1. Egan AM, Dreyer ML, Odar CC, Beckwith M, Garrison CB. {{Obesity in Young Children with Autism Spectrum Disorders: Prevalence and Associated Factors}}. {Child Obes};2013 (Mar 13)
Abstract Background: The purpose of this study was to identify rates of overweight and obesity in young children with autism spectrum disorders (ASD) and factors related to overweight. Methods: Retrospective chart reviews were conducted for 273 children with ASD [i.e., autistic disorder, Asperger’s disorder, pervasive developmental disorder not otherwise specified (PDD-NOS)] after receiving outpatient services with a developmental pediatrician or the developmental team at a children’s hospital. Information on child demographics, height and weight, medications prescribed, and adaptive functioning was collected from charts. Results: Rates of overweight and obesity in children with ASD were found to be above nationally representative prevalence estimates for children. Among children with autistic disorder, 17.16% had a body mass index (BMI) percentile in the overweight range and 21.89% had a BMI percentile in the obese range. For children with Asperger’s disorder/PDD-NOS, 12.50% were considered overweight and 10.58% were considered obese. Neither psychotropic medications prescribed nor adaptive functioning was found to be related to whether the child was overweight or obese. Conclusions: Children with ASD are at risk for overweight and obesity, and children with autistic disorder are at greater risk for weight problems than children with Asperger’s disorder/PDD-NOS. Further research is needed to identify factors related to overweight in children with ASD.
Lien vers le texte intégral (Open Access ou abonnement)
2. Freeth M, Sheppard E, Ramachandran R, Milne E. {{A Cross-Cultural Comparison of Autistic Traits in the UK, India and Malaysia}}. {J Autism Dev Disord};2013 (Mar 15)
The disorder of autism is widely recognised throughout the world. However, the diagnostic criteria and theories of autism are based on research predominantly conducted in Western cultures. Here we compare the expression of autistic traits in a sample of neurotypical individuals from one Western culture (UK) and two Eastern cultures (India and Malaysia), using the Autism-spectrum Quotient (AQ) in order to identify possible cultural differences in the expression of autistic traits. Behaviours associated with autistic traits were reported to a greater extent in the Eastern cultures than the Western culture. Males scored higher than females and science students scored higher than non-science students in each culture. Indian students scored higher than both other groups on the Imagination sub-scale, Malaysian students scored higher than both other groups on the Attention Switching sub-scale. The underlying factor structures of the AQ for each population were derived and discussed.
Lien vers le texte intégral (Open Access ou abonnement)
3. Hawkins M, Boyle J, Wright KE, Elles R, Ramsden SC, O’Grady A, Sweeney M, Barton DE, Burgess T, Moore M, Burns C, Stacey G, Gray E, Metcalfe P, Hawkins JR. {{Preparation and validation of the first WHO international genetic reference panel for Fragile X syndrome}}. {Eur J Hum Genet};2013 (Apr);21(4):478.
Lien vers le texte intégral (Open Access ou abonnement)
4. Iliff AJ, Renoux AJ, Krans A, Usdin K, Sutton MA, Todd PK. {{Impaired activity-dependent FMRP translation and enhanced mGluR-dependent LTD in Fragile X premutation mice}}. {Hum Mol Genet};2013 (Mar 15);22(6):1180-1192.
Fragile X premutation-associated disorders, including Fragile X-associated Tremor Ataxia Syndrome, result from unmethylated CGG repeat expansions in the 5′ untranslated region (UTR) of the FMR1 gene. Premutation-sized repeats increase FMR1 transcription but impair rapid translation of the Fragile X mental retardation protein (FMRP), which is absent in Fragile X Syndrome (FXS). Normally, FMRP binds to RNA and regulates metabotropic glutamate receptor (mGluR)-mediated synaptic translation, allowing for dendritic synthesis of several proteins. FMRP itself is also synthesized at synapses in response to mGluR activation. However, the role of activity-dependent translation of FMRP in synaptic plasticity and Fragile X-premutation-associated disorders is unknown. To investigate this question, we utilized a CGG knock-in mouse model of the Fragile X premutation with 120-150 CGG repeats in the mouse Fmr1 5′ UTR. These mice exhibit increased Fmr1 mRNA production but impaired FMRP translational efficiency, leading to a modest reduction in basal FMRP expression. Cultured hippocampal neurons and synaptoneurosomes derived from CGG KI mice demonstrate impaired FMRP translation in response to the group I mGluR agonist 3,5-dihydroxyphenylglycine. Electrophysiological analysis reveals enhanced mGluR-mediated long-term depression (mGluR-LTD) at CA3-CA1 synapses in acute hippocampal slices prepared from CGG KI mice relative to wild-type littermates, similar to Fmr1 knockout mice. However, unlike mGluR-LTD in mice completely lacking FMRP, mGluR-LTD in CGG knock-in mice remains dependent on new protein synthesis. These studies demonstrate partially overlapping synaptic plasticity phenotypes in mouse models of FXS and Fragile X premutation disorders and support a role for activity-dependent synthesis of FMRP in enduring forms of synaptic plasticity.
Lien vers le texte intégral (Open Access ou abonnement)
5. Lloyd-Fox S, Blasi A, Elwell CE, Charman T, Murphy D, Johnson MH. {{Reduced neural sensitivity to social stimuli in infants at risk for autism}}. {Proc Biol Sci};2013;280(1758):20123026.
In the hope of discovering early markers of autism, attention has recently turned to the study of infants at risk owing to being the younger siblings of children with autism. Because the condition is highly heritable, later-born siblings of diagnosed children are at substantially higher risk for developing autism or the broader autism phenotype than the general population. Currently, there are no strong predictors of autism in early infancy and diagnosis is not reliable until around 3 years of age. Because indicators of brain functioning may be sensitive predictors, and atypical social interactions are characteristic of the syndrome, we examined whether temporal lobe specialization for processing visual and auditory social stimuli during infancy differs in infants at risk. In a functional near-infrared spectroscopy study, infants aged 4-6 months at risk for autism showed less selective neural responses to social stimuli (auditory and visual) than low-risk controls. These group differences could not be attributed to overall levels of attention, developmental stage or chronological age. Our results provide the first demonstration of specific differences in localizable brain function within the first 6 months of life in a group of infants at risk for autism. Further, these differences closely resemble known patterns of neural atypicality in children and adults with autism. Future work will determine whether these differences in infant neural responses to social stimuli predict either later autism or the broader autism phenotype frequently seen in unaffected family members.
Lien vers le texte intégral (Open Access ou abonnement)
6. Strickland DC, Coles CD, Southern LB. {{JobTIPS: A Transition to Employment Program for Individuals with Autism Spectrum Disorders}}. {J Autism Dev Disord};2013 (Mar 15)
This study evaluated the effectiveness of an internet accessed training program that included Theory of Mind-based guidance, video models, visual supports, and virtual reality practice sessions in teaching appropriate job interview skills to individuals with high functioning Autism Spectrum Disorders. In a randomized study, twenty-two youth, ages 16-19, were evaluated during two employment interviews. Half received a training intervention following the initial interview and the half who served as a contrast group did not. Their performance pre and post intervention was assessed by four independent raters using a scale that included evaluation of both Content and Delivery. Results suggest that youth who completed the JobTIPS employment program demonstrated significantly more effective verbal content skills than those who did not.
Lien vers le texte intégral (Open Access ou abonnement)
7. Takeuchi K, Gertner MJ, Zhou J, Parada LF, Bennett MV, Zukin RS. {{Dysregulation of synaptic plasticity precedes appearance of morphological defects in a Pten conditional knockout mouse model of autism}}. {Proc Natl Acad Sci U S A};2013 (Mar 4)
The phosphoinositide signaling system is a crucial regulator of neural development, cell survival, and plasticity. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) negatively regulates phosphatidylinositol 3-kinase signaling and downstream targets. Nse-Cre Pten conditional knockout mice, in which Pten is ablated in granule cells of the dentate gyrus and pyramidal neurons of the hippocampal CA3, but not CA1, recapitulate many of the symptoms of humans with inactivating PTEN mutations, including progressive hypertrophy of the dentate gyrus and deficits in hippocampus-based social and cognitive behaviors. However, the impact of Pten loss on activity-dependent synaptic plasticity in this clinically relevant mouse model of Pten inactivation remains unclear. Here, we show that two phosphatidylinositol 3-kinase- and protein synthesis-dependent forms of synaptic plasticity, theta burst-induced long-term potentiation and metabotropic glutamate receptor (mGluR)-dependent long-term depression, are dysregulated at medial perforant path-to-dentate gyrus synapses of young Nse-Cre Pten conditional knockout mice before the onset of visible morphological abnormalities. In contrast, long-term potentiation and mGluR-dependent long-term depression are normal at CA3-CA1 pyramidal cell synapses at this age. Our results reveal that deletion of Pten in dentate granule cells dysregulates synaptic plasticity, a defect that may underlie abnormal social and cognitive behaviors observed in humans with Pten inactivating mutations and potentially other autism spectrum disorders.
