Autism Science

Impaired Language Pathways in Tuberous Sclerosis Complex Patients with Autism Spectrum Disorders

Source: 
Cerebral Cortex
Date Published: 
June 1, 2012
Abstract: 

"The purpose of this study was to examine the relationship between language pathways and autism spectrum disorders (ASDs) in patients with tuberous sclerosis complex (TSC). "

Genetic and Functional Analyses of SHANK2 Mutations Suggest A Multiple Hit Model of Autism Spectrum Disorders

Source: 
PLOS Genetics
Date Published: 
February 2012
Abstract: 

"Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders with a complex inheritance pattern. While many rare variants in synaptic proteins have been identified in patients with ASD, little is known about their effects at the synapse and their interactions with other genetic variations. Here, following the discovery of two de novo SHANK2 deletions by the Autism Genome Project, we identified a novel 421 kb de novo SHANK2 deletion in a patient with autism. We then sequenced SHANK2 in 455 patients with ASD and 431 controls and integrated these results with those reported by Berkel et al. 2010 (n = 396 patients and n = 659 controls). We observed a significant enrichment of variants affecting conserved amino acids in 29 of 851 (3.4%) patients and in 16 of 1,090 (1.5%) controls (P = 0.004, OR = 2.37, 95% CI = 1.23-4.70). In neuronal cell cultures, the variants identified in patients were associated with a reduced synaptic density at dendrites compared to the variants only detected in controls (P = 0.0013). Interestingly, the three patients with de novo SHANK2 deletions also carried inherited CNVs at 15q11-q13 previously associated with neuropsychiatric disorders. In two cases, the nicotinic receptor CHRNA7 was duplicated and in one case the synaptic translation repressor CYFIP1 was deleted. These results strengthen the role of synaptic gene dysfunction in ASD but also highlight the presence of putative modifier genes, which is in keeping with the "multiple hit model" for ASD. A better knowledge of these genetic interactions will be necessary to understand the complex inheritance pattern of ASD."

The Role of the Amygdala In Atypical Gaze On Emotional Faces In Autism Spectrum Disorders

Source: 
Journal of Neuroscience
Date Published: 
July 11, 2012
Abstract: 

"Reduced focus toward the eyes is a characteristic of atypical gaze on emotional faces in autism spectrum disorders (ASD). Along with the atypical gaze, aberrant amygdala activity during face processing compared with neurotypically developed (NT) participants has been repeatedly reported in ASD. It remains unclear whether the previously reported dysfunctional amygdalar response patterns in ASD support an active avoidance of direct eye contact or rather a lack of social attention. Using a recently introduced emotion classification task, we investigated eye movements and changes in blood oxygen level-dependent (BOLD) signal in the amygdala with a 3T MRI scanner in 16 autistic and 17 control adult human participants. By modulating the initial fixation position on faces, we investigated changes triggered by the eyes compared with the mouth. Between-group interaction effects revealed different patterns of gaze and amygdalar BOLD changes in ASD and NT: Individuals with ASD gazed more often away from than toward the eyes, compared with the NT group, which showed the reversed tendency. An interaction contrast of group and initial fixation position further yielded a significant cluster of amygdala activity. Extracted parameter estimates showed greater response to eyes fixation in ASD, whereas the NT group showed an increase for mouth fixation. The differing patterns of amygdala activity in combination with differing patterns of gaze behavior between groups triggered by direct eye contact and mouth fixation, suggest a dysfunctional profile of the amygdala in ASD involving an interplay of both eye-avoidance processing and reduced orientation."

Structure, Function and Diversity of The Healthy Human Microbiome

Source: 
Nature
Date Published: 
June 13, 2012
Abstract: 

"Studies of the human microbiome have revealed that even healthy individuals differ remarkably in the microbes that occupy habitats such as the gut, skin and vagina. Much of this diversity remains unexplained, although diet, environment, host genetics and early microbial exposure have all been implicated. Accordingly, to characterize the ecology of human-associated microbial communities, the Human Microbiome Project has analysed the largest cohort and set of distinct, clinically relevant body habitats so far. We found the diversity and abundance of each habitat's signature microbes to vary widely even among healthy subjects, with strong niche specialization both within and among individuals. The project encountered an estimated 81-99% of the genera, enzyme families and community configurations occupied by the healthy Western microbiome. Metagenomic carriage of metabolic pathways was stable among individuals despite variation in community structure, and ethnic/racial background proved to be one of the strongest associations of both pathways and microbes with clinical metadata. These results thus delineate the range of structural and functional configurations normal in the microbial communities of a healthy population, enabling future characterization of the epidemiology, ecology and translational applications of the human microbiome."

Fractionation of Social Brain Circuits in Autism Spectrum Disorders

Source: 
Brain
Date Published: 
September 2012
Abstract: 

"Here, we evaluate the hypothesis that decreased connectivity in high-functioning adolescents with an autism spectrum disorder relative to typically developing adolescents is concentrated within domain-specific circuits that are specialized for social processing. Using a novel whole-brain connectivity approach in functional magnetic resonance imaging, we found that not only are decreases in connectivity most pronounced between regions of the social brain but also they are selective to connections between limbic-related brain regions involved in affective aspects of social processing from other parts of the social brain that support language and sensorimotor processes."

Derivation of Autism Spectrum Disorder-specific Induced Pluripotent Stem Cells from Peripheral Blood Mononuclear Cells

Source: 
Neuroscience Letters
Date Published: 
May 10, 2012
Abstract: 

"Induced pluripotent stem cells (iPSCs) hold tremendous potential both as a biological tool to uncover the pathophysiology of disease by creating relevant cell models and as a source of stem cells for cell-based therapeutic applications. Typically, iPSCs have been derived by the transgenic overexpression of transcription factors associated with progenitor cell or stem cell function in fibroblasts derived from skin biopsies. However, the need for skin punch biopsies to derive fibroblasts for reprogramming can present a barrier to study participation among certain populations of individuals, including children with autism spectrum disorders (ASDs). In addition, the acquisition of skin punch biopsies in non-clinic settings presents a challenge. One potential mechanism to avoid these limitations would be the use of peripheral blood mononuclear cells (PBMCs) as the source of the cells for reprogramming. In this article we describe, for the first time, the derivation of iPSC lines from PBMCs isolated from the whole blood of autistic children, and their subsequent differentiation in GABAergic neurons."

Neonatal Levels of Cytokines and Risk of Autism Spectrum Disorders: An Exploratory Register-based Historic Birth Cohort Study Utilizing the Danish Newborn Screening Biobank

Source: 
Journal of Neuroimmunology
Date Published: 
November 15, 2012
Abstract: 

"The aim of the study was to analyze cytokine profiles in neonatal dried blood samples (n-DBSS) retrieved from The Danish Newborn Screening Biobank of children developing Autism Spectrum Disorders (ASD) later in life and controls. Samples of 359 ASD cases and 741 controls were analyzed using Luminex xMAP technology and clinical data were retrieved from nationwide registers. Findings showed that children developing ASD were more likely to have decreased levels of both T helper-1(Th-1)-like cytokines (i.e. IFN-γ) and Th-2like cytokines (i.e. IL-4, IL-10) which may suggest a depressed or hypoactive immune cell activity during neonatal period in ASD."

Design of a Virtual Reality Based Adaptive Response Technology for Children with Autism

Source: 
IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date Published: 
January 4, 2013
Abstract: 

Results from this preliminary study suggest that an interactive virtual reality game can improve social communication skills in teens with ASD.

Modeling an Autism Risk Factor in Mice Leads to Permanent Immune Dysregulation

Source: 
Proceedings of the National Academy of Sciences
Date Published: 
July 31, 2012
Abstract: 

"Increasing evidence highlights a role for the immune system in the pathogenesis of autism spectrum disorder (ASD), as immune dysregulation is observed in the brain, periphery, and gastrointestinal tract of ASD individuals. Furthermore, maternal infection (maternal immune activation, MIA) is a risk factor for ASD. Modeling this risk factor in mice yields offspring with the cardinal behavioral and neuropathological symptoms of human ASD."

Placental Regulation of Maternal-fetal Interactions and Brain Development

Source: 
Developmental Neurobiology
Date Published: 
August 23, 2012
Abstract: 

"A variety prenatal insults are associated with the incidence of neurodevelopmental disorders such as schizophrenia, autism and cerebral palsy. While the precise mechanisms underlying how transient gestational challenges can lead to later life dysfunctions are largely unknown, the placenta is likely to play a key role. The literal interface between maternal and fetal cells resides in the placenta, and disruptions to the maternal or intrauterine environment are necessarily conveyed to the developing embryo via the placenta. Placental cells bear the responsibility of promoting maternal tolerance of the semiallogeneic fetus and regulating selective permeability of nutrients, gases, and antibodies, while still providing physiological protection of the embryo from adversity. The placenta's critical role in modulating immune protection and the availability of nutrients and endocrine factors to the offspring implicates its involvement in autoimmunity, growth restriction and hypoxia, all factors associated with the development of neurological complications. In this review, we summarize primary maternal-fetal interactions that occur in the placenta and describe pathways by which maternal insults can impair these processes and disrupt fetal brain development. We also review emerging evidence for placental dysfunction in the prenatal programming of neurodevelopmental disorders."