Pathology Of Autism Research Articles

Assessment of 8-Hydroxy-2’-Deoxyguanosine (8-OH-dG) Level in Urine as a Urinary Marker of Oxidative Stress in Children with Autism Spectrum Disorder

Abstract Background Autism spectrum disorder (ASD) is a developmental disorder characterized by deficits in social interaction, restricted interest and repetitive behavior. Oxidative stress in response to environmental exposure plays a role in virtually every human disease and represents a significant avenue of research into the etiology of ASD. Objective The aim of this study was to asses 8-hydroxy-2’-deoxyguanosine (8-OH-dG) level in urine as a urinary marker of oxidative stress in children with autism spectrum disorder in comparison to sex and age matched healthy control group. Patients and Methods We included 51 children with autism (43 males and 8 females whose age ranged from 2 to 16 years). They were compared to 51 children of the same age as a control group. The diagnosis of autism was made based on the criteria of autistic disorders as defined in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSMV). In the patients group, detailed medical history included sociodemographic form and family history was taken for autistic group also Intelligence Quotient test IQ test and Childhood Autism Rating Scale (CARS) used to measure the severity of autism. In the study, 8-OHdG values in urine were investigated using the enzyme-linked immunosorbent assay (ELISA) method and Urinary creatinine was determined with the Beckham Coulter analyzer and was used to normalize all biochemical measurements then the urinary 8-OHdG/creatinine levels were corrected to the urinary concentration of creatinine. Results The median age was 9.9 in the ASD group and 9.1 in the control group (P = 0.256). In the ASD group, (8-OH-dG)/creatinine ratio values were found to be significantly higher than those of the controls (P < 0.001). but also No statistically significant correlation between (8-OH- dG)/creatinie ratio and CARS score or IQ score (P = 0,7). Conclusion The data from this study supported the hypothesis of the oxidant/antioxidant balance as a key piece that may contribute to the autistic pathology

The protective role of prenatal administration of ascorbic acid on autistic-like behavior in a rat model of autism

BackgroundAutism is a complicated neurodevelopmental disorder characterized by several behavioral impairments. The pathology of autism is complex and not fully known. Several recent studies have shown alterations in the activities of antioxidant enzymes in autism. Vitamin C is a potent antioxidant that is present in high concentrations in the brain and acts as a neuromodulator. Prefrontal abnormality has been hypothesized to underlie autistic symptoms. The present study investigated the protective effect of prenatally Vitamin C on autistic-like behaviors, oxidative stress status, and histopathological change of prefrontal in valproic acid (VPA) rat model of autism. MethodThe model of autism was induced by subcutaneous administration of Valproic acid (600 mg/kg) to pregnant rats at gestational day 12.5. Vitamin C was administered 600 mg/L in drinking water from the 5th day of gestaion (GD5) up to postnatal day 23 (PND23). Thirty-two rat offspring were divided into four groups: Control, Vitamin C, VPA, and Vitamin C + VPA. The offspring were tested for repetitive behaviors and cognitive ability with a Y-maze task and social interaction with a play behavior task on 31st of Postnatal days. Glutathione (GSH), superoxide dismutase (SOD) activity, and the histological change in the prefrontal lobe were assessed at the end of the study. The number of neurons from the left prefrontal lobe was counted in duplicate from slides stained with hematoxylin-eosin. ResultsIn the Y-maze apparatus, spontaneous alteration significantly decreased in the prenatal VPA treated rats compared to control rats showing autistic-like behavior; pre and postnatal Vitamin C treatment increased the alternation indicated benefit effect of Vitamin C. Prenatal VPA treatment impaired play behavior such as sniffing, grooming and darting. Vitamin C treatment attenuated the problems in male offspring social behavior. Histological examination showed an increase in the number of cells in the prefrontal cortex of valproic acid offspring rats compared to other groups. Moreover, prenatal VPA decreased antioxidant enzyme activities in the cortex (PFC) attenuated by Vitamin C administration. ConclusionThe present study showed that valproic acid induced oxidative stress and neural changes in the prefrontal lobe when administered prenatally which in turn may cause the development of some autistic-like behaviors, and vitamin C may reduce this symptom with its antioxidant effects

Distinct patterns of GABAergic interneuron pathology in autism are associated with intellectual impairment and stereotypic behaviors.

Autism spectrum disorder is a neurodevelopmental condition characterized by deficits in sociability and communication and the presence of repetitive behaviors. How specific pathological alterations of the brain contribute to the clinical profile of autism spectrum disorder remains unknown. We previously found that a specific type of inhibitory interneuron is reduced in number in the autism spectrum disorder prefrontal cortex. Here, we assessed the relationship between interneuron reduction and autism spectrum disorder symptom severity. We collected clinical records from autism spectrum disorder (n = 20) and assessed the relationship between the severity of symptoms and interneuron number. We found that the reduced number of inhibitory interneurons that we previously reported is linked to specific symptoms of autism spectrum disorder, particularly stereotypic movements and intellectual impairments.

Alterations of presynaptic proteins in autism spectrum disorder.

The expanded use of hypothesis-free gene analysis methods in autism research has significantly increased the number of genetic risk factors associated with the pathogenesis of autism. A further examination of the implicated genes directly revealed the involvement in processes pertinent to neuronal differentiation, development, and function, with a predominant contribution from the regulators of synaptic function. Despite the importance of presynaptic function in synaptic transmission, the regulation of neuronal network activity, and the final behavioral output, there is a relative lack of understanding of the presynaptic contribution to the pathology of autism. Here, we will review the close association among autism-related mutations, autism spectrum disorders (ASD) phenotypes, and the altered presynaptic protein functions through a systematic examination of the presynaptic risk genes relating to the critical stages of synaptogenesis and neurotransmission.

The Neuroprotective Role of Acorus calamus in Developmental and Histopathological Changes in Autism-Induced Wistar Rats.

Introduction Autism spectrum disorder (ASD) is a neurodevelopmental disorder, and a tremendous increase in the incidence of autism poses challenges in identifying the different treatment modalities. Since the defined etiology, pathophysiology, and treatment of autism are unavailable, translational research is being done by creating animal models of autism. This study aimed to assess the effects of Acorus calamus on developmental and histopathological changes in autism-induced Wistar rats. Materials and methods A rat model of autism was created by administering sodium valproate on the 12th day of pregnancy, and rat pups of this group were considered autism-induced. Rat pups of pregnant rats who had received normal saline on the 12th day of pregnancy were consideredgroup I (negative control group). Neural reflexes were assessed in early postnatal days (PND) to confirm the development of autism. Autism-induced rat pups were divided into the following two groups: group II, autism (positive control group), and group III, autism + A. calamus (drug-treated group). On the 21st postnatal day (PND), group III was given an ethanolic extract of A. calamus (200 mg/kg), and group I and group II were given normal saline orally for 15 days. After 15 days of drug exposure, at 36thPND, the rats were sacrificed, and brain tissue was collected for histopathological analysis. Results When compared to the negative control group, autism-induced rat pups showed delayed appearance of neurological reflexes. Neurodegenerative changes were well appreciated in group II (autism-induced rats) than in group III (autism + A. calamus). In the histomorphometric analysis, group II showed a significant reduction in the number of neurons in the frontal cortex and Purkinje cells in the cerebellum. However, when compared to group II, group III (autism treated with A. calamus) did not show significant alteration. Conclusion Valproate exposure at mid-pregnancy creates autism by disturbing neural structures among rat pups. This was clinically represented as the delayed appearance of neural reflexes. Acorus calamus in the early postnatal period protects rat pups' brain morphology against autism pathology.

Frequency-specific age-related changes in the amplitude of spontaneous fluctuations in autism.

BackgroundAutism spectrum disorder is characterized by atypical developmental changes during brain maturation, but regional brain functional changes that occur with age and across different frequency bands are unknown. Therefore, the current study aimed to explore potential age and frequency band-related changes in the regional brain activities in autism.MethodsA total of 65 participants who met the DSM-IV criteria for autistic disorder and 55 typically developed (TD) participants (both age 6–30 years) were recruited in the current study. The two groups were matched in age (t=−1.314, P=0.191) and gender (χ2=2.760, P=0.097). The amplitude of low-frequency fluctuations (ALFF) was employed to explore the effect of development on spontaneous brain activity in individuals with autism and in TD participants across slow-5 (0.01–0.027 Hz), slow-4 (0.027–0.073 Hz), and slow-3 (0.073–0.1 Hz) frequency bands. The diagnosis-by-age interaction effect in the whole brain voxels in autism and TD groups was investigated.ResultsAutism individuals showed significantly higher ALFF in the dorsal striatum in childhood (Caudate cluster: t=3.626, P=0.001; Putamen cluster: t=2.839, P=0.007) and remarkably lower ALFF in the dorsal striatum in adulthood (Caudate cluster: t=−2.198, P=0.038; Putamen cluster: t=−2.314, P=0.030) relative to TD, while no significant differences were observed in adolescence (all P>0.05). In addition, abnormal ALFF amplitudes were specific to the slow-4 (0.027–0.073 Hz) frequency band in the clusters above.ConclusionsThe current study indicated abnormal development patterns in the spontaneous activity of the dorsal striatum in autism and highlighted the potential role of the slow-4 frequency band in the pathology of autism. Also, the potential brain mechanism of autism was revealed, suggesting that autism-related variations should be investigated in a specific frequency.

Degraded cortical temporal processing in the valproic acid-induced rat model of autism

Hearing disorders, such as abnormal speech perception, are frequently reported in individuals with autism. However, the mechanisms underlying these auditory-associated signature deficits in autism remain largely unknown. In this study, we documented significant behavioral impairments in the sound temporal rate discrimination task for rats prenatally exposed to valproic acid (VPA), a well-validated animal model for studying the pathology of autism. In parallel, there was a large-scale degradation in temporal information-processing in their primary auditory cortices (A1) at both levels of spiking outputs and synaptic inputs. Substantially increased spine density of excitatory neurons and decreased numbers of parvalbumin- and somatostatin-labeled inhibitory inter-neurons were also recorded in the A1 after VPA exposure. Given the fact that cortical temporal processing of sound is associated with speech perception in humans, these results in the animal model of VPA exposure provide insight into a possible neurological mechanism underlying auditory and language-related deficits in individuals with autism.

Novel Probable Glance at Inflammatory Scenario Development in Autistic Pathology.

Autism Spectrum Disorder (ASD) is characterized by persistent deficits in social communication and restricted-repetitive patterns of behavior, interests, or activities. ASD is generally associated with chronic inflammatory states, which are linked to immune system dysfunction and/or hyperactivation. The latter might be considered as one of the factors damaging neuronal cells. Several cell types trigger and sustain such neuroinflammation. In this study, we traced different markers of immune system activation on both cellular (immune cell phenotypes) and mediatory levels (production of cytokines) alongside adverse hematology and biochemistry screening in a group of autistic children. In addition, we analyzed the main metabolic pathways potentially involved in ASD development: energy (citric acid cycle components), porphyrin, and neurotransmitter metabolism. Several ASD etiological factors, like heavy metal intoxication, and risk factors—genetic polymorphisms of the relevant neurotransmitters and vitamin D receptors—were also analyzed. Finally, broad linear regression analysis allowed us to elucidate the possible scenario that led to the development of chronic inflammation in ASD patients. Obtained data showed elevated levels of urinary cis-aconitate, isocitrate, alfa-ketoglutarate, and HMG. There were no changes in levels of metabolites of monoamine neurotransmitters, however, the liver-specific tryptophan kinurenine pathway metabolites showed increased levels of quinolinate (QUIN) and picolinate, whereas the level of kynurenate remained unchanged. Abovementioned data demonstrate the infringement in energy metabolism. We found elevated levels of lead in red blood cells, as well as altered porphyrin metabolism, which support the etiological role of heavy metal intoxication in ASD. Lead intoxication, the effect of which is intensified by a mutation of the VDR-Taq and MAO-A, leads to quinolinic acid increase, resulting in energy metabolism depletion and mitochondrial dysfunction. Moreover, our data backing the CD4+CD3+ T-cell dependence of mitochondrial dysfunction development in ASD patients reported in our previous study leads us to the conclusion that redox-immune cross-talk is considered a main functional cell damaging factor in ASD patients.

AUTISM AND AGRESSION: THE POSSIBLE RELEVANCE OF ZEBRAFIH STUDIES

Autism spectrum disorder (ASD) is a complex neurodevelopment disease with multifactorial causes, which is charaterized by a dramatic loss of the communication, social interaction and the repetition of actions. In this minireview we did focus on the agression part of the autistic pathology, and how this can be replicated in zebrafish experimental studies.

Research Article Epidemiology and screening for autistic pathology in Nghe An province, Vietnam

Research Article Epidemiology and screening for autistic pathology in Nghe An province, Vietnam

Small fiber pathology in autism and clinical implications.

To investigate small fiber innervation of the skin and its relationships with clinicometry of autism and peripheral afferents for contact heat-evoked potential (CHEP) and psychophysical measures of thermal thresholds. We recruited 32 men with autism (26.5 ± 5.9 years) and conducted small fiber assessments of skin biopsy with quantifying intraepidermal nerve fiber (IENF) density, CHEP, quantitative sensory testing, and large fiber physiology of nerve conduction studies. Results were compared with age-matched controls and analyzed with clinical measures of autism. Patients with autism showed a lower IENF density than controls (5.53 ± 2.09 vs 11.13 ± 3.49 fibers/mm, p < 0.0001). The IENF density was reduced in 17 (53.1%) men with autism classified as skin denervation group. On psychophysics, 9 (28%) men with autism had elevated thermal thresholds, and the warm threshold of the big toe was negatively correlated with IENF density (p = 0.0073), indicating functional impairments of small fiber sensory nerves. IENF density was negatively correlated with CHEP amplitude in autism (p = 0.003), in contrast to the pattern of positive correlation in controls, indicating different processing of nociceptive afferent in autism. Clinically, IENF density was related to distinct tactile symptom patterns in the skin denervation vs normal innervation group, respectively. Furthermore, IENF density was associated with autistic symptoms measured by the Autism Spectrum Quotient in a U-shaped model (p = 0.014). These observations indicated that a substantial portion of individuals with autism had small fiber pathology, which was associated with tactile and autistic symptoms, providing structural and physiologic evidence for the involvement of peripheral sensory nerves in autism.

Efficacy of Novavit in ameliorating the neurotoxicity of propionic acid.

Oxidative stress, abnormal fatty acid metabolism, and impaired gut microbiota play a serious role in the pathology of autism. The use of dietary supplements to improve the core symptoms of autism is a common therapeutic strategy. The present study analyzed the effects of oral supplementation with Novavit, a multi-ingredient supplement, on ameliorating oxidative stress and impaired lipid metabolism in a propionic acid (PPA)-induced rodent model of autism. Male western albino rats were divided into three groups. The first group is the control, the second group was given an oral neurotoxic dose of PPA (250 mg/kg body weight/day) for 3 days and then received buffered saline until the end of the experiment. The third group received Novavit (70 mg/kg body weight/day for 30 days after the 3-day PPA treatment). Markers of oxidative stress and impaired fatty acid metabolism were measured in brain homogenates obtained from each group. Novavit modulation of the gut microbiota was also evaluated. While PPA induced significant increases in lipid peroxides and 5-lipoxygenase, together with significantly decreased glutathione, and cyclooxygenase 2, oral supplementation with Novavit ameliorated PPA-induced oxidative stress and impaired fatty acid metabolism. Our results showed that the presence of multivitamins, coenzyme Q10, minerals, and colostrum, the major components of Novavit, protects against PPA-induced neurotoxicity.

MECP2 Duplication Causes Aberrant GABA Pathways, Circuits and Behaviors in Transgenic Monkeys: Neural Mappings to Patients with Autism.

MECP2 gain-of-function and loss-of-function in genetically engineered monkeys recapitulates typical phenotypes in patients with autism, yet where MECP2 mutation affects the monkey brain and whether/how it relates to autism pathology remain unknown. Here we report a combination of gene-circuit-behavior analyses including MECP2 coexpression network, locomotive and cognitive behaviors, and EEG and fMRI findings in 5 MECP2 overexpressed monkeys (Macaca fascicularis; 3 females) and 20 wild-type monkeys (Macaca fascicularis; 11 females). Whole-genome expression analysis revealed MECP2 coexpressed genes significantly enriched in GABA-related signaling pathways, whereby reduced β-synchronization within fronto-parieto-occipital networks was associated with abnormal locomotive behaviors. Meanwhile, MECP2-induced hyperconnectivity in prefrontal and cingulate networks accounted for regressive deficits in reversal learning tasks. Furthermore, we stratified a cohort of 49 patients with autism and 72 healthy controls of 1112 subjects using functional connectivity patterns, and identified dysconnectivity profiles similar to those in monkeys. By establishing a circuit-based construct link between genetically defined models and stratified patients, these results pave new avenues to deconstruct clinical heterogeneity and advance accurate diagnosis in psychiatric disorders.SIGNIFICANCE STATEMENT Autism spectrum disorder (ASD) is a complex disorder with co-occurring symptoms caused by multiple genetic variations and brain circuit abnormalities. To dissect the gene-circuit-behavior causal chain underlying ASD, animal models are established by manipulating causative genes such as MECP2 However, it is unknown whether such models have captured any circuit-level pathology in ASD patients, as demonstrated by human brain imaging studies. Here, we use transgenic macaques to examine the causal effect of MECP2 overexpression on gene coexpression, brain circuits, and behaviors. For the first time, we demonstrate that the circuit abnormalities linked to MECP2 and autism-like traits in the monkeys can be mapped to a homogeneous ASD subgroup, thereby offering a new strategy to deconstruct clinical heterogeneity in ASD.

Cell-Type-Specific Analysis of Molecular Pathology in Autism Identifies Common Genes and Pathways Affected Across Neocortical Regions.

Despite its heterogeneity, autism is characterized by a defined behavioral phenotype, suggesting that the molecular pathology affects specific neural substrates to cause behavioral dysfunction. Previous studies identified genes dysregulated in autism cortex but did not address their cell-type specificity. Moreover, it is unknown whether there is a core of genes dysregulated across multiple neocortical regions. We applied RNA sequencing to postmortem brain tissue samples from autism patients and neurologically normal controls and combined our data with previously published datasets. We then identified genes, pathways, and alternative splicing events which are dysregulated in five neocortical regions in autism. To gain information about cell-type specificity of the dysregulated genes, we analyzed single-nuclei RNA sequencing data of adult human cortex and intersected cell-type-specific gene signatures with genes dysregulated in autism in specific cortical regions. We found that autism-associated gene expression changes across 4 frontal and temporal cortex regions converge on 27 genes related to immune response and enriched in human astrocytes, microglia, and brain endothelium. Shared splicing changes, however, are found in genes predominantly associated with synaptic function and adult interneurons and projection neurons. Finally, we demonstrate that regions of DNA differentially methylated in autism overlap genes associated with development and enriched in human cortical oligodendrocytes. Our study identifies signatures of autism molecular pathology shared across neocortical regions, as well as neural cell types enriched for common dysregulated genes, thus paving way for assessing cell-type-specific mechanisms of autism pathology.

Postnatal development and maturation of layer 1 in the lateral prefrontal cortex and its disruption in autism

Autism is a neurodevelopmental connectivity disorder characterized by cortical network disorganization and imbalance in excitation/inhibition. However, little is known about the development of autism pathology and the disruption of laminar-specific excitatory and inhibitory cortical circuits. To begin to address these issues, we examined layer 1 of the lateral prefrontal cortex (LPFC), an area with prolonged development and maturation that is affected in autism. We focused on layer 1 because it contains a distinctive, diverse population of interneurons and glia, receives input from feedback and neuromodulatory pathways, and plays a critical role in the development, maturation, and function of the cortex. We used unbiased quantitative methods at high resolution to study the morphology, neurochemistry, distribution, and density of neurons and myelinated axons in post-mortem brain tissue from children and adults with and without autism. We cross-validated our findings through comparisons with neighboring anterior cingulate cortices and optimally-fixed non-human primate tissue. In neurotypical controls we found an increase in the density of myelinated axons from childhood to adulthood. Neuron density overall declined with age, paralleled by decreased density of inhibitory interneurons labeled by calretinin (CR), calbindin (CB), and parvalbumin (PV). Importantly, we found PV neurons in layer 1 of typically developing children, previously detected only perinatally. In autism there was disorganization of cortical networks within layer 1: children with autism had increased variability in the trajectories and thickness of myelinated axons in layer 1, while adults with autism had a reduction in the relative proportion of thin axons. Neurotypical postnatal changes in layer 1 of LPFC likely underlie refinement of cortical activity during maturation of cortical networks involved in cognition. Our findings suggest that disruption of the maturation of feedback pathways, rather than interneurons in layer 1, has a key role in the development of imbalance between excitation and inhibition in autism.

Neuronal morphology alterations in autism and possible role of oxytocin.

Current understanding of the neuroanatomical abnormalities in autism includes gross anatomical changes in several brain areas and microstructural alterations in neuronal cells as well. There are many controversies in the interpretation of the imaging data, evaluation of volume and size of particular brain areas, and their functional translation into a broad autism phenotype. Critical questions of neuronal pathology in autism include the concept of the reversible plasticity of morphological changes, volume alterations of brain areas, and both short- and long-term consequences of adverse events present during the brain development. At the cellular level, remodeling of the actin cytoskeleton is considered as one of the critical factors associated with the autism spectrum disorders. Alterations in the composition of the neuronal cytoskeleton, in particular abnormalities in the polymerization of actin filaments and their associated proteins underlie the functional consequences in behavior resulting in symptoms and clinical correlates of autism spectrum disorder. In the present review, a special attention is devoted to the role of oxytocin in experimental models of neurodevelopmental disorders manifesting alterations in neuronal morphology.

The Independent and Combined Effects of Omega-3 and Vitamin B12 in Ameliorating Propionic Acid Induced Biochemical Features in Juvenile Rats as Rodent Model of Autism.

Metabolites of proper fatty acids modulate the inflammatory response and are essential for normal brain development; equally, abnormal fatty acid metabolism plays a critical role in the pathology of autism. Currently, dietary supplements are often used to improve the core symptoms of Autism spectrum disorder (ASD). The present study analyzed the effects of orally supplemented omega-3 (ω-3) and vitamin B12 on ameliorating oxidative stress and impaired lipid metabolism in a propionic acid (PPA)-induced rodent model of autism, together with their effect on the gut microbial composition, where great fluctuations in the bacterial number and strains were observed; interestingly, polyunsaturated fatty acids such as omega-3 induced higher growth of the gram-positive bacterium Staphylococcus aureus and decreased the survival rates of Clostridia sp. as well as other enteric bacterial strains. Thirty-five young male western albino rats were divided into five equal groups. The first group served as the control; the second group was given an oral neurotoxic dose of PPA (250mg/kg body weight/day) for 3days. The third group received an oral dose of ω-3 (200mg/kg body weight/day) for 30days after the 3-day PPA treatment. Group four was given an oral dose of vitamin B12 (16.7mg/kg/day) for 30days after PPA treatment. Finally, group five was given a combination of both ω-3 and vitamin B12 at the same dose for the same duration after PPA treatment. Biochemical parameters related to oxidative stress and impaired fatty acid metabolism were investigated in the brain homogenates of each group. The effects of the dietary supplements on the gut microbiota were also observed. The PPA-treated autistic model expressed significantly higher levels of lipid peroxides and 5-lipoxygenase (5-LOX) and significantly less glutathione (GSH), glutathione S-transferase (GST), and cyclooxygenase 2 (COX2) than the control group. However, a remarkable amelioration of most of the impaired markers was observed with oral supplementation with ω-3 and vitamin B12, either alone or in combination. Our results concluded that impairment at various steps of the lipid metabolic pathways may contribute to the development of autism; however, supplementation with ω-3 and vitamin B12 can result in a positive therapeutic effect.

Identifying specific prefrontal neurons that contribute to autism-associated abnormalities in physiology and social behavior.

Functional imaging and gene expression studies both implicate the medial prefrontal cortex (mPFC), particularly deep layer projection neurons, as a potential locus for autism pathology. Here, we explored how specific deep-layer prefrontal neurons contribute to abnormal physiology and behavior in mouse models of autism. First, we find that across three etiologically distinct models – in utero valproic acid (VPA) exposure, CNTNAP2 knockout, and FMR1 knockout – layer 5 subcortically-projecting (SC) neurons consistently exhibit reduced input resistance and action potential firing. To explore how altered SC neuron physiology might impact behavior, we took advantage of the fact that in deep layers of the mPFC, dopamine D2 receptors (D2Rs) are mainly expressed by SC neurons, and used D2-Cre mice to label D2R+ neurons for calcium imaging or optogenetics. We found that social exploration preferentially recruits mPFC D2R+ cells, but that this recruitment is attenuated in VPA-exposed mice. Stimulating mPFC D2R+ neurons disrupts normal social interaction. Conversely inhibiting these cells enhances social behavior in VPA-exposed mice. Importantly, this effect was not reproduced by nonspecifically inhibiting mPFC neurons in VPA-exposed mice, or by inhibiting D2R+ neurons in wildtype mice. These findings suggest that multiple forms of autism may alter the physiology of specific deep-layer prefrontal neurons which project to subcortical targets. Furthermore, a highly overlapping population – prefrontal D2R+ neurons – plays an important role in both normal and abnormal social behavior, such that targeting these cells can elicit potentially therapeutic effects.

Intranasal Oxytocin in Autism: Models, Pain and Oxidative Stress

There is an increased interest in the current literature in how relevant the administration of oxytocin, mostly by using its intranasal administration, could be in some neuropsychiatric disorders and especially in those manifesting a deficit at their sociability level. These aspects made the possible usage of oxytocin as extremely attractive for some management and treatment solutions in the autistic pathology. Thus, we are describing here some original data and current literature status on how oxytocin could help pathophysiological autistic manifestations in both animal models and human patients, by mainly focusing on some specific behavioural or pain manifestations and related oxidative stress status.

M11 - DE NOVO GENIC MUTATIONS AMONG A CHINESE AUTISM SPECTRUM DISORDER COHORT

Background Autism spectrum disorders (ASD) are characterized by impairments in social communication and restricted or repetitive behaviors or interests. ASD has a strong but complex genetic component and the prevalence worldwide has been estimated as closer to 1%. Recurrent de novo (DN) and likely gene-disruptive (LGD) mutations are important risk factors for autism spectrum disorders (ASD) but have been primarily investigated in cohorts of European ancestry. However, no study has explored on a large scale the spectrum of DN mutations in these ASD risk genes in the Chinese population. Here we sequenced 189 risk genes in 1,543 ASD probands (1,045 from trios) with Chinese ancestry. Methods We selected autism risk genes for targeted sequencing mainly based on the frequency and severity of DN mutations from previously published exome sequencing studies under the hypothesis that DN mutations in genes contributing to autism pathology will not differ significantly between global populations. In total, we designed 11,394 single-molecule molecular inversion probes (smMIPs) to rapidly and cost-effectively sequence the coding regions for 213 candidate genes, of which 10,493 smMIPs for 189 genes passed QC measures, across a large cohort of 1,543 autism probands (1,045 from trios) from the Autism Clinical and Genetic Resources in China (ACGC). We selected LGD (nonsense, frameshift and splice site) mutations and missense mutations with a combined annotation dependent depletion (CADD) score of greater than 30 (MIS30) for sanger validation. Results We discovered 4,226 rare variants predicted to alter the amino acid sequence or gene splicing, and selected 120 LGD mutations and 216 MIS30 mutations for sanger validation. We report an 11-fold increase in the odds of DN LGD mutations compared to expectation under an exome-wide mutational rate model based on chimpanzee–human divergence. In aggregate, ~4% of ASD patients carry a DN mutation in one of just 29 autism risk genes. The most prevalent gene for recurrent DN mutations was SCN2A (1.1% of patients) followed by CHD8, DSCAM, MECP2, POGZ, WDFY3 and ASH1L. We identify novel DN LGD recurrences (GIGYF2, MYT1L, CUL3, DOCK8 and ZNF292) and DN mutations in genes previously implicated in ASD (ARHGAP32, NCOR1, PHIP, STXBP1, CDKL5 and SHANK1). Discussion We have performed an investigation of DN mutations among ASD candidate risk genes in a Chinese ASD patient cohort. Among the 1,045 trios tested, we discovered 43 DN mutations in 29 of the 189 candidate genes queried by our MIP-based approach. DN mutations in SCN2A accounted for ~1.1 % of ASD patients in our Chinese cohort. This rate was higher than exome- and MIP-sequenced ASD cohorts of European descent. Patient follow-up confirms phenotypic features associated with the genetic subtypes and highlights how large global cohorts might be leveraged to identify individually rare mutations in genes that together prove pathogenic significance. Our study helps identify global risk genes providing evidence and motivation for further functional and translational studies of specific ASD risk genes, which may guide future personalized treatments.