1. Anderson GM, Hertzig ME, McBride PA. {{Brief Report: Platelet-Poor Plasma Serotonin in Autism}}. {J Autism Dev Disord};2011 (Oct 7)
Possible explanations for the well-replicated platelet hyperserotonemia of autism include an alteration in the platelet’s handling of serotonin (5-hydroxyserotonin, 5-HT) or an increased exposure of the platelet to 5-HT. Measurement of platelet-poor plasma (PPP) levels of 5-HT appears to provide the best available index of in vivo exposure of the platelet to 5-HT. Mean (+/-SD) concentrations of PPP 5-HT observed in the autism (N = 18), hyperserotonemic subgroup (N = 5) and control (N = 24) groups were 0.86 +/- 0.53, 0.87 +/- 0.43 and 0.86 +/- 0.36 nM, respectively. The results suggest that the hyperserotonemia of autism is not due to increased exposure of the platelet to 5-HT and make it more likely that the factor(s) contributing to the hyperserotonemia of autism have to do with the platelet’s handling of 5-HT.
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2. Boyd BA, Woodard CR, Bodfish JW. {{Feasibility of exposure response prevention to treat repetitive behaviors of children with autism and an intellectual disability: a brief report}}. {Autism};2011 (Oct 5)
There is a lack of evidence-based behavioral therapies or pharmacotherapies to treat repetitive behaviors found in autism. Effective behavioral therapies are needed to counter any negative consequences these behaviors may have on the child’s early learning and socialization. The purpose of this proof-of-principle study was to test the feasibility of modifying exposure response prevention, an evidence-based strategy for obsessive-compulsive disorder, to treat the repetitive behaviors found in autism. Five school-aged participants (ages 5-11) diagnosed with an autism spectrum disorder participated in the study. Our preliminary findings suggest it is feasible, and potentially efficacious, to modify standard exposure response prevention to treat the specific forms of repetitive behaviors found in individuals with autism and comorbid intellectual disabilities. A larger clinical trial is needed to substantiate these preliminary findings.
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3. Crane L, Goddard L, Pring L. {{Autobiographical Memory in Adults With Autism Spectrum Disorder: The Role of Depressed Mood, Rumination, Working Memory and Theory of Mind}}. {Autism};2011 (Oct 5)
Autobiographical memory difficulties have been widely reported in adults with autism spectrum disorder (ASD). The aim of the current study was to explore the potential correlates of autobiographical memory performance (including depressed mood, rumination, working memory and theory of mind) in adults with ASD, relative to a group of typical adults matched for age, gender and IQ. Results demonstrated that the adults with ASD reported higher levels of depressed mood and rumination than the typical adults, and also received lower scores on measures of theory of mind and working memory. Correlational analysis suggested that theory of mind and working memory were associated with autobiographical memory performance in the adults with ASD, but no significant relationships were observed between autobiographical memory, depressed mood and rumination in this group. To explore these patterns further, two cases of adults with a dual diagnosis of ASD and depression are discussed. These participants present a profile in line with the idea that depressed mood and rumination do not have the same influence on autobiographical memory in adults with ASD as they do in typical adults.
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4. Demurie E, Roeyers H, Baeyens D, Sonuga-Barke E. {{Common alterations in sensitivity to type but not amount of reward in ADHD and autism spectrum disorders}}. {J Child Psychol Psychiatry};2011 (Nov);52(11):1164-1173.
Background: Children with attention deficit/hyperactivity disorder (ADHD) display abnormalities in reward processing. Most reward studies have focused on the effects of material or monetary rewards. Studies with autism spectrum disorder (ASD) have focused on social rewards. In this study we compared the effects of amount and type of reward in children with ADHD and those with ASD. Methods: Two adapted versions of the Monetary Incentive Delay Task were used to study the effects of monetary and social reward anticipation on performance in 40 typically developing (TD) children and adolescents (8-16y), 35 children and adolescents with ADHD and 31 children and adolescents with ASD. Results: Monetary and social reward improved accuracy and response time (RT) in all groups. The higher the anticipated reward, the more accurate and faster were responses. Independent of these effects, there was a differential effect of reward type. Both clinical groups, but not TD, responded faster for monetary than social rewards. Conclusions: The results, while not supporting hyposensitivity to changes in reward amount in ADHD and ASD, do suggest that both groups are generally less motivated in settings where social as opposed to monetary rewards can be earned.
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5. Enticott PG, Kennedy HA, Rinehart NJ, Tonge BJ, Bradshaw JL, Taffe JR, Daskalakis ZJ, Fitzgerald PB. {{Mirror Neuron Activity Associated with Social Impairments but not Age in Autism Spectrum Disorder}}. {Biol Psychiatry};2011 (Oct 3)
BACKGROUND: The neurobiology of autism spectrum disorder (ASD) is not particularly well understood, and biomedical treatment approaches are therefore extremely limited. A prominent explanatory model suggests that social-relating symptoms may arise from dysfunction within the mirror neuron system, while a recent neuroimaging study suggests that these impairments in ASD might reduce with age. METHODS: Participants with autism spectrum disorder (i.e., DSM-IV autistic disorder or Asperger’s disorder) (n = 34) and matched control subjects (n = 36) completed a transcranial magnetic stimulation study in which corticospinal excitability was assessed during the observation of hand gestures. RESULTS: Regression analyses revealed that the ASD group presented with significantly reduced corticospinal excitability during the observation of a transitive hand gesture (relative to observation of a static hand) (p < .05), which indicates reduced putative mirror neuron system activity within ventral premotor cortex/inferior frontal gyrus. Among the ASD group, there was also a negative association between putative mirror neuron activity and self-reported social-relating impairments, but there was no indication that mirror neuron impairments in ASD decrease with age. CONCLUSIONS: These data provide general support for the mirror neuron hypothesis of autism; researchers now must clarify the precise functional significance of mirror neurons to truly understand their role in the neuropathophysiology of ASD and to determine whether they should be used as targets for the treatment of ASD.
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6. Erickson LC, Scott-Van Zeeland AA, Hamilton G, Lincoln A, Golomb BA. {{Brief Report: Approaches to (31)P-MRS in Awake, Non-Sedated Children with and without Autism Spectrum Disorder}}. {J Autism Dev Disord};2011 (Oct 7)
We piloted a suite of approaches aimed to facilitate a successful series of up to four brain and muscle (31)Phosphorus-Magnetic Resonance Spectroscopy ((31)P-MRS) scans performed in one session in 12 awake, non-sedated subjects (ages 6-18), 6 with autism spectrum disorders (ASD) and 6 controls. We targeted advanced preparation, parental input, physical comfort, short scan protocols, allocation of extra time, and subject emotional support. 100% of subjects completed at least one brain scan and one leg muscle scan: 42 of 46 attempted scans were completed (91%), with failures dominated by exercise muscle scans (completed in 6/6 controls but 3/6 cases). One completed scan lacked usable data unrelated to subject/scan procedure (orthodonture affected a frontal brain scan). As a group, these methods provide a foundation for conduct and enhancement of future MR studies in pediatric subjects with ASD.
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7. Palomo Seldas R. {{[The symptoms of autism spectrum disorders in the first two years of life: a review of longitudinal prospective studies.]}}. {An Pediatr (Barc)};2011 (Oct 7)
The prospective longitudinal studies of infant siblings of children with Autism Spectrum Disorders (ASD) are revolutionising our understanding of the disorder, offering us the opportunity to examine its development in detail from birth. In this paper we will present a detailed summary of the early symptoms that characterise children with autism from birth to two years of age. The description of the symptoms description will be based on the data from longitudinal prospective studies of children with ASD published to date. The review will conclude with research employing retrospective methodologies. We will discuss the ASD symptoms reviewing those in the first and second year separately, as well as the onset patterns of the disorder. We will highlight those symptoms that allow us to differentiate ASD from other developmental disabilities. ASD are defined by a constellation of symptoms. Studies did not find any differences between ASD and typical development at 6 months of age. The data show that the earliest specific manifestations of ASD are not seen until the end of the first year of life and involve a decreased interest in social stimuli. Other social, communicative, symbolic and in some cases, repetitive and stereotyped interests and behaviours gradually appear in the second year of life, as well as atypical sensorial behaviours. In the second year of life the difficulties in sharing interests with others are noticeable. We will conclude by commenting on the relevance of the data reviewed for the theoretical models explaining autism.
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8. Smith SE, Zhou YD, Zhang G, Jin Z, Stoppel DC, Anderson MP. {{Increased gene dosage of ube3a results in autism traits and decreased glutamate synaptic transmission in mice}}. {Sci Transl Med};2011 (Oct 5);3(103):103ra197.
People with autism spectrum disorder are characterized by impaired social interaction, reduced communication, and increased repetitive behaviors. The disorder has a substantial genetic component, and recent studies have revealed frequent genome copy number variations (CNVs) in some individuals. A common CNV that occurs in 1 to 3% of those with autism-maternal 15q11-13 duplication (dup15) and triplication (isodicentric extranumerary chromosome, idic15)-affects several genes that have been suggested to underlie autism behavioral traits. To test this, we tripled the dosage of one of these genes, the ubiquitin protein ligase Ube3a, which is expressed solely from the maternal allele in mature neurons, and reconstituted the three core autism traits in mice: defective social interaction, impaired communication, and increased repetitive stereotypic behavior. The penetrance of these autism traits depended on Ube3a gene copy number. In animals with increased Ube3a gene dosage, glutamatergic, but not GABAergic, synaptic transmission was suppressed as a result of reduced presynaptic release probability, synaptic glutamate concentration, and postsynaptic action potential coupling. These results suggest that Ube3a gene dosage may contribute to the autism traits of individuals with maternal 15q11-13 duplication and support the idea that increased E3A ubiquitin ligase gene dosage results in reduced excitatory synaptic transmission.
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9. Talkowski ME, Mullegama SV, Rosenfeld JA, van Bon BW, Shen Y, Repnikova EA, Gastier-Foster J, Thrush DL, Kathiresan S, Ruderfer DM, Chiang C, Hanscom C, Ernst C, Lindgren AM, Morton CC, An Y, Astbury C, Brueton LA, Lichtenbelt KD, Ades LC, Fichera M, Romano C, Innis JW, Williams CA, Bartholomew D, Van Allen MI, Parikh A, Zhang L, Wu BL, Pyatt RE, Schwartz S, Shaffer LG, de Vries BB, Gusella JF, Elsea SH. {{Assessment of 2q23.1 Microdeletion Syndrome Implicates MBD5 as a Single Causal Locus of Intellectual Disability, Epilepsy, and Autism Spectrum Disorder}}. {Am J Hum Genet};2011 (Oct 7);89(4):551-563.
Persons with neurodevelopmental disorders or autism spectrum disorder (ASD) often harbor chromosomal microdeletions, yet the individual genetic contributors within these regions have not been systematically evaluated. We established a consortium of clinical diagnostic and research laboratories to accumulate a large cohort with genetic alterations of chromosomal region 2q23.1 and acquired 65 subjects with microdeletion or translocation. We sequenced translocation breakpoints; aligned microdeletions to determine the critical region; assessed effects on mRNA expression; and examined medical records, photos, and clinical evaluations. We identified a single gene, methyl-CpG-binding domain 5 (MBD5), as the only locus that defined the critical region. Partial or complete deletion of MBD5 was associated with haploinsufficiency of mRNA expression, intellectual disability, epilepsy, and autistic features. Fourteen alterations, including partial deletions of noncoding regions not typically captured or considered pathogenic by current diagnostic screening, disrupted MBD5 alone. Expression profiles and clinical characteristics were largely indistinguishable between MBD5-specific alteration and deletion of the entire 2q23.1 interval. No copy-number alterations of MBD5 were observed in 7878 controls, suggesting MBD5 alterations are highly penetrant. We surveyed MBD5 coding variations among 747 ASD subjects compared to 2043 non-ASD subjects analyzed by whole-exome sequencing and detected an association with a highly conserved methyl-CpG-binding domain missense variant, p.79Gly>Glu (c.236G>A) (p = 0.012). These results suggest that genetic alterations of MBD5 cause features of 2q23.1 microdeletion syndrome and that this epigenetic regulator significantly contributes to ASD risk, warranting further consideration in research and clinical diagnostic screening and highlighting the importance of chromatin remodeling in the etiology of these complex disorders.
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10. Toth K, Stobbe G. {{Diagnosis of autism spectrum disorders}}. {Pediatr Ann};2011 (Oct);40(10):488-492.
