Intellectual disability and autism spectrum disorders: causal genes and molecular mechanisms

Should We Continue to Tell Autistic People that Their Brains are Different?

Autism is often considered to reflect categorically 'different brains'. Neuropsychological research on autism spectrum disorder (ASD) however, has struggled to define this difference, or derive clear-cut boundaries between autism and non-autism. Consequently, restructuring or disbanding the ASD diagnosis is becoming increasingly advocated within research. Nonetheless, autism now exists as a salient social construction, of which 'difference' is a key facet. Clinical and educational professionals must influence this cautiously, as changes to autism's social construction may counterproductively affect the quality of life of autistic people. This paper therefore reviews ASD's value as both neuropsychological and social constructs. Although lacking neuropsychological validity, the autism label may be beneficial for autistic self-identity, reduction of stigma, and administering support. Whilst a shift away from case-control ASD research is warranted, lay notions of 'different brains' may be preserved.

Catatonia and autism spectrum disorder: A common comorbid syndrome or a core feature?

Autism spectrum disorder (ASD) is an early-onset neurodevelopmental disorder marked by persistent deficits in social communication and interaction, alongside restricted, repetitive patterns of behaviors (RRB), interests, or activities. It often co-occurs with various neuropsychiatric disorders, though their frequency varies widely due to unclear boundaries between the core features of ASD and common comorbidities. Catatonia, increasingly noted in neurodevelopmental conditions like ASD, shares striking similarities with ASD in symptomatology, brain mechanisms, and treatment responses, prompting the question of whether it is a core feature of ASD or a distinct condition. This paper delved into this overlap, exploring the relationship between catatonia and ASD through a narrative review of peer-reviewed literature from 1943 to 2024, sourced from PubMed and psychiatric journals. Focusing on ASD diagnostic evolution, symptom overlap with catatonia, and shared neurobiological and therapeutic characteristics, we used thematic analysis to synthesize findings into key areas such as historical nosology, phenomenological overlap, neurobiological parallels, and treatment response. The evidence revealed weak support for separating catatonia from overlapping RRB features of ASD, suggesting that some RRB might align more with comorbid catatonia than intrinsic ASD traits. However, this idea needs further validation through rigorous clinical trials. Clarifying this relationship could refine diagnostic approaches and open doors to targeted treatments, potentially improving outcomes for those affected.

The Effects of a Ball Combination Training Program Combined with a Continuous Theta Burst Stimulation Intervention on Eating Behaviors in Autistic Children with Accompanying Intellectual Disabilities: A Preliminary Study

Background: Eating behavior problems significantly affect the physical health and quality of life of children with autism spectrum disorder and intellectual disabilities (co-occurring ASD/ID). This study aimed to evaluate the effects of a 12-week Ball Combination Training Program (BCTP), continuous theta burst stimulation (cTBS), and an intervention combining both (in the CIG) on the eating behaviors of children with co-occurring ASD/ID. Methods: A total of 48 participants were assigned into one of four groups: the BCTP (n = 13), cTBS (n = 12), the CIG (n = 11), and a control group (n = 12). The intervention groups received their respective treatments in addition to the routine institutional rehabilitation, whereas the control group only received the standard institutional rehabilitation. The intervention outcomes were assessed using the parent-reported Children's Eating Behavior Questionnaire (CEBQ). Results: The results indicated that all three intervention methods led to improvements in their eating behavior after 12 weeks. Specifically, the BCTP group and the CIG demonstrated significantly reduced Food Fussiness behavior, while the children's Enjoyment of Food was markedly enhanced in the cTBS group and the CIG. Furthermore, the CIG experienced a particularly notable effect in terms of the improvement in the Satiety Responsiveness dimension of their eating behavior. Among the three approaches, the CIG demonstrated a clear advantage over the single interventions in terms of both the breadth and magnitude of its improvements. Conclusions: This study confirmed the effectiveness of these three intervention strategies in addressing dietary behavior problems among children with co-occurring ASD/ID. Future research should focus on exploring the combined intervention approach further, particularly its potential synergy, while delving deeper into the neural mechanisms underlying these behavioral improvements.

Serious Games for constipation management for people with intellectual disabilities: A scoping review and narrative synthesis

INTRODUCTION

People with intellectual disability (PwID) are 2% of the UK population. Constipation and bowel movement (BM) problems (diarrhoea/faecal incontinence etc.) affects over a third of PwID and is a serious cause of morbidity and mortality. Pw ID rely heavily on outside support (family/professional carers/healthcare professionals), many of whom are ignorant to bowel related harms. There is significant stigma to discuss BM particularly constipation. Serious Games (SG) are increasingly used for education of health needs. This review examines if game-based technology can assist improving knowledge and reducing stigma of BM problems particularly constipation.

OBJECTIVE

To identify and gain evidence of SGs aimed at improving knowledge of BM management particularly constipation.

METHODS

A systematic search of publications between 2010 and 2024 was conducted following the PRISMA ScR statement for scoping reviews. The search inclusion/exclusion criteria were designed and overseen by an information specialist. PUBMED, EMBASE and PsychINFO databases were searched. Extracted variables included SG title, co-production and expert involvement, target outcome, evaluation methodology, effectiveness, sustainability and game platform. Results were narratively synthesised.

RESULTS

Of 2966 papers retrieved, three were selected for inclusion, none RCTs. All three included SGs aimed to teach BM management or recognition to healthcare workers/ professionals. Two studies evaluated game efficacy. No SGs were assessed after initial trials, none were implemented in clinical practice. Only one game successfully improved participant knowledge. All game creators consulted experts during game design, but none consulted patients. None discussed reducing stigma amongst their audience.

CONCLUSION

Only one of three SGs identified improved BM knowledge in healthcare workers/professionals and was not specific to PwID. There is potential to co-produce with PwID and their carers a SG to support BM problems particularly constipation to reduce stigma, improve outcomes and be a templar for other similarly vulnerable groups like those with dementia.

Orthodontic aligner therapy outcomes in children with autism spectrum disorder

BACKGROUND

Children with autism spectrum disorder (ASD) face unique challenges in oral care. Aligner therapy offers a promising alternative to conventional approaches for this patient group.

AIM

To evaluate orthodontic aligner therapy outcomes in children with ASD using the Peer Assessment Rating (PAR) Index and the Index of Complexity, Outcome, and Need (ICON), and to investigate whether concomitant disorders affect ICON, PAR scores, and treatment duration.

DESIGN

Two calibrated observers assessed digital dental casts and intraoral pictures of 37 children with ASD before (T0) and after (T1) their treatment. At T0, the participants' average age was 12.9 years (SD = 1.68); at T1, post-therapy, the average age was 14.9 years (SD = 1.51). All participants underwent orthodontic aligner therapy. Statistical methods employed in this study included descriptive analysis, Wilcoxon tests, and univariate linear regression.

RESULTS

Posttreatment, median ICON scores decreased significantly from 74 to 14, and median PAR scores from 36 to 8 (p < .0001), demonstrating "excellent to substantial" improvement in 89.2% (n = 33) of the children. Comorbidities, present in 62% of patients, did not significantly affect treatment duration (22.6 ± 11.02 months).

CONCLUSION

Children with ASD significantly benefit from orthodontic aligner therapy, emphasizing the need for tailored orthodontic care.

Cortex-Specific Tmem169 Deficiency Induces Defects in Cortical Neuron Development and Autism-Like Behaviors in Mice

The development of the nervous system is a complex process, with many challenging scientific questions yet to be resolved. Disruptions in brain development are strongly associated with neurodevelopmental disorders, such as intellectual disability and autism. While the genetic basis of autism is well established, the precise pathological mechanisms remain unclear. Variations on chromosome 2q have been linked to autism, yet the specific genes responsible for the disorder have not been identified. This study investigates the role of the transmembrane protein 169 (TMEM169) gene, located on human chromosome 2q35, which has not been previously characterized. Our findings indicate that Tmem169 is highly expressed in the nervous system, and its deletion in the male mouse dorsal forebrain results in neuronal morphological abnormalities and synaptic dysfunction. Notably, Tmem169-deficient mice, irrespective of sex, display behavioral traits resembling those observed in individuals with autism. These results suggest that Tmem169 interacts with several key neuronal proteins, many of which are implicated in neurodevelopmental diseases. Furthermore, we demonstrate that Tmem169 promotes neuronal process and synapse development through its interaction with Shank3.

Role of androgen receptors in sexually dimorphic phenotypes in UBE3A-dependent autism spectrum disorder

Autism spectrum disorders (ASDs) involve social, communication, and behavioral challenges. ASDs display a remarkable sex difference with a 4:1 male to female prevalence ratio; however, the underlying mechanism remains largely unknown. Using the UBE3A-overexpressing mouse model for ASD, we studied sexually dimorphic changes at behavioral, genetic, and molecular levels. We found that male mice with extra copies of Ube3A exhibited greater impairments in social communication, long-term memory, and pain sensitivity compared to females. UBE3A-mediated degradation reduced androgen receptor (AR) levels in both sexes but only male mice showed significant dysregulation in the expression of AR target genes. Importantly, restoring AR levels in the brain normalized levels of AR target genes, and rescued the deficits in social preference, grooming, and memory in male UBE3A-overexpressing mice, without affecting females. These findings reveal the critical role of AR signaling in sex-specific changes linked to UBE3A-dependent ASD.

Cryo-ET suggests tubulin chaperones form a subset of microtubule lumenal particles with a role in maintaining neuronal microtubules

The functional architecture of the long-lived neuronal microtubule (MT) cytoskeleton is maintained by various MT-associated proteins (MAPs), most of which are known to bind to the MT outer surface. However, electron microscopy (EM) has long ago revealed the presence of particles inside the lumens of neuronal MTs, of yet unknown identity and function. Here, we use cryogenic electron tomography (cryo-ET) to analyze the three-dimensional (3D) organization and structures of MT lumenal particles in primary hippocampal neurons, human induced pluripotent stem cell-derived neurons, and pluripotent and differentiated P19 cells. We obtain in situ density maps of several lumenal particles from the respective cells and detect common structural features underscoring their potential overarching functions. Mass spectrometry-based proteomics combined with structural modeling suggest that a subset of lumenal particles could be tubulin-binding cofactors (TBCs) bound to tubulin monomers. A different subset of smaller particles, which remains unidentified, exhibits densities that bridge across the MT protofilaments. We show that increased lumenal particle concentration within MTs is concomitant with neuronal differentiation and correlates with higher MT curvatures. Enrichment of lumenal particles around MT lattice defects and at freshly polymerized MT open-ends suggests a MT protective role. Together with the identified structural resemblance of a subset of particles to TBCs, these results hint at a role in local tubulin proteostasis for the maintenance of long-lived neuronal MTs.

Mental Health Care Needs and Access to Care for Adults With Intellectual Disabilities

BACKGROUND

Adults with intellectual disabilities (IDs) are at greater risk for psychiatric disorders than the general population. Yet, they have limited access to mental health services.

OBJECTIVES

To examine the prevalence of psychiatric disorders in adults with ID. To describe evidence-based interventions for this population, their access to mental health care, and outline opportunities for improved access.

DESIGN

This manuscript summarizes literature regarding psychiatric disorders in adults with ID and their access to behavioral health care. We considered articles referencing mental health care for adults with ID. PubMed and a variety of search terms were used. Studies published in English from 2010 to the date of the searches were included. Quantitative and qualitative study designs, review articles, program descriptions, and opinion papers were considered for inclusion. Additional references from the selected articles were also considered.

RESULTS

We identified 2864 records. One hundred two records were included, consisting of work commenting on mental health and ID and access to care in the United States. The articles describe increased psychiatric comorbidities in adults with ID. They highlight the few evidence-based interventions for psychiatric comorbidities and the limited access to care.

CONCLUSIONS

Our mental health care providers generally have minimal training and experience with people with ID, limiting access to appropriate care for these individuals. Improved access could be created by increasing education and experiences with these populations for mental health providers. Aligning policies, financing, and adequate insurance reimbursement to develop a continuum of care will be critical for these individuals.

Targeting epigenetic dysregulation in autism spectrum disorders

Autism spectrum disorders (ASD) comprise a range of neurodevelopmental pathologies characterized by deficits in social interaction and repetitive behaviors, collectively affecting almost 1% of the worldwide population. Deciphering the etiology of ASD has proven challenging due to the intricate interplay of genetic and environmental factors and the variety of molecular pathways affected. Epigenomic alterations have emerged as key players in ASD etiology. Their research has led to the identification of biomarkers for diagnosis and pinpointed specific gene targets for therapeutic interventions. This review examines the role of epigenetic alterations, resulting from both genetic and environmental influences, as a central causative factor in ASD, delving into its contribution to pathogenesis and treatment strategies.

Effects of visual and auditory cognitive tasks on postural balance in adolescents with intellectual disability: A comparative analysis of trained versus non-trained individuals

This study aimed to investigate the influence of visual and auditory cognitive tasks on postural balance in adolescents with intellectual disabilities (ID). Participants included two groups: a trained group (n = 11) with experience in athletic activities and a sedentary group (n = 14). The experiment used a comparative cross-sectional design, with data collection involving single-task (ST) and Visual dual-task (VDT), and auditory dual-task (ADT) conditions in both firm and foam surface conditions. Cognitive tests included the Working Memory Test (WMT) and the Selective Attention Test (SAT). Results revealed that the trained group demonstrated significantly superior balance performance (p < 0.05). During the SAT, VDT conditions had lower center of pressure (CoP) values than ADT conditions in the sedentary group (p < 0.01), this result was observed in the training group only in the WMT, suggesting greater postural instability during ADT. These findings highlight the complex relationship between cognitive function and motor control in adolescents with ID, highlighting the potential benefits of regular physical activity interventions to improve postural balance abilities in this population.

Specific EEG resting state biomarkers in FXS and ASD

BACKGROUND

Fragile X syndrome (FXS) and autism spectrum disorder (ASD) are neurodevelopmental conditions that often have a substantial impact on daily functioning and quality of life. FXS is the most common cause of inherited intellectual disability (ID) and the most common monogenetic cause of ASD. Previous literature has shown that electrophysiological activity measured by electroencephalogram (EEG) during resting state is perturbated in FXS and ASD. However, whether electrophysiological profiles of participants with FXS and ASD are similar remains unclear. The aim of this study was to compare EEG alterations found in these two clinical populations presenting varying degrees of cognitive and behavioral impairments.

METHODS

Resting state EEG signal complexity, alpha peak frequency (APF) and power spectral density (PSD) were compared between 47 participants with FXS (aged between 5-20), 49 participants with ASD (aged between 6-17), and 52 neurotypical (NT) controls with a similar age distribution using MANCOVAs with age as covariate when appropriate. MANCOVAs controlling for age, when appropriate, and nonverbal intelligence quotient (NVIQ) score were subsequently performed to determine the impact of cognitive functioning on EEG alterations.

RESULTS

Our results showed that FXS participants manifested decreased signal complexity and APF compared to ASD participants and NT controls, as well as altered power in the theta, alpha and low gamma frequency bands. ASD participants showed exaggerated beta power compared to FXS participants and NT controls, as well as enhanced low and high gamma power compared to NT controls. However, ASD participants did not manifest altered signal complexity or APF. Furthermore, when controlling for NVIQ, results of decreased complexity in higher scales and lower APF in FXS participants compared to NT controls and ASD participants were not replicated.

CONCLUSIONS

These findings suggest that signal complexity and APF might reflect cognitive functioning, while altered power in the low gamma frequency band might be associated with neurodevelopmental conditions, particularly FXS and ASD.

Genetic Testing for Global Developmental Delay in Early Childhood

Importance

Global developmental delay (GDD) is characterized by a complex etiology, diverse phenotypes, and high individual heterogeneity, presenting challenges for early clinical etiologic diagnosis. Cognitive impairment is the core symptom, and despite the pivotal role of genetic factors in GDD development, the understanding of them remains limited.

Objectives

To assess the utility of genetic detection in patients with GDD and to examine the potential molecular pathogenesis of GDD to identify targets for early intervention.

Design, Setting, and Participants

This multicenter, prospective cohort study enrolled patients aged 12 to 60 months with GDD from 6 centers in China from July 4, 2020, to August 31, 2023. Participants underwent trio whole exome sequencing (trio-WES) coupled with copy number variation sequencing (CNV-seq). Bioinformatics analysis was used to unravel pathogenesis and identify therapeutic targets.

Main Outcomes and Measures

The main outcomes of this study involved enhancing the rate of positive genetic diagnosis for GDD, broadening the scope of genetic testing indications, and investigating the underlying pathogenesis. The classification of children into levels of cognitive impairment was based on the developmental quotient assessed using the Gesell scale.

Results

The study encompassed 434 patients with GDD (262 [60%] male; mean [SD] age, 25.75 [13.24] months) with diverse degrees of cognitive impairment: mild (98 [23%]), moderate (141 [32%]), severe (122 [28%]), and profound (73 [17%]). The combined use of trio-WES and CNV-seq resulted in a 61% positive detection rate. Craniofacial abnormalities (odds ratio [OR], 2.27; 95% CI, 1.45-3.56), moderate or severe cognitive impairment (OR, 1.69; 95% CI, 1.05-2.70), and age between 12 and 24 months (OR, 1.57; 95% CI, 1.05-2.35) were associated with a higher risk of carrying genetic variants. Additionally, bioinformatics analysis suggested that genetic variants may induce alterations in brain development and function, which may give rise to cognitive impairment. Moreover, an association was found between the dopaminergic pathway and cognitive impairment.

Conclusions and Relevance

In this cohort study of patients with GDD, combining trio-WES with CNV-seq was a demonstrable, instrumental strategy for advancing the diagnosis of GDD. The close association among genetic variations, brain development, and clinical phenotypes contributed valuable insights into the pathogenesis of GDD. Notably, the dopaminergic pathway emerged as a promising focal point for potential targets in future precision medical interventions for GDD.

Selective vulnerability of the ventral hippocampus-prelimbic cortex axis parvalbumin interneuron network underlies learning deficits of fragile X mice

High-penetrance mutations affecting mental health can involve genes ubiquitously expressed in the brain. Whether the specific patterns of dysfunctions result from ubiquitous circuit deficits or might reflect selective vulnerabilities of targetable subnetworks has remained unclear. Here, we determine how loss of ubiquitously expressed fragile X mental retardation protein (FMRP), the cause of fragile X syndrome, affects brain networks in Fmr1y/- mice. We find that in wild-type mice, area-specific knockout of FMRP in the adult mimics behavioral consequences of area-specific silencing. By contrast, the functional axis linking the ventral hippocampus (vH) to the prelimbic cortex (PreL) is selectively affected in constitutive Fmr1y/- mice. A chronic alteration in late-born parvalbumin interneuron networks across the vH-PreL axis rescued by VIP signaling specifically accounts for deficits in vH-PreL theta-band network coherence, ensemble assembly, and learning functions of Fmr1y/- mice. Therefore, vH-PreL axis function exhibits a selective vulnerability to loss of FMRP in the vH or PreL, leading to learning and memory dysfunctions in fragile X mice.

Characterizing the clinical and sociodemographic profiles of hospitalized adolescents with autism spectrum disorder

The prevalence of autism spectrum disorder (ASD) is increasing worldwide. Youngsters with ASD demonstrate higher rates of intellectual disabilities (IDs), comorbid psychopathology and psychiatric hospitalizations, compared to children in the general population. This study characterizes the demographics and clinical parameters of adolescent psychiatric inpatients with ASD compared to inpatients without ASD, all hospitalized during the study period. Additionally, within the ASD group, those with ID were compared to those without. The rate of males among participants with ASD was significantly higher than among those without ASD, and the duration of hospitalization was longer. In contrast, the rate of cigarette smoking, major depressive disorder and suicidal thoughts among those with ASD was lower. One-third of those with ASD had moderate to severe ID, about 10% had comorbid epilepsy, and about half of them demonstrated aggressive behavior. Most ASD patients showed significant improvement upon discharge, although the extent of improvement was more prominent among ASD patients with no ID. Our findings, consistent with previous research, indicate that hospitalization is beneficial to youths with ASD, both those with and those without ID. Further studies that include long-term follow-up are needed.

Sexually dimorphic phenotypes and the role of androgen receptors in UBE3A-dependent autism spectrum disorder

Autism spectrum disorders (ASDs) are characterized by social, communication, and behavioral challenges. UBE3A is one of the most common ASD genes. ASDs display a remarkable sex difference with a 4:1 male to female prevalence ratio; however, the underlying mechanism remains largely unknown. Using the UBE3A-overexpressing mouse model for ASD, we studied sex differences at behavioral, genetic, and molecular levels. We found that male mice with extra copies of Ube3A exhibited greater impairments in social interaction, repetitive self-grooming behavior, memory, and pain sensitivity, whereas female mice with UBE3A overexpression displayed greater olfactory defects. Social communication was impaired in both sexes, with males making more calls and females preferring complex syllables. At the molecular level, androgen receptor (AR) levels were reduced in both sexes due to enhanced degradation mediated by UBE3A. However, AR reduction significantly dysregulated AR target genes only in male, not female, UBE3A-overexpressing mice. Importantly, restoring AR levels in the brain effectively normalized the expression of AR target genes, and rescued the deficits in social preference, grooming behavior, and memory in male UBE3A-overexpressing mice, without affecting females. These findings suggest that AR and its signaling cascade play an essential role in mediating the sexually dimorphic changes in UBE3A-dependent ASD.

Therapeutic Potential for Metabotropic Glutamate Receptor 7 Modulators in Cognitive Disorders

Metabotropic glutamate receptor 7 (mGlu7) is the most highly conserved and abundantly expressed mGlu receptor in the human brain. The presynaptic localization of mGlu7, coupled with its low affinity for its endogenous agonist, glutamate, are features that contribute to the receptor's role in modulating neuronal excitation and inhibition patterns, including long-term potentiation, in various brain regions. These characteristics suggest that mGlu7 modulation may serve as a novel therapeutic strategy in disorders of cognitive dysfunction, including neurodevelopmental disorders that cause impairments in learning, memory, and attention. Primary mutations in the GRM7 gene have recently been identified as novel causes of neurodevelopmental disorders, and these patients exhibit profound intellectual and cognitive disability. Pharmacological tools, such as agonists, antagonists, and allosteric modulators, have been the mainstay for targeting mGlu7 in its endogenous homodimeric form to probe effects of its function and modulation in disease models. However, recent research has identified diversity in dimerization, as well as trans-synaptic interacting proteins, that also play a role in mGlu7 signaling and pharmacological properties. These novel findings represent exciting opportunities in the field of mGlu receptor drug discovery and highlight the importance of further understanding the functions of mGlu7 in complex neurologic conditions at both the molecular and physiologic levels. SIGNIFICANCE STATEMENT: Proper expression and function of mGlu7 is essential for learning, attention, and memory formation at the molecular level within neural circuits. The pharmacological targeting of mGlu7 is undergoing a paradigm shift by incorporating an understanding of receptor interaction with other cis- and trans- acting synaptic proteins, as well as various intracellular signaling pathways. Based upon these new findings, mGlu7's potential as a drug target in the treatment of cognitive disorders and learning impairments is primed for exploration.

A nonsense CC2D1A variant is associated with congenital anomalies, motor delay, hypotonia, and slight deformities

Background

Autosomal recessive intellectual developmental disorder-3 is caused by homozygous or compound heterozygous mutations in the CC2D1A gene. The disorder is characterized by intellectual disability (ID) and autism spectrum disorder (ASD). To date, 39 patients from 17 families with CC2D1A -related disorders have been reported worldwide, in whom only six pathogenic or likely pathogenic loss-of-function variants and three variants of uncertain significance (VUS) in the CC2D1A gene have been identified in these patients.

Methods

We described a patient with ID from a non-consanguineous Chinese family and whole-exome sequencing (WES) was used to identify the causative gene.

Results

The patient presented with severe ID and ASD, speech impairment, motor delay, hypotonia, slight facial anomalies, and finger deformities. Threatened abortion and abnormal fetal movements occurred during pregnancy with the proband but not his older healthy sister. WES analysis identified a homozygous nonsense variant, c.736C > T (p.Gln246Ter), in the CC2D1A gene. In addition, six novel likely pathogenic CC2D1A variants were identified by a retrospective review of the in-house database.

Conclusions

This study expands the genetic and clinical spectra of CC2D1A-associated disorders, and may aid in increasing awareness of this rare condition. Our findings have provided new insights into the clinical heterogeneity of the disease and further phenotype-genotype correlation, which could help to offer scope for more accurate genetic testing and counseling to affected families.

Effects of Social Defeat Stress on Microtubule Regulating Proteins and Tubulin Polymerization

Objective

: Microtubule (MT) stability in neurons is vital for brain development; instability is associated with neuropsychiatric disorders. The present study examined the effects of social defeat stress (SDS) on MT-regulating proteins and tubulin polymerization.

Methods

: After 10 days of SDS, defeated mice were separated into susceptible (Sus) and unsusceptible (Uns) groups based on their performance in a social avoidance test. Using extracted brain tissues, we measured the expression levels of α-tubulin, acetylated α-tubulin, tyrosinated α-tubulin, MT-associated protein-2 (MAP2), stathmin (STMN1), phospho stathmin serine 16 (p-STMN1 [Ser16]), phospho stathmin serine 25 (p-STMN1 [Ser25]), phospho stathmin serine 38 (p-STMN1 [Ser38]), stathmin2 (STMN2), phospho stathmin 2 serine 73 (p-STMN2 [Ser73]), 78-kDa glucose-regulated protein (GRP-78), and CCAAT/enhancer binding protein (C/EBP)-homologous protein (CHOP) using Western blot assay. The tubulin polymerization rate was also measured.

Results

: We observed increased and decreased expression of acetylated and tyrosinated α-tubulin, respectively, decreased expression of p-STMN1 (Ser16) and increased expression of p-STMN1 (Ser25), p-STMN2 (Ser73) and GRP-78 and CHOP in the prefrontal cortex and/or hippocampus of defeated mice. A reduced tubulin polymerization rate was observed in the Sus group compared to the Uns and Con groups.

Conclusion

: Our findings suggest that SDS has detrimental effects on MT stability, and a lower tubulin polymerization rate could be a molecular marker for susceptibility to SDS.

Neuroimmune mechanisms in autism etiology - untangling a complex problem using human cellular models

Autism spectrum disorder (ASD) affects 1 in 36 people and is more often diagnosed in males than in females. Core features of ASD are impaired social interactions, repetitive behaviors and deficits in verbal communication. ASD is a highly heterogeneous and heritable disorder, yet its underlying genetic causes account only for up to 80% of the cases. Hence, a subset of ASD cases could be influenced by environmental risk factors. Maternal immune activation (MIA) is a response to inflammation during pregnancy, which can lead to increased inflammatory signals to the fetus. Inflammatory signals can cross the placenta and blood brain barriers affecting fetal brain development. Epidemiological and animal studies suggest that MIA could contribute to ASD etiology. However, human mechanistic studies have been hindered by a lack of experimental systems that could replicate the impact of MIA during fetal development. Therefore, mechanisms altered by inflammation during human pre-natal brain development, and that could underlie ASD pathogenesis have been largely understudied. The advent of human cellular models with induced pluripotent stem cell (iPSC) and organoid technology is closing this gap in knowledge by providing both access to molecular manipulations and culturing capability of tissue that would be otherwise inaccessible. We present an overview of multiple levels of evidence from clinical, epidemiological, and cellular studies that provide a potential link between higher ASD risk and inflammation. More importantly, we discuss how stem cell-derived models may constitute an ideal experimental system to mechanistically interrogate the effect of inflammation during the early stages of brain development.

Autosomal recessive intellectual disability caused by compound heterozygous variants of the EEF1D gene in a Chinese family

BACKGROUND

Intellectual disability is a prevalent neurodevelopmental disorder, with the majority of affected children exhibiting global developmental delay before the age of 5 years. In recent years, certain children have been found to carry homozygous variations of the EEF1D gene, leading to autosomal recessive intellectual disability. However, the pathogenicity of compound heterozygous variations in this gene remains largely unknown.

METHODS

Trio whole-exome sequencing and copy number variation sequencing were done for the genetic etiological diagnosis of a 3-year and 11-month-old Chinese boy who presented with brachycephaly, severe to profound global developmental delay, and hypotonia in the lower limbs.

RESULTS

In this case, compound heterozygous variants of the EEF1D gene were found in the child through trio whole-exome sequencing; one was a splice variant (NM_032378.6:c.1905+1G>A) inherited from his father, and the other was a nonsense variant (NM_032378.6:c.676C>T) inherited from his mother. The nonsense variant leads to the production of a premature termination (p.Gln226*). These variations have the ability to explain the clinical phenotypes of the child.

CONCLUSIONS

Our study expands the variation spectrum and provides compelling evidence for EEF1D as a candidate gene for autosomal recessive intellectual disability. However, due to the deficient number of reported cases, researchers need to further study EEF1D and supplement the clinical phenotypes and treatment measures.

PLPPR4 haploinsufficiency causes neurodevelopmental disorders by disrupting synaptic plasticity via mTOR signalling

Phospholipid phosphatase related 4 (PLPPR4), a neuron-specific membrane protein located at the postsynaptic density of glutamatergic synapses, is a putative regulator of neuronal plasticity. However, PLPPR4 dysfunction has not been linked to genetic disorders. In this study, we report three unrelated patients with intellectual disability (ID) or autism spectrum disorder (ASD) who harbour a de novo heterozygous copy number loss of PLPPR4 in 1p21.2p21.3, a heterozygous nonsense mutation in PLPPR4 (NM_014839, c.4C > T, p.Gln2*) and a homozygous splice mutation in PLPPR4 (NM_014839: c.408 + 2 T > C), respectively. Bionano single-molecule optical mapping confirmed PLPPR4 deletion contains no additional pathogenic genes. Our results suggested that the loss of function of PLPPR4 is associated with neurodevelopmental disorders. To test the pathogenesis of PLPPR4, peripheral blood mononuclear cells obtained from the patient with heterozygous deletion of PLPPR4 were induced to specific iPSCs (CHWi001-A) and then differentiated into neurons. The neurons carrying the deletion of PLPPR4 displayed the reduced density of dendritic protrusions, shorter neurites and reduced axon length, suggesting the causal role of PLPPR4 in neurodevelopmental disorders. As the mTOR signalling pathway was essential for regulating the axon maturation and function, we found that mTOR signalling was inhibited with a higher level of p-AKT, p-mTOR and p-ERK1/2, decreased p-PI3K in PLPPR4-iPSCs neurons. Additionally, we found silencing PLPPR4 disturbed the mTOR signalling pathway. Our results suggested PLPPR4 modulates neurodevelopment by affecting the plasticity of neurons via the mTOR signalling pathway.

A Novel Mutation in the MAP7D3 Gene in Two Siblings with Severe Intellectual Disability and Autistic Traits: Concurrent Assessment of BDNF Functional Polymorphism, X-Inactivation and Oxidative Stress to Explain Disease Severity

Intellectual disabilities (ID) and autism spectrum disorders (ASD) are characterized by extreme genetic and phenotypic heterogeneity. However, understanding this heterogeneity is difficult due to the intricate interplay among multiple interconnected genes, epigenetic factors, oxidative stress, and environmental factors. Employing next-generation sequencing (NGS), we revealed the genetic cause of ID and autistic traits in two patients from a consanguineous family followed by segregation analysis. Furthermore, in silico prediction methods and 3D modeling were conducted to predict the effect of the variants. To establish genotype-phenotype correlation, X-chromosome inactivation using Methylation-specific PCR and oxidative stress markers were also investigated. By analyzing the NGS data of the two patients, we identified a novel frameshift mutation c.2174_2177del (p.Thr725MetfsTer2) in the MAP7D3 gene inherited from their mother along with the functional BDNF Val66Met polymorphism inherited from their father. The 3D modeling demonstrated that the p.Thr725MetfsTer2 variant led to the loss of the C-terminal tail of the MAP7D3 protein. This change could destabilize its structure and impact kinesin-1's binding to microtubules via an allosteric effect. Moreover, the analysis of oxidative stress biomarkers revealed an elevated oxidative stress in the two patients compared to the controls. To the best of our knowledge, this is the first report describing severe ID and autistic traits in familial cases with novel frameshift mutation c.2174_2177del in the MAP7D3 gene co-occurring with the functional polymorphism Val66M in the BDNF gene. Besides, our study underlines the importance of investigating combined genetic variations, X-chromosome inactivation (XCI) patterns, and oxidative stress markers for a better understanding of ID and autism etiology.

Imprinted small nucleolar RNAs: Missing link in development and disease?

The 14q32.2 (DLK1-DIO3) and 15q11-q13 (SNURF-SNRPN) imprinted gene loci harbor the largest known small nucleolar RNA clusters expressed from the respective maternal and paternal alleles. Recent studies have demonstrated significant roles for the 15q11-q13 located SNORD115-SNORD116 C/D box snoRNAs in Prader-Willi syndrome (PWS), a neurodevelopmental disorder. Even though the effect of SNORD116 deletion is apparent in the PWS phenotype, similar effects of a SNORD113-SNORD114 cluster deletion from the 14q32.2 locus in Kagami-Ogata syndrome (KOS14) and upregulation in Temple syndrome (TS14) remain to be explored. Moreover, apart from their probable involvement in neurodevelopmental disorders, snoRNAs from the SNORD113-SNORD114 cluster have been implicated in multiple biological processes, including pluripotency, development, cancers, and RNA modifications. Here we summarize the current understanding of the system to explore the possibility of a link between developmental disorders and C/D box snoRNA expression from the imprinted 14q32.2 locus. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA in Disease and Development > RNA in Development RNA Processing > Processing of Small RNAs.

Age-related physical health of older autistic adults in Sweden: a longitudinal, retrospective, population-based cohort study

BACKGROUND

Research of health outcomes in older autistic adults (≥45 years) is concerningly scarce, and little is known about whether intellectual disability and sex affect the health outcomes of this population. The aim of this study was to investigate the association between autism and physical health conditions in older adults and to examine these associations by intellectual disability and sex.

METHODS

We conducted a longitudinal, retrospective, population-based cohort study of the Swedish population born between Jan 1, 1932, and Dec 31, 1967, using linked data from the nationwide Total Population Register and the National Patient Register. We excluded individuals who died or emigrated before the age of 45 years, or with any chromosomal abnormalities. Follow-up started at age 45 years for all individuals, and ended at emigration, death, or Dec 31, 2013 (the latest date of available follow-up), whichever was soonest. Diagnoses of autism, intellectual disability, 39 age-related physical conditions, and five types of injury (outcomes) were obtained from the National Patient Register. For each outcome, we calculated 25-year cumulative incidence and used Cox models to estimate hazard ratios (HRs). All analyses were repeated separately by intellectual disability and sex.

FINDINGS

Of 4 200 887 older adults (2 063 718 women [49·1%] and 2 137 169 men [50·9%]) in the study cohort, 5291 (0·1%) had a diagnosis of autism recorded in the National Patient Register. Older autistic adults (median follow-up 8·4 years [IQR 4·2-14·6]) had higher cumulative incidence and HRs of various physical conditions and injuries than their non-autistic counterparts (median follow-up 16·4 years [8·2-24·4]). In autistic individuals, the highest cumulative incidence was observed for bodily injuries (50·0% [95% CI 47·6-52·4]). Conditions that autistic adults were at higher risk of than were non-autistic adults included heart failure (HR 1·89 [95% CI 1·61-2·22]), cystitis (2·03 [1·66-2·49]), glucose dysregulation (2·96 [2·04-4·29]), iron deficiency anaemia (3·12 [2·65-3·68]), poisoning (4·63 [4·13-5·18]), and self-harm (7·08 [6·24-8·03]). These increased risks mainly persisted regardless of intellectual disability or sex.

INTERPRETATION

Our data indicate that older autistic adults are at substantially increased risk of age-related physical conditions and injuries compared with non-autistic adults. These findings highlight the need for collaborative efforts from researchers, health services, and policy makers to provide older autistic individuals with the necessary support to attain healthy longevity and a high quality of life.

FUNDING

Swedish Research Council, Servier Affaires Medicales.

TRANSLATION

For the Swedish translation of the abstract see Supplementary Materials section.

Cell consequences of loss of function of the epigenetic factor EHMT1

EHMT1 is an epigenetic factor with histone methyltransferase activity that appears mutated in Kleefstra syndrome, a neurodevelopmental genetic disorder characterized by developmental delay, intellectual disability, and autistic-like features. Despite recent progress in the study of the function of this gene and the molecular etiology of the disease, our knowledge of how EHMT1 haploinsufficiency causes Kleefstra syndrome is still very limited. Here, we show that EHMT1 depletion in RPE1 cells leads to alterations in the morphology and distribution of different subcellular structures, such as the Golgi apparatus, the lysosomes and different cell adhesion components. EHMT1 downregulation also increases centriolar satellites detection, which may indicate a role for EHMT1 in centrosome functioning. Furthermore, the migration process is also altered in EHMT1 depleted cells, which show reduced migration capacity. We consider that the described phenotypes could open new possibilities for understanding the functional impact of EHMT1 haploinsufficiency in Kleefstra syndrome, helping to elucidate the link between epigenetic regulation and the underlying cellular mechanisms that result in this neurodevelopmental disorder. This knowledge could be relevant not only for the treatment of this syndrome, but also for other neurodevelopmental conditions that could share similar deregulated cellular pathways.

Systematic Review: Emotion Dysregulation in Syndromic Causes of Intellectual and Developmental Disabilities

OBJECTIVE

To summarize the current state of the literature regarding emotion dysregulation (ED) in syndromic intellectual disabilities (S-IDs) in 6 of the most common forms of S-IDs-Down syndrome, fragile X syndrome (FXS), tuberous sclerosis complex, Williams syndrome, Prader-Willi syndrome, and Angelman syndrome-and to determine future research directions for identification and treatment of ED.

METHOD

PubMed bibliographic database was searched from date of inception to May 2021. PRISMA 2020 guidelines were followed with the flowchart, table of included studies, list of excluded studies, and checklist provided. Filters applied included human research and English. Only original research articles were included in the final set, but review articles were used to identify secondary citations of primary studies. All articles were reviewed for appropriateness by 2 authors and summarized. Inclusion criteria were met by 145 articles (Down syndrome = 29, FXS = 55, tuberous sclerosis complex = 11, Williams syndrome = 18, Prader-Willi syndrome = 24, Angelman syndrome = 8).

RESULTS

Each syndrome review was summarized separately and further subdivided into articles related to underlying neurobiology, behaviors associated with ED, assessment, and targeted intervention. FXS had the most thorough research base, followed by Down syndrome and Prader-Willi syndrome, with the other syndromes having more limited available research. Very limited research was available regarding intervention for all disorders except FXS.

CONCLUSION

Core underlying characteristics of S-IDs appear to place youth at higher risk for ED, but further research is needed to better assess and treat ED in S-IDs. Future studies should have a standard assessment measure of ED, such as the Emotion Dysregulation Inventory, and explore adapting established curricula for ED from the neurotypical and autism spectrum disorder fields.

Consensus recommendations on mental health issues in Phelan-McDermid syndrome

Phelan-McDermid syndrome is a rare genetic condition caused by a deletion encompassing the 22q13.3 region or a pathogenic variant of the gene SHANK3. The clinical presentation is variable, but main characteristics include global developmental delay/intellectual disability (ID), marked speech impairment or delay, along with other features like hypotonia and somatic or psychiatric comorbidities. This publication delineates mental health, developmental and behavioural themes across the lifetime of individuals with PMS as informed by parents/caregivers, experts, and other key professionals involved in PMS care. We put forward several recommendations based on the available literature concerning mental health and behaviour in PMS. Additionally, this article aims to improve our awareness of the importance of considering developmental level of the individual with PMS when assessing mental health and behavioural issues. Understanding how the discrepancy between developmental level and chronological age may impact concerning behaviours offers insight into the meaning of those behaviours and informs care for individuals with PMS, enabling clinicians to address unmet (mental health) care needs and improve quality of life.

Maternal Intake of Polyunsaturated Fatty Acids in Autism Spectrum Etiology and Its Relation to the Gut Microbiota: What Do We Know?

Maternal food habits and gut microbiota composition have potential effects on fetal neurodevelopment, impacting Autism Spectrum Disorder (ASD). Our research aims to outline the relationship that ingestion of polyunsaturated fatty acids (PUFAs) and the composition of maternal gut microbiota have with the possible development of ASD in offspring. We suggest that genetic factors could be related to the different conversions between unsaturated fatty acids according to sex and, mainly, the impact of the pregnancy diet on the higher or lower risk of neurological impairments. The proportion of the phyla Firmicutes/Bacteroidetes is high with an increased consumption of linoleic acid (LA, n-6 PUFA), which is associated with maternal intestinal dysbiosis and consequently starts the inflammatory process, harming myelinization. In contrast, the consumption of α-linolenic acid (ALA, n-3 PUFA) tends to re-establish the balance of the maternal microbiota with anti-inflammatory action. Moreover, human observational studies showed a strong correlation between the consumption of n-3 PUFA, mainly above 340 g of fish per week, with beneficial effects on infant neurodevelopment. Therefore, we suggest that the proper intake of foods rich in n-3 PUFAs and their supplementation during pregnancy until lactation has an impact on reducing the development of ASD. Controlled studies with n-3 PUFA supplementation are still necessary to verify the ideal dose and the best form of administration.

High Performance of a Dominant/X-Linked Gene Panel in Patients with Neurodevelopmental Disorders

Neurodevelopmental disorders (NDDs) affect 2–5% of the population and approximately 50% of cases are due to genetic factors. Since de novo pathogenic variants account for the majority of cases, a gene panel including 460 dominant and X-linked genes was designed and applied to 398 patients affected by intellectual disability (ID)/global developmental delay (GDD) and/or autism (ASD). Pathogenic variants were identified in 83 different genes showing the high genetic heterogeneity of NDDs. A molecular diagnosis was established in 28.6% of patients after high-depth sequencing and stringent variant filtering. Compared to other available gene panel solutions for NDD molecular diagnosis, our panel has a higher diagnostic yield for both ID/GDD and ASD. As reported previously, a significantly higher diagnostic yield was observed: (i) in patients affected by ID/GDD compared to those affected only by ASD, and (ii) in females despite the higher proportion of males among our patients. No differences in diagnostic rates were found between patients affected by different levels of ID severity. Interestingly, patients harboring pathogenic variants presented different phenotypic features, suggesting that deep phenotypic profiling may help in predicting the presence of a pathogenic variant. Despite the high performance of our panel, whole exome-sequencing (WES) approaches may represent a more robust solution. For this reason, we propose the list of genes included in our customized gene panel and the variant filtering procedure presented here as a first-tier approach for the molecular diagnosis of NDDs in WES studies.

Relationship of Nonsteroidal Anti-Inflammatory Drug Use During Pregnancy with Autism Spectrum Disorder and Intellectual Disability Among Offspring

Objective: This study aimed to examine the association of nonsteroidal anti-inflammatory drug (NSAID) use by pregnant women during pregnancy with autism spectrum disorder (ASD) and intellectual disability (ID) in their children among Medicaid-insured mother-child dyads. Materials and Methods: We conducted a retrospective cohort study linking multiple datasets of South Carolina for the years between 2010 and 2017, in which the main exposure variable was NSAID use during pregnancy and outcome variables were ASD only, ID only, and ASD with ID. We conducted a multinomial logistic regression analysis, controlling for identified risk factors for ASD (mother's age, race, body-mass index, preeclampsia, and gestational diabetes). Results: NSAID use during pregnancy was found to be associated with ID only in both unadjusted and adjusted analyses. Children with mothers who had NSAID prescriptions were 26% more likely to have ID in comparison with children whose mothers did not have NSAID prescriptions (odds ratio: 1.26 [1.10-1.46]). The other risk factors identified for ASD were maternal age, race, preeclampsia, smoking, low birth weight, and obesity. For ID, the risk factors were maternal age, race, smoking, birth weight, overweight, and obesity, all of which were also associated with ASD with ID, except for overweight. Conclusions: NSAID usage during pregnancy was found to be associated with ID only and not with ASD. However, more research is needed to validate the effect of NSAIDs during pregnancy on ASD and ID among children.

Prevalence and Disparities in the Detection of Autism Without Intellectual Disability

BACKGROUND

Intellectual ability predicts functional outcomes for children with autism spectrum disorder (ASD). It is essential to classify ASD children with and without intellectual disability (ID) to aid etiological research, provide services, and inform evidence-based educational and health planning.

METHODS

Using a cross-sectional study design, data from 2000 to 2016 active ASD surveillance among 8-year-olds residing in the New York-New Jersey Metropolitan Area were analyzed to determine ASD prevalence with and without ID. Multivariable Poisson regression models were used to identify trends for ASD with ID (ASD-I) and without ID (ASD-N).

RESULTS

Overall, 4661 8-year-olds were identified with ASD. Those that were ASI-I were 1505 (32.3%) and 2764 (59.3%) were ASD-N. Males were 3794 (81.4%), 946 (20.3%) were non-Hispanic Black (Black), 1230 (26.4%) were Hispanic, and 2114 (45.4%) were non-Hispanic white (white). We observed 2-fold and 5-fold increases in the prevalence of ASD-I and ASD-N, respectively, from 2000-2016. Black children were 30% less likely to be identified with ASD-N compared with white children. Children residing in affluent areas were 80% more likely to be identified with ASD-N compared with children in underserved areas. A greater proportion of children with ASD-I resided in vulnerable areas compared with children with ASD-N. Males had higher prevalence compared with females regardless of ID status; however, male-to-female ratios were slightly lower among ASD-I compared with ASD-N cases.

CONCLUSIONS

One-in-3 children with ASD had ID. Disparities in the identification of ASD without ID were observed among Black and Hispanic children as well as among children residing in underserved areas.

Investigating and comparing the psychometric properties of the Chinese Mandarin version of social responsiveness scale-2 and its shortened version in preschool-age children with autism spectrum disorder

We aimed to investigate and compare the psychometric properties of the Chinese Mandarin Social Responsiveness Scale-2 (SRS-2) and its shortened version. The study assessed 670 children with autism spectrum disorder (ASD) aged 30-54 months and 138 typical developmental (TD) children of the same age in mainland China. Our item reliability test revealed that only 36 items of the 65 items in the Chinese Mandarin SRS-2 (Preschool) met the reliability criteria. Moreover, the shortened version of SRS-2 (Preschool) with four subscales and 30 items maintained strong correlations (r = 0.961) with the Chinese Mandarin SRS-2 (Preschool), and demonstrated improved psychometric performance on the 4-week test-retest reliability (intraclass correlations was 0.70), internal consistency (Cronbach's alpha 0.71-0.91), construct validity, and convergent validity with the Autism Diagnostic Observation Schedule, Autism Diagnostic Interview-Revised, and Child Behavior Checklist. Receiver operating characteristics (ROC) analyses showed excellent and comparable discriminant validity of the shortened version with an area under the curve of 0.992. Our data suggested a cutoff ≥ 22.5 for the shortened version, with good accuracy in screening autism symptoms (sensitivity=96.9 %, specificity=94.2 %). Our findings demonstrated that the shortened version of SRS-2 (Preschool) was a reliable and valid instrument for identifying preschoolers with ASD in mainland China.

Diminished activity-dependent BDNF signaling differentially causes autism-like behavioral deficits in male and female mice

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders with strong genetic heterogeneity and more prevalent in males than females. Recent human genetic studies have identified multiple high-risk genes for ASD, which produce similar phenotypes, indicating that diverse genetic factors converge to common molecular pathways. We and others have hypothesized that activity-dependent neural signaling is a convergent molecular pathway dysregulated in ASD. However, the causal link between diminished activity-dependent neural signaling and ASD remains unclear. Brain-derived neurotrophic factor (BDNF) is a key molecule mediating activity-dependent neural signaling. We therefore hypothesize that diminished activity-dependent BDNF signaling could confer autism-like behavioral deficits. Here, we investigated the effect of diminished activity-dependent BDNF signaling on autism-like behavioral deficits by using mice with genetic knock-in of a human BDNF methionine (Met) allele, which has decreased activity-dependent BDNF release without altering basal BDNF level. Compared with wild-type (WT) controls, diminished activity-dependent BDNF signaling similarly induced anxiety-like behaviors in male and female mice. Notably, diminished activity-dependent BDNF signaling differentially resulted in autism-like social deficits and increased self-grooming in male and female mice, and male mice were more severe than female mice. Again, sexually dimorphic spatial memory deficits were observed in female BDNF^+/Met mice, but not in male BDNF^+/Met mice. Our study not only reveals a causal link between diminished activity-dependent BDNF signaling and ASD-like behavioral deficits, but also identifies previously underappreciated sex-specific effect of diminished activity-dependent BDNF signaling in ASD. These mice with genetic knock-in of the human BDNF Met variant provide a distinct mouse model for studying the cellular and molecular mechanisms underlying diminished activity-dependent neural signaling, the common molecular pathway dysregulated in ASD.

Axonal transport deficits in neuropsychiatric disorders

Axonal transport is a major cellular process that mediates bidirectional signaling between the soma and synapse, enabling both intracellular and intercellular communications. Cellular materials, such as proteins, RNAs, and organelles, are transported by molecular motor proteins along cytoskeletal highways in a highly regulated manner. Several studies have demonstrated that axonal transport is central to normal neuronal function, plasticity, and memory storage. Importantly, disruptions in axonal transport result in neuronal dysfunction and are associated with several neurodegenerative disorders. However, we do not know much about axonal transport deficits in neuropsychiatric disorders. Here, we briefly discuss our current understanding of the role of axonal transport in schizophrenia, bipolar and autism.

Integrated gene analyses of de novo variants from 46,612 trios with autism and developmental disorders

Most genetic studies consider autism spectrum disorder (ASD) and developmental disorder (DD) separately despite overwhelming comorbidity and shared genetic etiology. Here, we analyzed de novo variants (DNVs) from 15,560 ASD (6,557 from SPARK) and 31,052 DD trios independently and also combined as broader neurodevelopmental disorders (NDDs) using three models. We identify 615 NDD candidate genes (false discovery rate [FDR] < 0.05) supported by ≥1 models, including 138 reaching Bonferroni exome-wide significance (P < 3.64e-7) in all models. The genes group into five functional networks associating with different brain developmental lineages based on single-cell nuclei transcriptomic data. We find no evidence for ASD-specific genes in contrast to 18 genes significantly enriched for DD. There are 53 genes that show mutational bias, including enrichments for missense (n = 41) or truncating (n = 12) DNVs. We also find 10 genes with evidence of male- or female-bias enrichment, including 4 X chromosome genes with significant female burden (DDX3X, MECP2, WDR45, and HDAC8). This large-scale integrative analysis identifies candidates and functional subsets of NDD genes.

The Clinical Implications of the Academic Performance of the Siblings of Individuals With Autism Spectrum Disorder

We all know that autism spectrum disorder (ASD) can affect academic performance. Many children with autism face different challenges at school. However, less attention is paid to the siblings of autistic children, who are at a high risk of ASD or the broad autism phenotype (BAP). Recent data also shows that many siblings of ASD children suffer from neurodevelopmental disorders, mental health problems as well as poor academic performance. This review will look at the possible etiologies of the poor school performance of autistic children's siblings, with an emphasis on the challenges they face. We will also highlight the clinical implications of these findings, and the possible solutions that can help this vulnerable group.

Strategies for enhancing social skills of individuals with intellectual disability: A systematic review

Individuals with intellectual disability who suffer from comorbid mental health problems are likely to experience difficulties in socialising. Deficits in social skills are also associated with challenging behaviours and self-injury. This paper presents global evidence from a systematic review of literature on such issues as 'interventions'; 'social skills development', and 'individuals with intellectual disability'. A thorough search of various bibliographic databases identified 1 124 academic papers. Ten papers met the inclusion criteria for in-depth analysis concerning the use of interventions to develop social skills among individuals with intellectual disability. The study revealed that the social skills of individuals with intellectual disability had been fostered using different strategies, such as classroom-based intervention, emotional intelligence training, use of a peer network intervention, computer games of emotion regulation, and puppet play therapy. Furthermore, the findings suggest that various aspects like communication, bridging the gap in social skills deficits, emotional recognition and regulation, and adaptive behaviour were fostered using the identified intervention strategy. This review revealed that social skills interventions appeared modestly effective but may not be generalisable to school settings or self-reported social behaviour for individuals with intellectual disability. It is also necessary to increase the sample size in future studies to draw generalisable conclusions.

Prkn knockout mice show autistic-like behaviors and aberrant synapse formation

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with high genetic heterogeneity, affecting one in 44 children in the United States. Recent genomic sequencing studies from autistic human individuals indicate that PARK2, a gene that has long been considered in the pathogenesis of Parkinson's disease, is involved in ASD. Here, we report that Prkn knockout (KO) mice demonstrate autistic-like behaviors including impaired social interaction, elevated repetitive behaviors, and deficits in communication. In addition, Prkn KO mice show reduced neuronal activity in the context of sociability in the prelimbic cortex. Cell morphological examination of layer 5 prelimbic cortical neurons shows a reduction in dendritic arborization and spine number. Furthermore, biochemistry and immunocytochemistry analyses reveal alterations in synapse density and the molecular composition of synapses. These findings indicate that Prkn is implicated in brain development and suggest the potential use of the Prkn KO mouse as a model for autism research.

Tubulinopathy mutations in TUBA1A that disrupt neuronal morphogenesis and migration override XMAP215/Stu2 regulation of microtubule dynamics

Heterozygous, missense mutations in α- or β-tubulin genes are associated with a wide range of human brain malformations, known as tubulinopathies. We seek to understand whether a mutation’s impact at the molecular and cellular levels scale with the severity of brain malformation. Here, we focus on two mutations at the valine 409 residue of TUBA1A, V409I, and V409A, identified in patients with pachygyria or lissencephaly, respectively. We find that ectopic expression of TUBA1A-V409I/A mutants disrupt neuronal migration in mice and promote excessive neurite branching and a decrease in the number of neurite retraction events in primary rat neuronal cultures. These neuronal phenotypes are accompanied by increased microtubule acetylation and polymerization rates. To determine the molecular mechanisms, we modeled the V409I/A mutants in budding yeast and found that they promote intrinsically faster microtubule polymerization rates in cells and in reconstitution experiments with purified tubulin. In addition, V409I/A mutants decrease the recruitment of XMAP215/Stu2 to plus ends in budding yeast and ablate tubulin binding to TOG (tumor overexpressed gene) domains. In each assay tested, the TUBA1A-V409I mutant exhibits an intermediate phenotype between wild type and the more severe TUBA1A-V409A, reflecting the severity observed in brain malformations. Together, our data support a model in which the V409I/A mutations disrupt microtubule regulation typically conferred by XMAP215 proteins during neuronal morphogenesis and migration, and this impact on tubulin activity at the molecular level scales with the impact at the cellular and tissue levels.

Proteins are molecules made up of long chains of building blocks called amino acids. When a mutation changes one of these amino acids, it can lead to the protein malfunctioning, which can have many effects at the cell and tissue level. Given that human proteins are made up of 20 different amino acids, each building block in a protein could mutate to any of the other 19 amino acids, and each mutations could have different effects.

Tubulins are proteins that form microtubules, thin tubes that help give cells their shape and allow them to migrate. These proteins are added or removed to microtubules depending on the cell’s needs, meaning that microtubules can grow or shrink depending on the situation. Mutations in the tubulin proteins have been linked to malformations of varying severities involving the formation of ridges and folds on the surface of the brain, including lissencephaly, pachygyria or polymicrogyria.

Hoff et al. wanted to establish links between tubulin mutations and the effects observed at both cell and tissue level in the brain. They focused on two mutations in the tubulin protein TUBA1A that affect the amino acid in position 409 in the protein, which is normally a valine. One of the mutations turns this valine into an amino acid called isoleucine. This mutation is associated with pachygyria, which leads to the brain developing few ridges that are broad and flat. The second mutation turns the valine into an alanine, and is linked to lissencephaly, a more severe condition in which the brain develops no ridges, appearing smooth.

Hoff et al. found that both mutations interfere with the development of the brain by stopping neurons from migrating properly, which prevents them from forming the folds in the brain correctly. At the cellular level, the mutations lead to tubulins becoming harder to remove from microtubules, making microtubules more stable than usual. This results in longer microtubules that are harder for the cell to shorten or destroy as needed. Additionally, Hoff et al. showed that the mutant versions of TUBA1A have weaker interactions with a protein called XMAP215, which controls the addition of tubulin to microtubules. This causes the microtubules to grow uncontrollably.

Hoff et al. also established that the magnitude of the effects of each mutation on microtubule growth scale with the severity of the disorder they cause. Specifically, cells in which TUBA1A is not mutated have microtubules that grow at a normal rate, and lead to typical brain development. Meanwhile, cells carrying the mutation that turns a valine into an alanine, which is linked to the more severe condition lissencephaly, have microtubules that grow very fast. Finally, cells in which the valine is mutated to an isoleucine – the mutation associated with the less severe malformation pachygyria – have microtubules that grow at an intermediate rate.

These findings provide a link between mutations in tubulin proteins and larger effects on cell movement that lead to brain malformations. Additionally, they also link the severity of the malformation to the severity of the microtubule defect caused by each mutation. Further work could examine whether microtubule stabilization is also seen in other similar diseases, which, in the long term, could reveal ways to detect and treat these illnesses.

Clinical characterization of a novel RAB39B nonstop mutation in a family with ASD and severe ID causing RAB39B downregulation and study of a Rab39b knock down mouse model

Autism spectrum disorder (ASD) and intellectual disability (ID) often exist together in patients. The RAB39B gene has been reported to be mutated in ID patients with additional clinical features ranging from ASD, macrocephaly, seizures and/or early-onset parkinsonism. Here, we describe a novel RAB39B nonstop mutation [Xq28; c.640 T > C; p.(*214Glnext*21)] in a family with ASD, severe ID and poor motor coordination, and we assessed the pathogenicity of the mutation. A heterologous cell system and a Rab39b knockdown (KD) murine model, which mimic the nonstop mutation, were used to validate the deleterious effect of the RAB39B mutation. The mutation led to RAB39B protein instability, resulting in its increased degradation and consequent downregulation. Using a Rab39b KD mouse model, we demonstrated that the downregulation of RAB39B led to increased GluA2 lacking Ca2+-permeable AMPAR composition at the hippocampal neuronal surface and increased dendritic spine density that remained in an immature filopodia-like state. These phenotypes affected behavioural performance in a disease-specific manner. Rab39b KD mice revealed impaired social behaviour but intact social recognition. They also showed normal anxiety-like, exploratory and motivational behaviours but impaired working and associative memories. In conclusion, we found a novel RAB39B nonstop variant that segregated in a family with a clinical phenotype including ID, ASD and poor motor coordination. The pathogenicity of mutations causing the downregulation of RAB39B proteins, impacting AMPAR trafficking and dendritic spine morphogenesis, reinforced the idea that AMPAR modulation and dendritic spine assets could be considered hallmarks of neurodevelopmental disorders.

A homozygous nonsense HECW2 variant is associated with neurodevelopmental delay and intellectual disability

Intellectual disability is characterized by a significant impaired intellectual and adaptive functioning, affecting approximately 1-3% of the population, which can be caused by a variety of environmental and genetic factors. In this respect, de novo heterozygous HECW2 variants were associated recently with neurodevelopmental disorders associated to hypotonia, seizures, and absent language. HECW2 encodes an E3 ubiquitin-protein ligase that stabilizes and enhances transcriptional activity of p73, a key factor regulating proliferation, apoptosis, and neuronal differentiation, which are together essential for proper brain development. Here, using whole exome sequencing, we identified a homozygous nonsense HECW2 variant: c.736C > T; p.Arg246* in a proband from a Moroccan consanguineous family, with developmental delay, intellectual disability, hypotonia, generalized tonico-clonic seizures and a persistent tilted head. Thus this study describes the first homozygous HECW2 variant, inherited as an autosomal recessive pattern, contrasting with former reported de novo variants found in HECW2 patients.

Family quality of life among families who have children with mild intellectual disability associated with mild autism spectrum disorder

BACKGROUND

Intellectual disability (ID) and autism spectrum disorder (ASD) are often concomitant childhood developmental disorders. These disorders can alter family quality of life (FQoL).

OBJECTIVE

To investigate FQoL among families who have children with mild ID, associated with mild ASD.

METHODS

Cross-sectional descriptive study with 69 families who have children with mild ID and ASD, ranging from six to 16 years old, and who were provided with disability-related services in Brazil. Data were collected using a family sociodemographic questionnaire, an ID and ASD personal profile form, the Barthel index for activities of daily living and the Beach Center FQoL scale.

RESULTS

People with ID and ASD had an average score of 88.2±11.5 in the Barthel index, thus indicating moderate dependency in basic activities of daily living. The average total FQoL score (3.56±0.34) was lower than the scores for the "family interaction" (3.91±0.42; p<0.001), "parenting" (3.79±0.35; p<0.001) and "disability-related support" (3.98±0.16; p<0.001) domains; and higher than the scores for the "physical/material well-being" (3.19±0.64; p<0.001) and "emotional wellbeing" (2.75±0.62; p<0.001) domains. Parents' marital condition, monthly family income, family religious practice and effective communication skills among the people with ID and ASD were predictors for FQoL (R2=0.407; p<0.001).

CONCLUSIONS

FQoL was sustained through factors such as family interaction and parents' care for their children. Improving families' emotional wellbeing and physical and material conditions is likely to positively affect the FQoL of these families.

Study of decision-making capacity in Prader-Willi syndrome with a Gambling Task

BACKGROUND

The present study investigated decision-making in patients with Prader-Willi syndrome (PWS) using the Soochow Gambling Task (SGT). The objective was to assess whether adults with PWS have impaired hot executive functions and whether the deficit is specific to PWS or linked to intellectual disabilities.

METHOD

The SGT performance of 26 adults with PWS was compared to that of 26 healthy adults matched on chronological age, and to that of 26 adults with intellectual disabilities but without PWS, matched on intellectual quotient level and chronological age.

RESULTS

The PWS adults showed an absence of learning pattern over trials in the SGT, unlike the healthy individuals, and showed equivalent performances to adults with intellectual disabilities.

CONCLUSIONS

The results suggest a deficit of hot executive functions in PWS, which is linked to intellectual disabilities and not specific to the syndrome.

Childhood infections and autism spectrum disorders and/or intellectual disability: a register-based cohort study

Objective

To explore the associations between childhood infections and subsequent diagnoses of autism spectrum disorder (ASD), intellectual disability (ID), and their co-occurrence.

Methods

The association between specialized care for any infection, defined by ICD-codes, and later ASD or ID was investigated in a register-based cohort of 556,732 individuals born 1987–2010, resident in Stockholm County, followed from birth to their 18th birthday or December 31, 2016. We considered as potential confounders children’s characteristics, family socioeconomic factors, obstetric complications, and parental histories of treatment for infection and psychiatric disorders in survival analyses with extended Cox regression models. Residual confounding by shared familial factors was addressed in sibling analyses using within-strata estimation in Cox regression models. Sensitivity analyses with the exclusion of congenital causes of ASD/ID and documented risk for infections were also performed.

Results

Crude estimates indicated that infections during childhood were associated with later ASD and ID with the largest risks observed for diagnoses involving ID. Inclusion of covariates, exclusion of congenital causes of ASD/ID from the population, and sibling comparisons highlighted the potential for confounding by both heritable and non-heritable factors, though risks remained in all adjusted models. In adjusted sibling comparisons, excluding congenital causes, infections were associated with later “ASD without ID” (HR 1.24, 95%CI 1.15–1.33), “ASD with ID” (1.57, 1.35–1.82), and “ID without ASD” (2.01, 1.76–2.28). Risks associated with infections varied by age at exposure and by age at diagnosis of ASD/ID.

Conclusions

Infections during childhood may contribute to a later diagnosis of ID and ASD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09422-4.

Therapeutic Alliance in Cognitive Behavioural Therapy in Child and Adolescent Mental Health-Current Trends and Future Challenges

This extended literature review proposes to present the trends in the therapeutic alliance, outcomes, and measures in the last decade within the premises of individual cognitive behaviour therapy (CBT) and its innovations, used as an interventional measure in the context of child and adolescent mental health setting. A brief background of the rationale for conducting this literature search is presented at the start. This is followed by the methodology and design which incorporates the inclusion and exclusion criteria and the basis for the same. The critical appraisal of the primary studies is presented in the literature review section with a brief description of the summary features of the studies in the study tables followed by the results and discussion of the study findings. To summarise, the literature review of primary studies conducted in the last decade demonstrates the need for further research to be conducted both in the field of CBT in children and therapeutic alliance, competence, and therapy outcomes, integrating perspectives in child development, carer alliance, and the social construct theory in children, to allow for further innovations in CBT in the context of increasing challenges in the current times of exponentially developing technology and its utility without compromising the quality of therapy. In conclusion, recommendations are made as a guideline for future studies and research in this field.

Disrupted Mitochondrial Network Drives Deficits of Learning and Memory in a Mouse Model of FOXP1 Haploinsufficiency

Reduced cognitive flexibility, characterized by restricted interests and repetitive behavior, is associated with atypical memory performance in autism spectrum disorder (ASD), suggesting hippocampal dysfunction. FOXP1 syndrome is a neurodevelopmental disorder characterized by ASD, language deficits, global developmental delay, and mild to moderate intellectual disability. Strongly reduced Foxp1 expression has been detected in the hippocampus of Foxp1+/- mice, a brain region required for learning and memory. To investigate learning and memory performance in these animals, fear conditioning tests were carried out, which showed impaired associative learning compared with wild type (WT) animals. To shed light on the underlying mechanism, we analyzed various components of the mitochondrial network in the hippocampus. Several proteins regulating mitochondrial biogenesis (e.g., Foxo1, Pgc-1α, Tfam) and dynamics (Mfn1, Opa1, Drp1 and Fis1) were significantly dysregulated, which may explain the increased mitophagy observed in the Foxp1+/- hippocampus. The reduced activity of complex I and decreased expression of Sod2 most likely increase the production of reactive oxygen species and the expression of the pre-apoptotic proteins Bcl-2 and Bax in this tissue. In conclusion, we provide evidence that a disrupted mitochondrial network and the resulting oxidative stress in the hippocampus contribute to the altered learning and cognitive impairment in Foxp1+/- mice, suggesting that similar alterations also play a major role in patients with FOXP1 syndrome.

Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses

Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.

New Candidates for Autism/Intellectual Disability Identified by Whole-Exome Sequencing

Intellectual disability (ID) is characterized by impairments in the cognitive processes and in the tasks of daily life. It encompasses a clinically and genetically heterogeneous group of neurodevelopmental disorders often associated with autism spectrum disorder (ASD). Social and communication abilities are strongly compromised in ASD. The prevalence of ID/ASD is 1–3%, and approximately 30% of the patients remain without a molecular diagnosis. Considering the extreme genetic locus heterogeneity, next-generation sequencing approaches have provided powerful tools for candidate gene identification. Molecular diagnosis is crucial to improve outcome, prevent complications, and hopefully start a therapeutic approach. Here, we performed parent–offspring trio whole-exome sequencing (WES) in a cohort of 60 mostly syndromic ID/ASD patients and we detected 8 pathogenic variants in genes already known to be associated with ID/ASD (SYNGAP1, SMAD6, PACS1, SHANK3, KMT2A, KCNQ2, ACTB, and POGZ). We found four de novo disruptive variants of four novel candidate ASD/ID genes: MBP, PCDHA1, PCDH15, PDPR. We additionally selected via bioinformatic tools many variants in unknown genes that alone or in combination can contribute to the phenotype. In conclusion, our data confirm the efficacy of WES in detecting pathogenic variants of known and novel ID/ASD genes.