Developmental Variability in Autism Across 17 000 Autistic Individuals and 4000 Siblings Without an Autism Diagnosis: Comparisons by Cohort, Intellectual Disability, Genetic Etiology, and Age at Diagnosis

Multiparametric Assays Capture Sex- and Environment-Dependent Modifiers of Behavioral Phenotypes in Autism Mouse Models

Background

Current phenotyping approaches for murine autism models often focus on one selected behavioral feature, making the translation onto a spectrum of autistic characteristics in humans challenging. Furthermore, sex and environmental factors are rarely considered. Here, we aimed to capture the full spectrum of behavioral manifestations in 3 autism mouse models to develop a "behavioral fingerprint" that takes environmental and sex influences under consideration.

Methods

To this end, we employed a wide range of classical standardized behavioral tests and 2 multiparametric behavioral assays-the Live Mouse Tracker and Motion Sequencing-on male and female Shank2, Tsc1, and Purkinje cell-specific Tsc1 mutant mice raised in standard or enriched environments. Our aim was to integrate our high dimensional data into one single platform to classify differences in all experimental groups along dimensions with maximum discriminative power.

Results

Multiparametric behavioral assays enabled a more accurate classification of experimental groups than classical tests, and dimensionality reduction analysis demonstrated significant additional gains in classification accuracy, highlighting the presence of sex, environmental, and genotype differences in our experimental groups.

Conclusions

Together, our results provide a complete phenotypic description of all tested groups, suggesting that multiparametric assays can capture the entire spectrum of the heterogeneous phenotype in autism mouse models.

Postnatal outcome of fetal cortical malformations: systematic review

OBJECTIVE

Parental counseling for fetal malformations of cortical development (MCD) is based on data from studies in children and adults undergoing imaging investigation for abnormal neurodevelopment. However, such postnatal findings may not be applicable to prenatally diagnosed cases. The aim of this study was to review the existing data on postnatal neurodevelopmental outcome for fetuses diagnosed with MCD.

METHODS

A literature search was conducted in PubMed, Web of Science and EMBASE for articles published between 2013 and 2023, using standardized keywords to describe fetal cortical malformations. Full-text articles were accessed for the retrieved citations and data on participant characteristics, imaging findings, and pregnancy and neonatal outcomes were extracted. Fetal MCD was defined as either complex or isolated, according to the presence or absence, respectively, of additional brain or extracranial defects.

RESULTS

Overall, 30 articles including 371 cases of fetal MCD were reviewed. The cases were classified as complex (n = 324), isolated (n = 21) or unknown (n = 26). There were 144 terminations and four stillbirths, with pregnancy outcome unreported in 149 cases. A total of 108 cases had postnatal magnetic resonance imaging or postmortem examination data available. In nine of these cases, a diagnosis of complex fetal MCD was changed to isolated MCD after birth, and one case was found not to have MCD. There were 74 live births, for which postnatal neurodevelopment data were available in only 30 cases. Normal neurodevelopmental outcome was reported in seven (23.3% (95% CI, 9.9-42.2%)) infants, with the remaining 23 exhibiting various levels of neurodevelopmental delay (three mild, seven moderate and 13 severe) from 6 months to 7 years of age.

CONCLUSIONS

Most reviewed cases of fetal MCD were complex in nature and underwent termination of pregnancy. There is a paucity of data on postnatal neurological development in fetuses diagnosed with MCD. The available data suggest antenatal overdiagnosis of case severity in about 5% of cases with known outcome, and either normal neurodevelopment or mild neurodevelopmental delay in approximately one-third of liveborn cases with neurological follow-up. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Integrating genomic variants and developmental milestones to predict cognitive and adaptive outcomes in autistic children

Although the first signs of autism are often observed as early as 18-36 months of age, there is a broad uncertainty regarding future development, and clinicians lack predictive tools to identify those who will later be diagnosed with co-occurring intellectual disability (ID). Here, we developed predictive models of ID in autistic children (n=5,633 from three cohorts), integrating different classes of genetic variants alongside developmental milestones. The integrated model yielded an AUC ROC=0.65, with this predictive performance cross-validated and generalised across cohorts. Positive predictive values reached up to 55%, accurately identifying 10% of ID cases. The ability to stratify the probabilities of ID using genetic variants was up to twofold greater in individuals with delayed milestones compared to those with typical development. These findings underscore the potential of models in neurodevelopmental medicine that integrate genomics and clinical observations to predict outcomes and target interventions.

Early developmental milestone clusters of autistic children based on electronic health records

Autistic children vary in symptoms, co-morbidities, and response to interventions. This study aimed to identify clusters of autistic children with a distinct pattern of attaining early developmental milestones (EDMs). The clustering of 5836 autistic children was based on the attainment of 43 gross motor, fine motor, language, and social developmental milestones during the first 3 years of life as recorded in baby wellness visits. K-means cluster analysis detected four EDM clusters: mild (n = 1686); moderate (n = 1691); severe (n = 2265); and global (n = 194). The most prominent cluster differences were in the language domain. The global cluster showed earlier and greater developmental delay across domains, unique early gross motor delays, and more were born preterm via cesarean section. The severe cluster had poor language development prominently in the second year of life, and later fine motor delays. Moderate cluster had mainly language delays in the third year of life. The mild cluster mostly passed milestones. EDM clusters differed demographically, with higher socioeconomic status in mild cluster and lowest in global cluster. However, the severe cluster had more immigrant and non-Jewish mothers followed by the moderate cluster. The rates of parental concerns and provider developmental referrals were significantly higher in the global, followed by the severe, moderate, and mild EDM clusters. Autistic children's language and motor delay in the first 3 years can be grouped by common magnitude and onset profiles as distinct groups that may link to specific etiologies (like prematurity or genetics) and specific intervention programs. Early autism screening should be tailored to these different developmental profiles.

The neurobiological mechanisms underlying the effects of exercise interventions in autistic individuals

Autism spectrum disorder is a pervasive and heterogeneous neurodevelopmental condition characterized by social communication difficulties and rigid, repetitive behaviors. Owing to the complex pathogenesis of autism, effective drugs for treating its core features are lacking. Nonpharmacological approaches, including education, social-communication, behavioral and psychological methods, and exercise interventions, play important roles in supporting the needs of autistic individuals. The advantages of exercise intervention, such as its low cost, easy implementation, and high acceptance, have garnered increasing attention. Exercise interventions can effectively improve the core features and co-occurring conditions of autism, but the underlying neurobiological mechanisms are unclear. Abnormal changes in the gut microbiome, neuroinflammation, neurogenesis, and synaptic plasticity may individually or interactively be responsible for atypical brain structure and connectivity, leading to specific autistic experiences and characteristics. Interestingly, exercise can affect these biological processes and reshape brain network connections, which may explain how exercise alleviates core features and co-occurring conditions in autistic individuals. In this review, we describe the definition, diagnostic approach, epidemiology, and current support strategies for autism; highlight the benefits of exercise interventions; and call for individualized programs for different subtypes of autistic individuals. Finally, the possible neurobiological mechanisms by which exercise improves autistic features are comprehensively summarized to inform the development of optimal exercise interventions and specific targets to meet the needs of autistic individuals.

Profiles of minimally verbal autistic children: Illuminating the neglected end of the spectrum

Heterogeneity among individuals on the autism spectrum is widely acknowledged as a barrier to develop effective interventions. Overcoming this challenge requires characterization of individual differences, especially for children that are minimally verbal and often excluded from research studies. Most studies that describe autistic subgroups identify a single minimally verbal verbal group based on a single identifying measure (e.g., ADOS module one or single item indicating absence of phrase speech). Determining personalized courses of intervention requires a more detailed understanding since a single intervention will not be effective for all who are minimally verbal. The present study identified comprehensive profiles of cognitive, language, and social communication skills within a large, diverse, group of minimally verbal children with autism. The analysis combined baseline data from two studies to yield a sample of 344 participants, who were 3 to 8 years old at the time of study onset, with 60% who identified as having a race/ethnicity other than White. Via latent profile analysis (LPA), a three-group model was identified as best fit to the data. Profile identification was dependent on a participant's combination of cognitive, expressive, and social communication characteristics, rather than a single domain. One group (n = 206) had global delays, while the other two groups (n = 95 and n = 43) had variable strengths in cognition and communication. Findings suggest that low-frequency/minimally verbal communicators with autism have heterogeneous characteristics that can be systematically organized.

A systematic review of self and observer assessment of pain and related functioning in youth with brain-based developmental disabilities

ABSTRACT

Pain experiences of youth with brain-based developmental disabilities are often overlooked and/or misinterpreted, increasing the risk for poor or inadequate pain assessment and management. Ample measures exist to assess acute and chronic pain, yet their utility and frequency of use in youth with brain-based developmental disabilities is unclear and available measures do not have strong measurement properties for this diverse group. This systematic review identified the scope of self-reported and observer-reported pain assessment in studies of youth (aged 3-24 years) with brain-based developmental disabilities (phase 1) and summarized other measures of pain-related functioning for acute and chronic pain (ie, physical, emotional, social, sleep, and quality of life, within the subset of quantitative studies focused primarily on pain, phase 2). A comprehensive search for English-language studies was conducted in August 2022 in Web of Science, CINAHL, MEDLINE, Cochrane CENTRAL, EMBASE, and APA PsychINFO (PROSPERO registration: CRD42021237444). A total of 17,029 unique records were screened. Of the 707 articles included in phase 1, most assessed chronic pain (n = 314; 62.0%) and primarily used observer-report (n = 155; 31%) over self-report (n = 67; 13%). Of the 137 articles included in phase 2, other outcomes assessed alongside pain intensity included motor ability (16.8%), adaptive functioning (11%), quality of life (8%), pain interference (6.6%), mental health (5.8%), and communication ability (2.9%). Cerebral palsy was the most common population in both phase 1 (n = 343; 48.5%) and phase 2 (n = 83; 59.7%). This review provides a foundational understanding of pain assessment in brain-based developmental disabilities and highlights continued inequities in holistic pain assessment for this population.

Risky driving behavior among individuals with Autism, ADHD, and typically developing persons

INTRODUCTION

Many individuals with Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) often experience difficulty with driving, including difficulty with obtaining a driver's license as well as driving safely and efficiently. Such difficulties negatively impact their ability to function independently and participate in daily activities that require driving. ASD and ADHD commonly occur co-morbidly and share many overlapping clinical features. Few studies have directly compared the nature of difficulties in driving safety outcomes between ASD and ADHD. The overarching goal of the current study was to characterize and compare self-reported driving behavior among young autistic drivers, ADHD drivers, and typically developing (TD) drivers.

METHOD

Fifty-four participants (14 ASD, 20 ADHD, 20 TD); ages 16-30) completed the Autism Spectrum Quotient and ADHD Adult Rating scale as a method of screening of symptoms. All three groups then completed the Driving Behavior Questionnaire (DBQ), which measured self-reported driving violations, driving errors, and overall risky driving behavior. The three groups of ASD, ADHD, and TD individuals were then compared regarding symptomology and driving behavior differences.

RESULTS

One-way ANOVAs indicated group differences in DBQ total scores and DBQ errors. Drivers with ADHD reported significantly greater overall risky driving behaviors and driving errors compared to ASD and TD drivers. There were no significant differences between ASD and TD drivers in reported risky driving behaviors and errors. Linear regressions indicated that among all drivers, self-reported ADHD symptoms were significantly associated with higher levels of self-reported overall risky driving and driving errors, regardless of diagnostic group.

DISCUSSION

Risky driving and driving errors may be more closely related to symptoms that are characteristic of ADHD. This has implications for individuals with ADHD and autistic individuals who often show or report higher rates of ADHD symptoms. Future studies should compare driving skills of ASD and ADHD drivers using objective measures of driving performance, such as driving simulators or on-road tests.

Zebrafish (Danio rerio) as a translational model for neuro-immune interactions in the enteric nervous system in autism spectrum disorders

Autism spectrum disorders (ASD) affect about 1% of the population and are strongly associated with gastrointestinal diseases creating shortcomings in quality of life. Multiple factors contribute to the development of ASD and although neurodevelopmental deficits are central, the pathogenesis of the condition is complex and the high prevalence of intestinal disorders is poorly understood. In agreement with the prominent research establishing clear bidirectional interactions between the gut and the brain, several studies have made it evident that such a relation also exists in ASD. Thus, dysregulation of the gut microbiota and gut barrier integrity may play an important role in ASD. However, only limited research has investigated how the enteric nervous system (ENS) and intestinal mucosal immune factors may impact on the development of ASD-related intestinal disorders. This review focuses on the mechanistic studies that elucidate the regulation and interactions between enteric immune cells, residing gut microbiota and the ENS in models of ASD. Especially the multifaceted properties and applicability of zebrafish (Danio rerio) for the study of ASD pathogenesis are assessed in comparison to studies conducted in rodent models and humans. Advances in molecular techniques and in vivo imaging, combined with genetic manipulation and generation of germ-free animals in a controlled environment, appear to make zebrafish an underestimated model of choice for the study of ASD. Finally, we establish the research gaps that remain to be explored to further our understanding of the complexity of ASD pathogenesis and associated mechanisms that may lead to intestinal disorders.

Prototypical autism: New diagnostic criteria and asymmetrical bifurcation model

The current "autism spectrum" DSM 5 diagnostic criteria and autism standardized diagnostic instruments promote considerable heterogeneity or clinical indecision and may be detrimental to the advancement of fundamental research on autism mechanisms. To increase clinical specificity and reorient research towards core autistic presentations, we propose new diagnostic criteria for prototypical autism during the age of 2- to 5-years. We include autism within other non-dominant, familiarly aggregated phenomena sharing asymmetrical developmental bifurcations, such as twin pregnancy, left handedness, and breech presentation/delivery. Following this model, nature, trajectory, and positive/negative signs structure of autism would result from the polarized problem of whether or not language and information is processed in a socially biased manner. Prototypical autism would follow a canonical developmental trajectory by which a gradual decline in social bias in the processing of incoming information, overtly beginning at the end of the first year, bifurcates into a prototypical autistic presentation in the second half of the second year of life. This bifurcation event is followed by a plateau, in which these atypicalities show maximal stringency and distinctiveness, and then ultimately, in most cases, by partial normalization. During the plateau period, the orientation towards, and processing of, information is considerably modified, with an absence of bias for social information, contrasting with a high level of interest in complex, unbiased information, independently of its social or non-social nature. Integrating autism into asymmetrical developmental bifurcations would explain the absence of deleterious neurological and genetic markers and the presence of familial transmission in canonical autistic presentations.

Diagnostic delay in children with neurodevelopmental conditions attending a publicly funded developmental assessment service: findings from the Sydney Child Neurodevelopment Research Registry

OBJECTIVES

Early developmental assessment is crucial for effective support and intervention. This study examined factors that contribute to (a) older child age when caregivers first became concerned about their child's development and (b) older child age at the point of entry into developmental and diagnostic assessment. We also quantified how factors contributed to risk of children not receiving an assessment by 5 years and considered the acceptability of electronic data capture for families.

DESIGN

This cross-sectional study collected information about caregiver developmental concerns, family history and child characteristics.

SETTING

Children and families entered a large, publicly funded hospital-based paediatric developmental assessment service.

PARTICIPANTS

Consecutively enrolled children (N=916) aged 6 months to 17 years with neurodevelopmental concerns and their caregivers.

MAIN OUTCOMES AND MEASURES

A developmental history questionnaire completed by caregivers.

RESULTS

The average age that caregivers identified developmental concerns was 3.0 years of age but the average age of a receiving a developmental assessment was 6.6 years. Only 46.4% of children received a diagnostic assessment by 5 years of age, even though 88.0% of caregivers were concerned about their child's development by that age. Parental age, relationship status, education level, prior use of support services and being from a culturally and linguistically diverse background contributed to age at identification of concern, age at diagnostic assessment and the likelihood of receiving a diagnostic assessment by 5 years. Electronic data capture had high acceptability, with 88.2% of caregivers reporting a preference for electronic completion of questionnaires.

CONCLUSIONS

The study shows a substantial delay in diagnostic assessments that leaves most vulnerable children without an assessment by school age and highlights contributors to delays. These delays highlight the complexity of delivering early intervention and support policies that rely on swift and appropriate developmental assessment to vulnerable families.

Heterogeneity thwarts autism explanatory power: A proposal for endophenotypes

Many researchers now believe that autism heterogeneity is likely to include many disorders, but most research is based on samples defined by the DSM-5 Autism Spectrum Disorder (ASD) criteria. However, individuals diagnosed with autism have complex and varied biological causes for their symptoms. Therefore, autism is not a unitary biological entity. And although autism is significantly different from typical development, autism is not a unitary clinical disorder because diagnosed individuals vary in symptom patterns, comorbidities, biomarkers, and gene variants. The DSM-5 ASD criteria were designed to reduce heterogeneity, and there have been many other efforts to reduce autism heterogeneity including using more stringent clinical criteria, dividing autism into low and high functioning groups, creating subgroups, and by studying larger samples. However, to date these efforts have not been successful. Heterogeneity is extensive and remains unexplained, and no autism pathophysiology has been discovered. Most importantly, heterogeneity has hindered the explanatory power of the autism diagnosis to discover drug regimens and effective behavioral treatments. The paper proposes that possible transdiagnostic endophenotypes may reduce autism heterogeneity. Searching for transdiagnostic endophenotypes requires exploring autism symptoms outside of the framework of the DSM-5 autism diagnosis. This paper proposes that researchers relax diagnostic criteria to increase the range of phenotypes to support the search for transdiagnostic endophenotypes. The paper proposes possible candidates for transdiagnostic endophenotypes. These candidates are taken from DSM-5 ASD criteria, from concepts that have resulted from researched theories, and from symptoms that are the result of subtyping. The paper then sketches a possible basis for a future transdiagnostic endophenotypes screening tool that includes symptoms of autism and other neurodevelopmental disorders.