Global prevalence of autism and other pervasive developmental disorders

A randomized double blind placebo controlled clinical trial of N-Acetylcysteine added to risperidone for treating autistic disorders

BACKGROUND

This study examined the efficacy and safety of N-acetylcysteine (NAC) augmentation for treating irritability in children and adolescents with autism spectrum disorders (ASD).

METHOD

Forty children and adolescents met diagnostic criteria for ASD according to DSM-IV. They were randomly allocated into one of the two groups of NAC (1200 mg/day)+risperidone or placebo+risperidone. NAC and placebo were administered in the form of effervescent and in two divided doses for 8 weeks. Irritability subscale score of Aberrant Behavior Checklist (ABC) was considered as the main outcome measure. Adverse effects were also checked.

RESULTS

The mean score of irritability in the NAC+risperidone and placebo+risperidone groups at baseline was 13.2(5.3) and 16.7(7.8), respectively. The scores after 8 weeks were 9.7(4.1) and 15.1(7.8), respectively. Repeated measures of ANOVA showed that there was a significant difference between the two groups after 8 weeks. The most common adverse effects in the NAC+risperidone group were constipation (16.1%), increased appetite (16.1%), fatigue (12.9%), nervousness (12.9%), and daytime drowsiness (12.9%). There was no fatal adverse effect.

CONCLUSIONS

Risperidone plus NAC more than risperidone plus placebo decreased irritability in children and adolescents with ASD. Meanwhile, it did not change the core symptoms of autism. Adverse effects were not common and NAC was generally tolerated well.

TRIAL REGISTRATION

This trial was registered at http://www.irct.ir. The registration number of this trial was IRCT201106103930N6.

The genetic landscapes of autism spectrum disorders

The autism spectrum disorders (ASD) are characterized by impairments in social interaction and stereotyped behaviors. For the majority of individuals with ASD, the causes of the disorder remain unknown; however, in up to 25% of cases, a genetic cause can be identified. Chromosomal rearrangements as well as rare and de novo copy-number variants are present in ∼10-20% of individuals with ASD, compared with 1-2% in the general population and/or unaffected siblings. Rare and de novo coding-sequence mutations affecting neuronal genes have also been identified in ∼5-10% of individuals with ASD. Common variants such as single-nucleotide polymorphisms seem to contribute to ASD susceptibility, but, taken individually, their effects appear to be small. Despite a heterogeneous genetic landscape, the genes implicated thus far-which are involved in chromatin remodeling, metabolism, mRNA translation, and synaptic function-seem to converge in common pathways affecting neuronal and synaptic homeostasis. Animal models developed to study these genes should lead to a better understanding of the diversity of the genetic landscapes of ASD.

Current progress and challenges in the search for autism biomarkers

Autism spectrum disorders (ASD) encompass a range of neurodevelopmental conditions that are clinically and etiologically very heterogeneous. ASD is currently diagnosed entirely on behavioral criteria, but intensive research efforts are focused on identifying biological markers for disease risk and early diagnosis. Here, we discuss recent progress toward identifying biological markers for ASD and highlight specific challenges as well as ethical aspects of translating ASD biomarker research into the clinic.

Ketogenic diet improves core symptoms of autism in BTBR mice

Autism spectrum disorders share three core symptoms: impaired sociability, repetitive behaviors and communication deficits. Incidence is rising, and current treatments are inadequate. Seizures are a common comorbidity, and since the 1920's a high-fat, low-carbohydrate ketogenic diet has been used to treat epilepsy. Evidence suggests the ketogenic diet and analogous metabolic approaches may benefit diverse neurological disorders. Here we show that a ketogenic diet improves autistic behaviors in the BTBR mouse. Juvenile BTBR mice were fed standard or ketogenic diet for three weeks and tested for sociability, self-directed repetitive behavior, and communication. In separate experiments, spontaneous intrahippocampal EEGs and tests of seizure susceptibility (6 Hz corneal stimulation, flurothyl, SKF83822, pentylenetetrazole) were compared between BTBR and control (C57Bl/6) mice. Ketogenic diet-fed BTBR mice showed increased sociability in a three-chamber test, decreased self-directed repetitive behavior, and improved social communication of a food preference. Although seizures are a common comorbidity with autism, BTBR mice fed a standard diet exhibit neither spontaneous seizures nor abnormal EEG, and have increased seizure susceptibility in just one of four tests. Thus, behavioral improvements are dissociable from any antiseizure effect. Our results suggest that a ketogenic diet improves multiple autistic behaviors in the BTBR mouse model. Therefore, ketogenic diets or analogous metabolic strategies may offer novel opportunities to improve core behavioral symptoms of autism spectrum disorders.

Prosocial effects of oxytocin in two mouse models of autism spectrum disorders

Clinical evidence suggests that oxytocin treatment improves social deficits and repetitive behavior in autism spectrum disorders (ASDs). However, the neuropeptide has a short plasma half-life and poor ability to penetrate the blood-brain barrier. In order to facilitate the development of more bioavailable oxytocinergic compounds as therapeutics to treat core ASD symptoms, small animal models must be validated for preclinical screens. This study examined the preclinical utility of two inbred mouse strains, BALB/cByJ and C58/J, that exhibit phenotypes relevant to core ASD symptoms. Mice from both strains were intraperitoneally administered oxytocin, using either acute or sub-chronic regimens. Acute oxytocin did not increase sociability in BALB/cByJ; however, sub-chronic oxytocin had significant prosocial effects in both BALB/cByJ and C58/J. Increased sociability was observed 24 h following the final oxytocin dose in BALB/cByJ, while prosocial effects of oxytocin emerged 1-2 weeks post-treatment in C58/J. Furthermore, acute oxytocin decreased motor stereotypy in C58/J and did not induce hypoactivity or anxiolytic-like effects in an open field test. This study demonstrates that oxytocin administration can attenuate social deficits and repetitive behavior in mouse models of ASD, dependent on dose regimen and genotype. These findings provide validation of the BALB/cByJ and C58/J models as useful platforms for screening novel drugs for intervention in ASDs and for elucidating the mechanisms contributing to the prosocial effects of oxytocin.

Possible use of Trichuris suis ova in autism spectrum disorders therapy

Autism and autism spectrum disorders (ASDs) are heterogeneous, severe neurodevelopmental pathologies. The main core symptoms are: dysfunctions in social interactions and communication skills, restricted interests, repetitive and stereotypic verbal and non-verbal behaviors. Several biochemical processes are associated with ASDs: oxidative stress; endoplasmic reticulum stress; decreased methylation capacity; limited production of glutathione; mitochondrial dysfunction; intestinal dysbiosis; increased toxic metal burden; immune dysregulation. Current available treatments for ASDs can be divided into behavioral, nutritional and medical approaches, although no defined standard approach exists. Current drugs fail to benefit the ASD core symptoms and can have marked adverse effects, are mainly palliative and only sometimes efficacy in attenuating specific autistic behaviors. Helminthic therapy shows potential for application as anti-inflammatory agent. Several human diseases can be treated by helminths (i.e. inflammatory bowel disease, asthma, multiple sclerosis and autoimmune diabetes). Trichuris suis ova (TSO) show strong immunomodulatory properties. Authors hypothesize that TSO could be useful in addressing ASD immune dysregulations. TSO could be a novel therapeutic option for ASD management.

Prevalence of autism spectrum disorders among children in China: a systematic review

BACKGROUND

There are no reliable estimates of the prevalences of autism and autism spectrum disorders (ASD) in China.

OBJECTIVE

Combine results across studies to estimate the prevalences of autism and ASD among Chinese children under the age of 18, and assess variations in the prevalences with respect to gender, ethnicity, and urban versus rural residence.

METHODS

Based on pre-defined inclusion and exclusion criteria, studies were identified by searching the following databases: Chinese National Knowledge Infrastructure, Chongqing VIP database for Chinese Technical Periodicals, WANFANG DATA, Chinese Biological Medical Literature Database, Pubmed, and Web of Science. Statistical analysis was conducted using R-2.15.2 software.

RESULTS

The 24 studies meeting inclusion criteria included 5 registry studies from Taiwan and Hong Kong (covering a total of 14570 369 children) and 19 community-based screening and diagnostic studies from mainland China (with a combined sample of 771 413 children). The annually reported prevalence of autism in the registry studies ranged from 1.8 to 424.6 per 10 000. A meta-analysis of 18 of the studies from mainland China (excluding a large nationwide study with the lowest prevalence of autism) with a range in rates from 2.8 to 30.4 per 10 000 generated an estimated pooled prevalence of autism of 12.8 per 10 000 (95%CI, 9.4 to 17.5). The pooled prevalence of ASD estimated from 5 of these studies (which had a range in rates from 7.3 to 75.3 per 10 000) was 24.5 per 10000 (95%CI, 10.4 to 57.4). The reported prevalence of autism varied substantially by gender, location of residence, date of publication, and source of the sample.

CONCLUSION

The huge difference between the rates for autism reported from registry systems in Hong Kong and Taiwan (a 200-fold difference) and the large differences in rates reported from community-based screening studies in mainland China (a 10- to 15-fold difference) highlight the urgent need for establishing standardized methods for estimating the prevalences of autism and ASD. Until these methodological improvements have been made, it will not be possible to develop evidence-based prevention and treatment strategies for the management of these uncommon but seriously disabling conditions.

Reading comprehension in autism spectrum disorders: the role of oral language and social functioning

Reading comprehension is an area of difficulty for many individuals with autism spectrum disorders (ASD). According to the Simple View of Reading, word recognition and oral language are both important determinants of reading comprehension ability. We provide a novel test of this model in 100 adolescents with ASD of varying intellectual ability. Further, we explore whether reading comprehension is additionally influenced by individual differences in social behaviour and social cognition in ASD. Adolescents with ASD aged 14-16 years completed assessments indexing word recognition, oral language, reading comprehension, social behaviour and social cognition. Regression analyses show that both word recognition and oral language explain unique variance in reading comprehension. Further, measures of social behaviour and social cognition predict reading comprehension after controlling for the variance explained by word recognition and oral language. This indicates that word recognition, oral language and social impairments may constrain reading comprehension in ASD.

Job Burnout among Iranian Elementary School Teachers of Students with Autism: a Comparative Study

OBJECTIVE

Teachers often experience burnout and challenges during their active career. Different studies have shown that those directly involved with teaching children with special needs are more subject to burnout. Due to advance screening tools, more children with autism are now diagnosed and involved in special education. The aim of the present study was to investigate the professional burnout in teachers of children with autism compared to teachers of other children with special needs.

METHODS

Casual Comparative study design was used for this research. Three self-reported measures (Maslach Burnout Inventory, Job Descriptive Index, and General Health Questionnaire) were distributed; clustered sampling selection was conducted to select participants. Ninety three female teachers (32 teachers of children with autism, 30 teachers in schools for deaf and 31 for teachers of children with mental retardation) from 12 schools located in 4 districts of Tehran were selected. Pearson's and Spearman's correlation statistical tests, analysis of variances and regression were used to analyze the results.

RESULTS

Results of the current study revealed a significant difference in criterion validity between the three groups of teachers The three groups were different in terms of general health (p=0.010), emotional exhaustion (p=0.005) and depersonalization (p<0.001); however considering other variables no significant differences were observed. Comparison between groups showed that the average scores of teachers of children with autism were significantly higher than teachers of deaf and hard of hearing and mentally retarded children in general health, fatigue, and depersonalization variables. No significant differences were observed in average scores of teachers for mentally retarded and deaf children.

CONCLUSIONS

Female teachers' of children with autism are experiencing significantly higher levels of burnout and general mental health problems compared to teachers of children with other disabilities requiring special education.

Insights on the functional impact of microRNAs present in autism-associated copy number variants

Autism spectrum disorder is a complex neurodevelopmental disorder that appears during the first three years of infancy and lasts throughout a person’s life. Recently a large category of genomic structural variants, denoted as copy number variants (CNVs), were established to be a major contributor of the pathophysiology of autism. To date almost all studies have focussed only on the genes present in the CNV loci, but the impact of non-coding regulatory microRNAs (miRNAs) present in these regions remain largely unexplored. Hence we attempted to elucidate the biological and functional significance of miRNAs present in autism-associated CNV loci and their target genes by using a series of computational tools. We demonstrate that nearly 11% of the CNV loci harbor miRNAs and a few of these miRNAs were previously reported to be associated with autism. A systematic analysis of the CNV-miRNAs based on their interactions with the target genes enabled the identification of top 10 miRNAs namely hsa-miR-590-3p, hsa-miR-944, hsa-miR-570, hsa-miR-34a, hsa-miR-124, hsa-miR-548f, hsa-miR-429, hsa-miR-200b, hsa-miR-195 and hsa-miR-497 as hub molecules. Further, the CNV-miRNAs formed a regulatory loop with transcription factors and their downstream target genes, and annotation of these target genes indicated their functional involvement in neurodevelopment and synapse. Moreover, miRNAs present in deleted and duplicated CNV loci may explain the difference in dosage of the crucial genes controlled by them. These CNV-miRNAs can also impair the global processing and biogenesis of all miRNAs by targeting key molecules in the miRNA pathway. To our knowledge, this is the first report to highlight the significance of CNV-microRNAs and their target genes to contribute towards the genetic heterogeneity and phenotypic variability of autism.

Levels of heavy metals and essential minerals in hair samples of children with autism in Oman: a case-control study

Toxic levels of heavy metals and low levels of essential minerals have been suggested to play a critical role in the pathogenesis of autism spectrum disorders (ASD). This study documents the levels of heavy metals and essential minerals in hair samples of children with ASD in Muscat, the urbanized capital of Oman, Muscat. The study included 27 children with ASD and 27 matched non-ASD controls. Parental interviews were held and dietary intake questionnaires completed in conjunction with the collection of hair samples. Analysis of heavy metals and essential minerals was carried out by inductively coupled plasma mass spectrometry. Chi-square analysis and non-parametric Fisher's exact tests were used to assess statistical significance. Children with ASD had significantly higher levels of all 11 analyzed heavy metals in their hair samples (P < 0.05), ranging from 150 to 365 % of control levels. ASD children also had significantly higher levels of essential minerals sulfur, sodium, magnesium, potassium, zinc, and iron, but lower levels of calcium and copper in their hair samples. This study corroborates data from previous studies in different parts of the world indicating the presence of elevated levels of heavy metals and selective depletion of essential minerals in the hair of children with ASD.

Association analysis of two single-nucleotide polymorphisms of the RELN gene with autism in the South African population

BACKGROUND

Autism (MIM209850) is a neurodevelopmental disorder characterized by a triad of impairments, namely impairment in social interaction, impaired communication skills, and restrictive and repetitive behavior. A number of family and twin studies have demonstrated that genetic factors play a pivotal role in the etiology of autistic disorder. Various reports of reduced levels of reelin protein in the brain and plasma in autistic patients highlighted the role of the reelin gene (RELN) in autism. There is no such published study on the South African (SA) population.

AIMS

The aim of the present study was to find the genetic association of intronic rs736707 and exonic rs362691 (single-nucleotide polymorphisms [SNPs] of the RELN gene) with autism in a SA population.

METHODS

Genomic DNA was isolated from cheek cell swabs from autistic (136) as well as control (208) subjects. The TaqMan(®) Real-Time polymerase chain reaction and genotyping assay was utilized to determine the genotypes.

RESULTS

A significant association of SNP rs736707, but not for SNP rs362691, with autism in the SA population is observed.

CONCLUSION

There might be a possible role of RELN in autism, especially for SA populations. The present study represents the first report on genetic association studies on the RELN gene in the SA population.

Clinical outcomes of an early intervention program for preschool children with Autism Spectrum Disorder in a community group setting

Background

Available evidence indicates that early intervention programs, such as the Early Start Denver Model (ESDM), can positively affect key outcomes for children with Autism Spectrum Disorder (ASD). However, programs involving resource intensive one-to-one clinical intervention are not readily available or deliverable in the community, resulting in many children with ASD missing out on evidence-based intervention during their early and most critical preschool years. This study evaluated the effectiveness of the ESDM for preschool-aged children with ASD using a predominantly group-based intervention in a community child care setting.

Methods

Participants were 26 children (21 male) with ASD with a mean age of 49.6 months. The ESDM, a comprehensive early intervention program that integrates applied behaviour analysis with developmental and relationship-based approaches, was delivered by trained therapists during the child’s attendance at a child care centre for preschool-aged children with ASD. Children received 15–20 hours of group-based, and one hour of one-to-one, ESDM intervention per week. The average intervention period was ten months. Outcome measures were administered pre- and post-intervention, and comprised a developmental assessment - the Mullen Scales of Early Learning (MSEL); and two parent-report questionnaires - the Social Communication Questionnaire (SCQ) and Vineland Adaptive Behaviours Scales–Second Edition (VABS-II).

Results

Statistically significant post-intervention improvements were found in children’s performance on the visual reception, receptive language and expressive language domains of the MSEL in addition to their overall intellectual functioning, as assessed by standardised developmental quotients. Parents reported significant increases in their child’s receptive communication and motor skills on the VABS-II, and a significant decrease in autism-specific features on the SCQ. These effects were of around medium size, and appeared to be in excess of what may have been expected due to maturation. Nonetheless, these results need to be confirmed in a controlled study.

Conclusions

This study suggests community dissemination of the ESDM using predominantly group-based intervention may be an effective intervention. Making the ESDM accessible to the wider ASD community in child care settings has the potential for significant clinical and economic benefits. Further studies are indicated in this area, including those with younger children, and which incorporate a control group and standardised ASD assessments.

Trial registration

This trial is registered with the Australian New Zealand Clinical Trials Registry: Registry number ACTRN12612000461897.

A randomised controlled trial of bumetanide in the treatment of autism in children

Gamma aminobutyric acid (GABA)-mediated synapses and the oscillations they orchestrate are altered in autism. GABA-acting benzodiazepines exert in some patients with autism paradoxical effects, raising the possibility that like in epilepsies, GABA excites neurons because of elevated intracellular concentrations of chloride. Following a successful pilot study,(1) we have now performed a double-blind clinical trial using the diuretic, chloride-importer antagonist bumetanide that reduces intracellular chloride reinforcing GABAergic inhibition. Sixty children with autism or Asperger syndrome (3-11 years old) received for 3 months placebo or bumetanide (1 mg daily), followed by 1-month wash out. Determination of the severity of autism was made with video films at day 0 (D0) and D90 by blind, independent evaluators. Bumetanide reduced significantly the Childhood Autism Rating Scale (CARS) (D90-D0; P<0.004 treated vs placebo), Clinical Global Impressions (P<0.017 treated vs placebo) and Autism Diagnostic Observation Schedule values when the most severe cases (CARS values above the mean ± s.d.; n=9) were removed (Wilcoxon test: P-value=0.031; Student's t-test: P-value=0.017). Side effects were restricted to an occasional mild hypokalaemia (3.0-3.5 mM l(-1) K(+)) that was treated with supplemental potassium. In a companion study, chronic bumetanide treatment significantly improved accuracy in facial emotional labelling, and increased brain activation in areas involved in social and emotional perception (Hadjikhani et al., submitted). Therefore, bumetanide is a promising novel therapeutic agent to treat autism. Larger trials are warranted to better determine the population best suited for this treatment.

Differential brain responses to cries of infants with autistic disorder and typical development: an fMRI study

This study used fMRI to measure brain activity during adult processing of cries of infants with autistic disorder (AD) compared to cries of typically developing (TD) infants. Using whole brain analysis, we found that cries of infants with AD compared to those of TD infants elicited enhanced activity in brain regions associated with verbal and prosodic processing, perhaps because altered acoustic patterns of AD cries render them especially difficult to interpret, and increased activity in brain regions associated with emotional processing, indicating that AD cries also elicit more negative feelings and may be perceived as more aversive and/or arousing. Perceived distress engendered by AD cries related to increased activation in brain regions associated with emotional processing. This study supports the hypothesis that cry is an early and meaningful anomaly displayed by children with AD. It could be that cries associated with AD alter parent-child interactions much earlier than the time that reliable AD diagnosis normally occurs.

Physical exercise and intermittent administration of lactulose may improve autism symptoms through hydrogen production

Autism is neuro-developmental disorder. Oxidative stress is enhanced in some children with autism. Hydrogen is a gas with anti-oxidative effects suggested for treating or prevention of some medical problems. It is hypothesized that lactulose or hydrogen water may provide hydrogen to reduce oxidative stress in autism.

A global public health strategy for autism spectrum disorders

In recent years, there has been increasing awareness about autism spectrum disorders (ASD) around the world, including in low and middle income countries. Unlike countries in Western Europe and North America where infrastructure and capacity are available to help meet some of the needs of individuals with ASD, little expertise or capacity exists in most of the developing world. In 2008 Autism Speaks launched the Global Autism Public Health (GAPH) Initiative to facilitate the development of systematic and sustainable solutions for enhancing global autism awareness, research, training and service delivery. In the last 3 years Autism Speaks has established collaboration with stakeholders from over 20 countries who are working alongside dedicated local and international stakeholders to effect change. In this article, the GAPH framework is described, along with a few brief case examples that illustrate how the framework for implementation of the model can occur. GAPH is still in its infancy but has the potential to have significant impact through inclusive collaboration with local and international stakeholders to develop effective and sustainable public health solutions for disseminating best practices and delivering tangible benefits to individuals with ASD and their families.