Williams-Beuren syndrome

Anesthesiological Management of a Patient with Williams Syndrome Undergoing Spine Surgery

Williams Syndrome (WS) is a complex neurodevelopmental disorder associated with a mutation on chromosome 7. Patients with WS usually display dysmorphic facial and musculoskeletal features, congenital heart diseases, metabolic disturbances and cognitive impairment. Structural cardiovascular abnormalities are present in the majority of the children and may provide a substrate for perioperative Sudden Cardiac Death, as presented by several reports, something that creates a great challenge to the anesthetic conduct. We present the case of a 12-year old girl who required anesthetic care for surgical correction of an acquired kyphoscoliosis. Potential anesthesiological implications of WS are subsequently reviewed.

Reciprocal Microduplication of the Williams-Beuren Syndrome Chromosome Region in a 9-Year-Old Omani Boy

BACKGROUND

Microdeletions of the 7q11.23 Williams-Beuren syndrome chromosome region (WBSCR) are reported with a frequency of 1 in 10,000, whereas microduplications of the region, although expected to occur at the same frequency, are not widely reported.

METHOD

We evaluated a 9-year old Omani boy for idiopathic intellectual disability using genetic methods, including multiplex ligation-dependent probe amplification (MLPA), for detection of microdeletions (P064-B3).

RESULTS

MLPA analysis revealed that the boy has a rare microduplication of the WBSCR. Prominent clinical features include global developmental delay with pronounced speech delay, dysmorphic facies, and autistic features.

CONCLUSION

Microduplications, in general, are reported at a lesser frequency, perhaps owing to their milder phenotype. Complete genetic assessment in children with idiopathic intellectual disability would help in identifying rare conditions such as duplication of the WBSCR.

Surface-based morphometry reveals distinct cortical thickness and surface area profiles in Williams syndrome

Morphometric investigations of brain volumes in Williams syndrome (WS) consistently show significant reductions in gray matter volume compared to controls. Cortical thickness (CT) and surface area (SA) are two constituent parts of cortical gray matter volume that are considered genetically distinguishable features of brain morphology. Yet, little is known about the independent contribution of cortical CT and SA to these volumetric differences in WS. Thus, our objectives were: (i) to evaluate whether the microdeletion in chromosome 7 associated with WS has a distinct effect on CT and SA, and (ii) to evaluate age-related variations in CT and SA within WS. We compared CT and SA values in 44 individuals with WS to 49 age- and sex-matched typically developing controls. Between-group differences in CT and SA were evaluated across two age groups: young (age range 6.6-18.9 years), and adults (age range 20.2-51.5 years). Overall, we found contrasting effects of WS on cortical thickness (increases) and surface area (decreases). With respect to brain topography, the between-group pattern of CT differences showed a scattered pattern while the between-group surface area pattern was widely distributed throughout the brain. In the adult subgroup, we observed a cluster of increases in cortical thickness in WS across the brain that was not observed in the young subgroup. Our findings suggest that extensive early reductions in surface area are the driving force for the overall reduction in brain volume in WS. The age-related cortical thickness findings might reflect delayed or even arrested development of specific brain regions in WS.

Array CGH - A Powerful Tool in Molecular Diagnostic of Pathogenic Microdeletions - Williams-Beuren Syndrome - A Case Report

ABSTRACT: Williams-Beuren syndrome (WBS) (OMIM 194050) is caused by interstitial deletions or duplications of the 7q11.23 chromosomal region and characterised through a complex phenotype. We described a case diagnosed clinically and genetically confirmed through aCGH. Genetic assessment identified three microdeletions with a total size of 1.35 Mb located at 7q11.23. The deleted regions encompasses more than 30 genes including several protein coding genes such as ELN, LIMK1, FZDS, WBSCR22, WBSCR27, WBSCR28, STX1A, CLDN3, CLDN4, LAT2, ABHD11 or EIF4H .

Gtf2ird1-Dependent Mohawk Expression Regulates Mechanosensing Properties of the Tendon

Mechanoforces experienced by an organ are translated into biological information for cellular sensing and response. In mammals, the tendon connective tissue experiences and resists physical forces, with tendon-specific mesenchymal cells called tenocytes orchestrating extracellular matrix (ECM) turnover. We show that Mohawk (Mkx), a tendon-specific transcription factor, is essential in mechanoresponsive tenogenesis through regulation of its downstream ECM genes such as type I collagens and proteoglycans such as fibromodulin both in vivo and in vitro Wild-type (WT) mice demonstrated an increase in collagen fiber diameter and density in response to physical treadmill exercise, whereas in Mkx(-/-) mice, tendons failed to respond to the same mechanical stimulation. Furthermore, functional screening of the Mkx promoter region identified several upstream transcription factors that regulate Mkx In particular, general transcription factor II-I repeat domain-containing protein 1 (Gtf2ird1) that is expressed in the cytoplasm of unstressed tenocytes translocated into the nucleus upon mechanical stretching to activate the Mkx promoter through chromatin regulation. Here, we demonstrate that Gtf2ird1 is essential for Mkx transcription, while also linking mechanical forces to Mkx-mediated tendon homeostasis and regeneration.

Induced pluripotent stem cells: at the heart of cardiovascular precision medicine

The advent of human induced pluripotent stem cell (hiPSC) technology has revitalized the efforts in the past decade to realize more fully the potential of human embryonic stem cells for scientific research. Adding to the possibility of generating an unlimited amount of any cell type of interest, hiPSC technology now enables the derivation of cells with patient-specific phenotypes. Given the introduction and implementation of the large-scale Precision Medicine Initiative, hiPSC technology will undoubtedly have a vital role in the advancement of cardiovascular research and medicine. In this Review, we summarize the progress that has been made in the field of hiPSC technology, with particular emphasis on cardiovascular disease modelling and drug development. The growing roles of hiPSC technology in the practice of precision medicine will also be discussed.

Mouse Genetic Models of Human Brain Disorders

Over the past three decades, genetic manipulations in mice have been used in neuroscience as a major approach to investigate the in vivo function of genes and their alterations. In particular, gene targeting techniques using embryonic stem cells have revolutionized the field of mammalian genetics and have been at the forefront in the generation of numerous mouse models of human brain disorders. In this review, we will first examine childhood developmental disorders such as autism, intellectual disability, Fragile X syndrome, and Williams-Beuren syndrome. We will then explore psychiatric disorders such as schizophrenia and lastly, neurodegenerative disorders including Alzheimer’s disease and Parkinson’s disease. We will outline the creation of these mouse models that range from single gene deletions, subtle point mutations to multi-gene manipulations, and discuss the key behavioral phenotypes of these mice. Ultimately, the analysis of the models outlined in this review will enhance our understanding of the in vivo role and underlying mechanisms of disease-related genes in both normal brain function and brain disorders, and provide potential therapeutic targets and strategies to prevent and treat these diseases.

Double chamber right ventricle in Williams syndrome: a rare cardiac anomaly reported

Cardiovascular abnormality is the most consistent finding and occur in almost 80 % of all Williams syndrome (WS). Although a number of cardiovascular defects are common to WS, the majority presents in some form of arterial stenosis whereas supravalvular aortic stenosis is the most common one. Here we describe a 12 year old boy with elfin facies, presenting with urinary incontinence and a systolic murmur in right upper parasternal region. Echocardiography showed presence of double chambered right ventricle (DCRV) along with supravalvular aortic stenosis (SVAS) and coronary artery aneurysms, left pulmonary artery stenosis and multiple bladder diverticula in CT abdomen. With the clinical suspicion the diagnosis of WS was made and confirmed by fluorescent in situ hybridisation (FISH) study showing deletion in 7q11.23. Though different forms of arterial stenosis at multiple sites have been demonstrated in WS, DCRV in Williams syndrome is not reported till date in medical literature.

Endocrine dysfunctions in children with Williams-Beuren syndrome

PURPOSE

Williams-Beuren syndrome (WBS) is caused by a hemizygous microdeletion of chromosome 7q11.23 and is characterized by global cognitive impairment, dysmorphic facial features, and supravalvular aortic stenosis. Endocrine dysfunctions have been reported in patients with WBS. This study was performed to investigate the frequency, clinical features, and outcomes of endocrine dysfunctions in children with WBS.

METHODS

One hundred two patients were included. The diagnosis was confirmed by chromosome analysis and fluorescent in situ hybridization. Medical charts were reviewed retrospectively to analyze endocrine dysfunctions such as short stature, precocious puberty, thyroid dysfunctions, and hypocalcemia.

RESULTS

The age at diagnosis was 3.7±4.4 years (one month to 19 years). Height- and weight-standard deviation score (SDS) were -1.1±1.1 and -1.4±1.4 at presentation, respectively. Short stature was found in 26 patients (28.3%) among those older than 2 years. Body mass index-SDS increased as the patients grew older (P<0.001). Two males and one female (2.9%) were diagnosed with central precocious puberty. Nine patients (8.8%) were diagnosed with primary hypothyroidism at age 4.0±4.3 years (one month to 12.1 years); their serum thyroid stimulating hormone and free T4 levels were 15.2±5.4 µU/mL and 1.2±0.2 ng/dL, respectively. Hypercalcemia was observed in 12 out of 55 patients under age 3 (22%) at the age of 14.3±6.6 months (7 to 28 months) with a mean serum calcium level of 13.1±2.1 mg/dL.

CONCLUSION

Endocrine dysfunctions are not uncommon causes of morbidity in patients with WBS. The severity and outcomes of their endocrine manifestations were heterogeneous. Long-term follow-up is needed to predict the prognosis of endocrine features.

Mother-Child Interaction as a Window to a Unique Social Phenotype in 22q11.2 Deletion Syndrome and in Williams Syndrome

Mother-child interactions in 22q11.2 Deletion syndrome (22q11.2DS) and Williams syndrome (WS) were coded for maternal sensitivity/intrusiveness, child's expression of affect, levels of engagement, and dyadic reciprocity. WS children were found to express more positive emotions towards their mothers compared to 22q11.2DS children and those with developmental delay in a conflict interaction. During the same interaction, dyads of 22q11.2DS children were characterized by higher levels of maternal intrusiveness, lower levels of child's engagement and reduced reciprocity compared to dyads of typically developing children. Finally, 22q11.2DS children with the COMT Met allele showed less adaptive behaviors than children with the Val allele. Dyadic behaviors partially coincided with the distinct social phenotypes in these syndromes and are potential behavioral markers of psychopathological trajectory.

Description of common musculoskeletal findings in Williams Syndrome and implications for therapies

Williams syndrome (WS), also referred to as Williams-Beuren syndrome (WBS), is a relatively rare genetic disorder affecting ∼1/10,000 persons. Since the disorder is caused by a micro-deletion of ∼1.5 Mb, it is not surprising that the manifestations of WS are extremely broad, involving most body systems. In this paper, we primarily focus on the musculoskeletal aspects of WS as these findings have not been the subject of a comprehensive review. We review the MSK features commonly seen in individuals with WS, along with related sensory and neurological issues interacting with and compounding underlying MSK abnormalities. We end by providing perspective, particularly from the vantage point of a physical therapist, on therapeutic interventions to address the most common MSK and related features seen in WS. Clin. Anat. 29:578-589, 2016. © 2016 Wiley Periodicals, Inc.

CHD associated with syndromic diagnoses: peri-operative risk factors and early outcomes

CHD is frequently associated with a genetic syndrome. These syndromes often present specific cardiovascular and non-cardiovascular co-morbidities that confer significant peri-operative risks affecting multiple organ systems. Although surgical outcomes have improved over time, these co-morbidities continue to contribute substantially to poor peri-operative mortality and morbidity outcomes. Peri-operative morbidity may have long-standing ramifications on neurodevelopment and overall health. Recognising the cardiovascular and non-cardiovascular risks associated with specific syndromic diagnoses will facilitate expectant management, early detection of clinical problems, and improved outcomes--for example, the development of syndrome-based protocols for peri-operative evaluation and prophylactic actions may improve outcomes for the more frequently encountered syndromes such as 22q11 deletion syndrome.

A Patient With Pansynostosis and Williams-Beuren Syndrome

BACKGROUND

Williams-Beuren syndrome (WBS) is a multisystemic genetic disorder caused by a gene deletion at gene locus 7q11.23. This article presents the first described case of a patient with WBS and simultaneous pansynostosis.

CASE PRESENTATION

This article presents the management of this young Caucasian boy from birth until the age of 12 years and provides an overview of previously described manifestations of WBS in the craniofacial region.

CONCLUSIONS

This case demonstrates the surgical treatment of pansynostosis in a child with WBS and might provide interesting aspects in the diagnostics and management of this rare malformation.

Human induced pluripotent stem cell derived neurons as a model for Williams-Beuren syndrome

Background

Williams-Beuren Syndrome (WBS) is caused by the microdeletion of approximately 25 genes on chromosome 7q11.23, and is characterized by a spectrum of cognitive and behavioural features.

Results

We generated cortical neurons from a WBS individual and unaffected (WT) control by directed differentiation of induced pluripotent stem cells (iPSCs). Single cell mRNA analyses and immunostaining demonstrated very efficient production of differentiated cells expressing markers of mature neurons of mixed subtypes and from multiple cortical layers. We found that there was a profound alteration in action potentials, with significantly prolonged WBS repolarization times and a WBS deficit in voltage-activated K⁺ currents. Miniature excitatory synaptic currents were normal, indicating that unitary excitatory synaptic transmission was not altered. Gene expression profiling identified 136 negatively enriched gene sets in WBS compared to WT neurons including gene sets involved in neurotransmitter receptor activity, synaptic assembly, and potassium channel complexes.

Conclusions

Our findings provide insight into gene dysregulation and electrophysiological defects in WBS patient neurons.

Electronic supplementary material

The online version of this article (doi:10.1186/s13041-015-0168-0) contains supplementary material, which is available to authorized users.

The genetics of feed conversion efficiency traits in a commercial broiler line

Individual feed conversion efficiency (FCE) is a major trait that influences the usage of energy resources and the ecological footprint of livestock production. The underlying biological processes of FCE are complex and are influenced by factors as diverse as climate, feed properties, gut microbiota, and individual genetic predisposition. To gain an insight to the genetic relationships with FCE traits and to contribute to the improvement of FCE in commercial chicken lines, a genome-wide association study was conducted using a commercial broiler population (n = 859) tested for FCE and weight traits during the finisher period from 39 to 46 days of age. Both single-marker (generalized linear model) and multi-marker (Bayesian approach) analyses were applied to the dataset to detect genes associated with the variability in FCE. The separate analyses revealed 22 quantitative trait loci (QTL) regions on 13 different chromosomes; the integration of both approaches resulted in 7 overlapping QTL regions. The analyses pointed to acylglycerol kinase (AGK) and general transcription factor 2-I (GTF2I) as positional and functional candidate genes. Non-synonymous polymorphisms of both candidate genes revealed evidence for a functional importance of these genes by influencing different biological aspects of FCE.

Roles of LIM kinases in central nervous system function and dysfunction

LIM kinase 1 (LIMK1) and LIM kinase 2 (LIMK2) regulate actin dynamics by phosphorylating cofilin. In this review, we outline studies that have shown an involvement of LIMKs in neuronal function and we detail some of the pathways and molecular mechanisms involving LIMKs in neurodevelopment and synaptic plasticity. We also review the involvement of LIMKs in neuronal diseases and emphasize the differences in the regulation of LIMKs expression and mode of action. We finally present the existence of a cofilin-independent pathway also involved in neuronal function. A better understanding of the differences between both LIMKs and of the precise molecular mechanisms involved in their mode of action and regulation is now required to improve our understanding of the physiopathology of the neuronal diseases associated with LIMKs.

Autonomic response to approachability characteristics, approach behavior, and social functioning in Williams syndrome

Williams syndrome (WS) is a neurogenetic disorder that is saliently characterized by a unique social phenotype, most notably associated with a dramatically increased affinity and approachability toward unfamiliar people. Despite a recent proliferation of studies into the social profile of WS, the underpinnings of the pro-social predisposition are poorly understood. To this end, the present study was aimed at elucidating approach behavior of individuals with WS contrasted with typical development (TD) by employing a multidimensional design combining measures of autonomic arousal, social functioning, and two levels of approach evaluations. Given previous evidence suggesting that approach behaviors of individuals with WS are driven by a desire for social closeness, approachability tendencies were probed across two levels of social interaction: talking versus befriending. The main results indicated that while overall level of approachability did not differ between groups, an important qualitative between-group difference emerged across the two social interaction contexts: whereas individuals with WS demonstrated a similar willingness to approach strangers across both experimental conditions, TD individuals were significantly more willing to talk to than to befriend strangers. In WS, high approachability to positive faces across both social interaction levels was further associated with more normal social functioning. A novel finding linked autonomic responses with willingness to befriend negative faces in the WS group: elevated autonomic responsivity was associated with increased affiliation to negative face stimuli, which may represent an autonomic correlate of approach behavior in WS. Implications for underlying organization of the social brain are discussed.

Epilepsy is a possible feature in Williams-Beuren syndrome patients harboring typical deletions of the 7q11.23 critical region

Seizures are rarely reported in Williams-Beuren syndrome (WBS)--a contiguous-gene-deletion disorder caused by a 7q11.23 heterozygous deletion of 1.5-1.8 Mb--and no previous study evaluated electro-clinical features of epilepsy in this syndrome. Furthermore, it has been hypothesized that atypical deletion (e.g., larger than 1.8 Mb) may be responsible for a more pronounced neurological phenotypes, especially including seizures. Our objectives are to describe the electro-clinical features in WBS and to correlate the epileptic phenotype with deletion of the 7q11.23 critical region. We evaluate the electro-clinical features in one case of distal 7q11.23 deletion syndrome and in eight epileptic WBS (eWBS) patients. Additionally, we compare the deletion size-and deleted genes-of four epileptic WBS (eWBS) with that of four non-epileptic WBS (neWBS) patients. Infantile spasms, focal (e.g., motor and dyscognitive with autonomic features) and generalized (e.g., tonic-clonic, tonic, clonic, myoclonic) seizures were encountered. Drug-resistance was observed in one patient. Neuroimaging discovered one case of focal cortical dysplasia, one case of fronto-temporal cortical atrophy and one case of periventricular nodular heterotopia. Comparison of deletion size between eWBS and neWBS patients did not reveal candidate genes potentially underlying epilepsy. This is the largest series describing electro-clinical features of epilepsy in WBS. In WBS, epilepsy should be considered both in case of typical and atypical deletions, which do not involve HIP1, YWHAG or MAGI2.

Avaliação da consciência fonológica na síndrome de Williams

Resumo: OBJETIVOS: avaliar o desempenho de crianças e adolescentes com Síndrome de Williams em tarefas de consciência fonológica e analisar esse desempenho em função da idade, escolaridade e indicadores de habilidade intelectual. MÉTODOS: vinte e duas crianças e adolescentes (11 meninos e 11 meninas) com idades entre 7 e 18 anos realizaram os subtestes cubos e vocabulário das Escala Wechsler de Inteligência para estimativa de habilidades intelectuais e responderam a Prova de Consciência Fonológica por produção oral. RESULTADOS: os participantes obtiveram valores do quociente de inteligência estimado compatível com rebaixamento intelectual. Nas habilidades de consciência fonológica os resultados mostraram que os participantes com a síndrome obtiveram desempenho rebaixado em nove dos dez subtestes da prova de consciência fonológica em relação à pontuação padronizada em função da idade, assim como do nível escolar. Não foram encontradas correlações significantes entre consciência fonológica, indicadores de habilidade intelectual, idade e escolaridade. CONCLUSÃO: os resultados corroboram os encontrados em pesquisas internacionais sugerindo rebaixamento em consciência fonológica na Síndrome de Williams. Dada a relevância desses achados é necessário incluir programas de estimulação contínua, inclusive com intervenções precoces dirigidas a crianças com Síndrome de Williams em idade pré-escolar, adequação de métodos de ensino e de currículo adaptado.

Concurrent Relations between Face Scanning and Language: A Cross-Syndrome Infant Study

Typically developing (TD) infants enhance their learning of spoken language by observing speakers' mouth movements. Given the fact that word learning is seriously delayed in most children with neurodevelopmental disorders, we hypothesized that this delay partly results from differences in visual face scanning, e.g., focusing attention away from the mouth. To test this hypothesis, we used an eye tracker to measure visual attention in 95 infants and toddlers with Down syndrome (DS), fragile X syndrome (FXS), and Williams syndrome (WS), and compared their data to 25 chronological- and mental-age matched 16-month-old TD controls. We presented participants with two talking faces (one on each side of the screen) and a sound (/ga/). One face (the congruent face) mouthed the syllable that the participants could hear (i.e., /ga/), while the other face (the incongruent face) mouthed a different syllable (/ba/) from the one they could hear. As expected, we found that TD children with a relatively large vocabulary made more fixations to the mouth region of the incongruent face than elsewhere. However, toddlers with FXS or WS who had a relatively large receptive vocabulary made more fixations to the eyes (rather than the mouth) of the incongruent face. In DS, by contrast, fixations to the speaker's overall face (rather than to her eyes or mouth) predicted vocabulary size. These findings suggest that, at some point in development, different processes or strategies relating to visual attention are involved in language acquisition in DS, FXS, and WS. This knowledge may help further explain why language is delayed in children with neurodevelopmental disorders. It also raises the possibility that syndrome-specific interventions should include an early focus on efficient face-scanning behaviour.

A Novel Recurrent Breakpoint Responsible for Rearrangements in the Williams-Beuren Region

Copy number variants (CNVs) of the Williams-Beuren syndrome (WBS) 7q11.23 region are responsible for neurodevelopmental disorders with multisystem involvement and variable expressivity. We found 2 patients with a deletion and 1 patient with a duplication in this region sharing a common breakpoint located between the LIMK1 and EIF4H(WBSCR1) genes. One patient had a WBS phenotype, although testing with a commercially available FISH assay was negative for the deletion. A further test using array CGH showed an atypical WBS region deletion. The second patient showed global developmental delay, speech delay and poor motor skills with a deletion outside the WBS region. The third patient had manifestations compatible with an autism spectrum disorder showing a duplication in the WBS region. Our findings point to the existence of a previously unrecognized recurrent breakpoint responsible for rearrangements in the WBS region. Given that most commercial FISH assays include probes flanking this novel breakpoint, further testing with array CGH should be performed in patients with WBS and negative FISH results.

Williams-Beuren Syndrome: Experience of 43 Patients and a Report of an Atypical Case from a Tertiary Care Center in India

Williams-Beuren syndrome (WBS) or Williams syndrome (OMIM 194050) is a multisystem disorder manifested by neurodevelopmental delay and is caused by a hemizygous deletion of ∼ 1.5-1.8 Mb in the 7q11.23 region. Clinical features include cardiovascular anomalies (mainly supravalvular aortic stenosis), peripheral pulmonary stenosis, distinctive facies, intellectual disability (usually mild), unique personality characteristics, and growth and endocrine abnormalities. Clinical diagnostic criteria are available for WBS; however, the mainstay of diagnosis is the detection of the contiguous gene deletion. Although FISH remains the most widely used laboratory test, the diagnosis can also be established by means of qPCR, MLPA, microsatellite marker analysis, and chromosomal microarray (CMA). We evaluated the utility of MLPA to detect deletion/duplication in the 7q11.23 region in 43 patients suspected to have WBS using MLPA kits for microdeletion syndromes. A hemizygous deletion in the 7q11.23 region was found in 41 (95.3%) patients using MLPA. One patient had an atypical deletion detected by CMA. During the initial period of this study, the results of 12 patients tested by MLPA were also confirmed by FISH. Compared to FISH and CMA, MLPA is a cheaper, high-throughput, less labor-intensive and less time-consuming technique for the diagnosis of WBS. Although CMA is expensive and labor-intensive, its effectiveness is demonstrated to detect an atypical deletion and to delineate the breakpoints.

Lateral preference in Williams-Beuren syndrome is associated with cognition and language

Williams-Beuren syndrome (WBS) is a genetically defined neurodevelopmental disorder presenting with intellectual disability associated with a specific neurocognitive profile characterized by anxiety, hypersociability, poor visuospatial skills and relatively preserved language. We have defined the lateral preference in 69 individuals (40 males and 29 females, age range 5-47 years) with WBS confirmed by molecular testing, and explored its correlation with cognition, behavior problems, the main aspects of the behavioral phenotype, and specific molecular variants (parental origin and size of the 7q11.23 deletion). Lateral preference (hand, foot, eye and ear) and neurobehavioral features [intelligence quotient (IQ), sociability, visuospatial construction, narrative skills and behavior] were assessed by a battery of tests and parental interviews. A large proportion of WBS individuals showed either left or mixed handedness (26 and 19%, respectively). Hand, foot and ear lateral preference showed significant association with IQ, with individuals with mixed lateral preference presenting lower general IQ, especially verbal IQ, with respect to subjects with well-defined laterality. Approachability, visuospatial ability, behavior problems or molecular variants were not associated with lateral preference. Our results indicate that, as in other neurodevelopmental disorders, laterality is poorly defined in a significant proportion of WBS individuals, and reinforces the idea that a correct definition of lateral preference is important for cognition and language.

Intracisternal Gtf2i Gene Therapy Ameliorates Deficits in Cognition and Synaptic Plasticity of a Mouse Model of Williams-Beuren Syndrome

Williams-Beuren syndrome (WBS) is a neurodevelopmental disorder caused by a heterozygous deletion of 26-28 genes at chromosome band 7q11.23. Haploinsufficiency at GTF2I has been shown to play a major role in the neurobehavioral phenotype. By characterizing the neuronal architecture in four animal models with intragenic, partial, and complete deletions of the WBS critical interval (ΔGtf2i(+/-), ΔGtf2i( -/-), PD, and CD), we clarify the involvement of Gtf2i in neurocognitive features. All mutant mice showed hypersociability, impaired motor learning and coordination, and altered anxiety-like behavior. Dendritic length was decreased in the CA1 of ΔGtf2i(+/-), ΔGtf2i ( -/-), and CD mice. Spine density was reduced, and spines were shorter in ΔGtf2i ( -/-), PD, and CD mice. Overexpression of Pik3r1 and downregulation of Bdnf were observed in ΔGtf2i(+/-), PD, and CD mice. Intracisternal Gtf2i-gene therapy in CD mice using adeno-associated virus resulted in increased mGtf2i expression and normalization of Bdnf levels, along with beneficial effects in motor coordination, sociability, and anxiety, despite no significant changes in neuronal architecture. Our findings further indicate that Gtf2i haploinsufficiency plays an important role in the neurodevelopmental and cognitive abnormalities of WBS and that it is possible to rescue part of this neurocognitive phenotype by restoring Gtf2i expression levels in specific brain areas.

Structural integrity of the limbic-prefrontal connection: Neuropathological correlates of anxiety in Williams syndrome

Williams syndrome (WS) is a genetic condition characterized by a hypersocial personality and desire to form close relationships, juxtaposed with significant anxieties of nonsocial events. The neural underpinnings of anxiety in individuals with WS are currently unknown. Aberrations in the anatomical and microstructural integrity of the uncinate fasciculus (UF) have been recently implicated in social and generalized anxiety disorders. Based on these findings, we tested the hypothesis that the reported anxieties in individuals with WS share similar neuropathological correlates. Toward this end, diffusion tensor imaging (DTI) methods were employed to examine the microstructural integrity (fractional anisotropy, mean diffusivity, longitudinal diffusivity) of the UF in 18 WS and 15 typically developing adults (TD). Anxiety and sociability questionnaires were administered to determine associations with DTI indices of UF across groups. Results revealed comparable white matter integrity of the UF across groups, yet elevated subjective experience of anxiety in those with WS. Additionally, sociability and UF microstructural properties were dissociated across both groups. Whereas no relationships were found between DTI indices and anxiety in TD participants, strong negative associations were observed between these constructs in individuals with WS. Findings indicated that increased anxiety manifested by individuals with WS was associated with DTI measures of the UF and may signal structural or possibly physiological aberration involving this tract within the prefrontal-temporal network.

Imaging Cardiovascular Manifestations of Genetic Syndromes

Congenital structural cardiovascular defects are commonly associated and found concurrently with many different types of genetic diseases and syndromes. Understanding these cardiovascular manifestations is essential for diagnosing these genetic syndromes without delay and provides prompt attention and repair of life-threatening defects without complications. Computed tomography and magnetic resonance imaging are increasingly used in the evaluation of cardiovascular abnormalities, and it is imperative for radiologists to be cognizant of the syndromes associated with these abnormalities. In this article, we review the cardiovascular manifestations of the common genetic syndromes and illustrate the role of computed tomography and magnetic resonance imaging in the evaluation of these abnormalities.

Genetic Syndromes associated with Congenital Heart Disease

Recent research has demonstrated that genetic alterations or variations contribute considerably to the development of congenital heart disease. Many kinds of genetic tests are commercially available, and more are currently under development. Congenital heart disease is frequently accompanied by genetic syndromes showing both cardiac and extra-cardiac anomalies. Congenital heart disease is the leading cause of birth defects, and is an important cause of morbidity and mortality during infancy and childhood. This review introduces common genetic syndromes showing various types of congenital heart disease, including Down syndrome, Turner syndrome, 22q11 deletion syndrome, Williams syndrome, and Noonan syndrome. Although surgical techniques and perioperative care have improved substantially, patients with genetic syndromes may be at an increased risk of death or major complications associated with surgery. Therefore, risk management based on an accurate genetic diagnosis is necessary in order to effectively plan the surgical and medical management and follow-up for these patients. In addition, multidisciplinary approaches and care for the combined extra-cardiac anomalies may help to reduce mortality and morbidity accompanied with congenital heart disease.

Multiple Unerupted Permanent Teeth Associated with Noonan Syndrome

The present report describes a case of Noonan's syndrome from a dental viewpoint. Noonan syndrome is an autosomal dominant multisystem disorder. Congenital heart deformities, short stature, thoracic deformities, short neck with webbing, hypertelorism, and malocclusions are some of the frequently observed clinical features. Atypical dental anomalies such as multiple unerupted permanent teeth, multiple submerged and retained deciduous teeth, and supernumerary teeth were found in the present case. Oral prophylaxis and preventive resin restorations were done following which the supernumerary teeth were extracted. 54, 55, 64, 65, 74, 75 and 84 were extracted after orthodontic consultation to facilitate the eruption of permanent teeth. The patient is undergoing fixed orthodontic therapy for forced eruption of unerupted permanent teeth. General dentists should correlate dental anomalies with other systemic features in the diagnosis of such syndromes because of the variability in presentation and the need for multidisciplinary care.

Discovery of Rare Mutations in Autism: Elucidating Neurodevelopmental Mechanisms

Autism spectrum disorder (ASD) is a group of highly genetic neurodevelopmental disorders characterized by language, social, cognitive, and behavioral abnormalities. ASD is a complex disorder with a heterogeneous etiology. The genetic architecture of autism is such that a variety of different rare mutations have been discovered, including rare monogenic conditions that involve autistic symptoms. Also, de novo copy number variants and single nucleotide variants contribute to disease susceptibility. Finally, autosomal recessive loci are contributing to our understanding of inherited factors. We will review the progress that the field has made in the discovery of these rare genetic variants in autism. We argue that mutation discovery of this sort offers an important opportunity to identify neurodevelopmental mechanisms in disease. The hope is that these mechanisms will show some degree of convergence that may be amenable to treatment intervention.

Williams-Beuren Syndrome: A Clinical Study of 55 Brazilian Patients and the Diagnostic Use of MLPA

Williams-Beuren syndrome (WBS) is a genetic disease caused by a microdeletion in the 7q11.23 region. It is characterized by congenital heart disease, mainly supravalvular aortic stenosis, mental retardation, mild short stature, facial dysmorphisms, and variable abnormalities in different systems. Objectives. To report the clinical findings of 55 Brazilian patients confirmed by multiplex ligation-dependent probe amplification (MLPA). Methods. Patients were followed up for 4 years at the Genetics Unit of the Instituto da Criança of the Hospital das Clínicas, FMUSP, Brazil. A kit specific for WBS was used to detect the 7q11.23 microdeletion. Results. Two patients with negative FISH results had positive MLPA results for WBS. The characteristics of the patients with the deletion were as follows: typical WBS facies (98.2%), neuropsychomotor delay (98.2%), hypersocial behavior (94.5%), hyperacusis (94.5%), and congenital heart disease (81.8%). Conclusions. MLPA was effective in detecting the microdeletion in the 7q11.23 region to confirm the diagnosis of WBS. MLPA was also able to confirm the diagnosis of WBS in two patients with typical clinical characteristics but negative FISH results. Thus, MLPA is a promising method in the diagnostic investigation of WBS. WBS is a multisystemic disorder and therefore requires multidisciplinary care and specific follow-up to prevent complications.

Recognizable syndromes in the newborn period

Making the diagnosis of genetic syndromes in the neonatal period can be challenging, as limited information concerning growth and development is available. The pattern of dysmorphic features and malformations is, therefore, correspondingly more important in syndrome recognition. The authors provide specific examples of the differences in the presentation for selected syndromes between the newborn period and later childhood. The purpose is to describe the variation in presentation that can occur with chronologic age and to aid in the early diagnosis of these conditions.

The endoplasmic reticulum-localized protein TBL2 interacts with the 60S ribosomal subunit

Transducin (beta)-like 2 (TBL2) is a poorly characterized protein comprising the N-terminal transmembrane region and the C-terminal WD40 domain. We previously showed that TBL2 is an endoplasmic reticulum (ER)-localized protein that interacts with PKR-like ER-resident kinase (PERK), and under ER stress, it mediates protein expression of activating transcription factor 4 (ATF4). However, further molecular characterization of TBL2 is useful to better understand the function of this molecule. Here, we show that TBL2 associates with the eukaryotic 60S ribosomal subunit but not with the 40S subunit. The association of TBL2 with the 60S subunit was ER stress independent while the TBL2-PERK interaction occurred upon ER stress. Immunoprecipitation analysis using TBL2 deletion mutants revealed that the WD40 domain was essential for the 60S subunit association. These results could provide an important clue to understanding how TBL2 is involved in the expression of specific proteins under ER stress conditions.

Supravalvular aortic stenosis associated to infectious endocarditis and cerebral vascular disease in a patient with Williams-Beuren Syndrome

The Williams-Beuren syndrome is a rare genetic disease characterized by: (a) typical facial features; (b) psychomotor retardation with a specific neurocognitive profile; (c) cardiovascular condition and (d) likely transient hypocalcemia in infancy. The objective of this study was to describe the clinic evolution and diagnosis of patient with this syndrome that was associated with endocarditis caused by Streptococcus parasanguis in the ascending aorta and an aneurism located in the fronto-temporal area, which produced a parenchymal hematoma in the left lobe, and subarachnoid hemorrhage. He was treated with ceftriaxone and dicloxacillin. Then we proceeded to correct the aneurysm and perform vegetation resection in aortic arteries with supravalvular aortic stenosis correction. The evolution after one year has been favorable and is currently without neurologic sequelae. A 5-year-old male patient presented a diagnosis of supravalvular aortic stenosis. After cardiac catheterization was performed, he presented a fever and right side paresis. The echocardiogram showed multiple vegetations in the ascendant aortic arch and the supraortic arteries. The blood cultures reported S. parasanguis. The magnetic resonance showed a subarachnoid hemorrhage with an aneurysm and a hematoma.

What is nephrocalcinosis?

The available publications on nephrocalcinosis are wide-ranging and have documented multiple causes and associations of macroscopic or radiological nephrocalcinosis, most often located in the renal medulla, with various metabolic and genetic disorders; in fact, so many and various are these that it is difficult to define a common underlying mechanism. We have reviewed nephrocalcinosis in relation to its definition, genetic associations, animal models, and putative mechanisms. We have concluded, and hypothesized, that nephrocalcinosis is primarily a renal interstitial process, resembling metastatic calcification, and that it may have some features in common with, and pathogenic links to, vascular calcification.

Bisphenol A alters autonomic tone and extracellular matrix structure and induces sex-specific effects on cardiovascular function in male and female CD-1 mice

The aim of this study was to determine whether bisphenol A (BPA) has adverse effects on cardiovascular functions in CD-1 mice and define sex-specific modes of BPA action in the heart. Dams and analyzed progeny were maintained on a defined diet containing BPA (0.03, 0.3, 3, 30, or 300 ppm) that resulted in BPA exposures from 4-5 to approximately 5000 μg/kg · d or a diet containing 17α-ethinyl estradiol (EE; ∼0.02, 0.2, and 0.15 μg/kg · d) as an oral bioavailable estrogen control. Assessment of electrocardiogram parameters using noninvasive methods found that ventricular functions in both male and female mice were not altered by either BPA or EE. However, exposure-related changes in the rates of ventricular contraction, suggestive of a shift in sympathovagal balance of heart rate control toward increased parasympathetic activity, were detected in males. Decreased systolic blood pressure was observed in males exposed to BPA above 5 μg/kg · d and in females from the highest BPA exposure group. Morphometric histological measures revealed sexually dimorphic changes in the composition of the cardiac collagen extracellular matrix, increases in fibrosis, and evidence of modest exposure-related remodeling. Experiments using the α-selective adrenergic agonist phenylephrine found that BPA enhanced reflex bradycardia in females, but not males, revealed that BPA and EE exposure sex specifically altered the sympathetic regulation of the baroreflex circuits. Increased sensitivity to the cardiotoxic effects of the β-adrenergic agonist isoproterenol was observed in BPA- and EE-exposed females. This effect was not observed in males, in which BPA or EE exposures were protective of isoproterenol-induced ischemic damage and hypertrophy. The results of RNA sequence analysis identified significant sex-specific changes in gene expression in response to BPA that were consistent with the observed exposure-related phenotypic changes in the collagenous and noncollagenous extracellular matrix, cardiac remodeling, altered autonomic responses, changes in ion channel and transporter functions, and altered glycolytic and lipid metabolism.

Adverse cardiac events in children with Williams syndrome undergoing cardiovascular surgery: An analysis of the Society of Thoracic Surgeons Congenital Heart Surgery Database

OBJECTIVE

Patients with Williams syndrome (WS) undergoing cardiac surgery are at risk for major adverse cardiac events (MACE). Prevalence and risk factors for such events have not been well described. We sought to define frequency and risk of MACE in patients with WS using a multicenter clinical registry.

METHODS

We identified cardiac operations performed in patients with WS using the Society of Thoracic Surgeons Congenital Heart Surgery Database (2000-2012). Operations were divided into 4 groups: isolated supravalvular aortic stenosis, complex left ventricular outflow tract (LVOT), isolated right ventricular outflow tract (RVOT), and combined LVOT/RVOT procedures. The proportion of patients with MACE (in-hospital mortality, cardiac arrest, or postoperative mechanical circulatory support) was described and the association with preoperative factors was examined.

RESULTS

Of 447 index operations (87 centers), median (interquartile range) age and weight at surgery were 2.4 years (0.6-7.4 years) and 10.6 kg (6.5-21.5 kg), respectively. Mortality occurred in 20 patients (5%). MACE occurred in 41 patients (9%), most commonly after combined LVOT/RVOT (18 out of 87; 21%) and complex LVOT (12 out of 131; 9%) procedures, but not after isolated RVOT procedures. Odds of MACE decreased with age (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.98-0.99), weight (OR, 0.97; 95% CI, 0.93-0.99), but increased in the presence of any preoperative risk factor (OR, 2.08; 95% CI, 1.06-4.00), and in procedures involving coronary artery repair (OR, 5.37; 95% CI, 2.05-14.06).

CONCLUSIONS

In this multicenter analysis, MACE occurred in 9% of patients with WS undergoing cardiac surgery. Demographic and operative characteristics were associated with risk. Further study is needed to elucidate mechanisms of MACE in this high-risk population.

Metabolic abnormalities in Williams-Beuren syndrome

BACKGROUND

Williams-Beuren syndrome (WBS, OMIM-194050) is a neurodevelopmental disorder with multisystemic manifestations caused by a 1.55-1.83 Mb deletion at 7q11.23 including 26-28 genes. Reported endocrine and metabolic abnormalities include transient hypercalcaemia of infancy, subclinical hypothyroidism in ∼ 30% of children and impaired glucose tolerance in ∼ 75% of adult individuals. The purpose of this study was to further study metabolic alterations in patients with WBS, as well as in several mouse models, to establish potential candidate genes.

METHODS

We analysed several metabolic parameters in a cohort of 154 individuals with WBS (data available from 69 to 151 cases per parameter), as well as in several mouse models with complete and partial deletions of the orthologous WBS locus, and searched for causative genes and potential modifiers.

RESULTS

Triglyceride plasma levels were significantly decreased in individuals with WBS while cholesterol levels were slightly decreased compared with controls. Hyperbilirubinemia, mostly unconjugated, was found in 18.3% of WBS cases and correlated with subclinical hypothyroidism and hypotriglyceridemia, suggesting common pathogenic mechanisms. Haploinsufficiency at MLXIPL and increased penetrance for hypomorphic alleles at the UGT1A1 gene promoter might underlie the lipid and bilirubin alterations. Other disturbances included increased protein and iron levels, as well as the known subclinical hypothyroidism and glucose intolerance.

CONCLUSIONS

Our results show that several unreported biochemical alterations, related to haploinsufficiency for specific genes at 7q11.23, are relatively common in WBS. The early diagnosis, follow-up and management of these metabolic disturbances could prevent long-term complications in this disorder.

LIMK1 regulates long-term memory and synaptic plasticity via the transcriptional factor CREB

Deletion of the LIMK1 gene is associated with Williams syndrome, a unique neurodevelopmental disorder characterized by severe defects in visuospatial cognition and long-term memory (LTM). However, whether LIMK1 contributes to these deficits remains elusive. Here, we show that LIMK1-knockout (LIMK1(-/-)) mice are drastically impaired in LTM but not short-term memory (STM). In addition, LIMK1(-/-) mice are selectively defective in late-phase long-term potentiation (L-LTP), a form of long-lasting synaptic plasticity specifically required for the formation of LTM. Furthermore, we show that LIMK1 interacts and regulates the activity of cyclic AMP response element-binding protein (CREB), an extensively studied transcriptional factor critical for LTM. Importantly, both L-LTP and LTM deficits in LIMK1(-/-) mice are rescued by increasing the activity of CREB. These results provide strong evidence that LIMK1 deletion is sufficient to lead to an LTM deficit and that this deficit is attributable to CREB hypofunction. Our study has identified a direct gene-phenotype link in mice and provides a potential strategy to restore LTM in patients with Williams syndrome through the enhancement of CREB activity in the adult brain.

Insights into the genetic foundations of human communication

The human capacity to acquire sophisticated language is unmatched in the animal kingdom. Despite the discontinuity in communicative abilities between humans and other primates, language is built on ancient genetic foundations, which are being illuminated by comparative genomics. The genetic architecture of the language faculty is also being uncovered by research into neurodevelopmental disorders that disrupt the normally effortless process of language acquisition. In this article, we discuss the strategies that researchers are using to reveal genetic factors contributing to communicative abilities, and review progress in identifying the relevant genes and genetic variants. The first gene directly implicated in a speech and language disorder was FOXP2. Using this gene as a case study, we illustrate how evidence from genetics, molecular cell biology, animal models and human neuroimaging has converged to build a picture of the role of FOXP2 in neurodevelopment, providing a framework for future endeavors to bridge the gaps between genes, brains and behavior.