1. An JY, Claudianos C. {{Genetic heterogeneity in autism: From single gene to a pathway perspective}}. {Neurosci Biobehav Rev}. 2016.
The extreme genetic heterogeneity of autism spectrum disorder (ASD) represents a major challenge. Recent advances in genetic screening and systems biology approaches have extended our knowledge of the genetic etiology of ASD. In this review, we discuss the paradigm shift from a single gene causation model to pathway perturbation model as a guide to better understand the pathophysiology of ASD. We discuss recent genetic findings obtained through next-generation sequencing (NGS) and examine various integrative analyses using systems biology and complex networks approaches that identify convergent patterns of genetic elements associated with ASD.
Lien vers le texte intégral (Open Access ou abonnement)
2. Dean OM, Gray KM, Villagonzalo KA, Dodd S, Mohebbi M, Vick T, Tonge BJ, Berk M. {{A randomised, double blind, placebo-controlled trial of a fixed dose of N-acetyl cysteine in children with autistic disorder}}. {Aust N Z J Psychiatry}. 2016.
OBJECTIVE: Oxidative stress, inflammation and heavy metals have been implicated in the aetiology of autistic disorder. N-acetyl cysteine has been shown to modulate these pathways, providing a rationale to trial N-acetyl cysteine for autistic disorder. There are now two published pilot studies suggesting efficacy, particularly in symptoms of irritability. This study aimed to explore if N-acetyl cysteine is a useful treatment for autistic disorder. METHOD: This was a placebo-controlled, randomised clinical trial of 500 mg/day oral N-acetyl cysteine over 6 months, in addition to treatment as usual, in children with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision diagnosis of autistic disorder. The study was conducted in Victoria, Australia. The primary outcome measures were the Social Responsiveness Scale, Children’s Communication Checklist-Second Edition and the Repetitive Behavior Scale-Revised. Additionally, demographic data, the parent-completed Vineland Adaptive Behavior Scales, Social Communication Questionnaire and clinician-administered Autism Diagnostic Observation Schedule were completed. RESULTS: A total of 102 children were randomised into the study, and 98 (79 male, 19 female; age range: 3.1-9.9 years) attended the baseline appointment with their parent/guardian, forming the Intention to Treat sample. There were no differences between N-acetyl cysteine and placebo-treated groups on any of the outcome measures for either primary or secondary endpoints. There was no significant difference in the number and severity of adverse events between groups. CONCLUSION: This study failed to demonstrate any benefit of adjunctive N-acetyl cysteine in treating autistic disorder. While this may reflect a true null result, methodological issues particularly the lower dose utilised in this study may be confounders.
Lien vers le texte intégral (Open Access ou abonnement)
3. Johnson CR, DeMand A, Lecavalier L, Smith T, Aman M, Foldes E, Scahill L. {{Psychometric properties of the children’s sleep habits questionnaire in children with autism spectrum disorder}}. {Sleep Med}. 2016; 20: 5-11.
BACKGROUND AND PURPOSE: Sleep disturbances in autism spectrum disorder (ASD) are very common. Psychometrically sound instruments are essential to assess these disturbances. Children’s Sleep Habit Questionnaire (CSHQ) is a widely used measure in ASD. The purpose of this study was to explore the psychometric properties of the CSHQ in a sample of children with ASD. PARTICIPANTS AND METHODS: Parents/caregivers of 310 children (mean age: 4.7) with ASD completed the CSHQ at study enrollment. Correlations between intelligence quotient (IQ) scores and the original CSHQ scales were calculated. Item endorsement frequencies and percentages were also calculated. A principal component analysis (PCA) was performed, and internal consistency was assessed for the newly extracted components. RESULTS: Correlations between IQ scores and CSHQ subscales and total scores ranged from .015 to .001 suggesting a weak, if any, association. Item endorsement frequencies were high for bedtime resistance items, but lower for parasomnia and sleep-disordered breathing items. A PCA suggested that a five-component solution best fits the data. Internal consistency of the newly extracted five components ranged alpha = .87-.50. CONCLUSIONS: Item endorsement frequencies were highest for bedtime resistance items. A PCA suggested a five-component solution. Three of the five components (Sleep Routine Problems, Insufficient Sleep, and Sleep-onset Association Problems) were types of sleep disturbances commonly reported in ASD, but the other two components (Parasomnia/Sleep-disordered Breathing and Sleep Anxiety) were less clear. Internal consistencies ranged from mediocre to good. Further development of this measure for use in children with ASD is encouraged.
Lien vers le texte intégral (Open Access ou abonnement)
4. Low Kapalu CM, Gartstein MA. {{Boys with fragile X syndrome: investigating temperament in early childhood}}. {J Intellect Disabil Res}. 2016.
BACKGROUND: Fragile X syndrome (FXS) is an x-linked genetic disorder that represents the most common hereditary cause of Intellectual Disability (ID). Very specific behavioural features (e.g. attention deficit hyperactivity disorder and stereotyped behaviour) are associated with FXS in adolescents and adults, yet research on temperament and behavioural characteristics in young children with FXS has been more limited and less conclusive. METHOD: This study investigated temperament differences in young boys (3-7 years old) with FXS (N = 26) recruited from a national FXS centre and controls (N = 26) matched on age, gender and race. RESULTS: Compared with controls, boys with FXS exhibited less overall surgency/extraversion and effortful control. Boys with FXS also displayed significantly greater activity and shyness and less attentional focusing, inhibitory control, soothability and high intensity pleasure (tendency to enjoy intense/complex activities), relative to comparison children. A significant interaction between age and diagnosis (FXS or control) was observed for negative affectivity only. CONCLUSIONS: Attention difficulties commonly found in adolescents and adults with FXS appear to also be characteristic of young boys with FXS, as reflected by lower effortful control. Age-related findings concerning negative affectivity may be particularly significant, leading to improved intervention/preventative efforts.
Lien vers le texte intégral (Open Access ou abonnement)
5. McMahon AC, Rosbash M. {{Promiscuous or discriminating: Has the favored mRNA target of Fragile X Mental Retardation Protein been overlooked?}}. {Proc Natl Acad Sci U S A}. 2016.
Lien vers le texte intégral (Open Access ou abonnement)
6. Raut MS, Maheshwari A, Dubey S, Shivnani G, Makhija A, Mohanty A. {{Eustachian valve – Masquerading ASD rim}}. {Indian Heart J}. 2016; 68(3): 368-9.
Lien vers le texte intégral (Open Access ou abonnement)
7. Zhang S, Johnson CM, Cui N, Xing H, Zhong W, Wu Y, Jiang C. {{An optogenetic mouse model of rett syndrome targeting on catecholaminergic neurons}}. {J Neurosci Res}. 2016.
Rett syndrome (RTT) is a neurodevelopmental disorder affecting multiple functions, including the norepinephrine (NE) system. In the CNS, NE is produced mostly by neurons in the locus coeruleus (LC), where defects in intrinsic neuronal properties, NE biosynthetic enzymes, neuronal CO2 sensitivity, and synaptic currents have been reported in mouse models of RTT. LC neurons in methyl-CpG-binding protein 2 gene (Mecp2) null mice show a high rate of spontaneous firing, although whether such hyperexcitability might increase or decrease the NE release from synapses is unknown. To activate the NEergic axonal terminals selectively, we generated an optogenetic mouse model of RTT in which NEergic neuronal excitability can be manipulated with light. Using commercially available mouse breeders, we produced a new strain of double-transgenic mice with Mecp2 knockout and channelrhodopsin (ChR) knockin in catecholaminergic neurons. Several RTT-like phenotypes were found in the tyrosine hydroxylase (TH)-ChR-Mecp2-/Y mice, including hypoactivity, low body weight, hindlimb clasping, and breathing disorders. In brain slices, optostimulation produced depolarization and an increase in the firing rate of LC neurons from TH-ChR control mice. In TH-ChR control mice, optostimulation of presynaptic NEergic neurons augmented the firing rate of hypoglossal neurons (HNs), which was blocked by the alpha-adrenoceptor antagonist phentolamine. Such optostimulation of NEergic terminals had almost no effect on HNs from two or three TH-ChR-Mecp2-/Y mice, indicating that excessive excitation of presynaptic neurons does not benefit NEergic modulation in mice with Mecp2 disruption. These results also demonstrate the feasibility of generating double-transgenic mice for studies of RTT with commercially available mice, which are inexpensive, labor/time efficient, and promising for cell-specific stimulation. (c) 2016 Wiley Periodicals, Inc.
