Reframing autism as a behavioral syndrome and not a specific mental disorder: Implications of genetic and phenotypic heterogeneity

Differences of gut microbiota and behavioral symptoms between two subgroups of autistic children based on γδT cells-derived IFN-γ Levels: A preliminary study

Background

Autism Spectrum Disorders (ASD) are defined as a group of pervasive neurodevelopmental disorders, and the heterogeneity in the symptomology and etiology of ASD has long been recognized. Altered immune function and gut microbiota have been found in ASD populations. Immune dysfunction has been hypothesized to involve in the pathophysiology of a subtype of ASD.

Methods

A cohort of 105 ASD children were recruited and grouped based on IFN-γ levels derived from ex vivo stimulated γδT cells. Fecal samples were collected and analyzed with a metagenomic approach. Comparison of autistic symptoms and gut microbiota composition was made between subgroups. Enriched KEGG orthologues markers and pathogen-host interactions based on metagenome were also analyzed to reveal the differences in functional features.

Results

The autistic behavioral symptoms were more severe for children in the IFN-γ-high group, especially in the body and object use, social and self-help, and expressive language performance domains. LEfSe analysis of gut microbiota revealed an overrepresentation of Selenomonadales, Negatiyicutes, Veillonellaceae and Verrucomicrobiaceae and underrepresentation of Bacteroides xylanisolvens and Bifidobacterium longum in children with higher IFN-γ level. Decreased metabolism function of carbohydrate, amino acid and lipid in gut microbiota were found in the IFN-γ-high group. Additional functional profiles analyses revealed significant differences in the abundances of genes encoding carbohydrate-active enzymes between the two groups. And enriched phenotypes related to infection and gastroenteritis and underrepresentation of one gut-brain module associated with histamine degradation were also found in the IFN-γ-High group. Results of multivariate analyses revealed relatively good separation between the two groups.

Conclusions

Levels of IFN-γ derived from γδT cell could serve as one of the potential candidate biomarkers to subtype ASD individuals to reduce the heterogeneity associated with ASD and produce subgroups which are more likely to share a more similar phenotype and etiology. A better understanding of the associations among immune function, gut microbiota composition and metabolism abnormalities in ASD would facilitate the development of individualized biomedical treatment for this complex neurodevelopmental disorder.

Molecular Dynamic Simulation of Neurexin1α Mutations Associated with Mental Disorder

Neurexin1 gene is essential for formulating synaptic cell adhesion to establish synapses. In a previous work, 38 SNPs in Neurexin1 recoded in mental disorder patients have been collected. Five computational prediction tools have been used to predict the effect of SNPs on protein function and stability. Only four SNPs in Neurexin1α have deleterious prediction results from at least four tools. The current work aims to use molecular dynamic simulation (MD) to study the effects of the four mutations on Neurexin1α both on the whole protein as well as identifying affected domains by mutations. A protein model that consists of five domains out of six domains in the real protein was used; missing residues were added, and model was tested for quality. The MD experiment has last for 1.5 μs where four parameters have been used for studying the whole protein in addition to three more parameters for the domain analysis. The whole protein study has shown that two mutations E427I for Autism and R525C for non-syndromic intellectual disability (NSID) have distinctive behavior across the four used parameters. Domain study has confirmed the previous results where the five domains of R525C have acted differently from wild type (WT), while E427I has acted differently for four domains from wild type. The other two mutations D104H and G379E have three domains that only acted differently from wild type. The fourth domain of all mutations has an obvious distinctive behavior from wild type. Further study of E427I and R525C mutations can lead to better understanding of autism and NSID.

Symptoms of Autism, Comorbid Mental Health Conditions and Challenging Behaviors among Toddlers with Down Syndrome at Low Risk for ASD-Characterization Using the BISCUIT-Parts 1-3

Background: Autism spectrum disorder (ASD) may coexist with Down syndrome (DS). Most studies on this topic involve school-age children, adolescents, or adults with DS. This study looked at ASD symptoms, other mental health problems, and challenging behaviors in toddlers with DS at low risk of ASD. Methods: We used screening tools for autism in toddlers; BISCUIT–Parts 1–3 and Q-CHAT. We compared four groups of children aged 17–37 months: DS, ASD, Atypical Development (AD), and Typically Developing (TD). Results: Children with DS showed lower symptoms of ASD than children with ASD (without DS) and higher than TD children, except for repetitive behaviors/restricted interests. For comorbid mental health problems and difficult behaviors, children with DS scored lower than children with ASD. There were no differences between children with DS and TD children in this regard. Conclusions: The study results indicate that BISCUIT–Parts 1–3 are valid instruments to differentiate toddlers with DS from toddlers with ASD. However, they also show that toddlers with DS at low ASD risk are a very heterogeneous group when the ASD symptoms are considered. Autistic characteristics should be taken into account in supporting young children with this genetic condition.

Treatment Refractory Internalizing Behaviour Across Disorders: An Aetiological Model for Severe Emotion Dysregulation in Adolescence

Auto-aggressive behaviour, especially treatment refractory suicidality in adolescents with psychiatric disorders, may be challenging to clinicians. In search of therapeutic possibilities, we have integrated current opinions regarding causality and interdependency of suicidality and auto-aggressive behaviour across disorders within the HiTOP framework. We propose a developmental model regarding these unsettling behaviours in youths that may help to guide future directions for research and interventions. We argue that the interdependent development of biologic factors, attachment, moral reasoning and emotion regulation in an overprotective environment may lead to social anxiety and later during development to emotion dysregulation and severe internalizing behaviour disorders. To optimize treatment efficacy for both internalizing and externalizing behaviour, we emphasize the importance transdiagnostic interventions, such as addressing non-compliance, restoration of trust between parents and their child, and limitation of avoidance behaviour. These may be seen as higher order interventions within the HiTOP framework.

Melatonin: From Pharmacokinetics to Clinical Use in Autism Spectrum Disorder

The role of melatonin has been extensively investigated in pathophysiological conditions, including autism spectrum disorder (ASD). Reduced melatonin secretion has been reported in ASD and led to many clinical trials using immediate-release and prolonged-release oral formulations of melatonin. However, melatonin’s effects in ASD and the choice of formulation type require further study. Therapeutic benefits of melatonin on sleep disorders in ASD were observed, notably on sleep latency and sleep quality. Importantly, melatonin may also have a role in improving autistic behavioral impairments. The objective of this article is to review factors influencing treatment response and possible side effects following melatonin administration. It appears that the effects of exposure to exogenous melatonin are dependent on age, sex, route and time of administration, formulation type, dose, and association with several substances (such as tobacco or contraceptive pills). In addition, no major melatonin-related adverse effect was described in typical development and ASD. In conclusion, melatonin represents currently a well-validated and tolerated treatment for sleep disorders in children and adolescents with ASD. A more thorough consideration of factors influencing melatonin pharmacokinetics could illuminate the best use of melatonin in this population. Future studies are required in ASD to explore further dose-effect relationships of melatonin on sleep problems and autistic behavioral impairments.

Affording autism an early brain development re-definition

The national priority to advance early detection and intervention for children with autism spectrum disorder (ASD) has not reduced the late age of ASD diagnosis in the US over several consecutive Centers for Disease Control and Prevention (CDC) surveillance cohorts, with traditionally under-served populations accessing diagnosis later still. In this review, we explore a potential perceptual barrier to this enterprise which views ASD in terms that are contradicted by current science, and which may have its origins in the current definition of the condition and in its historical associations. To address this perceptual barrier, we propose a re-definition of ASD in early brain development terms, with a view to revisit the world of opportunities afforded by current science to optimize children's outcomes despite the risks that they are born with. This view is presented here to counter outdated notions that potentially devastating disability is determined the moment a child is born, and that these burdens are inevitable, with opportunities for improvement being constrained to only alleviation of symptoms or limited improvements in adaptive skills. The impetus for this piece is the concern that such views of complex neurodevelopmental conditions, such as ASD, can become self-fulfilling science and policy, in ways that are diametrically opposed to what we currently know, and are learning every day, of how genetic risk becomes, or not, instantiated as lifetime disabilities.

Effects of CBD-Enriched Cannabis sativa Extract on Autism Spectrum Disorder Symptoms: An Observational Study of 18 Participants Undergoing Compassionate Use

Autism Spectrum Disorders comprise conditions that may affect cognitive development, motor skills, social interaction, communication, and behavior. This set of functional deficits often results in lack of independence for the diagnosed individuals, and severe distress for patients, families, and caregivers. There is a mounting body of evidence indicating the effectiveness of pure cannabidiol (CBD) and CBD-enriched Cannabis sativa extract (CE) for the treatment of autistic symptoms in refractory epilepsy patients. There is also increasing data support for the hypothesis that non-epileptic autism shares underlying etiological mechanisms with epilepsy. Here we report an observational study with a cohort of 18 autistic patients undergoing treatment with compassionate use of standardized CBD-enriched CE (with a CBD to THC ratio of 75/1). Among the 15 patients who adhered to the treatment (10 non-epileptic and five epileptic) only one patient showed lack of improvement in autistic symptoms. Due to adverse effects, three patients discontinued CE use before 1 month. After 6-9 months of treatment, most patients, including epileptic and non-epileptic, showed some level of improvement in more than one of the eight symptom categories evaluated: Attention Deficit/Hyperactivity Disorder; Behavioral Disorders; Motor Deficits; Autonomy Deficits; Communication and Social Interaction Deficits; Cognitive Deficits; Sleep Disorders and Seizures, with very infrequent and mild adverse effects. The strongest improvements were reported for Seizures, Attention Deficit/Hyperactivity Disorder, Sleep Disorders, and Communication and Social Interaction Deficits. This was especially true for the 10 non-epileptic patients, nine of which presented improvement equal to or above 30% in at least one of the eight categories, six presented improvement of 30% or more in at least two categories and four presented improvement equal to or above 30% in at least four symptom categories. Ten out of the 15 patients were using other medicines, and nine of these were able to keep the improvements even after reducing or withdrawing other medications. The results reported here are very promising and indicate that CBD-enriched CE may ameliorate multiple ASD symptoms even in non-epileptic patients, with substantial increase in life quality for both ASD patients and caretakers.

Nutritional Supplements During Gestation and Autism Spectrum Disorder: What Do We Really Know and How Far Have We Gone?

Nutritional interventions are gaining remarkable attention as complementary management options for autism. Our aim is to provide literature data about the impact of the administration of dietary supplements during pregnancy on the risk of autism spectrum disorder in the offspring. A comprehensive search was undertaken by 2 reviewers independently using PubMed as the medical database source. Prospective clinical and experimental studies were considered and no year-of-publication restriction was placed. We were able to identify 4 basic (conducted in rodents) and 3 clinical research papers fulfilling our selection criteria. Supplements studied included folic acid, iron, multivitamins, choline, vitamin D, and docosahexaenoic acid. Choline and folic acid had a significant impact on the expression of autism-related genes. However, from a clinical point of view, prenatal folate administration did not reduce the risk of autism. Similarly, iron had no significant impact, while the use of multivitamins in moderate frequency had a protective effect. The use of vitamin D and docosahexaenoic acid during gestation decreased the incidence of autism in animal models. In conclusion, available data are controversial and cannot change current routine practice. More large-scale prospective studies are needed to identify the real effect of nutritional supplements and also optimize their administration.Key teaching pointsMultivitamins use during pregnancy can exert a protective effect on the risk of autism, although depending on the frequency of use. Nevertheless, prenatal iron and folate were not shown to have any significant impact.Research based on animal models showed that choline and folic acid can have a significant impact on the expression of autism-related genes in a sex-specific manner.Furthermore, the use of vitamin D and docosahexaenoic acid during gestation seem to decrease the incidence of autism in animal offspring.In the future, more clinical, large-scale prospective and methodologically homogenous clinical studies are needed to further investigate the effect of the periconceptional use of nutritional supplements on autism risk.

Biomarkers in Autism Spectrum Disorder: Challenges, Advances, and the Need for Biomarkers of Relevance to Public Health

Although autism spectrum disorder (ASD) is the most strongly genetic of all complex neuropsychiatric disorders, it is still defined and diagnosed behaviorally. The vast genotypic and phenotypic heterogeneity of the condition necessitate a vigorous search for biological markers capable of aiding in diagnosis, identifying more homogeneous subgroups for biological study, individualizing treatment, and measuring treatment response. Many candidate biomarkers are available, spanning genetic, metabolic, electroencephalographic, magnetic resonance imaging, and neuropsychological methods. Although biomarker research has focused primarily on mechanistic etiologic hypotheses, the biomarkers more likely to result in optimized clinical outcomes in the near term are cost-effective and community-viable measures obtained through eye-tracking technology involving infants and toddlers. Although these tools are still far from being ready for widespread application, the goal is to develop objective procedures and measures for population-based screening and diagnosis to increase access to early treatment and intervention.

The early development of infant siblings of children with autism spectrum disorder: Characteristics of sibling interactions

Although sibling interactions play an important role in children's early development, they are rarely studied in very young children with an older brother or sister with autism spectrum disorder (ASD). This study used a naturalistic, observational method to compare interactions between 18-month-old infants and their older sibling with ASD (n = 22) with a control group of 18-month-old infants and their typically developing (TD) older sibling (n = 29). In addition, role (a)symmetry and the influence of gender were evaluated. Sibling interactions in ASD-dyads were characterized by higher levels of negativity. Although somewhat less pronounced in ASD-dyads, role asymmetry was present in both groups, with the older child taking the dominant position. Finally, siblings pairs with an older sister were characterized by more positive behaviours. Since differences in sibling interactions may alter the developmental trajectories of both siblings, these early relationships should be taken into account in future ASD research and interventions.

Role of Genetics in the Etiology of Autistic Spectrum Disorder: Towards a Hierarchical Diagnostic Strategy

Progress in epidemiological, molecular and clinical genetics with the development of new techniques has improved knowledge on genetic syndromes associated with autism spectrum disorder (ASD). The objective of this article is to show the diversity of genetic disorders associated with ASD (based on an extensive review of single-gene disorders, copy number variants, and other chromosomal disorders), and consequently to propose a hierarchical diagnostic strategy with a stepwise evaluation, helping general practitioners/pediatricians and child psychiatrists to collaborate with geneticists and neuropediatricians, in order to search for genetic disorders associated with ASD. The first step is a clinical investigation involving: (i) a child psychiatric and psychological evaluation confirming autism diagnosis from different observational sources and assessing autism severity; (ii) a neuropediatric evaluation examining neurological symptoms and developmental milestones; and (iii) a genetic evaluation searching for dysmorphic features and malformations. The second step involves laboratory and if necessary neuroimaging and EEG studies oriented by clinical results based on clinical genetic and neuropediatric examinations. The identification of genetic disorders associated with ASD has practical implications for diagnostic strategies, early detection or prevention of co-morbidity, specific treatment and follow up, and genetic counseling.