1. Close HA, Lee LC, Kaufmann CN, Zimmerman AW. {{Co-occurring Conditions and Change in Diagnosis in Autism Spectrum Disorders}}. {Pediatrics};2012 (Jan 23)
OBJECTIVE:This study aimed to investigate descriptive characteristics and co-occurring neurodevelopmental and psychiatric conditions in young children, children, and adolescents with a current and consistent or past but not current (PBNC) diagnosis of autism spectrum disorder (ASD) and how such characteristics and conditions may engender a change in diagnosis of an ASD.METHODS:Cross-sectional data of 1366 children with a parent-reported current or PBNC ASD diagnosis were obtained from the National Survey of Children’s Health 2007 data set across 3 developmental stages: young children (aged 3-5 years), children (aged 6-11 years), and adolescents (aged 12-17 years). Multinomial logistic regression was used to examine demographic characteristics and co-occurring conditions that differentiate the groups with a current ASD from groups with a PBNC ASD.RESULTS:Results indicated the co-occurring conditions that distinguish groups currently diagnosed with an ASD from groups with a PBNC ASD diagnosis. In young children, current moderate/severe learning disability, and current moderate/severe developmental delay; in children, past speech problem, current moderate/severe anxiety, and past hearing problem; and in adolescents, current moderate/severe speech problem, current mild seizure/epilepsy, and past hearing problem.CONCLUSIONS:These findings suggest that the presence of co-occurring psychiatric and neurodevelopmental conditions are associated with a change in ASD diagnosis. Questions remain as to whether changes in diagnosis of an ASD are due to true etiologic differences or shifts in diagnostic determination.
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2. Goh S, Peterson BS. {{Imaging evidence for disturbances in multiple learning and memory systems in persons with autism spectrum disorders}}. {Dev Med Child Neurol};2012 (Jan 23)
Aim The aim of this article is to review neuroimaging studies of autism spectrum disorders (ASD) that examine declarative, socio-emotional, and procedural learning and memory systems. Method We conducted a search of PubMed from 1996 to 2010 using the terms ‘autism, »learning, »memory,’ and ‘neuroimaging.’ We limited our review to studies correlating learning and memory function with neuroimaging features of the brain. Results The early literature supports the following preliminary hypotheses: (1) abnormalities of hippocampal subregions may contribute to autistic deficits in episodic and relational memory; (2) disturbances to an amygdala-based network (which may include the fusiform gyrus, superior temporal cortex, and mirror neuron system) may contribute to autistic deficits in socio-emotional learning and memory; and (3) abnormalities of the striatum may contribute to developmental dyspraxia in individuals with ASD. Interpretation Characterizing the disturbances to learning and memory systems in ASD can inform our understanding of the neural bases of autistic behaviors and the phenotypic heterogeneity of ASD.
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3. Hoeffer CA, Sanchez E, Hagerman RJ, Mu Y, Nguyen DV, Wong H, Whelan AM, Zukin RS, Klann E, Tassone F. {{Altered mTOR signaling and enhanced CYFIP2 expression levels in subjects with Fragile X syndrome}}. {Genes Brain Behav};2012 (Jan 23)
Fragile X Syndrome (FXS) is the most common form of inherited intellectual disability and autism. The protein (FMRP) encoded by the fragile X mental retardation gene (FMR1), is an RNA-binding protein linked to translational control. Recently, in the Fmr1 knockout mouse model of FXS, dysregulated translation initiation signaling was observed. To investigate whether an altered signaling was also a feature of subjects with FXS compared to typical developing controls, we isolated total RNA and translational control proteins from lymphocytes of subjects from both groups (38 FXS and 14 TD). Although we did not observe any difference in the expression level of mRNAs for translational initiation control proteins isolated from participant with FXS, we found increased phosphorylation of the mammalian target of rapamycin (mTOR) substrate, p70 ribosomal subunit 6 kinase1 (S6K1) and of the mTOR regulator, the serine/threonine protein kinase (Akt), in their protein lysates. In addition, we observed increased phosphorylation of the cap binding protein eukaryotic initiation factor 4E (eIF4E) suggesting that protein synthesis is upregulated in FXS. Similarly to the findings in lymphocytes, we observed increased phosphorylation of S6K1 in brain tissue from patients with FXS (n=6) compared to normal age matched controls (n=4). Finally, we detected increased expression of the cytoplasmic FMR1-interacting protein 2 (CYFIP2), a known FMRP interactor. This data verify and extend previous findings using lymphocytes for studies of neuropsychiatric disorders and provide evidence that misregulation of mTOR signaling observed in a FXS mouse model also occurs in human FXS and may provide useful biomarkers for designing target treatments in FXS.
