The 22q13.3 Deletion Syndrome (Phelan-McDermid Syndrome)

Deletion of Autism Risk Gene Shank3 Disrupts Prefrontal Connectivity

Mutations in the synaptic scaffolding protein SHANK3 are a major cause of autism and are associated with prominent intellectual and language deficits. However, the neural mechanisms whereby SHANK3 deficiency affects higher-order socio-communicative functions remain unclear. Using high-resolution functional and structural MRI in adult male mice, here we show that loss of Shank3 (Shank3B ^-/-) results in disrupted local and long-range prefrontal and frontostriatal functional connectivity. We document that prefrontal hypoconnectivity is associated with reduced short-range cortical projections density, and reduced gray matter volume. Finally, we show that prefrontal disconnectivity is predictive of social communication deficits, as assessed with ultrasound vocalization recordings. Collectively, our results reveal a critical role of SHANK3 in the development of prefrontal anatomy and function, and suggest that SHANK3 deficiency may predispose to intellectual disability and socio-communicative impairments via dysregulation of higher-order cortical connectivity.SIGNIFICANCE STATEMENT Mutations in the synaptic scaffolding protein SHANK3 are commonly associated with autism, intellectual, and language deficits. Previous research has linked SHANK3 deficiency to basal ganglia dysfunction, motor stereotypies, and social deficits. However, the neural mechanism whereby Shank3 gene mutations affects cortical functional connectivity and higher-order socio-communicative functions remain unclear. Here we show that loss of SHANK3 in mice results in largely disrupted functional connectivity and abnormal gray matter anatomy in prefrontal areas. We also show that prefrontal connectivity disruption is tightly linked to socio-communicative deficits. Our findings suggest that SHANK3 is a critical orchestrator of frontocortical function, and that disrupted connectivity of prefrontal areas may underpin socio-communicative impairments observed in SHANK3 mutation carriers.

Shank3 modulates sleep and expression of circadian transcription factors

Autism Spectrum Disorder (ASD) is the most prevalent neurodevelopmental disorder in the United States and often co-presents with sleep problems. Sleep problems in ASD predict the severity of ASD core diagnostic symptoms and have a considerable impact on the quality of life of caregivers. Little is known, however, about the underlying molecular mechanisms of sleep problems in ASD. We investigated the role of Shank3, a high confidence ASD gene candidate, in sleep architecture and regulation. We show that mice lacking exon 21 of Shank3 have problems falling asleep even when sleepy. Using RNA-seq we show that sleep deprivation increases the differences in prefrontal cortex gene expression between mutants and wild types, downregulating circadian transcription factors Per3, Bhlhe41, Hlf, Tef, and Nr1d1. Shank3 mutants also have trouble regulating wheel-running activity in constant darkness. Overall, our study shows that Shank3 is an important modulator of sleep and clock gene expression.

A patient with Phelan-McDermid syndrome and dilation of the great vessels

We present a patient with Phelan-McDermid syndrome, a rare neurodevelopmental disorder caused by a 22q13 deletion, with the previously undescribed finding of progressive dilation of the great arteries. While congenital heart defects have been identified in patients previously, dilation of the great arteries has not been described to our knowledge.

Examining factors affecting parental satisfaction with speech therapy in children with Phelan-McDermid Syndrome

Objectives: This paper explores the relationship between speech therapy intensity and parent satisfaction with speech therapy (ST) in children with Phelan-McDermid Syndrome (P-MS), a rare genetic disorder. Methods: ST intensity (ST Dose [minutes per session]) × (ST Dose Frequency) × (ST Length [years]) and parent satisfaction (modified PSQ-18) with ST were measured by online questionnaire. Non-parametric correlation, partial correlation, and linear regression calculations were performed. Results: Significant correlations between ST Dose and parent satisfaction were observed in the subscales of Time Spent with ST (r = .36, p < .05) and Accessibility and Convenience (r = .40, p < .05) in children with P-MS controlling for child age. ST Dose was also a significant independent predictor of parent satisfaction with ST in specific subscales. Conclusion: Significant positive correlation and linear regression results indicate increases in ST Dose (minutes per session) represent a mechanism for increasing parent satisfaction with ST in children with P-MS.

Functional genomics analysis of Phelan-McDermid syndrome 22q13 region during human neurodevelopment

Phelan-McDermid syndrome (PMS) is a neurodevelopmental disorder characterized by varying degrees of intellectual disability, severely delayed language development and specific facial features, and is caused by a deletion within chromosome 22q13.3. SHANK3, which is located at the terminal end of this region, has been repeatedly implicated in other neurodevelopmental disorders and deletion of this gene specifically is thought to cause much of the neurologic symptoms characteristic of PMS. However, it is still unclear to what extent SHANK3 deletions contribute to the PMS phenotype, and what other genes nearby are causal to the neurologic disease. In an effort to better understand the functional landscape of the PMS region during normal neurodevelopment, we assessed RNA-sequencing (RNA-seq) expression data collected from post-mortem brain tissue from developmentally normal subjects over the course of prenatal to adolescent age and analyzed expression changes of 65 genes on 22q13. We found that the majority of genes within this region were expressed in the brain, with ATNX10, MLC1, MAPK8IP2, and SULT4A1 having the highest overall expression. Analysis of the temporal profiles of the highest expressed genes revealed a trend towards peak expression during the early post-natal period, followed by a drop in expression later in development. Spatial analysis revealed significant region specific differences in the expression of SHANK3, MAPK8IP2, and SULT4A1. Region specific expression over time revealed a consistently unique gene expression profile within the cerebellum, providing evidence for a distinct developmental program within this region. Exon-specific expression of SHANK3 showed higher expression within exons contributing to known brain specific functional isoforms. Overall, we provide an updated roadmap of the PMS region, implicating several genes and time periods as important during neurodevelopment, with the hope that this information can help us better understand the phenotypic heterogeneity of PMS.

Intestinal dysmotility in a zebrafish (Danio rerio) shank3a;shank3b mutant model of autism

Background and aims

Autism spectrum disorder (ASD) is currently estimated to affect more than 1% of the world population. For people with ASD, gastrointestinal (GI) distress is a commonly reported but a poorly understood co-occurring symptom. Here, we investigate the physiological basis for GI distress in ASD by studying gut function in a zebrafish model of Phelan-McDermid syndrome (PMS), a condition caused by mutations in the SHANK3 gene.

Methods

To generate a zebrafish model of PMS, we used CRISPR/Cas9 to introduce clinically related C-terminal frameshift mutations in shank3a and shank3b zebrafish paralogues (shank3abΔC). Because PMS is caused by SHANK3 haploinsufficiency, we assessed the digestive tract (DT) structure and function in zebrafish shank3abΔC^+/− heterozygotes. Human SHANK3 mRNA was then used to rescue DT phenotypes in larval zebrafish.

Results

Significantly slower rates of DT peristaltic contractions (p < 0.001) with correspondingly prolonged passage time (p < 0.004) occurred in shank3abΔC^+/− mutants. Rescue injections of mRNA encoding the longest human SHANK3 isoform into shank3abΔC^+/− mutants produced larvae with intestinal bulb emptying similar to wild type (WT), but still deficits in posterior intestinal motility. Serotonin-positive enteroendocrine cells (EECs) were significantly reduced in both shank3abΔC^+/− and shank3abΔC^−/− mutants (p < 0.05) while enteric neuron counts and overall structure of the DT epithelium, including goblet cell number, were unaffected in shank3abΔC^+/− larvae.

Conclusions

Our data and rescue experiments support mutations in SHANK3 as causal for GI transit and motility abnormalities. Reductions in serotonin-positive EECs and serotonin-filled ENS boutons suggest an endocrine/neural component to this dysmotility. This is the first study to date demonstrating DT dysmotility in a zebrafish single gene mutant model of ASD.

Electronic supplementary material

The online version of this article (10.1186/s13229-018-0250-4) contains supplementary material, which is available to authorized users.

SHANK1 polymorphisms and SNP-SNP interactions among SHANK family: A possible cue for recognition to autism spectrum disorder in infant age

Autism spectrum disorder (ASD) is a serious lifelong neurodevelopmental disorder. ASD is diagnosed for children at the age of two. ASD diagnosis, as early as possible, lays the foundation for treatment and much better prognosis. Notably, gene-based test is an inherent method to recognize the potential infants with ASD before the age of two. To investigate whether SHANK family contributes to ASD prediction, on the basis of our previous studies of SHANK2 and SHANK3, we further investigated associations between SHANK1 polymorphisms and ASD risk as well as SNP-SNP interactions among SHANK family. We enrolled 470 subjects (229 cases and 241 healthy controls) who were northeast Chinese Han. Four tag SNPs (rs73042561, rs3745521, rs4801846, and rs12461427) of SHANK1 were selected and genotyped. We used the SNPStats online analysis program to assess the associations between the four SNPs and ASD risk. The SNP-SNP interactions among SHANK family were analyzed using multifactor dimensionality reduction method. We found that the four SHANK1 SNPs were not associated with ASD risk in northeast Chinese Han population. There existed a strong synergistic interaction between rs11236697 [SHANK2] and rs74336682 [SHANK2], and moderate synergistic interactions (rs74336682 [SHANK2]-rs73042561 [SHANK1], rs11236697 [SHANK2]-rs77716438 [SHANK2], and rs11236697 [SHANK2]-rs75357229 [SHANK2]). These SHANK1 variants may not affect the susceptibility to ASD in Chinese Han population. SNP-SNP interactions in SHANK family may confer ASD risk. Autism Res 2019, 12: 375-383 © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: ASD is a serious lifelong neurodevelopmental disorder with strong genetic components. We investigated associations between SHANK1 polymorphisms and ASD risk as well as SNP-SNP interactions among SHANK family. Our results indicated that there exists no association between SHANK1 SNPs and ASD, and SNP-SNP interactions in SHANK family may confer ASD risk in the Northeast Han Chinese population. Future studies are needed to test more SHANK family SNPs in a large sample to demonstrate the associations.

Synaptopathology Involved in Autism Spectrum Disorder

Autism spectrum disorder (ASD) encompasses a group of multifactorial neurodevelopmental disorders characterized by impaired social communication, social interaction and repetitive behaviors. ASD affects 1 in 59 children, and is about 4 times more common among boys than among girls. Strong genetic components, together with environmental factors in the early stage of development, contribute to the pathogenesis of ASD. Multiple studies have revealed that mutations in genes like NRXN, NLGN, SHANK, TSC1/2, FMR1, and MECP2 converge on common cellular pathways that intersect at synapses. These genes encode cell adhesion molecules, scaffolding proteins and proteins involved in synaptic transcription, protein synthesis and degradation, affecting various aspects of synapses including synapse formation and elimination, synaptic transmission and plasticity. This suggests that the pathogenesis of ASD may, at least in part, be attributed to synaptic dysfunction. In this article, we will review major genes and signaling pathways implicated in synaptic abnormalities underlying ASD, and discuss molecular, cellular and functional studies of ASD experimental models.

Genetic Basis for Congenital Heart Disease: Revisited: A Scientific Statement From the American Heart Association

This review provides an updated summary of the state of our knowledge of the genetic contributions to the pathogenesis of congenital heart disease. Since 2007, when the initial American Heart Association scientific statement on the genetic basis of congenital heart disease was published, new genomic techniques have become widely available that have dramatically changed our understanding of the causes of congenital heart disease and, clinically, have allowed more accurate definition of the pathogeneses of congenital heart disease in patients of all ages and even prenatally. Information is presented on new molecular testing techniques and their application to congenital heart disease, both isolated and associated with other congenital anomalies or syndromes. Recent advances in the understanding of copy number variants, syndromes, RASopathies, and heterotaxy/ciliopathies are provided. Insights into new research with congenital heart disease models, including genetically manipulated animals such as mice, chicks, and zebrafish, as well as human induced pluripotent stem cell-based approaches are provided to allow an understanding of how future research breakthroughs for congenital heart disease are likely to happen. It is anticipated that this review will provide a large range of health care-related personnel, including pediatric cardiologists, pediatricians, adult cardiologists, thoracic surgeons, obstetricians, geneticists, genetic counselors, and other related clinicians, timely information on the genetic aspects of congenital heart disease. The objective is to provide a comprehensive basis for interdisciplinary care for those with congenital heart disease.

Environmental enrichment has minimal effects on behavior in the Shank3 complete knockout model of autism spectrum disorder

INTRODUCTION

Several studies have supported the use of enriched environments to prevent the manifestation of ASD-like phenotypes in laboratory rodents. While the translational value of such experiments is unknown, the findings have been relatively consistent across many different models.

METHODS

In the current study, we tested the effects of early environmental enrichment on a mouse model of ASD with high construct validity, the Shank3 ∆e4-22 mice our laboratory previously generated and characterized.

RESULTS

Contrary to previous reports, we found no benefits of enriched rearing, including no change in repetitive self-grooming or hole-board exploration. Instead, we found that early environmental enrichment increased anxiety-like behavior in all mice regardless of genotype and decreased motor performance specifically in wild-type mice.

CONCLUSIONS

Although using a different enrichment protocol may have rescued the phenotypes in our mouse model, these results suggest that a "one-size fits all" approach may not be the best when it comes to behavioral intervention for ASD and underscores the need for effective pharmaceutical development in certain genetic syndromes with severe symptom presentation.

Dietary Zinc Supplementation Prevents Autism Related Behaviors and Striatal Synaptic Dysfunction in Shank3 Exon 13-16 Mutant Mice

The SHANK family of synaptic proteins (SHANK1–3) are master regulators of the organizational structure of excitatory synapses in the brain. Mutations in SHANK1–3 are prevalent in patients with autism spectrum disorders (ASD), and loss of one copy of SHANK3 causes Phelan-McDermid Syndrome, a syndrome in which Autism occurs in >80% of cases. The synaptic stability of SHANK3 is highly regulated by zinc, driving the formation of postsynaptic protein complexes and increases in excitatory synaptic strength. As ASD-associated SHANK3 mutations retain responsiveness to zinc, here we investigated how increasing levels of dietary zinc could alter behavioral and synaptic deficits that occur with ASD. We performed behavioral testing together with cortico-striatal slice electrophysiology on a Shank3^−/− mouse model of ASD (Shank3^{ex13–1616−/−}), which displays ASD-related behaviors and structural and functional deficits at striatal synapses. We observed that 6 weeks of dietary zinc supplementation in Shank3^{ex13–16−/−} mice prevented ASD-related repetitive and anxiety behaviors and deficits in social novelty recognition. Dietary zinc supplementation also increased the recruitment of zinc sensitive SHANK2 to synapses, reduced synaptic transmission specifically through N-methyl-D-aspartate (NMDA)-type glutamate receptors, reversed the slowed decay tau of NMDA receptor (NMDAR)-mediated currents and occluded long term potentiation (LTP) at cortico-striatal synapses. These data suggest that alterations in NMDAR function underlie the lack of NMDAR-dependent cortico-striatal LTP and contribute to the reversal of ASD-related behaviors such as compulsive grooming. Our data reveal that dietary zinc alters neurological function from synapses to behavior, and identifies dietary zinc as a potential therapeutic agent in ASD.

Strukturelle Chromosomenstörungen bei Intelligenzminderung

Strukturelle und numerische Chromosomenstörungen gehören zu den häufigen Ursachen der Intelligenzminderung und psychomotorischen Entwicklungsstörung. Die große Heterogenität der Intelligenzminderung spiegelt sich auch in der Vielfalt möglicher Aberrationstypen und ursächlicher Chromosomenregionen wider. Die konventionelle lichtmikroskopische Zytogenetik kann hierbei u. a. strukturelle Aberrationen mit Größen über ca. 5–10 Megabasenpaaren (Mb) auch in Form kleinerer Mosaike nachweisen und diese im Genom lokalisieren. Durch Fluoreszenz-in situ-Hybridisierung können bei klinischem Verdacht gezielt auch deutlich kleinere Aberrationen, z. B. Mikrodeletionen, detektiert werden. Chromosomale Mikroarrays (CMA) detektieren dank ihrer besseren Auflösung, die bis deutlich unter 0,1 Mb reichen kann, genomweit submikroskopische Mikrodeletionen und Mikroduplikationen, machen jedoch bei Duplikationen keine Aussage zu deren genomischer Lokalisation und können meist niedriggradige Mosaike unter 20 % kaum nachweisen. Zytogenetik und CMA ergänzen sich aufgrund ihrer unterschiedlichen Fähigkeiten und weisen einschließlich der Trisomie 21 jeweils in ungefähr 15 % der Patienten mit Intelligenzminderung ursächliche Chromosomenaberrationen nach. Sie stellen damit neben aktuellen Sequenzierungstechniken ein wichtiges Element der humangenetischen Ursachenabklärung bei Intelligenzminderung dar. Typische chromosomale Aberrationstypen werden beispielhaft besprochen und in das heutige Gesamtbild eingeordnet.

Behavioral Phenotyping of an Improved Mouse Model of Phelan-McDermid Syndrome with a Complete Deletion of the Shank3 Gene

Phelan–McDermid syndrome (PMS) is a rare genetic disorder in which one copy of the SHANK3 gene is missing or mutated, leading to a global developmental delay, intellectual disability (ID), and autism. Multiple intragenic promoters and alternatively spliced exons are responsible for the formation of numerous isoforms. Many genetically-modified mouse models of PMS have been generated but most disrupt only some of the isoforms. In contrast, the vast majority of known SHANK3 mutations found in patients involve deletions that disrupt all isoforms. Here, we report the production and thorough behavioral characterization of a new mouse model in which all Shank3 isoforms are disrupted. Domains and tasks examined in adults included measures of general health, neurological reflexes, motor abilities, sensory reactivity, social behavior, repetitive behaviors, cognition and behavioral inflexibility, and anxiety. Our mice are more severely affected than previously published models. While the deficits were typically more pronounced in homozygotes, an intermediate phenotype was observed for heterozygotes in many paradigms. As in other Shank3 mouse models, stereotypies, including increased grooming, were observed. Additionally, sensory alterations were detected in both neonatal and adult mice, and motor behavior was strongly altered, especially in the open field and rotarod locomotor tests. While social behaviors measured with the three-chambered social approach and male-female interaction tests were not strongly impacted, Shank3-deficient mice displayed a strong escape behavior and avoidance of inanimate objects in novel object recognition, repetitive novel object contact, marble burying, and nest building tasks, indicating increased novelty-induced anxiety. Similarly, increased freezing was observed during fear conditioning training and amygdala-dependent cued retrieval. Finally, deficits were observed in both initial training and reversal in the Barnes maze and in contextual fear testing, which are memory tasks involving hippocampal-prefrontal circuits. In contrast, working memory in the Y-maze spontaneous alternation test was not altered. This new mouse model of PMS, engineered to most closely represent human mutations, recapitulates core symptoms of PMS providing improvements for both construct and face validity, compared to previous models.

Dysbiosis of microbiome and probiotic treatment in a genetic model of autism spectrum disorders

Recent studies have determined that the microbiome has direct effects on behavior, and may be dysregulated in neurodevelopmental conditions. Considering that neurodevelopmental conditions, such as autism, have a strong genetic etiology, it is necessary to understand if genes associated with neurodevelopmental disorders, such as Shank3, can influence the gut microbiome, and if probiotics can be a therapeutic tool. In this study, we have identified dysregulation of several genera and species of bacteria in the gut and colon of both male and female Shank3 KO mice. L. reuteri, a species with decreased relative abundance in the Shank3 KO mice, positively correlated with the expression of gamma-Aminobutyric acid (GABA) receptor subunits in the brain. Treatment of Shank3 KO mice with L. reuteri induced an attenuation of unsocial behavior specifically in male Shank3 mice, and a decrease in repetitive behaviors in both male and female Shank3 KO mice. In addition, L. reuteri treatment affected GABA receptor gene expression and protein levels in multiple brain regions. This study identifies bacterial species that are sensitive to an autism-related mutation, and further suggests a therapeutic potential for probiotic treatment.

Phelan-McDermid syndrome data network: Integrating patient reported outcomes with clinical notes and curated genetic reports

The heterogeneity of patient phenotype data are an impediment to the research into the origins and progression of neuropsychiatric disorders. This difficulty is compounded in the case of rare disorders such as Phelan-McDermid Syndrome (PMS) by the paucity of patient clinical data. PMS is a rare syndromic genetic cause of autism and intellectual deficiency. In this paper, we describe the Phelan-McDermid Syndrome Data Network (PMS_DN), a platform that facilitates research into phenotype-genotype correlation and progression of PMS by: a) integrating knowledge of patient phenotypes extracted from Patient Reported Outcomes (PRO) data and clinical notes-two heterogeneous, underutilized sources of knowledge about patient phenotypes-with curated genetic information from the same patient cohort and b) making this integrated knowledge, along with a suite of statistical tools, available free of charge to authorized investigators on a Web portal https://pmsdn.hms.harvard.edu. PMS_DN is a Patient Centric Outcomes Research Initiative (PCORI) where patients and their families are involved in all aspects of the management of patient data in driving research into PMS. To foster collaborative research, PMS_DN also makes patient aggregates from this knowledge available to authorized investigators using distributed research networks such as the PCORnet PopMedNet. PMS_DN is hosted on a scalable cloud based environment and complies with all patient data privacy regulations. As of October 31, 2016, PMS_DN integrates high-quality knowledge extracted from the clinical notes of 112 patients and curated genetic reports of 176 patients with preprocessed PRO data from 415 patients.

Syndromic autism spectrum disorders: moving from a clinically defined to a molecularly defined approach

Autism spectrum disorder (ASD) encompasses a group of neurodevelopmental conditions diagnosed solely on the basis of behavioral assessments that reveal social deficits. Progress has been made in understanding its genetic underpinnings, but most ASD-associated genetic variants, which include copy number variants (CNVs) and mutations in ASD-risk genes, account for no more than 1 % of ASD cases. This high level of genetic heterogeneity leads to challenges obtaining and interpreting genetic testing in clinical settings. The traditional definition of syndromic ASD is a disorder with a clinically defined pattern of somatic abnormalities and a neurobehavioral phenotype that may include ASD. Most have a known genetic cause. Examples include fragile X syndrome and tuberous sclerosis complex. We propose dividing syndromic autism into the following two groups: (i) ASD that occurs in the context of a clinically defined syndrome-recognizing these disorders depends on the familiarity of the clinician with the features of the syndrome, and the diagnosis is typically confirmed by targeted genetic testing (eg, mutation screening of FMR1); (ii) ASD that occurs as a feature of a molecularly defined syndrome-for this group of patients, ASD-associated variants are identified by genome-wide testing that is not hypothesis driven (eg, microarray, whole exome sequencing). These ASD groups cannot be easily clinically defined because patients with a given variant have variable somatic abnormalities (dysmorphism and birth defects). In this article, we review common diagnoses from the above categories and suggest a testing strategy for patients, guided by determining whether the individual has essential or complex ASD; patients in the latter group have multiple morphologic anomalies on physical examination. Finally, we recommend that the syndromic versus nonsyndromic designation ultimately be replaced by classification of ASD according to its genetic etiology, which will inform about the associated spectrum and penetrance of neurobehavioral and somatic manifestations.

Genomics in neurodevelopmental disorders: an avenue to personalized medicine

Despite the remarkable number of scientific breakthroughs of the last 100 years, the treatment of neurodevelopmental disorders (e.g., autism spectrum disorder, intellectual disability) remains a great challenge. Recent advancements in genomics, such as whole-exome or whole-genome sequencing, have enabled scientists to identify numerous mutations underlying neurodevelopmental disorders. Given the few hundred risk genes that have been discovered, the etiological variability and the heterogeneous clinical presentation, the need for genotype—along with phenotype-based diagnosis of individual patients has become a requisite. In this review we look at recent advancements in genomic analysis and their translation into clinical practice.

The identification of genetic mutations associated with neurodevelopmental disorders (NDDs) along with routine diagnosis based on patients’ characteristics is aiding the delivery of personalized therapies. Dora Tarlungeanu and Gaia Novarino at the Institute of Science and Technology in Klosterneuburg, Austria, review recent advances in genetic technologies, such as whole exome sequencing, that can lead to early intervention, guide choice of treatment and prompt genetic counseling. Introducing the mutations associated with NDDs into model organisms or stem cells is revealing some of the mechanisms underlying NDDs and enabling the evaluation of novel therapeutic strategies that target core symptoms of the disorders. To accelerate the implementation of individualized treatments for NDD the authors highlight the need to adopt interdisciplinary research approaches and to keep clinical staff updated on the latest findings in NDD genetics.

Progress in the molecular mechanisms of genetic epilepsies using patient-induced pluripotent stem cells

Research findings on the molecular mechanisms of epilepsy almost always originate from animal experiments, and the development of induced pluripotent stem cell (iPSC) technology allows the use of human cells with genetic defects for studying the molecular mechanisms of genetic epilepsy (GE) for the first time. With iPSC technology, terminally differentiated cells collected from GE patients with specific genetic etiologies can be differentiated into many relevant cell subtypes that carry all of the GE patient's genetic information. iPSCs have opened up a new research field involving the pathogenesis of GE. Using this approach, studies have found that gene mutations induce GE by altering the balance between neuronal excitation and inhibition, which is associated. among other factors, with neuronal developmental disturbances, ion channel abnormalities, and synaptic dysfunction. Simultaneously, astrocyte activation, mitochondrial dysfunction, and abnormal signaling pathway activity are also important factors in the molecular mechanisms of GE.

[Dichotomous classification of autism spectrum disorders: syndromal and non-syndromal forms]

In foreign literature on research into the etiopathogenesis of autism spectrum disorders (ASDs), the division of this group of diseases into two forms is getting more and more frequent. These two forms are 'syndromal' and 'non-syndromal' forms of autistic disorders. The literature review aims to cover the issues of the dichotomous classification of ASDs based on the genetic and molecular psychiatric views on the etiopathogenesis of this group of diseases. It also covers the purpose of this classification, the opportunities of its usage in routine clinical practice and the network resources, which allow classifying a form of ASD correctly. Special attention is paid to the multidisciplinary approach to dichotomous classification and its difference from the clinical view on the systematization of autism and the importance of this method for selection of target therapy.

Prospects of Zinc Supplementation in Autism Spectrum Disorders and Shankopathies Such as Phelan McDermid Syndrome

The loss of one copy of SHANK3 (SH3 and multiple ankyrin repeat domains 3) in humans highly contributes to Phelan McDermid syndrome (PMDS). In addition, SHANK3 was identified as a major autism candidate gene. Interestingly, the protein encoded by the SHANK3 gene is regulated by zinc. While zinc deficiency depletes synaptic pools of Shank3, increased zinc levels were shown to promote synaptic scaffold formation. Therefore, the hypothesis arises that patients with PMDS and Autism caused by Shankopathies, having one intact copy of SHANK3 left, may benefit from zinc supplementation, as elevated zinc may drive remaining Shank3 into the post-synaptic density (PSD) and may additional recruit Shank2, a second zinc-dependent member of the SHANK gene family. Further, elevated synaptic zinc levels may modulate E/I ratios affecting other synaptic components such as NMDARs. However, several factors need to be considered in relation to zinc supplementation such as the role of Shank3 in the gastrointestinal (GI) system-the location of zinc absorption in humans. Therefore, here, we briefly discuss the prospect and impediments of zinc supplementation in disorders affecting Shank3 such as PMDS and propose a model for most efficacious supplementation.

Current Enlightenment About Etiology and Pharmacological Treatment of Autism Spectrum Disorder

Autistic Spectrum Disorder (ASD) is a complex neurodevelopmental brain disorder characterized by two core behavioral symptoms, namely impairments in social communication and restricted/repetitive behavior. The molecular mechanisms underlying ASD are not well understood. Recent genetic as well as non-genetic animal models contributed significantly in understanding the pathophysiology of ASD, as they establish autism-like behavior in mice and rats. Among the genetic causes, several chromosomal mutations including duplications or deletions could be possible causative factors of ASD. In addition, the biochemical basis suggests that several brain neurotransmitters, e.g., dopamine (DA), serotonin (5-HT), gamma-amino butyric acid (GABA), acetylcholine (ACh), glutamate (Glu) and histamine (HA) participate in the onset and progression of ASD. Despite of convincible understanding, risperidone and aripiprazole are the only two drugs available clinically for improving behavioral symptoms of ASD following approval by Food and Drug Administration (FDA). Till date, up to our knowledge there is no other drug approved for clinical usage specifically for ASD symptoms. However, many novel drug candidates and classes of compounds are underway for ASD at different phases of preclinical and clinical drug development. In this review, the diversity of numerous aetiological factors and the alterations in variety of neurotransmitter generation, release and function linked to ASD are discussed with focus on drugs currently used to manage neuropsychiatric symptoms related to ASD. The review also highlights the clinical development of drugs with emphasis on their pharmacological targets aiming at improving core symptoms in ASD.

Common Ribs of Inhibitory Synaptic Dysfunction in the Umbrella of Neurodevelopmental Disorders

The term neurodevelopmental disorder (NDD) is an umbrella term used to group together a heterogeneous class of disorders characterized by disruption in cognition, emotion, and behavior, early in the developmental timescale. These disorders are heterogeneous, yet they share common behavioral symptomatology as well as overlapping genetic contributors, including proteins involved in the formation, specialization, and function of synaptic connections. Advances may arise from bridging the current knowledge on synapse related factors indicated from both human studies in NDD populations, and in animal models. Mounting evidence has shown a link to inhibitory synapse formation, specialization, and function among Autism, Angelman, Rett and Dravet syndromes. Inhibitory signaling is diverse, with numerous subtypes of inhibitory interneurons, phasic and tonic modes of inhibition, and the molecular and subcellular diversity of GABA_A receptors. We discuss common ribs of inhibitory synapse dysfunction in the umbrella of NDD, highlighting alterations in the developmental switch to inhibitory GABA, dysregulation of neuronal activity patterns by parvalbumin-positive interneurons, and impaired tonic inhibition. Increasing our basic understanding of inhibitory synapses, and their role in NDDs is likely to produce significant therapeutic advances in behavioral symptom alleviation for interrelated NDDs.

nArgBP2-SAPAP-SHANK, the core postsynaptic triad associated with psychiatric disorders

Despite the complex genetic architecture, a broad spectrum of psychiatric disorders can still be caused by mutation(s) in the same gene. These disorders are interrelated with overlapping causative mechanisms including variations in the interaction among the risk-associated proteins that may give rise to the specific spectrum of each disorder. Additionally, multiple lines of evidence implicate an imbalance between excitatory and inhibitory neuronal activity (E/I imbalance) as the shared key etiology. Thus, understanding the molecular mechanisms underlying E/I imbalance provides essential insight into the etiology of these disorders. One important class of candidate risk genes is the postsynaptic scaffolding proteins, such as nArgBP2, SAPAP, and SHANK that regulate the actin cytoskeleton in dendritic spines of excitatory synapses. This review will cover and discuss recent studies that examined how these proteins, especially nArgBP2, are associated with psychiatric disorders. Next, we propose a possibility that variations in the interaction among these proteins in a specific brain region might contribute to the onset of diverse phenotypes of psychiatric disorders.

The assembly of scaffolding proteins, key regulators of many signaling pathways, found in the brain’s synapses underpin a diverse range of neuropsychiatric disorders. Sunghoe Chang and colleagues from Seoul National University, South Korea, review how these postsynaptic proteins regulate the cellular cytoskeleton in nerve cell protrusions to maintain the balance between excitatory and inhibitory inputs in the brain. They discuss how perturbations in three particular proteins can cause an imbalance in synaptic signals that leads to conditions such as bipolar disorder, schizophrenia and autism. The authors propose that these proteins form a “core scaffolding triad” and interact in different ways to cause different mental illnesses. Dysregulation of these proteins could explain how mutations in the same genes, depending on whether they boost or decrease gene expression, contribute to the onset of diverse psychiatric disorders.

Psychiatry in a Dish: Stem Cells and Brain Organoids Modeling Autism Spectrum Disorders

Autism spectrum disorders are a group of pervasive neurodevelopmental conditions with heterogeneous etiology, characterized by deficits in social cognition, communication, and behavioral flexibility. Despite an increasing scientific effort to find the pathophysiological explanations for the disease, the neurobiological links remain unclear. A large amount of evidence suggests that pathological processes taking place in early embryonic neurodevelopment might be responsible for later manifestation of autistic symptoms. This dysfunctional development includes altered maturation/differentiation processes, disturbances in cell-cell communication, and an unbalanced ratio between certain neuronal populations. All those processes are highly dependent on the interconnectivity and three-dimensional organizations of the brain. Moreover, in order to gain a deeper understanding of the complex neurobiology of autism spectrum disorders, valid disease models are pivotal. Induced pluripotent stem cells could potentially help to elucidate the complex mechanisms of the disease and lead to the development of more effective individualized treatment. The induced pluripotent stem cells approach allows comparison between the development of various cellular phenotypes generated from cell lines of patients and healthy individuals. A newly advanced organoid technology makes it possible to create three-dimensional in vitro models of brain development and structural interconnectivity, based on induced pluripotent stem cells derived from the respective individuals. The biggest challenge for modeling psychiatric diseases in vitro is finding and establishing the link between cellular and molecular findings with the clinical symptoms, and this review aims to give an overview over the feasibility and applicability of this new tissue engineering tool in psychiatry.

Cc2d1a Loss of Function Disrupts Functional and Morphological Development in Forebrain Neurons Leading to Cognitive and Social Deficits

Loss-of-function (LOF) mutations in CC2D1A cause a spectrum of neurodevelopmental disorders, including intellectual disability, autism spectrum disorder, and seizures, identifying a critical role for this gene in cognitive and social development. CC2D1A regulates intracellular signaling processes that are critical for neuronal function, but previous attempts to model the human LOF phenotypes have been prevented by perinatal lethality in Cc2d1a-deficient mice. To overcome this challenge, we generated a floxed Cc2d1a allele for conditional removal of Cc2d1a in the brain using Cre recombinase. While removal of Cc2d1a in neuronal progenitors using Cre expressed from the Nestin promoter still causes death at birth, conditional postnatal removal of Cc2d1a in the forebrain via calcium/calmodulin-dependent protein kinase II-alpha (CamKIIa) promoter-driven Cre generates animals that are viable and fertile with grossly normal anatomy. Analysis of neuronal morphology identified abnormal cortical dendrite organization and a reduction in dendritic spine density. These animals display deficits in neuronal plasticity and in spatial learning and memory that are accompanied by reduced sociability, hyperactivity, anxiety, and excessive grooming. Cc2d1a conditional knockout mice therefore recapitulate features of both cognitive and social impairment caused by human CC2D1A mutation, and represent a model that could provide much needed insights into the developmental mechanisms underlying nonsyndromic neurodevelopmental disorders.

Prospective longitudinal overnight video-EEG evaluation in Phelan-McDermid Syndrome

OBJECTIVE

Phelan-McDermid Syndrome (PMS) is a rare genetic condition associated with loss of function mutations, including deletions, in the chromosome 22q13 region. This PMS phenotype includes intellectual disability, often minimal to absent verbal skills, and other neurologic features including autism spectrum disorder and seizures. Reports indicate seizures and abnormal electroencephalograms (EEGs) in this population, but previous studies do not describe EEG findings during sleep or prognostic value of abnormal EEG over any time period.

METHODS

During a natural history study, 16 consecutively enrolled participants (mean age 10years) with PMS underwent both routine (approximately 25min) and overnight (average 9.65h) video-EEG, in addition to genetic testing, neurodevelopmental assessment, neurological examination, and epilepsy phenotyping. Over 240h of EEG, data was recorded. Comparison of findings from the routine EEG was made with prolonged EEG acquired during awake and sleep the same night. In a subset of nine participants, the overnight EEG was repeated one or more years later to observe the natural evolution and prognostic value of any abnormalities noted at baseline.

RESULTS

A history of epilepsy, with multiple seizure types, was confirmed in seven of the 16 participants, giving a prevalence of 43.8% in this cohort. All but one EEG was abnormal (15 of 16), and 75% (12 of 16) showed epileptiform activity. Of these, only 25% of participants (3 of 12) showed definitive epileptiform discharges during the routine study. Overnight EEGs (sleep included) did not show any clinical events consistent with seizures or electrophic seizures, however, overnight EEG showed either more frequent and/or more definitive epileptiform activity in 68.75% (11 of 16) participants. All seven of the 16 participants who had previously been diagnosed with epilepsy showed epileptiform abnormalities. In addition to a wide range of epileptiform activity observed, generalized slowing with poor background organization was frequently noted. Follow-up EEG confirmed persistence of abnormal discharges, but none of the abnormal EEGs showed evolution to electrographic seizures. Clinically, there was no emergence of epilepsy or significant developmental regression noted in the time frame observed.

CONCLUSIONS

This is the first and most abundant prolonged awake and sleep video-EEG data recorded in a PMS cohort to date. The importance of overnight prolonged EEGs is highlighted by findings from this study, as they can be used to document the varied topographies of EEG abnormalities in conditions such as PMS, which are often missed during routine EEG studies. While the long-term significance of the EEG abnormalities found (beyond 1year) remains uncertain despite their persistence over time, these findings do underscore the current clinical recommendation that overnight prolonged EEG studies (with sleep) should be conducted in individuals with PMS.

Familial intellectual disability as a result of a derivative chromosome 22 originating from a balanced translocation (3;22) in a four generation family

Background

Balanced reciprocal translocation is usually an exchange of two terminal segments from different chromosomes without phenotypic effect on the carrier while leading to increased risk of generating unbalanced gametes. Here we describe a four-generation family in Shandong province of China with at least three patients sharing severe intellectual disability and developmental delay resulting from a derivative chromosome 22 originating from a balanced translocation (3;22) involving chromosomes 3q28q29 and 22q13.3.

Methods

The proband and his relatives were detected by using karyotyping, chromosome microarray analysis, fluorescent in situ hybridization and real-time qPCR.

Results

The proband, a 17 month-old boy, presented with severe intellectual disability, developmental delay, specific facial features and special posture of hands. Pedigree analysis showed that there were at least three affected patients. The proband and other two living patients manifested similar phenotypes and were identified to have identically abnormal cytogenetic result with an unbalanced translocation of 9.0 Mb duplication at 3q28q29 and a 1.7Mb microdeletion at 22q13.3 by karyotyping and chromosome microarray analysis. His father and other five relatives had a balanced translocation of 3q and 22q. Fluorescence in situ hybridization and real-time qPCR definitely validated the results.

Conclusions

The abnormal phenotypes of the proband and his two living members in four generations of the family confirmed the 3q duplication and 22q13.3 deletion inherited from familial balanced translocation. This is the first report of familial balanced reciprocal translocation involving chromosomes 3q28q29 and 22q13.3 segregating through four generations.

Identification of 22q13 genes most likely to contribute to Phelan McDermid syndrome

Chromosome 22q13.3 deletion (Phelan McDermid) syndrome (PMS) is a rare genetic neurodevelopmental disorder resulting from deletions or other genetic variants on distal 22q. Pathological variants of the SHANK3 gene have been identified, but terminal chromosomal deletions including SHANK3 are most common. Terminal deletions disrupt up to 108 protein-coding genes. The impact of these losses is highly variable and includes both significantly impairing neurodevelopmental and somatic manifestations. The current review combines two metrics, prevalence of gene loss and predicted loss pathogenicity, to identify likely contributors to phenotypic expression. These genes are grouped according to function as follows: molecular signaling at glutamate synapses, phenotypes involving neuropsychiatric disorders, involvement in multicellular organization, cerebellar development and functioning, and mitochondrial. The likely most impactful genes are reviewed to provide information for future clinical and translational investigations.

Accelerating Scientific Advancement for Pediatric Rare Lung Disease Research. Report from a National Institutes of Health-NHLBI Workshop, September 3 and 4, 2015

Pediatric rare lung disease (PRLD) is a term that refers to a heterogeneous group of rare disorders in children. In recent years, this field has experienced significant progress marked by scientific discoveries, multicenter and interdisciplinary collaborations, and efforts of patient advocates. Although genetic mechanisms underlie many PRLDs, pathogenesis remains uncertain for many of these disorders. Furthermore, epidemiology and natural history are insufficiently defined, and therapies are limited. To develop strategies to accelerate scientific advancement for PRLD research, the NHLBI of the National Institutes of Health convened a strategic planning workshop on September 3 and 4, 2015. The workshop brought together a group of scientific experts, intramural and extramural investigators, and advocacy groups with the following objectives: (1) to discuss the current state of PRLD research; (2) to identify scientific gaps and barriers to increasing research and improving outcomes for PRLDs; (3) to identify technologies, tools, and reagents that could be leveraged to accelerate advancement of research in this field; and (4) to develop priorities for research aimed at improving patient outcomes and quality of life. This report summarizes the workshop discussion and provides specific recommendations to guide future research in PRLD.

Learning-dependent chromatin remodeling highlights noncoding regulatory regions linked to autism

Autism spectrum disorder (ASD) is a prevalent neurodevelopmental disorder that is associated with genetic risk factors. Most human disease-associated single-nucleotide polymorphisms (SNPs) are not located in genes but rather are in regulatory regions that control gene expression. The function of regulatory regions is determined through epigenetic mechanisms. Parallels between the cellular basis of development and the formation of long-term memory have long been recognized, particularly the role of epigenetic mechanisms in both processes. We analyzed how learning alters chromatin accessibility in the mouse hippocampus using a new high-throughput sequencing bioinformatics strategy we call DEScan (differential enrichment scan). DEScan, which enabled the analysis of data from epigenomic experiments containing multiple replicates, revealed changes in chromatin accessibility at 2365 regulatory regions-most of which were promoters. Learning-regulated promoters were active during forebrain development in mice and were enriched in epigenetic modifications indicative of bivalent promoters. These promoters were disproportionally intronic, showed a complex relationship with gene expression and alternative splicing during memory consolidation and retrieval, and were enriched in the data set relative to known ASD risk genes. Genotyping in a clinical cohort within one of these promoters (SHANK3 promoter 6) revealed that the SNP rs6010065 was associated with ASD. Our data support the idea that learning recapitulates development at the epigenetic level and demonstrate that behaviorally induced epigenetic changes in mice can highlight regulatory regions relevant to brain disorders in patients.

The contribution of GTF2I haploinsufficiency to Williams syndrome

Williams syndrome (WS) is a neurodevelopmental disorder involving hemideletion of as many as 26-28 genes, resulting in a constellation of unique physical, cognitive and behavior phenotypes. The haploinsufficiency effect of each gene has been studied and correlated with phenotype(s) using several models including WS subjects, animal models, and peripheral cell lines. However, links for most of the genes to WS phenotypes remains unclear. Among those genes, general transcription factor 2I (GTF2I) is of particular interest as its haploinsufficiency is possibly associated with hypersociability in WS. Here, we describe studies of atypical WS cases as well as mouse models focusing on GTF2I that support a role for this protein in the neurocognitive and behavioral profiles of WS individuals. We also review collective studies on diverse molecular functions of GTF2I that may provide mechanistic explanation for phenotypes recently reported in our relevant cellular model, namely WS induced pluripotent stem cell (iPSC)-derived neurons. Finally, in light of the progress in gene-manipulating approaches, we suggest their uses in revealing the neural functions of GTF2I in the context of WS.

Clinical and molecular characterization of three genomic rearrangements at chromosome 22q13.3 associated with autism spectrum disorder

OBJECTIVES

Chromosome 22q13 is a hot region of genomic rearrangements that may result in deletion, duplication, and translocation, and that may lead to neurodevelopmental disorders in affected patients.

MATERIALS AND METHODS

We carried out an array-based comparative genomic hybridization analysis to detect copy number variations (CNVs) of genomic DNA in patients with autism spectrum disorders (ASD) who were consecutively recruited into our molecular genetic study of ASD. Karyotyping, fluorescent in-situ hybridization analysis, and real time-quantitative PCR were used for validation tests.

RESULTS

We completed a genome-wide CNV analysis of 335 patients with ASD from Taiwan. Three unrelated male patients were found to carry three different CNVs at 22q13.3, respectively, including a de novo terminal deletion of ∼106 kb at 22q13.33, a de novo interstitial duplication of ∼1.8 Mb at 22q13.32-q13.33, and a microdeletion of ∼147 kb at 22q13.33. These three CNVs all involved the dosage change of the SHANK3 gene. The last patient also carried a genomic duplication of ∼3.86 Mb at 19q13.42-q13.4 in addition to a microdeletion of ∼147 kb at 22q13.33. His younger sister also carried these two CNVs, but she had developmental delay and other neurological deficits without ASD. These two CNVs were transmitted from their unaffected father, who carried a balanced translocation between chromosome 22q and 19q.

CONCLUSION

Our data support that recurrent genomic rearrangements at 22q13.3 are part of the genetic landscape of ASD in our patients and changes in SHANK3 dosage are associated with neurodevelopmental disorders. However, the clinical symptoms of patients with 22q13.3 rearrangements can vary depending on other genetic and nongenetic factors, not limited to genes involved in CNVs in this region.

Current status of biological treatment options in Autism Spectrum Disorder

Autism Spectrum Disorders (ASDs) are characterised by deficits in social communication and restricted and repetitive behaviours. With an onset in early childhood, ASDs are thought to be heterogeneous, both genetically and clinically. This has led to the notion that "autism" is "autisms", however, there has been limited progress in understanding the different subgroups and the unique pathogenesis that would then allow targeted intervention. Although existing treatments are mainly symptom focussed, research is beginning to unravel the underlying genetic and molecular pathways, structural and functional neuronal circuitry involvement and the associated neurochemicals. This paper will review selected biological models with regard to pharmacological targets while also covering some of the non-pharmacological treatments such as neuro-stimulation.

Syndromic autism spectrum disorders: moving from a clinically defined to a molecularly defined approach

Autism spectrum disorder (ASD) encompasses a group of neurodevelopmental conditions diagnosed solely on the basis of behavioral assessments that reveal social deficits. Progress has been made in understanding its genetic underpinnings, but most ASD-associated genetic variants, which include copy number variants (CNVs) and mutations in ASD-risk genes, account for no more than 1 % of ASD cases. This high level of genetic heterogeneity leads to challenges obtaining and interpreting genetic testing in clinical settings. The traditional definition of syndromic ASD is a disorder with a clinically defined pattern of somatic abnormalities and a neurobehavioral phenotype that may include ASD. Most have a known genetic cause. Examples include fragile X syndrome and tuberous sclerosis complex. We propose dividing syndromic autism into the following two groups: (i) ASD that occurs in the context of a clinically defined syndrome-recognizing these disorders depends on the familiarity of the clinician with the features of the syndrome, and the diagnosis is typically confirmed by targeted genetic testing (eg, mutation screening of FMR1); (ii) ASD that occurs as a feature of a molecularly defined syndrome-for this group of patients, ASD-associated variants are identified by genome-wide testing that is not hypothesis driven (eg, microarray, whole exome sequencing). These ASD groups cannot be easily clinically defined because patients with a given variant have variable somatic abnormalities (dysmorphism and birth defects). In this article, we review common diagnoses from the above categories and suggest a testing strategy for patients, guided by determining whether the individual has essential or complex ASD; patients in the latter group have multiple morphologic anomalies on physical examination. Finally, we recommend that the syndromic versus nonsyndromic designation ultimately be replaced by classification of ASD according to its genetic etiology, which will inform about the associated spectrum and penetrance of neurobehavioral and somatic manifestations.

Prospective study of autism phenomenology and the behavioural phenotype of Phelan-McDermid syndrome: comparison to fragile X syndrome, Down syndrome and idiopathic autism spectrum disorder

Background

The limited behavioural phenotype literature on Phelan–McDermid syndrome (PMS) indicates atypically high levels of activity, impulsivity and autism spectrum disorder (ASD) behaviours. Divergent profiles of ASD in PMS are also reported, with some studies demonstrating similarities to idiopathic ASD and others indicating an uneven profile of social and communication impairments and repetitive behaviours. An evaluation of the behavioural phenotype of PMS and the prevalence and phenomenology of ASD is warranted, particularly given the causal involvement of the SHANK3 gene in the aetiology of PMS.

Methods

Carers of individuals with PMS (N = 30; mean age = 10.55, SD = 7.08) completed questionnaires relating to impulsivity, overactivity, mood, interest and pleasure, repetitive behaviour and ASD phenomenology. These data were compared to data from matched samples of individuals with fragile X and Down syndromes and idiopathic ASD. In order to evaluate the profile of ASD phenomenology in PMS, two comparisons were made: first, including the total sample with PMS, and second, including only those who met the threshold indicative of autism on an ASD screening measure.

Results

The results revealed lower mood in individuals with PMS, but no differences in impulsivity and overactivity. Compulsive and routine-driven repetitive behaviours were less common in the total sample with PMS; however, motor-based stereotyped behaviours were more common. ASD phenomenology was highly prevalent, with 87% of the sample meeting the cutoff score for ASD and 57% meeting the cutoff for autism. The profile of ASD phenomenology in the total sample with PMS differed from those with idiopathic ASD across impairments in communication and social interaction and repetitive behaviour. However, the profile of those who met the threshold for autism was commensurate to those with idiopathic ASD.

Conclusions

ASD phenomenology is common within PMS. Whilst the total sample may display an atypical profile of ASD behaviour, the profile in those who met the threshold for autism was very similar to those with idiopathic ASD. These results are discussed in relation to the wider behavioural phenotype and the emerging evidence of an autism endophenotype in PMS.

A framework to identify contributing genes in patients with Phelan-McDermid syndrome

Phelan-McDermid syndrome (PMS) is characterized by a variety of clinical symptoms with heterogeneous degrees of severity, including intellectual disability (ID), absent or delayed speech, and autism spectrum disorders (ASD). It results from a deletion of the distal part of chromosome 22q13 that in most cases includes the SHANK3 gene. SHANK3 is considered a major gene for PMS, but the factors that modulate the severity of the syndrome remain largely unknown. In this study, we investigated 85 patients with different 22q13 rearrangements (78 deletions and 7 duplications). We first explored the clinical features associated with PMS, and provide evidence for frequent corpus callosum abnormalities in 28% of 35 patients with brain imaging data. We then mapped several candidate genomic regions at the 22q13 region associated with high risk of clinical features, and suggest a second locus at 22q13 associated with absence of speech. Finally, in some cases, we identified additional clinically relevant copy-number variants (CNVs) at loci associated with ASD, such as 16p11.2 and 15q11q13, which could modulate the severity of the syndrome. We also report an inherited SHANK3 deletion transmitted to five affected daughters by a mother without ID nor ASD, suggesting that some individuals could compensate for such mutations. In summary, we shed light on the genotype-phenotype relationship of patients with PMS, a step towards the identification of compensatory mechanisms for a better prognosis and possibly treatments of patients with neurodevelopmental disorders.

Shank3-deficient rats exhibit degraded cortical responses to sound

Individuals with SHANK3 mutations have severely impaired receptive and expressive language abilities. While brain responses are known to be abnormal in these individuals, the auditory cortex response to sound has remained largely understudied. In this study, we document the auditory cortex response to speech and non-speech sounds in the novel Shank3-deficient rat model. We predicted that the auditory cortex response to sounds would be impaired in Shank3-deficient rats. We found that auditory cortex responses were weaker in Shank3 heterozygous rats compared to wild-type rats. Additionally, Shank3 heterozygous responses had less spontaneous auditory cortex firing and were unable to respond well to rapid trains of noise bursts. The rat model of the auditory impairments in SHANK3 mutation could be used to test potential rehabilitation or drug therapies to improve the communication impairments observed in individuals with Phelan-McDermid syndrome. Autism Res 2018, 11: 59-68. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Individuals with SHANK3 mutations have severely impaired language abilities, yet the auditory cortex response to sound has remained largely understudied. In this study, we found that auditory cortex responses were weaker and were unable to respond well to rapid sounds in Shank3-deficient rats compared to control rats. The rat model of the auditory impairments in SHANK3 mutation could be used to test potential rehabilitation or drug therapies to improve the communication impairments observed in individuals with Phelan-McDermid syndrome.

Phelan-McDermid syndrome due to SHANK3 mutation in an intellectually disabled adult male: successful treatment with lithium

For 30 years, Phelan and co-workers described a syndrome characterised by neonatal hypotonia, global developmental delay, strongly impaired speech, sleep disturbances and hyperreactivity to sensory stimuli. This Phelan-McDermid syndrome (PMS), also presenting with symptoms from the autism spectrum and a higher risk of developing seizure disorders, may be caused by a deletion of chromosome 22q13 or by a mutation in the SHANK3 gene. Its core psychopathological phenotype comprises symptoms from the bipolar spectrum for which generally treatment with a mood-stabilising anticonvulsant in combination with an atypical antipsychotic seems to be most effective. In addition to two elsewhere published adolescent patients, we here describe in detail the history of an adult male patient with PMS caused by a SHANK3 mutation in whom successive treatment regimens with antipsychotics and mood-stabilising anticonvulsants were all ineffective. Ultimately, addition of lithium to existing olanzapine therapy led to enduring stabilisation of mood and behaviour.

Autism spectrum disorders and disease modeling using stem cells

Autism spectrum disorders (ASD) represent a variety of disorders characterized as complex lifelong neurodevelopment disabilities, which may affect the ability of communication and socialization, including typical comportments like repetitive and stereotyped behavior. Other comorbidities are usually present, such as echolalia, hypotonia, intellectual disability and difficulties in processing figured speech. Furthermore, some ASD individuals may present certain abilities, such as eidetic memory, outstanding musical or painting talents and special mathematical skills, among others. Considering the variability of the clinical symptoms, one autistic individual can be severely affected in communication while others can speak perfectly, sometimes having a vocabulary above average in early childhood. The same variability can be seen in other clinical symptoms, thus the "spectrum" can vary from severe to mild. Induced pluripotent stem cell technology has been used to model several neurological diseases, including syndromic and non-syndromic autism. We discuss how modeling the central nervous system cells in a dish may help to reach a better understanding of ASD pathology and variability, as well as personalize their treatment.

Comprehensive analysis of two Shank3 and the Cacna1c mouse models of autism spectrum disorder

To expand, analyze and extend published behavioral phenotypes relevant to autism spectrum disorder (ASD), we present a study of three ASD genetic mouse models: Feng's Shank3^tm2Gfng model, hereafter Shank3/F, Jiang's Shank3^tm1Yhj model, hereafter Shank3/J and the Cacna1c deletion model. The Shank3 models mimick gene mutations associated with Phelan-McDermid Syndrome and the Cacna1c model recapitulates the deletion underlying Timothy syndrome. This study utilizes both standard and novel behavioral tests with the same methodology used in our previously published companion report on the Cntnap2 null and 16p11.2 deletion models. We found that some but not all behaviors replicated published findings and those that did replicate, such as social behavior and overgrooming in Shank3 models, tended to be milder than reported elsewhere. The Shank3/F model, and to a much lesser extent, the Shank3/J and Cacna1c models, showed hypoactivity and a general anxiety-like behavior triggered by external stimuli which pervaded social interactions. We did not detect deficits in a cognitive procedural learning test nor did we observe perseverative behavior in these models. We did, however, find differences in exploratory patterns of Cacna1c mutant mice suggestive of a behavioral effect in a social setting. In addition, only Shank3/F showed differences in sensory-gating. Both positive and negative results from this study will be useful in identifying the most robust and replicable behavioral signatures within and across mouse models of autism. Understanding these phenotypes may shed light of which features to study when screening compounds for potential therapeutic interventions.

Long noncoding RNA and its contribution to autism spectrum disorders

Recent studies have indicated that long noncoding RNAs (lncRNAs) play important roles in multiple processes, such as epigenetic regulation, gene expression regulation, development, nutrition-related and other diseases, toxic response, and response to drugs. Although the functional roles and mechanisms of several lncRNAs have been discovered, a better understanding of the vast majority of lncRNAs remains elusive. To understand the functional roles and mechanisms of lncRNAs is critical because these transcripts represent the majority of the transcriptional output of the mammalian genome. Recent studies have also suggested that lncRNAs are more abundant in the human brain and are involved in neurodevelopment and neurodevelopmental disorders, including autism spectrum disorders (ASDs). In this study, we review several known functions of lncRNAs and the potential contribution of lncRNAs to ASDs and to other genetic syndromes that have a similar clinical presentation to ASDs, such as fragile X syndrome and Rett syndrome.

The PHF21B gene is associated with major depression and modulates the stress response

Major depressive disorder (MDD) affects around 350 million people worldwide; however, the underlying genetic basis remains largely unknown. In this study, we took into account that MDD is a gene-environment disorder, in which stress is a critical component, and used whole-genome screening of functional variants to investigate the 'missing heritability' in MDD. Genome-wide association studies (GWAS) using single- and multi-locus linear mixed-effect models were performed in a Los Angeles Mexican-American cohort (196 controls, 203 MDD) and in a replication European-ancestry cohort (499 controls, 473 MDD). Our analyses took into consideration the stress levels in the control populations. The Mexican-American controls, comprised primarily of recent immigrants, had high levels of stress due to acculturation issues and the European-ancestry controls with high stress levels were given higher weights in our analysis. We identified 44 common and rare functional variants associated with mild to moderate MDD in the Mexican-American cohort (genome-wide false discovery rate, FDR, <0.05), and their pathway analysis revealed that the three top overrepresented Gene Ontology (GO) processes were innate immune response, glutamate receptor signaling and detection of chemical stimulus in smell sensory perception. Rare variant analysis replicated the association of the PHF21B gene in the ethnically unrelated European-ancestry cohort. The TRPM2 gene, previously implicated in mood disorders, may also be considered replicated by our analyses. Whole-genome sequencing analyses of a subset of the cohorts revealed that European-ancestry individuals have a significantly reduced (50%) number of single nucleotide variants compared with Mexican-American individuals, and for this reason the role of rare variants may vary across populations. PHF21b variants contribute significantly to differences in the levels of expression of this gene in several brain areas, including the hippocampus. Furthermore, using an animal model of stress, we found that Phf21b hippocampal gene expression is significantly decreased in animals resilient to chronic restraint stress when compared with non-chronically stressed animals. Together, our results reveal that including stress level data enables the identification of novel rare functional variants associated with MDD.

Shank is a dose-dependent regulator of Cav1 calcium current and CREB target expression

Shank is a post-synaptic scaffolding protein that has many binding partners. Shank mutations and copy number variations (CNVs) are linked to several psychiatric disorders, and to synaptic and behavioral defects in mice. It is not known which Shank binding partners are responsible for these defects. Here we show that the C. elegans SHN-1/Shank binds L-type calcium channels and that increased and decreased shn-1 gene dosage alter L-channel current and activity-induced expression of a CRH-1/CREB transcriptional target (gem-4 Copine), which parallels the effects of human Shank copy number variations (CNVs) on Autism spectrum disorders and schizophrenia. These results suggest that an important function of Shank proteins is to regulate L-channel current and activity induced gene expression.

DOI:http://dx.doi.org/10.7554/eLife.18931.001

Pharmacological enhancement of mGlu5 receptors rescues behavioral deficits in SHANK3 knock-out mice

SHANK3 (also called PROSAP2) genetic haploinsufficiency is thought to be the major cause of neuropsychiatric symptoms in Phelan-McDermid syndrome (PMS). PMS is a rare genetic disorder that causes a severe form of intellectual disability (ID), expressive language delays and other autistic features. Furthermore, a significant number of SHANK3 mutations have been identified in patients with autism spectrum disorders (ASD), and SHANK3 truncating mutations are associated with moderate to profound ID. The Shank3 protein is a scaffold protein that is located in the postsynaptic density (PSD) of excitatory synapses and is crucial for synapse development and plasticity. In this study, we investigated the molecular mechanisms associated with the ASD-like behaviors observed in Shank3Δ11^-/- mice, in which exon 11 has been deleted. Our results indicate that Shank3 is essential to mediating metabotropic glutamate receptor 5 (mGlu5)-receptor signaling by recruiting Homer1b/c to the PSD, specifically in the striatum and cortex. Moreover, augmenting mGlu5-receptor activity by administering 3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide ameliorated the functional and behavioral defects that were observed in Shank3Δ11^-/- mice, suggesting that pharmaceutical treatments that increase mGlu5 activity may represent a new approach for treating patients that are affected by PMS and SHANK3 mutations.