Mechanisms Underlying Microbial-Mediated Changes in Social Behavior in Mouse Models of Autism Spectrum Disorder
Mechanisms Underlying Microbial-Mediated Changes in Social Behavior in Mouse Models of Autism Spectrum Disorder
on 4:15 PM
Friday, December 21, 2018
Thursday, December 20, 2018
The contribution of environmental exposure to the etiology of autism spectrum disorder
on 11:11 AM
The contribution of environmental exposure to the etiology of autism spectrum disorder
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental condition of heterogeneous etiology. While it is widely recognized that genetic and environmental factors and their interactions contribute to autism phenotypes, their precise causal mechanisms remain poorly understood. This article reviews our current understanding of environmental risk factors of ASD and their presumed adverse physiological mechanisms. It comprehensively maps the significance of parental age, teratogenic compounds,
perinatal risks, medication, smoking and alcohol use, nutrition, vaccination, toxic exposures, as well as the role of extreme psychosocial factors. Further, we consider the role of potential protective factors such as folate and fatty acid intake. Evidence indicates an increased offspring vulnerability to ASD through advanced maternal and paternal age, valproate intake, toxic chemical exposure, maternal diabetes, enhanced steroidogenic activity, immune activation, and possibly altered zinc–copper cycles and treatment with selective serotonin reuptake inhibitors. Epidemiological studies demonstrate no evidence for vaccination posing an autism risk. It is concluded that future research needs to consider categorical autism, broader autism phenotypes, as well as autistic traits, and examine more homogenous autism variants by subgroup stratification. Our understanding of autism etiology could be advanced by research aimed at disentangling the causal and non-causal environmental effects, both founding and moderating, and gene–environment interplay using twin studies, longitudinal and experimental
designs. The specificity of many environmental risks for ASD remains unknown and control of multiple confounders has been limited. Further understanding of the critical windows of neurodevelopmental vulnerability and investigating the fit of multiple hit and cumulative risk models are likely promising approaches in enhancing the understanding of role of environmental factors in the etiology of ASD.
Tuesday, December 18, 2018
Genome-wide de novo risk score implicates promoter variation in autism spectrum disorder
on 10:37 AM
Genome-wide de novo risk score implicates promoter variation in autism spectrum disorder
INTRODUCTION: The DNA of protein-coding
genes is transcribed into mRNA, which is translated into proteins. The “coding genome” describes the DNA that contains the information to make these proteins and represents ~1.5% of the human genome. Newly arising de novo mutations (variants observed in a child but not in either parent) in the coding genome contribute to numerous childhood developmental disorders, including autism spectrum disorder
(ASD). Discovery of these effects is aided by the triplet code that enables the functional impact of many mutationsto be readily deciphered. In contrast, the “noncoding genome” covers the remaining ~98.5% and includes elements that regulate when, where, and to what degree protein-coding genes are transcribed. Understanding this noncoding sequence could provide insights into human disorders and refined control of emerging genetic therapies. Yet little is known about the role of mutations in noncoding regions, including whether they contribute to childhood developmental disorders, which noncoding elements are most vulnerable to disruption, and the manner in which information is encoded in the noncoding genome
Tuesday, December 4, 2018
The Prevalence of ParentReported Autism Spectrum Disorder Among US Children
on 11:20 AM
The Prevalence of ParentReported Autism Spectrum Disorder Among US Children
OBJECTIVES: To estimate the national prevalence of parent-reported autism spectrum disorder
(ASD) diagnosis among US children aged 3 to 17 years as well as their treatment and health
care experiences using the 2016 National Survey of Children’s Health (NSCH).
METHODS: The 2016 NSCH is a nationally representative survey of 50 212 children focused
on the health and well-being of children aged 0 to 17 years. The NSCH collected parentreported information on whether children ever received an ASD diagnosis by a care
provider, current ASD status, health care use, access and challenges, and methods of
treatment. We calculated weighted prevalence estimates of ASD, compared health care
experiences of children with ASD to other children, and examined factors associated with
increased likelihood of medication and behavioral treatment.
RESULTS: Parents of an estimated 1.5 million US children aged 3 to 17 years (2.50%) reported
that their child had ever received an ASD diagnosis and currently had the condition.
Children with parent-reported ASD diagnosis were more likely to have greater health
care needs and difficulties accessing health care than children with other emotional or
behavioral disorders (attention-deficit/hyperactivity disorder, anxiety, behavioral or
conduct problems, depression, developmental delay, Down syndrome, intellectual disability,
learning disability, Tourette syndrome) and children without these conditions. Of children
with current ASD, 27% were taking medication for ASD-related symptoms, whereas 64%
received behavioral treatments in the last 12 months, with variations by sociodemographic
characteristics and co-occurring conditions.
CONCLUSIONS: The estimated prevalence of US children with a parent-reported ASD
diagnosis is now 1 in 40, with rates of ASD-specific treatment usage varying by children’s
sociodemographic and co-occurring conditions.
Monday, December 3, 2018
Delayed autism spectrum disorder recognition in children and adolescents previously diagnosed with attention-deficit/ hyperactivity disorder
on 6:37 PM
Delayed autism spectrum disorder recognition in children and adolescents previously diagnosed with attention-deficit/ hyperactivity disorder
Abstract
Phenotypic elements of autism spectrum disorder can be masked by attention-deficit/hyperactivity disorder symptoms, potentially leading to a misdiagnosis or delaying an autism spectrum disorder diagnosis. This study explored differences in the age of autism spectrum disorder diagnosis between participants with previously diagnosed attention-deficit/ hyperactivity disorder versus autism spectrum disorder–only respondents. Children and adolescents, but not adults, initially diagnosed with attention deficit/hyperactivity disorder received an autism spectrum disorder diagnosis an average
of 1.8years later than autism spectrum disorder–only children, although the findings regarding the adult sample should be interpreted with caution. Gender differences were also explored, revealing that the delay in receiving an autism diagnosis was 1.5 years in boys and 2.6 years in girls with pre-existing attention-deficit/hyperactivity disorder, compared with boys and girls without prior attention-deficit/hyperactivity disorder. No significant gender differences were observed in the
adult sample. We argue that overlapping symptoms between autism spectrum disorder and attention-deficit/hyperactivity disorder might delay a formal diagnosis of autism either by leading to a misdiagnosis of attention-deficit/hyperactivity disorder or by making it difficult to identify the presence of co-occurring autism spectrum disorder conditions once an initial diagnosis of attention-deficit/hyperactivity disorder has been obtained. Current findings highlight the need to recruit
multidimensional and multidisciplinary screening procedures to assess for potential emerging autism spectrum disorder hallmarks in children and adolescents diagnosed or presenting with attention-deficit/hyperactivity disorder symptoms