Pubmed du 27/05/11

Pubmed du jour

2011-05-27 12:03:50

1. Chiang HM, Cheung YK, Hickson L, Xiang R, Tsai LY. {{Predictive Factors of Participation in Postsecondary Education for High School Leavers with Autism}}. {J Autism Dev Disord};2011 (May 27)

This exploratory study was designed to identify the factors predictive of participation in postsecondary education for high school leavers with autism. A secondary data analysis of the National Longitudinal Transition Study 2 (NLTS2) data was performed for this study. Potential predictors of participation in postsecondary education were assessed using a backward logistic regression analysis. This study found that the high school’s primary post-high school goal for the student, parental expectations, high school type, annual household income, and academic performance were significant predictors of participation in postsecondary education. The findings of this current study may provide critical information for parents of children with autism as well as educators and professionals who work with students with autism.

2. Hagerman R, Au J, Hagerman P. {{FMR1 premutation and full mutation molecular mechanisms related to autism}}. {J Neurodev Disord};2011 (May 27)

Fragile X syndrome (FXS) is caused by an expanded CGG repeat (>200 repeats) in the 5′ un-translated portion of the fragile X mental retardation 1 gene (FMR1) leading to a deficiency or absence of the FMR1 protein (FMRP). FMRP is an RNA-binding protein that regulates the translation of a number of other genes that are important for synaptic development and plasticity. Furthermore, many of these genes, when mutated, have been linked to autism in the general population, which may explain the high comorbidity that exists between FXS and autism spectrum disorders (ASD). Additionally, premutation repeat expansions (55 to 200 CGG repeats) may also give rise to ASD through a different molecular mechanism that involves a direct toxic effect of FMR1 mRNA. It is believed that RNA toxicity underlies much of the premutation-related involvement, including developmental concerns like autism, as well as neurodegenerative issues with aging such as the fragile X-associated tremor ataxia syndrome (FXTAS). RNA toxicity can also lead to mitochondrial dysfunction, which is common in older premutation carriers both with and without FXTAS. Many of the problems with cellular dysregulation in both premutation and full mutation neurons also parallel the cellular abnormalities that have been documented in idiopathic autism. Research regarding dysregulation of neurotransmitter systems caused by the lack of FMRP in FXS, including metabotropic glutamate receptor 1/5 (mGluR1/5) pathway and GABA pathways, has led to new targeted treatments for FXS. Preliminary evidence suggests that these new targeted treatments will also be beneficial in non-fragile X forms of autism.

3. Karsten AM, Carr JE, Lepper TL. {{Description of a practitioner model for identifying preferred stimuli with individuals with autism spectrum disorders}}. {Behav Modif};2011 (Jul);35(4):347-369.

The rich technology of stimulus preference assessment (SPA) is a product of 40 years of experimental research. Basic principles of reinforcement and a modest empirical literature suggest that high-preference stimuli identified via SPA may enhance treatment efficacy and decrease problem behavior more effectively than less-preferred stimuli. SPAs can be conducted using one of several methods associated with different time requirements and outcomes. Despite the broad applicability of preference assessments, we are unaware of widely available practitioner guidelines that prescribe when to use SPAs, how to select and modify specific SPA procedures, and how to supplement SPAs with other procedures for maximizing performance. The purpose of the current article is to describe a model for practitioners to select and conduct preference assessments based on practical considerations and research findings. Data are also reported from the application of the proposed model to preference assessments for 20 individuals diagnosed with autism spectrum disorders.

4. Voineagu I, Wang X, Johnston P, Lowe JK, Tian Y, Horvath S, Mill J, Cantor RM, Blencowe BJ, Geschwind DH. {{Transcriptomic analysis of autistic brain reveals convergent molecular pathology}}. {Nature};2011 (May 25)

Autism spectrum disorder (ASD) is a common, highly heritable neurodevelopmental condition characterized by marked genetic heterogeneity. Thus, a fundamental question is whether autism represents an aetiologically heterogeneous disorder in which the myriad genetic or environmental risk factors perturb common underlying molecular pathways in the brain. Here, we demonstrate consistent differences in transcriptome organization between autistic and normal brain by gene co-expression network analysis. Remarkably, regional patterns of gene expression that typically distinguish frontal and temporal cortex are significantly attenuated in the ASD brain, suggesting abnormalities in cortical patterning. We further identify discrete modules of co-expressed genes associated with autism: a neuronal module enriched for known autism susceptibility genes, including the neuronal specific splicing factor A2BP1 (also known as FOX1), and a module enriched for immune genes and glial markers. Using high-throughput RNA sequencing we demonstrate dysregulated splicing of A2BP1-dependent alternative exons in the ASD brain. Moreover, using a published autism genome-wide association study (GWAS) data set, we show that the neuronal module is enriched for genetically associated variants, providing independent support for the causal involvement of these genes in autism. In contrast, the immune-glial module showed no enrichment for autism GWAS signals, indicating a non-genetic aetiology for this process. Collectively, our results provide strong evidence for convergent molecular abnormalities in ASD, and implicate transcriptional and splicing dysregulation as underlying mechanisms of neuronal dysfunction in this disorder.