Molecular Autism最新文献

Autism spectrum disorder (ASD) is characterized by difficulties in social interaction, communication challenges, and repetitive behaviors. Despite extensive research, the molecular mechanisms underlying these neurodevelopmental abnormalities remain elusive. We integrated microscale brain gene expression data with macroscale MRI data from 1829 participants, including individuals with ASD and typically developing controls, from the autism brain imaging data exchange I and II. Using fractal dimension as an index for quantifying cortical complexity, we identified significant regional alterations in ASD, within the left temporoparietal, left peripheral visual, right central visual, left somatomotor (including the insula), and left ventral attention networks. Partial least squares regression analysis revealed gene sets associated with these cortical complexity changes, enriched for biological functions related to synaptic transmission, synaptic plasticity, mitochondrial dysfunction, and chromatin organization. Cell-specific analyses, protein-protein interaction network analysis and gene temporal expression profiling further elucidated the dynamic molecular landscape associated with these alterations. These findings indicate that ASD-related alterations in cortical complexity are closely linked to specific genetic pathways. The combined analysis of neuroimaging and transcriptomic data enhances our understanding of how genetic factors contribute to brain structural changes in ASD.

Background: Angelman syndrome (AS), a severe neurodevelopmental disorder resulting from the loss of the maternal UBE3A gene, is marked by changes in the brain's white matter (WM). The extent of WM abnormalities seems to correlate with the severity of clinical symptoms, but these deficits are still poorly characterized or understood. This study provides the first large-scale measurement of WM volume reduction in children with AS. Furthermore, we probed the possibility of underlying WM neuropathology by examining the progression of myelination in an AS mouse model.

Methods: We conducted magnetic resonance imaging (MRI) on children with AS (n = 32) and neurotypical controls (n = 99) aged 0.5-12 years. In parallel, we examined myelination in postnatal Ube3a maternal-null mice (Ube3a^m-/p+; AS model), Ube3a paternal-null mice (Ube3a^m+/p-), and wildtype controls (Ube3a^m+/p+) using MRI, immunohistochemistry, western blotting, and electron microscopy.

Results: Our data revealed that AS individuals exhibit significant reductions in brain volume by ~ 1 year of age, and by 6-12 years of age WM is reduced by 26% and gray matter by 21%-approximately twice the reductions observed in the adult AS mouse model. Our AS mouse model saw a global delay in the onset of myelination, which normalized within days (likely corresponding to months or years in human development). This myelination delay is caused by the loss of UBE3A in neurons rather than UBE3A haploinsufficiency in oligodendrocytes. Interestingly, ultrastructural analyses did not reveal abnormalities in myelinated or unmyelinated axons.

Limitations: It is difficult to extrapolate the timing and duration of the myelination delay observed in AS model mice to individuals with AS.

Conclusions: This study reveals WM deficits as a hallmark in children with AS, demonstrating for the first time that these deficits are already apparent at 1 year of age. Parallel studies in a mouse model of AS show these deficits occur alongside the delayed onset of myelination, which results from the loss of neuronal (but not glial) UBE3A, though the causal relationship between these phenotypes remains to be determined. These findings emphasize the potential of WM as both a therapeutic target for interventions and a valuable biomarker for tracking the progression of AS and the effectiveness of potential treatments.

Background: Difficulties with (non-verbal) social communication, including facial expression processing, constitute a hallmark of autism. Intranasal administration of oxytocin has been considered a potential therapeutic option for improving social difficulties in autism, either by enhancing the salience of social cues or by reducing the social stress and anxiety experienced in social encounters.

Methods: We recorded fMRI brain activity while presenting neutral, fearful and scrambled faces, to compare the neural face processing signature of autistic children (n = 58) with that of matched non-autistic controls (n = 38). Next, in the autistic children group, we implemented this fMRI face processing task in a double-blind, placebo-controlled, multiple-dose oxytocin clinical trial, to evaluate the impact of four-week repeated oxytocin administration (24 IU daily dose) on brain activity in face processing regions.

Results: No significant diagnostic-group differences were identified between autistic versus non-autistic children with regard to neural face processing. Furthermore, no significant treatment effects were found in the oxytocin clinical trial. However, exploratory analyses (uncorrected for multiple comparisons) demonstrated decreases in brain activity in the left superior temporal sulcus (STS) and inferior frontal region in the oxytocin compared to the placebo group, and change-from-baseline analyses in the oxytocin group revealed significantly reduced neural activity in the core face-processing network (STS, inferior occipital, and posterior fusiform), as well as in amygdala and inferior frontal region.

Conclusion: These findings suggest an attenuating effect of multiple-dose oxytocin administration on neural face processing, potentially supporting the anxiolytic account of oxytocin.

Background: SHANK3, a gene encoding a synaptic scaffolding protein, is implicated in autism spectrum disorder (ASD) and is disrupted in Phelan-McDermid syndrome (PMS). Despite evidence of regression or worsening of ASD-like symptoms in individuals with PMS, the underlying mechanisms remain unclear. Although Shank3 is highly expressed in the cerebellar cortical granule cells, its role in cerebellar function and contribution to behavioral deficits in ASD models are unknown. This study investigates behavioral changes and cerebellar synaptic alterations in Shank3^Δex4-22 mice at two developmental stages.

Methods: Shank3^Δex4-22 wildtype, heterozygous, and homozygous knockout mice lacking exons 4-22 (all functional isoforms) were subjected to a behavioral battery in both juvenile (5-7 weeks old) and adult (3-5 months old) mouse cohorts of both sexes. Immunostaining was used to show the expression of Shank3 in the cerebellar cortex. Spontaneous excitatory postsynaptic currents (sEPSCs) from cerebellar granule cells (CGCs) were recorded by whole-cell patch-clamp electrophysiology.

Results: Deletion of Shank3 caused deficits in motor function, heightened anxiety, and repetitive behaviors. These genotype-dependent behavioral alterations were more prominent in adult mice than in juveniles. Reduced social preference was only identified in adult Shank3^Δex4-22 knockout male mice, while self-grooming was uniquely elevated in males across both age groups. Heterozygous mice showed little to no changes in behavioral phenotypes in most behavioral tests. Immunofluorescence staining indicated the presence of Shank3 predominantly in the dendrite-containing rosette-like structures in CGCs, colocalizing with presynaptic markers of glutamatergic mossy fiber. Electrophysiological findings identified a parallel relationship between the age-related exacerbation of behavioral impairments and the enhancement of sEPSC amplitude in CGCs.

Limitations: Other behavioral tests of muscle strength (grip strength test), memory (Barnes/water maze), and communication (ultrasonic vocalization), were not performed. Further study is necessary to elucidate how Shank3 modulates synaptic function at the mossy fiber-granule cell synapse in the cerebellum and whether these changes shape the behavioral phenotype.

Conclusions: Our findings reveal an age-related exacerbation of behavioral impairments in Shank3^Δex4-22 mutant mice. These results suggest that Shank3 may alter the function of glutamatergic receptors at the mossy fiber-cerebellar granule cell synapse as a potential mechanism causing cerebellar disruption in ASD.

Background: Very large sample sizes are often needed to capture heterogeneity in autism, necessitating data sharing across multiple studies with diverse assessment instruments. In these cases, data harmonization can be a critical tool for deriving a single dataset for analysis. This can be done through computational approaches that enable the conversion of scores across various instruments. To this end, our study examined the use of analytical approaches for mapping scores on two measures of adaptive functioning, namely predicting the scores on the vineland adaptive behavior scales II (VABS) from the scores on the adaptive behavior assessment system II (ABAS).

Methods: Data from the province of Ontario neurodevelopmental disorders network were used. The dataset included scores VABS and the ABAS for 720 participants (autism n = 547, 433 male, age: 11.31 ± 3.63 years; neurotypical n = 173, 95 male, age: 12.53 ± 4.05 years). Six regression approaches (ordinary least squares (OLS) linear regression, ridge regression, ElasticNet, LASSO, AdaBoost, random forest) were used to predict VABS total scores from the ABAS scores, demographic variables (age, sex), and phenotypic measures (diagnosis; core and co-occurring features; IQ; internalizing and externalizing symptoms).

Results: The VABS scores were significantly higher than the ABAS scores in the autism group, but not the neurotypical group (median difference: 8, 95% CI = (7,9)). The difference was negatively associated with age (beta = -1.2 ± 0.12, t = -10.6, p < 0.0001). All estimators demonstrated similar performance, with no statistically significant differences in mean absolute error (MAE) values across estimators (MAE range: 4.96-6.91). The highest contributing features to the prediction model were ABAS composite score, diagnosis, and age.

Limitations: This study has several strengths, including the large sample. We did not examine the conversion of domain scores across the two measures of adaptive functioning and suggest this as a future area of investigation.

Conclusion: Overall, our results supported the feasibility of harmonization. Our results suggest that a linear regression model trained on the ABAS composite score, the ABAS raw domain scores, and age, sex, and diagnosis would provide an acceptable trade-off between accuracy, parsimony, and data collection and processing complexity.

Background: A lack of serotonin (also known as 5-hydroxytryptamine, 5-HT) in the brain due to deficiency of the rate-limiting enzyme in 5-HT synthesis, tryptophan hydroxylase 2 (TPH2), was recently reported to result in impaired maternal affiliation across species, including mice, rats, and monkeys. In rodents, this was reflected in a lack of preference for maternal odors and reduced levels of isolation-induced ultrasonic vocalizations (USV), possibly contributing to a severe growth retardation phenotype.

Methods: Here, we tested whether growth retardation, maternal affiliation deficits, and/or impairments in socio-affective communication caused by Tph2 deficiency can be rescued through early social enrichment in rats. To this aim, we compared male and female Tph2^-/- knockout and Tph2^+/- heterozygous rat pups to Tph2^+/+ wildtype littermate controls, with litters being randomly assigned to standard nesting (SN; one mother with her litter) or communal nesting (CN; two mothers with their two litters).

Results: Our results show that Tph2 deficiency causes severe growth retardation, together with moderate impairments in somatosensory reflexes and thermoregulatory capabilities, partially aggravated by CN. Tph2 deficiency further led to deficits in socio-affective communication, as evidenced by reduced emission of isolation-induced USV, associated with changes in acoustic features, clustering of subtypes, and temporal organization. Although CN did not rescue the impairments in socio-affective communication, CN ameliorated the maternal affiliation deficit caused by Tph2 deficiency in the homing test. To close the communicative loop between mother and pup, we assessed maternal preference and showed that mothers display a preference for Tph2^+/+ controls over Tph2^-/- pups, particularly under CN conditions. This is consistent with the aggravated growth phenotype in Tph2^-/- pups exposed to the more competitive CN environment.

Conclusion: Together, this indicates that CN aggravates growth retardation despite ameliorating maternal affiliation deficits in Tph2-deficient rat pups, possibly due to reduced and acoustically altered isolation-induced USV, hindering efficient socio-affective communication between mother and pup.

Background: Autistic individuals often have difficulty flexibly adjusting their behavior. However, laboratory experiments have yielded inconsistent results, potentially due to various influencing factors, which need to be examined in detail. This study aimed to investigate the hypothesis that the social content of stimuli could play a specific role in some of the flexibility challenges faced by autistic individuals. The second aim was to explore sex differences in this context.

Methods: We analyzed data from 256 adult participants (124 with autism), matched on age, gender, and sex, who performed an emotional shifting task involving unpredictable shifts between positive and negative stimuli. Additionally, the task included both social and non-social conditions.

Results: Our results revealed a larger switch cost in the social than in the non-social condition, and this was more pronounced in autistic than in non-autistic individuals. Furthermore, we observed that autistic females differed from autistic males in the non-social condition and from non-autistic females in the social condition.

Limitations: The online nature of the study reduced the control over participant conditions. In addition, further studies are needed to investigate whether these results apply to the broader autism spectrum.

Conclusions: Building on previous research demonstrating a greater switch cost in autistic than non-autistic individuals for socio-emotional stimuli, our study further extends these findings by highlighting that the social context, rather than the emotional nature of the stimuli alone, may play a significant role in the flexibility challenges faced by autistic individuals. Our findings also contribute to the literature on sex differences in autism.

Background: "Frank autism," recognizable through the first minutes of an interaction, describes a behavioral presentation of a subset of autistic individuals that is closely tied to social communication challenges, and may be linked to so-called "prototypical autism." To date, there is no research on frank autism presentations of autistic adolescents and young adults, nor individuals diagnosed with autism spectrum disorder (ASD) in childhood who do not meet diagnostic criteria during or after adolescence (loss of autism diagnosis, LAD). In addition, there are currently no data on the factors that drive frank autism impressions in these adolescent groups.

Methods: This study quantifies initial impressions of autistic characteristics in 24 autistic, 24 LAD and 26 neurotypical (NT) individuals ages 12 to 39 years. Graduate student and expert clinicians completed five-minute impressions, rated confidence in their own impressions, and scored the atypicality of behaviors associated with impressions; impressions were compared with current gold-standard diagnostic outcomes.

Results: Overall, clinicians' impressions within the first five minutes generally matched current gold-standard diagnostic status (clinical best estimate), were highly correlated with ADOS-2 CSS, and were driven primarily by prosodic and facial cues. However, this brief observation did not detect autism in all cases. While clinicians noted some subclinical atypicalities in the LAD group, impressions of the LAD and NT groups were similar.

Limitations: The brief observations in this study were conducted during clinical research, including some semi-structured assessments. While results suggest overall concordance between initial impressions and diagnoses following more thorough evaluation, findings may not generalize to less structured, informal contexts. In addition, our sample was demographically homogeneous and comprised only speaking autistic participants. They were also unmatched for sex, with more females in the non-autistic group. Future studies should recruit samples that are diverse in demographic variables and ability level to replicate these findings and explore their implications.

Conclusions: Results provide insights into the behavioral characteristics that contribute to the diagnosis of adolescents and young adults and may help inform diagnostic decision making in the wake of an increase in the demand for autism evaluations later than childhood. They also substantiate claims of an absence of apparent autistic characteristics in individuals who have lost the diagnosis.

Fragile X syndrome (FXS) is a rare neurodevelopmental disorder caused by a CGG repeat expansion ≥ 200 repeats in 5' untranslated region of the FMR1 gene, leading to intellectual disability and cognitive difficulties, including in the domain of communication. A recent phase 2a clinical trial testing BPN14770, a phosphodiesterase 4D inhibitor, showed improved cognition in 30 adult males with FXS on drug relative to placebo. The initial study found significant improvements in clinical measures assessing cognition, language, and daily functioning in addition to marginal improvements in electroencephalography (EEG) results for the amplitude of the N1 event-related potential (ERP) component. These EEG results suggest BPN14770 improved neural hyperexcitability in FXS. The current study investigated the relationship between BPN14770 pharmacokinetics and the amplitude of the N1 ERP component from the initial data. Consistent with the original group-level finding post-period 1 of the study, participants who received BPN14770 in period 1 showed a significant correlation between N1 amplitude and serum concentration of BPN14770 measured at the end of period 1. These findings strengthen the validity of the original result, indicating that BPN14770 improves cognitive performance by modulating neural hyperexcitability. This study represents the first report of a significant correlation between a reliably abnormal EEG marker and serum concentration of a novel pharmaceutical in FXS.

Background: Children with Neurofibromatosis 1 (NF1) show cognitive, behavioural and social differences compared to their peers. However, the age and sequence at which these differences begin to emerge is not fully understood. This prospective cohort study examines the cognitive, behavioural, ADHD trait and autism symptom development in infant and pre-school children with NF1 compared with typically developing (TD) children without a family history of neurodevelopmental conditions.

Methods: Data from standardised tests was gathered at 5, 10, 14, 24 and 36 months of age (NF1 n = 35, TD n = 29). Developmental trajectories of cognitive (Mullen Scales of Early Learning, MSEL) and adaptive behavioural (Vineland Adaptive Behavior Scales, VABS) development from 5 to 36 months were analysed using linear mixed modelling. Measures of ADHD (Child Behavior Checklist) and autism traits (ADOS-2, BOSA-MV and ADI-R) were assessed at 24 and 36 months.

Results: The developmental trajectory of cognitive skills (all domains of the MSEL) and behavioural skills (four domains of the VABS) differed significantly between NF1 and TD groups. Post-hoc tests demonstrated that the NF1 participants scored significantly lower than TD participants at 24 months on all MSEL and VABS domains. The NF1 cohort demonstrated higher mean autism and ADHD traits at 24 months and 14% of the NF1 cohort met a research diagnostic classification for autism at 36 months.

Limitations: The study has a relatively small sample size due to variable retention and rolling recruitment. Due to limitations imposed by the COVID-19 pandemic, we utilised the Brief Observation of Symptoms of Autism for Minimally Verbal children (BOSA-MV) for some participants, which was administered online and may not gather as accurate a picture of traits as ADOS-2. The BOSA-MV was utilised for 41% of participants with NF1 at 36 months compared to 11% at 24 months. This may explain the reduction in the percentage of children with NF1 that met autism criteria at 36 months.

Conclusions: By 24 months of age, the NF1 cohort show lower cognitive skills and adaptive behaviour and higher levels of autism and ADHD traits as compared to TD children. This has implications for developmental monitoring and referral for early interventions.

Trial registration: Not applicable.