Journal of Neurodevelopmental Disorders

Background3q29 deletion syndrome (3q29del) is associated with a significantly increased risk for neurodevelopmental and neuropsychiatric phenotypes. Mild to moderate intellectual disability (ID) is common in this population, and previous work by our team identified substantial deficits in adaptive behavior. However, the full profile of adaptive function in 3q29del has not been described, nor has it been compared to other genomic syndromes associated with elevated risk for neurodevelopmental and neuropsychiatric phenotypes. MethodsIndividuals with 3q29del (n=32, 62.5% male) were evaluated using the Vineland Adaptive Behavior Scales, Third Edition, Comprehensive Parent/Caregiver Form (Vineland-3). We explored the relationship between adaptive behavior and cognitive function, executive function, and neurodevelopmental and neuropsychiatric comorbidities in our 3q29del study sample, and we compared subjects with 3q29del to published data on Fragile X syndrome, 22q11.2 deletion syndrome, and 16p11.2 deletion and duplication syndromes. ResultsIndividuals with 3q29del had global deficits in adaptive behavior that were not driven by specific weaknesses in any given domain. Individual neurodevelopmental and neuropsychiatric diagnoses had a small effect on adaptive behavior, and the cumulative number of comorbid diagnoses was significantly negatively associated with Vineland-3 performance. Both cognitive ability and executive function were significantly associated with adaptive behavior, and executive function was a better predictor of Vineland-3 performance than cognitive ability. Finally, the severity of adaptive behavior deficits in 3q29del was distinct from previously published data on comparable genomic disorders. ConclusionsIndividuals with 3q29del have significant deficits in adaptive behavior, affecting all domains assessed by the Vineland-3. Executive function is a better predictor of adaptive behavior than cognitive ability in this population and suggests that interventions targeting executive function may be an effective therapeutic strategy.

Some toddlers with autism spectrum disorder (ASD) have mild social symptoms and developmental improvement in skills, but for others, symptoms and abilities are moderately or even severely affected. Those with profound autism have the most severe social, language, and cognitive symptoms and are at the greatest risk of having a poor developmental outcome. The little that is known about the underlying biology of this important profound autism subtype, points clearly to embryonic dysregulation of proliferation, differentiation and neurogenesis. Because it is essential to gain foundational knowledge of the molecular biology associated with profound, moderate, and mild autism clinical subtypes, we used well-validated, data-driven patient subtyping methods to integrate clinical and molecular data at 1 to 3 years of age in a cohort of 363 ASD and controls representative of the general pediatric population in San Diego County. Clinical data were diagnostic, language, cognitive and adaptive ability scores. Molecular measures were 50 MSigDB Hallmark gene pathway activity scores derived from RNAseq gene expression. Subtyping identified four ASD, typical and mixed diagnostic clusters. 93% of subjects in one cluster were profound autism and 93% in a different cluster were control toddlers; a third cluster was 76% moderate ability ASD; and the last cluster was a mix of mild ASD and control toddlers. Among the four clusters, the profound autism subtype had the most severe social symptoms, language, cognitive, adaptive, social attention eye tracking, social fMRI activation, and age-related decline in abilities, while mild autism toddlers mixed within typical and delayed clusters had mild social symptoms, and neurotypical language, cognitive and adaptive scores that improved with age compared with profound and moderate autism toddlers in other clusters. In profound autism, 7 subtype-specific dysregulated gene pathways were found; they control embryonic proliferation, differentiation, neurogenesis, and DNA repair. To find subtype-common dysregulated pathways, we compared all ASD vs TD and found 17 ASD subtype-common dysregulated pathways. These common pathways showed a severity gradient with the greatest dysregulation in profound and least in mild. Collectively, results raise the new hypothesis that the continuum of ASD heterogeneity is moderated by subtype-common pathways and the distinctive nature of profound autism is driven by the differentially added profound subtype-specific embryonic pathways.

BackgroundThe 1.6 Mb 3q29 deletion is associated with neurodevelopmental and neuropsychiatric phenotypes, including a 19-fold increased risk for autism spectrum disorder (ASD). Previous work by our team identified elevated social disability in this population via parent-report questionnaires. However, clinical features of ASD in this population have not been explored in detail. Methods31 individuals with 3q29 deletion syndrome (3q29del, 61.3% male) were evaluated using two gold-standard clinical ASD evaluations: the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) and the Autism Diagnostic Interview, Revised (ADI-R). Four matched comparators for each subject were ascertained from the National Database for Autism Research. Item-level scores on the ADOS-2 and ADI-R were compared between subjects with 3q29del and matched comparators. ResultsSubjects with 3q29del and no ASD (3q29del-ASD) had greater evidence of social disability compared to typically developing (TD) comparison subjects across the ADOS-2. Subjects with 3q29del and ASD (3q29del+ASD) were largely indistinguishable from non-syndromic ASD (nsASD) subjects on the ADOS-2. 3q29del+ASD performed significantly better on social communication on the ADI-R than nsASD (3q29+ASD mean = 11.36; nsASD mean = 15.70; p = 0.01), and this was driven by reduced deficits in nonverbal communication (3q29+ASD mean = 1.73; nsASD mean = 3.63; p = 0.03). 3q29del+ASD reported significantly later age at first two-word phrase compared to nsASD (3q29del+ASD mean = 43.89 months; nsASD mean = 37.86 months; p = 0.01). However, speech delay was not related to the improved nonverbal communication in 3q29del+ASD. LimitationsThere were not enough TD comparators with ADI-R data in NDAR to include in the present analysis. Additionally, our relatively small sample size made it difficult to assess race and ethnicity effects. Conclusions3q29del is associated with significant social disability, irrespective of ASD diagnosis. 3q29del+ASD have similar levels of social disability to nsASD, while 3q29del-ASD have significantly increased social disability compared to TD individuals. However, social communication is reasonably well-preserved in 3q29del+ASD relative to nsASD. It is critical that verbal ability and social disability be examined separately in this population to ensure equal access to ASD and social skills evaluations and services.

Infants born preterm are at a significantly higher likelihood of having autism spectrum disorder (ASD). Preterm birth and ASD are both associated with neurological differences, notably autonomic nervous system (ANS) dysfunction, pointing to preterm ANS dysfunction as a potential pathway to ASD, particularly in VPT infants. In this study, a subset of very preterm (VPT) infants enrolled in a large, multisite clinical trial were enrolled in this study at birth (N=20). Continuous measures of minute-by-minute thermal gradients, defined by the difference between central and peripheral temperatures, and hour-by-hour abnormal heart rate characteristics (HRCs) were collected from birth-28 days (>40,000 samples/infant). Following NICU discharge, standardized measures of cognition, language, and motor skills were collected at adjusted ages 6, 9, and 12 months. At 12 months, assessments of social communication and early ASD symptoms were administered. Results suggest significant ASD concerns for half of the sample by 12 months of age. Neonatal abnormal HRCs were strongly associated with 12-month ASD symptoms (r=0.81, p<.01), as was birth gestational age (GA), birth weight (BW), and abnormal negative thermal gradients. ANS measures collected in the first month of neonatal life, more than a year prior to the ASD evaluation, were surprisingly strong predictors of ASD. This study highlights complementary ANS measures that describe how ANS dysfunction, likely resulting from an imbalance between the parasympathetic and sympathetic systems, may impact very early regulatory processes for neonates who later develop ASD. This finding offers a promising avenue for researching ANS-related etiological mechanisms and biomarkers of ASD.

IntroductionFragile X Syndrome (FXS), caused by Fmr1 mutations, is linked to cognitive and behavioral differences, including altered social interactions. Most mouse studies focus on adults, despite human research showing critical developmental changes in childhood and adolescence. We examined social behavior in juvenile male and female Fmr1 knockout (KO) mice as well as heterozygous (HET) females. We further assessed cortical activity in KO females to better understand early phenotypes. MethodsJuvenile mice of both sexes and genotypes were paired in same-sex, novel dyads for 10-minute interactions. Key social behaviors such as head, anogenital, and body sniffing, and physical touch, as well as distance travelled, were analyzed with a marker-less tracking software. Frontal-parietal EEG recordings were collected from wild-type (WT) and KO females in home cage and social contexts to analyze power spectra across frequency bands. ResultsHET and KO females engaged in more frequent but shorter interaction events compared to WT females, with HET females showing the highest counts. Males displayed similar trends when comparing KO and WT. Males engaged in overall higher interaction events than females. EEG analyses revealed altered oscillatory activity in KO females compared to WT females, especially within theta, alpha, and beta bands, most prominently during the early interaction phase. Locomotor activity correlated weakly with head/anogenital sniffing but more strongly with body sniffing and touch. DiscussionThese findings suggest that Fmr1-related differences in juvenile social behavior are sex-dependent and associated with cortical oscillatory changes. Characterizing these early phenotypes in both sexes allows us to further understand FXS development and informs potential routes for early intervention. Key PointsO_LIFragile X Syndrome (FXS), the leading inherited cause of autism, is associated with disruptions in social behavior. C_LIO_LIWhile social phenotypes are relatively well described in adult mouse models of FXS, juvenile manifestations remain poorly understood. C_LIO_LISocial behavior was assessed in juvenile male and female Fmr1 knockout (KO), heterozygous (HET, female only), and wildtype (WT) mice, and frontal-parietal EEG recordings were collected from WT and KO females. C_LIO_LIHET and KO females exhibited more frequent but shorter social interactions than WT females, with HET showing the greatest number of events. Males showed similar patterns when comparing KO and WT. Males engaged in higher overall interaction events than females. EEG recordings revealed altered oscillatory activity in KO compared to WT females, most pronounced during the early phase of social encounter. C_LIO_LIThese findings reveal sex- and genotype-dependent differences in juvenile social behavior and cortical activity, highlighting the importance of studying juvenile development in FXS. C_LI

Facial attractiveness plays a central role in first impressions, social interactions, and romantic relationships, yet remains difficult to quantify objectively due to its subjective and socially shaped nature. In the present study, we examined whether facial attractiveness and its modulation by social information can be captured using functional infrared thermal imaging (fITI). Participants rated the attractiveness of faces that were randomly preceded by an autism label. Although such labels influenced explicit attractiveness judgments, particularly among male participants, they did not modulate facial thermal responses. Instead, nose temperature systematically increased or decreased when participants rated faces as attractive or unattractive, respectively. Notably, temperature differences emerged several seconds after image onset, and for female faces, mean attractiveness ratings positively correlated with changes in nose temperature. Together, these findings reveal a dissociation between socially shaped explicit evaluations and autonomic physiological responses, highlighting the potential of fITI as a fully non-invasive tool for capturing implicit affective engagement with facial attractiveness.

Overgrowth intellectual disability syndromes (OGIDs) caused by mutations in the PI3K-AKT-MTOR pathway present significant neurobehavioral challenges. While PTEN Hamartoma Tumor Syndrome (PHTS) has been behaviorally characterized, Smith-Kingsmore Syndrome (SKS) has not, limiting our understanding of shared and unique features across OGIDs. We conducted comprehensive neurobehavioral assessments in 17 individuals with SKS and compared them to previously characterized cohorts with PHTS (n=74), macrocephaly-associated autism (n=33), and healthy controls (n=32). Assessments included standardized measures of motor coordination, adaptive functioning, social interaction, and executive functioning. We performed genotype-phenotype correlation analyses and developed diagnostic classification models using recursive partitioning. Individuals with SKS showed significant impairments across multiple domains compared to controls. Compared to the PTEN-ASD group, SKS individuals demonstrated particularly severe deficits in motor coordination and adaptive functioning, while executive functioning and behavioral regulation were similarly impaired. Novel clinical features were identified, including immune dysregulation and chronic constipation in SKS, and notably high rates of neonatal teeth (44.7%) in PHTS. Diagnostic classification models incorporating both behavioral and medical features achieved above-chance accuracy in distinguishing between conditions, with neonatal teeth emerging as a key distinguishing feature for PHTS. Domain-specific analyses showed variants in the PTEN phosphatase domain were associated with more severe social and executive function deficits compared to C2 domain variants. Correlation analyses between variant pathogenicity scores and clinical measures revealed limited consistent associations, though Combined Annotation Dependent Depletion (CADD) scores showed stable correlations with sensory processing measures across cohorts. Our findings establish distinct neurobehavioral profiles between SKS and PHTS, suggesting different impacts of MTOR versus PTEN mutations on neural circuit development. The identification of novel phenotypic features expands the clinical spectrum of these disorders and provides new diagnostic markers. The limited predictive value of variant pathogenicity scores for neurobehavioral outcomes emphasizes the need for comprehensive individual assessments. These results provide a foundation for developing targeted interventions while highlighting the complexity of genotype-phenotype relationships in PI3K-AKT-MTOR pathway disorders.

People with autism spectrum disorder (ASD) frequently exhibit challenging behaviors throughout the lifespan, which can have pervasive effects on quality of life. Challenging behaviors have been shown to change over time as a function of various individual-level factors (e.g., cognitive ability), yet research is primarily limited to parent-reported measures. To expand upon this work, the present study aimed to examine trajectories of teacher- and parent-reported challenging behaviors (i.e., hyperactivity, irritability, social withdrawal) and to test whether predictors including ASD features, verbal intelligence quotient, and consistency in reporter impact these trajectories among individuals with ASD or non-spectrum delays from ages 9 to 18. Multilevel models revealed that, according to both teacher and parent report, participants showed the greatest improvement in hyperactivity, less but still notable improvement in irritability, and stable levels of social withdrawal over time. Higher cognitive ability and fewer ASD features emerged as important individual differences related to fewer challenging behaviors. The multi-informant perspective and longitudinal design provide novel insight into the manifestations of these challenging behaviors across different contexts and across time. Findings highlight the importance of addressing challenging behaviors as these behaviors tend to persist throughout development in both home and school contexts, especially for children with particular diagnostic and cognitive profiles. Lay SummaryAccording to both teacher and parent report, youth with autism showed the greatest improvement in hyperactivity, less but still notable improvement in irritability, and stable levels of social withdrawal from school-age to adolescence. Fewer autism features and greater cognitive ability were related to fewer challenging behaviors. This studys use of multiple reporters (e.g., teachers and parents) across time provided insight into the persistence of challenging behaviors in the home and school settings and across development.

Background3q29 deletion syndrome (3q29del) is a rare ([~]1:30,000) genomic disorder associated with a wide array of neurodevelopmental and psychiatric phenotypes. Prior work by our team identified clinically significant executive function deficits in 47% of individuals with 3q29del; however, the nuances of executive function in this population have not been described. MethodsWe used the Behavior Rating Inventory of Executive Function (BRIEF) to perform the first in-depth assessment of real-world executive functioning in a cohort of 32 individuals with 3q29del (62.50% male, mean age=14.50{+/-}8.26 years). High-resolution structural magnetic resonance imaging was performed on a subset of participants (n=24). ResultsWe found global deficits in executive function; individuals with 3q29del scored significantly higher than the population mean on the BRIEF Global Executive Composite (GEC) and all subscales. 81.25% of study subjects (n=26) scored in the clinical range on at least one BRIEF subscale. BRIEF GEC T scores were significantly higher among 3q29del participants with a diagnosis of ADHD, and BRIEF GEC T scores were significantly associated with schizophrenia spectrum symptoms as measured by the SIPS. The BRIEF-2 ADHD Form accurately (sensitivity=86.70%) classified individuals with 3q29del based on ADHD diagnosis status, highlighting its potential use as a screener for ADHD in this population. BRIEF GEC T scores were significantly correlated with cerebellar white matter and subregional cerebellar cortex volumes. ConclusionsTogether, these data expand our understanding of the phenotypic spectrum of 3q29del and identify executive function as a core feature linked to both psychiatric and neuroanatomical features of the syndrome.

Social affective and communication symptoms stand at the center of autism, and usually become apparent within the first 1-3 years of life. Symptom severity differs widely across toddlers and clinical outcomes, ranging from near-neurotypical to poor. The biological bases of this early and wide symptom diversity are largely unknown. While more than two dozen studies have attempted to subgroup early-age clinical heterogeneity, most studies fail to rigorously validate discovered subtypes using multiple methods, and none linked observed clinical subtypes with underlying functional neural signatures. Using a well-established approach for precision medicine patient subtyping (Similarity Network Fusion) and multiple rigorous validation methods, we integrated thoroughly replicated measures of social neurofunctional activation and social and language ability in 137 toddlers at early ages. Results identified three distinct social neural-clinical ASD subtypes, validated using multiple methods. One subtype was consistent with a profound autism profile with negligible social neural activation, severe social and language symptoms, low social interest, and little clinical improvement. Another ASD subtype had a contrasting pattern with only mildly reduced social neural activity, near neurotypical social and language abilities, and substantial age-related clinical improvement. One principal implication of these results is that the "spectrum" of ASD heterogeneity is not truly a continuous spectrum from the neurobiological and clinical perspective. The profound autism subtype is the neurofunctional, clinical and developmental opposite of the mild ASD subtype, suggesting different etiological mechanisms. A second implication is that neurobiological and clinical subtype differences highlight the need to develop subtype-specific treatments, particularly for the profound subtype. Third, treatment studies with an undetermined mix of subtypes could fail or succeed based on how many patients from each subtype are included in the mix.

BackgroundThe neurometabolic profile of associated with autism spectrum disorder (ASD) has been reported to be abnormal by some studies showing region specific metabolite levels in ASD, while others report no group differences. The neurometabolic profile of the left dorsolateral prefrontal cortex (DLPFC) is of particular interest due to the DLPFC relevance to cognitive and executive function, and to ASD. MethodWe used 1H-MRS to investigate neurometabolic profiles in the DLPFC of ASD and sex/IQ-matched typically developing (TD) children (ages 9-13). We focused on levels of Glutamate and Glutamine (Glx) due to many reported Glx abnormalities ASD, and of Choline (Cho) because of its relationship to intelligence quotient (IQ) and to attentional re-orienting difficulties. ResultsWhile no significant group differences were observed in absolute concentrations, metabolite levels were correlated with the behavioral phenotype of ASD children. In the ASD group but not the TD group, nonverbal IQ (NVIQ) was negatively associated with Cho (r=-0.59, p=0.026) and positively associated with Glx/Cr (r=0.66, p=0.011). Furthermore, attentional-switching scores in the ASD group correlated negatively with Cho (r=-0.69, p=0.009), and positively with Glx/Cr for both the ASD (r=0.73, p=0.004) and TD (r=0.54, p=0.040) groups. ConclusionsCho and Glx/Cr have different neurometabolic roles in modulating NVIQ in ASD compared to TD children, while their role in attentional switching seems preserved in ASD. Elucidating the apparently divergent role of neurometabolites in ASD in the absence of significant group differences in absolute levels is an important step towards understanding and mapping the neural correlates of ASD. These results are also relevant in the context of the significant cognitive function heterogeneity associated with the ASD phenotype, as they suggest possible underlying neural mechanisms that do not overlap which those expected from typical development.

The ability to selectively attend to one talker in the presence of competing talkers is crucial to communication. Here we investigate whether cognitive deficits in the absences of hearing loss can impair speech perception. We tested typical hearing, neurodivergent adolescents/adults with autism spectrum disorder, fetal alcohol spectrum disorder, and an age- and sex-matched neurotypical group. We found a strong correlation between IQ and speech perception, with individuals with lower IQ scores having worse speech thresholds. These results demonstrate that deficits in cognitive ability, despite intact peripheral encoding, can impair listening under complex conditions. These findings have important implications for conceptual models of speech perception and for audiological services to improve communication in real-world environments for neurodivergent individuals.

Longitudinal, prospective analyses of marital status in parents of individuals with autism are needed. We describe the timing of divorce, and the factors that contribute to divorce in a longitudinal sample of families of individuals with autism. Participants included parents of 219 children, initially referred for autism and other developmental delays, followed to age 30 years. Approximately 36% of individuals with autism in our sample experienced a parental divorce by age 30. Higher rates of divorce were associated with maternal education, race and age at childs birth, as well as autism symptom severity and diagnosis. Divorces were most common in early years (under age 5) and also in the teenage years and beyond (over age 15). After age 15, higher risk was associated with higher cognitive ability and daily living skills, and being a multiplex family. Results suggest that divorce risk in families of children with autism remains high through childhood into early adulthood. Understanding factors related to changes in marital status may help us better support families across time.

Prevalence in autism spectrum disorder (ASD) diagnosis has long been strongly male-biased. Yet, consensus has not been reached on mechanisms and clinical features that underlie sex-based discrepancies. Whereas females may be under-diagnosed because of inconsistencies in diagnostic/ascertainment procedures (sex-biased criteria, social camouflaging), diagnosed males may have exhibited more overt behaviors (e.g., hyperactivity, aggression) that prompted clinical evaluation. Applying a novel network-theory-based approach, we extracted data-driven, clinically-relevant insights from a large, well-characterized sample (Simons Simplex Collection) of 2175 autistic males (Ages = 8.9{+/-}3.5 years) and 334 autistic females (Ages = 9.2{+/-}3.7 years). Exploratory factor analysis (EFA) and expert clinical review reduced data dimensionality to 15 factors of interest. To offset inherent confounds of an imbalanced sample, we identified a subset of males (N=331) matched to females on key variables (Age, IQ) and applied data-driven CDA using Greedy Fast Causal Inference (GFCI) for three groups (All Females, All Males, and Matched Males). Structural equation modeling (SEM) extracted measures of model fit and effect sizes for causal relationships between sex, age, and, IQ on EFA-selected factors capturing phenotypic representations of autism across sensory, social, and restricted and repetitive behavior domains. Our methodology unveiled sex-specific directional relationships to inform developmental outcomes and targeted interventions.

BackgroundThere is evidence that children with autism/autistic traits have higher risks of incontinence and constipation, but no studies have examined this in a large community-based cohort. Aim/Research questionare autistic traits and diagnosed autism prospectively associated with increased odds of incontinence and constipation in children and adolescents? MethodsThis was a population-based cohort study based on data from the Avon Longitudinal Study of Parents and Children (n=4233-4490 at age 9 years; n=3403-3697 at age 14). We used multivariable logistic regression to examine associations of parent-reported autistic traits (sociability, repetitive behaviours, social-communication, coherence) (at ages 3-9 years) and autism with incontinence (bedwetting, daytime-wetting, soiling) and constipation (parent-reported at age 9, self-reported at age 14). We adjusted for parity, maternal age at delivery, childs sex and developmental level, maternal depression, and anxiety (antenatal and postnatal), and indicators of family socioeconomic status. ResultsSocial-communication and speech coherence difficulties showed the strongest associations with incontinence, e.g. adjusted odds ratio (OR) and 95% confidence interval (CI) for the association between social-communication difficulties and daytime-wetting was 2.21 (1.47-3.32) and for coherence was 2.34 (1.60-3.43). The odds of soiling were also higher in children with social-communication (OR:1.88, 95%CI:1.28-2.75) and coherence difficulties (OR:2.04, 95%CI:1.43-2.93). Diagnosed autism was only associated with an increase in the odds of daytime-wetting (OR:3.18, 95%CI:1.44-7.02). At 14 years, there was less evidence of associations between autistic traits and incontinence but there was evidence of associations between autistic traits and constipation: social-communication (OR:1.68, 95%CI:1.13-2.49), coherence difficulties (OR:1.64, 95%CI:1.11-2.41). 5 ConclusionsEarly assessment and treatment of incontinence/constipation should be considered for children with autistic traits.

ImportanceMotor skill impairments affect up to 87% of children with autism spectrum disorder (ASD) and are associated with greater severity of repetitive behaviors. Yet, most research examining this relationship has treated ASD as a unitary condition. Understanding whether motor-behavior relationships differ by genetic etiology could inform stratified approaches to ASD research and clinical care. ObjectiveTo determine whether the relationship between motor function and restricted and repetitive behaviors (RRBs) differs between children with monogenic forms of ASD (SHANK3, DYRK1A, or SCN2A variants) and children with idiopathic ASD. Design, Setting, and ParticipantsMatched cohort cross-sectional study using data from the Simons Foundation Powering Autism Research for Knowledge (SPARK) database. Children with loss-of-function variants in SHANK3, DYRK1A, or SCN2A were matched to children with idiopathic autism and intellectual disability. Main Outcomes and MeasuresMotor function was assessed using the Developmental Coordination Disorder Questionnaire (DCDQ). Repetitive behaviors were assessed using the Repetitive Behavior Scale-Revised (RBS-R), with subscales categorized as lower-order (stereotyped, self-injurious) or higher-order (compulsive, ritualistic, sameness, restricted interests). The primary analysis compared motor-RRB correlations between groups. ResultsThe sample included 93 children with monogenic autism (SHANK3, n=34; DYRK1A, n=46; SCN2A, n=13) and 787 matched children with idiopathic ASD. In idiopathic ASD, motor function was negatively correlated with RRBs (r = -0.156); in monogenic ASD, this reversed to a positive correlation (r = +0.185; {Delta}r = 0.341, P = 0.002). This reversal was specific to higher-order RRBs (idiopathic r=-0.106; monogenic r=+0.234; {Delta}r=0.339, 95% CI 0.124-0.535, P=0.002) and was not observed for lower-order RRBs ({Delta}r=0.212, P=0.05). All three genes showed positive correlations (SHANK3 r=+0.033; DYRK1A r=+0.262; SCN2A r=+0.623) with no significant heterogeneity (P=0.153). Conclusions and RelevanceThe relationship between motor function and repetitive behaviors differs by genetic etiology, with children with monogenic ASD showing a positive motor-RRB correlation specific to higher-order behaviors, opposite to the negative correlation observed in idiopathic ASD. This reversal was consistent across three molecularly distinct genes. These findings support stratifying autism research and clinical care by genetic etiology. KEY POINTSO_ST_ABSQuestionC_ST_ABSDoes the relationship between motor function and restricted and repetitive behaviors (RRBs) differ between children with autism spectrum disorder (ASD) attributable to SHANK3, DYRK1A, or SCN2A variants and children with idiopathic ASD? FindingsWe conducted a matched cohort cross-sectional study comparing correlations between motor function and RRBs in children with monogenic ASD versus children with idiopathic ASD and intellectual disability. Motor function was negatively correlated with RRBs in children with idiopathic ASD but positively correlated in children with monogenic ASD. MeaningGenetic variants may alter behavioral organization, supporting the value of stratifying populations of individuals with ASD by genetic etiology in both research and clinical care.

Atypical eye gaze in joint attention is a clinical characteristic of autism spectrum disorder (ASD). Despite this documented symptom, neural processing of joint attention tasks in real-life social interactions is not understood. To address this knowledge gap, functional-near infrared spectroscopy (fNIRS) and eye-tracking data were acquired simultaneously as ASD and typically developed (TD) individuals engaged in a gaze-directed joint attention task with a live human and robot partner. We test the hypothesis that face processing deficits in ASD are greater for interactive faces than for simulated (robot) faces. Consistent with prior findings, neural responses during human gaze cueing modulated by face visual dwell time resulted in increased activity of ventral frontal regions in ASD and dorsal parietal systems in TD participants. Hypoactivity of the right dorsal parietal area during live human gaze cueing was correlated with autism spectrum symptom severity: Brief Observations of Symptoms of Autism (BOSA) scores (r = -0.86). Contrarily, neural activity in response to robot gaze cueing modulated by visual acquisition factors activated dorsal parietal systems in ASD, and this neural activity was not related to autism symptom severity (r = 0.06). These results are consistent with the hypothesis that altered encoding of incoming facial information to the dorsal parietal cortex is specific to live human faces in ASD. These findings open new directions for understanding joint attention difficulties in ASD by providing a connection between superior parietal lobule activity and live interaction with human faces. Lay SummaryLittle is known about why it is so difficult for autistic individuals to make eye contact with other people. We find that in a live face-to-face viewing task with a robot, the brains of autistic participants were similar to typical participants but not when the partner was a live human. Findings suggest that difficulties in real-life social situations for autistic individuals may be specific to difficulties with live social interaction rather than general face gaze.

Synaptopathies are neurodevelopmental disorders caused by genetic mutations disrupting the development and function of neuronal synapses. We administered the validated Social Responsiveness Scale, Second Edition (SRS-2) to investigate the phenotypic presentation of social-behavioral impairments for the synaptopathy--SYNGAP1-related Intellectual Disability (SYNGAP1-ID) (n=32) compared with a phenotypically similar disorder Phelan-McDermid Syndrome (PMD) (n=27) and healthy controls (n=43). A short form SRS-2 analysis (n=85) was also conducted. Both SYNGAP1-ID and PMD had significantly elevated total and subcategory T-scores, with no significant score differences between SYNGAP1-ID and PMD, consistent between the full and short form. Mild to severe deficiencies in reciprocal social behavior were found in 100% of PMD individuals and 87.1% of SYNGAP1-ID individuals. Additionally, the short form demonstrated greater utility for SYNGAP1-ID participants due to lower item-omission rates. In conclusion, significant impairment in reciprocal social behaviors is highly prevalent in SYNGAP1-ID.

The effect of pretend play in 2 to 5-year-old children with ASD was investigated in the largest and the longest observational study to-date. Parents assessed the development of 7,069 children quarterly for three years on five subscales: combinatorial receptive language, expressive language, sociability, sensory awareness, and health. Pretend play was associated with superior developmental trajectories: 1.9-fold faster improvement of combinatorial receptive language (p<0.0001), 1.4-fold faster improvement of expressive language (p<0.0001), and 1.3-fold faster improvement of sensory awareness (p=0.0009). Pretend play had little effect on sociability and health. The strong association of pretend play with combinatorial receptive language remained significant even when controlling for expressive language. Similarly, the effect of pretend play on expressive language remained significant even when controlling for combinatorial receptive language. The effect of pretend play on combinatorial receptive language (but not on the expressive language) was stronger than the effects of seizures, sleep problems or high-TV exposure. The strong effect of pretend-play supports earlier studies indicating that it is an important stepping stone for language acquisition, particularly, the acquisition of combinatorial language.

BackgroundThe expression of autism traits sufficient to meet criteria for a diagnosis can occur early (by 3 years) or later (from mid-childhood onwards). It remains unknown whether variation in age of onset is due to clinical recognition or whether it reflects distinct biological pathways. One way of addressing this question is by investigating biological differences very early in development associated with age of onset. We use a prospective design to look at event related potentials to faces, one of the most robust biomarkers in autism. MethodsA sample of 102 infants (aged 6-10 months, 54% female) with an older autistic sibling had EEG recorded whilst viewing faces (faces versus noise; gaze towards versus away). Autism diagnostic assessments were conducted at three years and again in mid-childhood (aged 6-12 years), resulting in early diagnosed (at age 3; N=22), later diagnosed (at mid-childhood; N=21) and no autism (N=59) groups. ResultsWhile a short latency response (P1) does not associate with autism outcome, a mid-latency component (N290) associates with early onset autism only, and a later latency component (P400) associates with both early and later onset autism. ConclusionTemporal stages of face processing in infancy differentially associate with age of autism onset such that an earlier age of diagnosis is associated with earlier stage deviation within the event-related waveform. Early and later onset autism may represent different biological subtypes, with different early brain development, challenging the view of one etiological pathway and that variation in diagnostic age is solely due to clinical ascertainment.