1. {{[Identification of candidate genes of autism on the basis of molecular cytogenetic and in silico studies of the genome organization of chromosomal regions involved in unbalanced rearrangements]}}. {Genetika};2010 (Oct);46(10):1348-1351.
Autism is one of the most widely spread mental diseases among children. Different genetic anomalies make a considerable contribution to the etiology of this disease; therefore, the identification of candidate genes of autism can be regarded as a topical task of modern medical genetics. The molecular cytogenetic examination of children with autism was carried out using high-resolution comparative genome hybridization and subsequent in silico analysis of chromosomal regions involved in unbalanced rearrangements. Five of 126 (4%) children with autism had unbalanced rearrangements of chromosomes 5, 17, 21 (deletions) and chromosomes 4 and 22 (duplications). The following candidate genes were identified in children with autism by in silico analysis: SCARB2, TPPP, PDCD6, SEPT5, GP1BB, PI4KA, NPTX1, STCH, NRIP1, and CXADR. These methods also allowed us to find a possible association between gene clusterization and the formation of the described chromosomal rearrangements. Thus, this study demonstrates that the molecular cytogenetic and bioinformatic methods can be successfully used to search for candidate genes of different diseases and analyze the genome organization.
2. Kwakye LD, Foss-Feig JH, Cascio CJ, Stone WL, Wallace MT. {{Altered auditory and multisensory temporal processing in autism spectrum disorders}}. {Front Integr Neurosci};2011;4:129.
Autism spectrum disorders (ASD) are characterized by deficits in social reciprocity and communication, as well as by repetitive behaviors and restricted interests. Unusual responses to sensory input and disruptions in the processing of both unisensory and multisensory stimuli also have been reported frequently. However, the specific aspects of sensory processing that are disrupted in ASD have yet to be fully elucidated. Recent published work has shown that children with ASD can integrate low-level audiovisual stimuli, but do so over an extended range of time when compared with typically developing (TD) children. However, the possible contributions of altered unisensory temporal processes to the demonstrated changes in multisensory function are yet unknown. In the current study, unisensory temporal acuity was measured by determining individual thresholds on visual and auditory temporal order judgment (TOJ) tasks, and multisensory temporal function was assessed through a cross-modal version of the TOJ task. Whereas no differences in thresholds for the visual TOJ task were seen between children with ASD and TD, thresholds were higher in ASD on the auditory TOJ task, providing preliminary evidence for impairment in auditory temporal processing. On the multisensory TOJ task, children with ASD showed performance improvements over a wider range of temporal intervals than TD children, reinforcing prior work showing an extended temporal window of multisensory integration in ASD. These findings contribute to a better understanding of basic sensory processing differences, which may be critical for understanding more complex social and cognitive deficits in ASD, and ultimately may contribute to more effective diagnostic and interventional strategies.
3. Rossignol DA, Frye RE. {{Mitochondrial dysfunction in autism spectrum disorders: a systematic review and meta-analysis}}. {Mol Psychiatry};2011 (Jan 25)
A comprehensive literature search was performed to collate evidence of mitochondrial dysfunction in autism spectrum disorders (ASDs) with two primary objectives. First, features of mitochondrial dysfunction in the general population of children with ASD were identified. Second, characteristics of mitochondrial dysfunction in children with ASD and concomitant mitochondrial disease (MD) were compared with published literature of two general populations: ASD children without MD, and non-ASD children with MD. The prevalence of MD in the general population of ASD was 5.0% (95% confidence interval 3.2, 6.9%), much higher than found in the general population ( approximately 0.01%). The prevalence of abnormal biomarker values of mitochondrial dysfunction was high in ASD, much higher than the prevalence of MD. Variances and mean values of many mitochondrial biomarkers (lactate, pyruvate, carnitine and ubiquinone) were significantly different between ASD and controls. Some markers correlated with ASD severity. Neuroimaging, in vitro and post-mortem brain studies were consistent with an elevated prevalence of mitochondrial dysfunction in ASD. Taken together, these findings suggest children with ASD have a spectrum of mitochondrial dysfunction of differing severity. Eighteen publications representing a total of 112 children with ASD and MD (ASD/MD) were identified. The prevalence of developmental regression (52%), seizures (41%), motor delay (51%), gastrointestinal abnormalities (74%), female gender (39%), and elevated lactate (78%) and pyruvate (45%) was significantly higher in ASD/MD compared with the general ASD population. The prevalence of many of these abnormalities was similar to the general population of children with MD, suggesting that ASD/MD represents a distinct subgroup of children with MD. Most ASD/MD cases (79%) were not associated with genetic abnormalities, raising the possibility of secondary mitochondrial dysfunction. Treatment studies for ASD/MD were limited, although improvements were noted in some studies with carnitine, co-enzyme Q10 and B-vitamins. Many studies suffered from limitations, including small sample sizes, referral or publication biases, and variability in protocols for selecting children for MD workup, collecting mitochondrial biomarkers and defining MD. Overall, this evidence supports the notion that mitochondrial dysfunction is associated with ASD. Additional studies are needed to further define the role of mitochondrial dysfunction in ASD.Molecular Psychiatry advance online publication, 25 January 2011; doi:10.1038/mp.2010.136.
4. Samyn V, Roeyers H, Bijttebier P. {{Effortful control in typically developing boys and in boys with ADHD or autism spectrum disorder}}. {Res Dev Disabil};2011 (Jan 19)
Despite increased interest in the role of effortful control (EC) in developmental disorders, few studies have focused on EC in autism spectrum disorders (ASD) and no study so far has directly compared children with ASD and children with ADHD. A first aim of this study was to investigate whether typically developing (TD) boys, boys with ADHD and boys with ASD can be differentiated based on EC levels. A second aim was to evaluate the relationship between EC and symptoms of ADHD and ASD. We assessed EC in 27 TD boys, 27 boys with ADHD and 27 boys with ASD (age 10-15) using different EC questionnaires. Clinical groups scored lower than the TD group on all EC total scales, but could only be differentiated from each other by means of self-reported persistence, impulsivity and activation control. Our data suggest that although EC is useful in differentiating TD boys from clinical groups, it is less efficient in distinguishing ADHD from ASD. Also, results suggest that EC plays a role in the manifestation of symptoms of both ADHD and ASD and that high levels of EC enable children to function more adequate in daily situations.
5. Soulieres I, Zeffiro TA, Girard ML, Mottron L. {{Enhanced mental image mapping in autism}}. {Neuropsychologia};2011 (Jan 20)
The formation and manipulation of mental images represents a key ability for successfully solving visuospatial tasks like Wechsler’s Block Design or visual reasoning problems, tasks where autistics perform at higher levels than predicted by their Wechsler IQ. Visual imagery can be used to compare two mental images, allowing judgment of their relative properties. To examine higher visual processes in autism, and their possible role in explaining autistic visuospatial peaks, we carried out two mental imagery experiments in 23 autistic and 14 age and IQ matched, non-autistic adolescents and adults. Among autistics, 11 had significantly higher Block Design scores than predicted by their IQ. Experiment 1 involved imagining a letter inside a circle, followed by a decision concerning which of two highlighted portions of the circle would contain the greater proportion of the letter. Experiment 2 involved four classic mental rotation tasks utilizing two- and three-dimensional geometric figures, hands and letters. Autistics were more accurate in the formation and comparison of mental images than non-autistics. Autistics with a Block Design peak outperformed other participants in both speed and accuracy of mental rotation. Also, Performance IQ and Block Design scores were better predictors of mental rotation accuracy in autistic compared to non-autistic participants. The ability to form, access and manipulate visual mental representations may be more developed in autistics. We propose two complementary mechanisms to explain these processing advantages: (1) a global advantage in perceptual processing, discussed in the framework of the Enhanced Perceptual Functioning Model, and (2) particular strengths in veridical mapping, the ability to efficiently detect isomorphisms among entities and then to use these mappings to process stimulus characteristics, thereby facilitating judgments about their differences.
