that the 40 Hz auditory steady-state response (ASSR) may be attenuated in nonpsychotic individuals with a 22q11.2 deletion.

METHODS

Eighteen young nonpsychotic 22q11.2 deletion carriers and a control group of 27 noncarriers with comparable age range (12-25 years) and sex ratio underwent 128-channel EEG. We recorded the cortical ASSR to a 40 Hz train of clicks, given either at a regular inter-stimulus interval of 25 ms or at irregular intervals jittered between 11 and 37 ms.

RESULTS

Healthy noncarriers expressed a stable ASSR to regular but not in the irregular 40 Hz click stimulation. Both gamma power and inter-trial phase coherence of the ASSR were markedly reduced in the 22q11.2 deletion group. The ability to phase lock cortical gamma activity to regular auditory 40 Hz stimulation correlated with the individual expression of negative symptoms in deletion carriers (ρ = -0.487, P = .041).

CONCLUSIONS

Nonpsychotic 22q11.2 deletion carriers lack efficient phase locking of evoked gamma activity to regular 40 Hz auditory stimulation. This abnormality indicates a dysfunction of fast intracortical oscillatory processing in the gamma-band. Since ASSR was attenuated in nonpsychotic deletion carriers, ASSR deficiency may constitute a premorbid risk marker of schizophrenia.

Congenital respiratory tract disorders in 22q11.2 deletion syndrome

OBJECTIVE

Respiratory tract disorders have been reported in patients with 22q11.2 deletion syndrome, however infrequently. This study describes the respiratory tract disorders encountered in a cohort of 278 patients with 22q11.2 deletion syndrome.

METHODS

We conducted a retrospective, cross-sectional, study at a single tertiary referral center. We identified the patients with 22q11.2 deletion syndrome and with an upper and/or lower respiratory tract disorder at our otorhinolaryngologic department. The different disorders were described.

RESULTS

Out of 278 patients referred to the otorhinolaryngologic department, we identified 14 patients with a laryngeal and/or tracheal disorder. Nine patients had more than one congenital disorder in this anatomical area. Disorders included a choanal stenosis (n = 1), laryngeal web (n = 5), laryngeal cleft (n = 2), subglottic stenosis (n = 3), pharyngo-, laryngo-, tracheo- and/or bronchomalacia (n = 11) and tracheal stenosis (n = 1).

CONCLUSION

Different types of respiratory tract disorders can be present in patients with 22q11.2 deletion syndrome. Clinicians should be aware of this clinical association for timely and accurate diagnosis and treatment. In addition, the diagnosis 22q11.2 deletion syndrome should be considered in patients presenting with a congenital respiratory tract disorder.

LINE-1 retrotransposons in healthy and diseased human brain

Long interspersed element-1 (LINE-1 or L1) is a transposable element with the ability to self-mobilize throughout the human genome. The L1 elements found in the human brain is hypothesized to date back 56 million years ago and has survived evolution, currently accounting for 17% of the human genome. L1 retrotransposition has been theorized to contribute to somatic mosaicism. This review focuses on the presence of L1 in the healthy and diseased human brain, such as in autism spectrum disorders. Throughout this exploration, we will discuss the impact L1 has on neurological disorders that can occur throughout the human lifetime. With this, we hope to better understand the complex role of L1 in the human brain development and its implications to human cognition. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 434-455, 2018.

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.

Developmental excitatory-to-inhibitory GABA-polarity switch is disrupted in 22q11.2 deletion syndrome: a potential target for clinical therapeutics

Individuals with 22q11.2 microdeletion syndrome (22q11.2 DS) show cognitive and behavioral dysfunctions, developmental delays in childhood and risk of developing schizophrenia and autism. Despite extensive previous studies in adult animal models, a possible embryonic root of this syndrome has not been determined. Here, in neurons from a 22q11.2 DS mouse model (Lgdel^+/−), we found embryonic-premature alterations in the neuronal chloride cotransporters indicated by dysregulated NKCC1 and KCC2 protein expression levels. We demonstrate with large-scale spiking activity recordings a concurrent deregulation of the spontaneous network activity and homeostatic network plasticity. Additionally, Lgdel^+/− networks at early development show abnormal neuritogenesis and void of synchronized spontaneous activity. Furthermore, parallel experiments on Dgcr8^+/− mouse cultures reveal a significant, yet not exclusive contribution of the dgcr8 gene to our phenotypes of Lgdel^+/− networks. Finally, we show that application of bumetanide, an inhibitor of NKCC1, significantly decreases the hyper-excitable action of GABA_A receptor signaling and restores network homeostatic plasticity in Lgdel^+/− networks. Overall, by exploiting an on-a-chip 22q11.2 DS model, our results suggest a delayed GABA-switch in Lgdel^+/− neurons, which may contribute to a delayed embryonic development. Prospectively, acting on the GABA-polarity switch offers a potential target for 22q11.2 DS therapeutic intervention.

Social cognitive impairment in 22q11 deletion syndrome: A review

Individuals with 22q11.2 deletion syndrome (22q11DS) exhibit a broad array of physical and psychiatric features, of which impaired social cognition and poor social functioning are common. This review seeks to (1) characterize the current understanding of impairment across social cognitive domains in the context of 22q11DS, and (2) synthesize the relevant literature on social cognition and psychosis, given that the prevalence of psychosis in 22q11DS is especially high compared to the general population. A total of 16 papers examining social cognition in 22q11DS were identified through a comprehensive literature search conducted using electronic databases such as PubMed and PSYCInfo. Results suggest that individuals with 22q11DS exhibit impaired emotion processing and complex theory of mind relative to their typically developing peers, though some findings were accounted for by neurocognitive and intellectual abilities. Further, no studies have examined the domains of attribution bias or social perception in 22q11DS, highlighting a critical gap in the extant literature. More research is needed to better elucidate the trajectory of how and why social cognitive impairment develops in 22q11DS, and to explore possible relationships to psychiatric comorbidities like psychosis. Treatment implications and future steps are considered.

Neuroradiographic findings in 22q11.2 deletion syndrome

22q11.2 deletion syndrome (22q11.2DS) is a common genetic disorder with enormous phenotypic heterogeneity. Despite the established prevalence of developmental and neuropsychiatric issues in this syndrome, its neuroanatomical correlates are not as well understood. A retrospective chart review was performed on 111 patients diagnosed with 22q11.2DS. Of the 111 patients, 24 with genetically confirmed 22q11.2 deletion and brain MRI or MRA were included in this study. The most common indications for imaging were unexplained developmental delay (6/24), seizures of unknown etiology (5/24), and unilateral weakness (3/24). More than half (13/24) of the patients had significant radiographic findings, including persistent cavum septi pellucidi and/or cavum vergae (8/24), aberrant cortical veins (6/24), polymicrogyria or cortical dysplasia (4/24), inner ear deformities (3/24), hypoplastic internal carotid artery (2/24), and hypoplastic cerebellum (1/24). These findings reveal the types and frequencies of brain malformations in this case series, and suggest that the prevalence of neuroanatomical abnormalities in 22q11.2DS may be underestimated. Understanding indications for imaging and frequently encountered brain malformations will result in early diagnosis and intervention in an effort to optimize patient outcomes.

Prevalence of hearing loss and clinical otologic manifestations in patients with 22q11.2 deletion syndrome: A literature review

BACKGROUND

Hearing loss and otitis media are frequently reported in patients with 22q11.2 deletion syndrome.

OBJECTIVE OF REVIEW

Our objective was to review the current literature on the prevalence of hearing loss and otologic manifestations in patients with 22q11.2 deletion syndrome.

TYPE OF REVIEW

Systematic review.

SEARCH STRATEGY

We conducted a systematic search in PubMed and Embase combining the term "22q11.2 deletion syndrome" and synonyms with "hearing loss" and "otologic manifestations" and synonyms.

EVALUATION METHOD

We screened title/abstract and full text of all retrieved articles on pre-defined in- and exclusion criteria. The remaining articles were assessed on risk of bias. Outcome measures included the prevalence of hearing loss and otologic manifestations such as otitis media.

RESULTS

Our search yielded 558 unique studies of which a total of 25 articles were included for critical appraisal and data extraction. Twenty-one studies reported on hearing loss, and 21 studies on otologic manifestations. The prevalence of hearing loss varied from 6.0% to 60.3%, where in most studies conductive hearing loss was most prevalent. Rates of recurrent or chronic otitis media varied from 2.2% to 89.8%.

CONCLUSION

Although a very broad range in prevalences is reported in different studies, hearing loss and recurrent or chronic otitis media are frequently present in patients with 22q11.2 deletion syndrome. Regular check-ups and audiometric testing are advised in these patients.

Trends in the presentation, surgical treatment, and outcomes of tethered cord syndrome: A nationwide study from 2001 to 2010

OBJECTIVE

This is a nationwide query into surgical management techniques for tethered cord syndrome, focusing on patient demographic, hospital characteristics, and treatment outcomes. Our hypothesis is that detethering vs. fusion for TCS results in different in-hospital complications.

MATERIALS AND METHODS

Retrospective review of the Nationwide Inpatient Sample 2001-2010. Inclusion: TCS discharges undergoing detethering or fusion. Sub-analysis compared TCS cases by age (pediatric [≤9years] vs. adolescent [10-18year]). Independent t-tests identified differences between fusion and detethering for hospital-related and surgical factors; multivariate analysis investigated procedure as a risk factor for complications/mortality.

RESULTS

6457 TCS discharges: 5844 detetherings, 613 fusions. Fusion TCS had higher baseline Deyo Index (0.16 vs. 0.06), procedure-related complications (21.3% vs. 7.63%), and mortality (0.33% vs. 0.09%) than detethering, all p<0.001. Detethering for TCS was a significant factor for reducing mortality (OR 0.195, p<0.001), cardiac (OR 0.27, p<0.001), respiratory (OR 0.26, p<0.001), digestive system (OR 0.32, p<0.001), puncture nerve/vessel (OR 0.56, p=0.009), wound (OR 0.25, p<0.001), infection (OR 0.29, p<0.001), posthemorrhagic anemia (OR 0.04, p=0.002), ARDS (OR 0.13, p<0.001), and venous thrombotic (OR 0.53, p=0.043) complications. Detethering increased nervous system (OR 1.34, p=0.049) and urinary (OR 2.60, p<0.001) complications. Adolescent TCS had higher Deyo score (0.08 vs. 0.03, p<0.001), LOS (5.77 vs. 4.13days, p<0.001), and charges ($54,592.28 vs. $33,043.83, p<0.001), but similar mortality. Adolescent TCS discharges had increased prevalence of all procedure-related complications, and higher overall complication rate (11.10% vs. 5.08%, p<0.001) than pediatric.

CONCLUSIONS

With fusion identified as a significant risk factor for mortality and multiple procedure-related complications in TCS surgical patients, this study could aid surgeons in counseling TCS patients to optimize outcomes.

The 22q11.2 Deletion Syndrome in Congenital Heart Defects: Prevalence of Microdeletion Syndrome in Cameroon

BACKGROUND

The 22q11.2 deletion syndrome is amongst the most common microdeletion syndrome in humans. Its prevalence remains unknown in sub-Saharan Africa, and its clinical features are under-reported for people of African descent.

OBJECTIVE

We have investigated the prevalence of the 22q11.2 deletion syndrome in patients with congenital heart defects in Cameroon.

METHODS

A total of 70 of 100 cases of congenital cardiac malformation with echocardiographic evidence were examined prospectively and tested for the 22q11.2 deletion, using multiplex ligation-dependent probe amplification and fluorescence in situ hybridization.

RESULTS

Two of 70 patients (2.8%) were found to have 22q11.2 deletion. Both cases had conotruncal heart defects and exhibited extracardiac features of the 22q11.2 deletion syndrome that were either classical (e.g., puffy upper eyelids, bulbous tip of the nose) or less identifiable (telecanthus, hooding of eyelids and prominent nasal bridge).

CONCLUSIONS

The report shows that the prevalence of the 22q11.2 deletion syndrome in patients with heart malformations in Cameroon (2.8%) is similar to that of various world populations. The clinical phenotypes will contribute to the Global Atlas for dysmorphology. "Omics" technologies offer much promise in genetic/genomic screening of severe global health problems.

No evidence for the presence of genetic variants predisposing to psychotic disorders on the non-deleted 22q11.2 allele of VCFS patients

The velo-cardio-facial syndrome (VCFS) is caused by hemizygous deletions on chromosome 22q11.2. The VCFS phenotype is complex and characterized by frequent occurrence of neuropsychiatric symptoms with up to 25-30% of cases suffering from psychotic disorders compared with only ~1% in the general population (odds ratio≈20-25). This makes the 22q11.2 deletion one of the most prominent risk factors for schizophrenia. However, its penetrance for neuropsychiatric phenotypes is incomplete suggesting that additional risk factors are required for disease development. These additional risk factors could lie anywhere on the genome, but by reducing the normal diploid to a haploid state, the 22q11.2 deletion could result in the unmasking of otherwise recessive alleles or functional variants on the non-deleted 22q11.2 allele. To test this hypothesis, we captured and sequenced the whole 22q11.2 non-deleted region in 88 VCFS patients with (n=40) and without (n=48) psychotic disorders to identify genetic variation that could increase the risk for schizophrenia. Single nucleotide variants (SNVs), small insertions/deletions (indels) and copy number variants were called and their distributions were compared between the two diagnostic groups using variant-, gene- and region-based association tests. None of these tests resulted in statistical evidence for the existence of a genetic variation in the non-deleted allele that would increase schizophrenia risk in VCFS patients. Power analysis showed that our study was able to achieve >80% statistical power to detect association of a risk variant with an odd ratio of ⩾22. However, it is certainly under-powered to detect risk variant of smaller effect sizes. Our study did not provide evidence that genetic variants of very large effect size located on the non-deleted 22q1.2 allele in VCFS patients increase the risk for developing psychotic disorders. Variants with smaller effects may be located in the remaining 22q11.2 allele and elsewhere in the genome. Therefore, whole exome or even genome sequencing for larger sample size would appear to be the next logical steps in the search for the genetic modifiers of the 22q11.2-deletion neuropsychiatric phenotype.