Gender bias, female resilience, and the sex ratio in autism

Risk of autism spectrum disorder and association of its symptoms with psychiatric and substance use disorders in non-clinical student sample in Kenya: cross-sectional study

BACKGROUND

The prevalence and patterns of autism spectrum disorder (ASD) symptoms/traits and the associations of ASD with psychiatric and substance use disorders has not been documented in non-clinical students in Sub-Saharan Africa, and Kenya in particular.

AIMS

To document the risk level of ASD and its traits in a Kenyan student population (high school, college and university) using the Autism-Spectrum Quotient (AQ); and to determine the associations between ASD and other psychiatric and substance use disorders.

METHOD

This was a cross-sectional study among students (n = 9626). We used instruments with sufficient psychometric properties and good discriminative validity to collect data. A cut-off score of ≥32 on the AQ was used to identify those at high risk of ASD. We conducted the following statistical tests: (a) basic descriptive statistics; (b) chi-squared tests and Fisher's exact tests to analyse associations between categorical variables and ASD; (c) independent t-tests to examine two-group comparisons with ASD; (d) one-way analysis of variance to make comparisons between categorical variables with three or more groups and ASD; (e) statistically significant (P < 0.05) variables fitted into an ordinal logistic regression model to identify determinants of ASD; (f) Pearson's correlation and reliability analysis.

RESULTS

Of the total sample, 54 (0.56%) were at high risk of ASD. Sociodemographic differences were found in the mean scores for the various traits, and statistically significant (P < 0.05) associations we found between ASD and various psychiatric and substance use disorders.

CONCLUSIONS

Risk of ASD, gender characteristics and associations with psychiatric and substance use disorders are similar in this Kenyan sample to those found in Western settings in non-clinical populations.

Advancing research on early autism through an integrated risk and resilience perspective

To date, a deficit-oriented approach dominates autism spectrum disorder (ASD) research, including studies of infant siblings of children with ASD at high risk (HR) for the disabilities associated with this disorder. Despite scientific advances regarding early ASD-related risk, there remains little systematic investigation of positive development, limiting the scope of research and quite possibly a deeper understanding of pathways toward and away from ASD-related impairments. In this paper, we argue that integrating a resilience framework into early ASD research has the potential to enhance knowledge on prodromal course, phenotypic heterogeneity, and developmental processes of risk and adaptation. We delineate a developmental systems resilience framework with particular reference to HR infants. To illustrate the utility of a resilience perspective, we consider the "female protective effect" and other evidence of adaptation in the face of ASD-related risk. We suggest that a resilience framework invites focal questions about the nature, timing, levels, interactions, and mechanisms by which positive adaptation occurs in relation to risk and developmental pathways toward and away from ASD-related difficulties. We conclude with recommendations for future research, including more focus on adaptive development and multisystem processes, pathways away from disorder, and reconsideration of extant evidence within an integrated risk-and-resilience framework.

A Data-Driven Approach in an Unbiased Sample Reveals Equivalent Sex Ratio of Autism Spectrum Disorder-Associated Impairment in Early Childhood

BACKGROUND

Sex differences in the prevalence of neurodevelopmental disorders are particularly evident in autism spectrum disorder (ASD). Heterogeneous symptom presentation and the potential of measurement bias hinder early ASD detection in females and may contribute to discrepant prevalence estimates. We examined trajectories of social communication (SC) and restricted and repetitive behaviors (RRBs) in a sample of infant siblings of children with ASD, adjusting for age- and sex-based measurement bias. We hypothesized that leveraging a prospective elevated familial likelihood sample, deriving data-driven behavioral constructs, and accounting for measurement bias would reveal less discrepant sex ratios than are typically seen in ASD.

METHODS

We conducted direct assessments of ASD symptoms at 6 to 9, 12 to 15, 24, and 36 to 60 months of age (total nobservations = 1254) with infant siblings of children with ASD (n = 377) and a lower ASD-familial-likelihood comparison group (n = 168; nobservations = 527). We established measurement invariance across age and sex for separate models of SC and RRB. We then conducted latent class growth mixture modeling with the longitudinal data and evaluated for sex differences in trajectory membership.

RESULTS

We identified 2 latent classes in the SC and RRB models with equal sex ratios in the high-concern cluster for both SC and RRB. Sex differences were also observed in the SC high-concern cluster, indicating that girls classified as having elevated social concerns demonstrated milder symptoms than boys in this group.

CONCLUSIONS

This novel approach for characterizing ASD symptom progression highlights the utility of assessing and adjusting for sex-related measurement bias and identifying sex-specific patterns of symptom emergence.

Maternal gut microbiota mediate intergenerational effects of high-fat diet on descendant social behavior

Dysbiosis of the maternal gut microbiome during pregnancy is associated with adverse neurodevelopmental outcomes. We previously showed that maternal high-fat diet (MHFD) in mice induces gut dysbiosis, social dysfunction, and underlying synaptic plasticity deficits in male offspring (F₁). Here, we reason that, if HFD-mediated changes in maternal gut microbiota drive offspring social deficits, then MHFD-induced dysbiosis in F₁ female MHFD offspring would likewise impair F₂ social behavior. Metataxonomic sequencing reveals reduced microbial richness among female F₁ MHFD offspring. Despite recovery of microbial richness among MHFD-descendant F₂ mice, they display social dysfunction. Post-weaning Limosilactobacillus reuteri treatment increases the abundance of short-chain fatty acid-producing taxa and rescues MHFD-descendant F₂ social deficits. L. reuteri exerts a sexually dimorphic impact on gut microbiota configuration, increasing discriminant taxa between female cohorts. Collectively, these results show multigenerational impacts of HFD-induced dysbiosis in the maternal lineage and highlight the potential of maternal microbiome-targeted interventions for neurodevelopmental disorders.

Analysis of Race and Sex Bias in the Autism Diagnostic Observation Schedule (ADOS-2)

IMPORTANCE

There are long-standing disparities in the prevalence of autism spectrum disorder (ASD) across race and sex. Surprisingly, few studies have examined whether these disparities arise partially out of systematic biases in the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2), the reference standard measure of ASD.

OBJECTIVE

To examine differential item functioning (DIF) of ADOS-2 items across sex and race.

DESIGN, SETTING, AND PARTICIPANTS

This is a cross-sectional study of children who were evaluated for ASD between 2014 and 2020 at a specialty outpatient clinic located in the Mid-Atlantic region of the US. Data were analyzed from July 2021 to February 2022.

EXPOSURES

Child race (Black/African American vs White) and sex (female vs male).

MAIN OUTCOMES AND MEASURES

Item-level biases across ADOS-2 harmonized algorithm items, including social affect (SA; 10 items) and repetitive/restricted behaviors (RRBs; 4 items), were evaluated across 3 modules. Measurement bias was identified by examining DIF and differential test functioning (DTF), within a graded response, item response theory framework. Statistical significance was determined by a likelihood ratio χ2 test, and a series of metrics was used to examine the magnitude of DIF and DTF.

RESULTS

A total of 6269 children (mean [SD] age, 6.77 [3.27] years; 1619 Black/African American [25.9%], 3151 White [50.3%], and 4970 male [79.4%]), were included in this study. Overall, 16 of 140 ADOS-2 diagnostic items (11%) had a significant DIF. For race, 8 items had a significant DIF, 6 of which involved SA. No single item showed DIF consistently across all modules. Most items with DIF had greater difficulty and poorer discrimination in Black/African American children compared with White children. For sex, 5 items showed significant DIF. DIF was split across SA and RRB. However, hand mannerisms evidenced DIF across all 5 algorithms, with generally greater difficulty. The magnitude of DIF was only moderate to large for 2 items: hand mannerisms (among female children) and repetitive interests (among Black/African American children). The overall estimated effect of DIF on total DTF was not large.

CONCLUSIONS AND RELEVANCE

These findings suggest that the ADOS-2 does not have widespread systematic measurement bias across race or sex. However, the findings raise some concerns around underdetection that warrant further research.

Elevated prenatal maternal sex hormones, but not placental aromatase, are associated with child neurodevelopment

Fetal exposure to testosterone may contribute to vulnerability for autism spectrum disorder (ASD). It is hypothesized that placental aromatase prevents fetal exposure to maternal testosterone, however, this pathway and the implications for child neurodevelopment have not been fully explored. We examined the relationships between prenatal maternal testosterone and estradiol at 19.2 ± 1.3 weeks, cord blood testosterone and estradiol at birth, placental aromatase mRNA expression, and neurodevelopment using the Social Communication Questionnaire (SCQ), the Behavioral Assessment System for Children, 3rd Edition (BASC-3), and the Empathizing Quotient for Children (EQ-C) at 4.5-6.5 years of age in a sample of 270 Nulliparous-Mothers-to-be (nuMoM2b) study participants. Maternal testosterone levels were positively associated with SCQ scores, but the association was not significant after adjusting for maternal age at delivery, nor was there a significant interaction with sex. Maternal estradiol levels were negatively associated with BASC-3 Clinical Probability scores among males (n = 139). We report a significant interaction effect of cord blood testosterone and fetal sex on both total SCQ scores and t-scores on the Developmental Social Disorders subscale. Placental aromatase was not associated with any neurodevelopmental or hormone measure, but under conditions of low placental aromatase expression, high maternal testosterone was positively associated with SCQ scores in males (n = 46). No other associations between hormone levels and neurodevelopment were significant. Our findings provide a foundation for further investigation of the mechanisms through which maternal sex hormones and placental steroidogenesis may affect fetal hormone production and neurobehavior.

Sex/gender differences in children with autism spectrum disorder: A brief overview on epidemiology, symptom profile, and neuroanatomy

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental conditions whose shared core features are impairments in social interaction and communication as well as restricted patterns of behavior, interests, and activities. The significant and consistent male preponderance in ASD prevalence has historically affected the scientific knowledge of autism in females as regards, inter alia, the clinical presentation, the genetic architecture, and the structural brain underpinnings. Indeed, females with ASD are under-investigated as samples recruited for clinical research typically reflect the strong male bias of the disorder. In the last years, the study of the various aspects of sex/gender (s/g) differences in ASD is gaining increased clinical and research interest resulting in a growing number of investigations on this topic. Here, I review and discuss evidence emerged from epidemiological, clinical, and neuroimaging studies in the last decade focusing on s/g differences in children with ASD. These studies are the prerequisites for the development of assessment and treatment practices which take into consideration s/g differences in ASD. Ultimately, a better understanding of s/g differences aims at improving healthcare for both ASD males and females.

Diagnostic Stability and Phenotypic Differences Among School-Age Children Diagnosed With ASD Before Age 2

Given the importance of early detection, it is critical to understand the non-linearity in manifestation of ASD before age 24 months, when ASD symptoms are beginning to consolidate, through the age of 36 months when stability of ASD diagnosis is reportedly high into school-age when increased demands may challenge previously successful compensatory processes and permit first ASD detection. We employed a prospective, longitudinal design focused on children with an older sibling with ASD (n = 210) who received diagnostic evaluations at mean ages of 15.4 months (Time 1), 36.6 months (Time 2), and 5.7 years (Time 3) to examine: (1) diagnostic stability, (2) developmental trajectories associated with different patterns of ASD vs. non-ASD classifications, and (3) predictors of classification group over time. Clinical best estimate (CBE) diagnosis of ASD or non-ASD was made at each time point. Linear mixed-effects models were implemented to examine differences in developmental trajectories of stable and dynamic diagnostic groups. Multinomial logistic regression analyses were used to examine predictors of the likelihood of belonging to each CBE diagnostic classification group. Results revealed that sensitivity and stability of an ASD diagnosis significantly increased from Time 1 (sensitivity: 52%; stability: 63%) to Time 2 (sensitivity: 86%; stability: 68%). Different developmental trajectories of autism symptom severity and non-verbal and verbal IQ were observed across groups, with differences first observed at Time 1 and becoming more pronounced through Time 3. Presence of restricted and repetitive behaviors as well as limitations in initiation of joint attention and expressive language skills differentially predicted the likelihood of belonging to the different CBE diagnostic classification groups. Results suggest that ASD symptoms may emerge or attenuate over time, with some children meeting diagnosis at follow-up, and other children no longer meeting diagnostic criteria. From a systems perspective, diagnostic non-linearity may be viewed as a dynamic developmental process, where emergent properties arising from various biological, genetic, and experiential factors interact, culminating in phenotypic phenomena that change over time. Clinical implications include extending universal ASD and social communication screening into school-age, supporting families' understanding of diagnostic shifts, and ensuring unbiased diagnostic decision-making when following children with ASD.

Positive and differential diagnosis of autism in verbal women of typical intelligence: A Delphi study

Diagnostic criteria for autism are relatively vague, and may lead to over and underdiagnosis when applied without clinical expertise. Indeed, autism is best reliably identified by experienced clinicians who take into account qualitative aspects of the condition. When assessing for autism in women, little guidance exists to support clinicians deciding whether to attribute adaptive difficulties to autism, a psychiatric condition, or both. The purpose of this study was therefore to propose guidelines for clinicians assessing for autism in women. To do this, we aimed to describe the clinical expertise involved in making positive and differential diagnoses of autism in adult women of typical intelligence. We interviewed 20 experienced clinicians from seven countries. We then elaborated Delphi statements summarizing participant views on the topic, which our participants rated. We obtained a final list of 37 suggested clinical guidelines to improve specificity and sensitivity of autism diagnosis in women. Participants had developed individual assessment strategies, although much overlap existed across participants. Participants provided insight to differentiate autism from post-traumatic stress disorder and Borderline Personality Disorder, and underlined the importance of being able to make differential diagnoses particularly in cases where non-autistic people had strongly self-identified with the spectrum.

Diagnostic Tools for Autism Spectrum Disorders by Gender: Analysis of Current Status and Future Lines

Studies on the prevalence of autism spectrum disorders have shown gender disproportion. In recent years, there has been an increasing interest in this investigation area. There are two main research lines; the first is focused mostly on gender-related biological reasons that could account for low ASD prevalence in women (i.e., related to some protective factors related to hormones or the immune system, among others), and the second research line studies possible diagnostic biases. In the present study, a review of the latter line of research is made based on two main objectives: (a) analysis of possible biases in diagnostic tools and (b) other nonbiological ASD prevalence explained by gender differences. As a result of our theoretical review, we found that the articles reviewed showed contradictory results and possible diagnostic biases, not only in their design but also in their assessment standards. We concluded that specific or complementary diagnostic tools and procedures differentiated by gender should be developed in order to reduce these biases.

Seeing the forest and the trees: Disentangling autism phenotypes in the age of DSM-5

This paper, written in honor of Professor Ed Zigler, focuses on some of the themes in developmental disabilities research that were so central to his work. It has now been nearly 80 years since Leo Kanner first identified the prototypic form - early infantile autism - of what is now autism spectrum disorder. In this article we summarize the development of the concept and the important accumulation of knowledge over time that has now led us to the recognition of a broader autism phenotype just as, at the same time, the current official diagnostic system in the USA has narrowed the concept. We also address current controversies regarding autism as the diagnosis is impacted by age and developmental factors, gender, and cultural issues. In parallel to the work on intellectual deficiency and development pioneered by Zigler and his colleagues, we summarize some of the challenges for the years ahead.

Sex differences in scores on standardized measures of autism symptoms: a multisite integrative data analysis

BACKGROUND

Concerns have been raised that scores on standard measures of autism spectrum disorder (ASD) symptoms may differ as a function of sex. However, these findings are hindered by small female samples studied thus far. The current study evaluated if, after accounting for age, IQ, and language level, sex affects ASD severity estimates from diagnostic measures among children with ASD.

METHODS

Data were obtained from eight sources comprising 27 sites. Linear mixed-effects models, including a random effect for site, were fit for 10 outcomes (Autism Diagnostic Observation Schedule [ADOS] domain-level calibrated severity scores, Autism Diagnostic Interview-Revised [ADI-R] raw scores by age-based algorithm, and raw scores from the two indices on the Social Responsiveness Scale [SRS]). Sex was added to the models after controlling for age, NVIQ, and an indicator for language level.

RESULTS

Sex significantly improved model fit for half of the outcomes, but least square mean differences were generally negligible (effect sizes [ES] < 0.20), increasing to small to moderate in adolescence (ES < 0.40). Boys received more severe RRB scores than girls on both the ADOS and ADI-R (age 4 + algorithm), and girls received more severe scores than boys on both SRS indices, which emerged in adolescence.

CONCLUSIONS

This study combined several available databases to create the largest sample of girls with ASD diagnoses. We found minimal differences due to sex beyond other known influences on ASD severity indicators. This may suggest that, among children who ultimately receive a clinical ASD diagnosis, severity estimates do not systematically differ to such an extent that sex-specific scoring procedures would be necessary. However, given the limitations inherent in clinically ascertained samples, future research must address questions about systematic sex differences among children or adults who do not receive clinical diagnoses of ASD. Moreover, while the current study helps resolve questions about widely used diagnostic instruments, we could not address sex differences in phenotypic aspects outside of these scores.

Intersection of Eating Disorders and the Female Profile of Autism

There is a moderate degree of comorbidity between autism and eating disorders, particularly anorexia nervosa in female individuals. Research indicates that up to 30% of patients with anorexia are autistic, or display high levels of autistic traits. Frequently, an autism diagnosis is secondary to an eating disorder diagnosis, which brings concomitant issues into treatment efficacy and outcomes for both conditions. Less is known about comorbidity with other eating disorder subtypes. Autistic traits can impede standard approaches to eating disorder treatment. Treatment options and settings may need to be modified to better accommodate autistic female individuals.

Brain function distinguishes female carriers and non-carriers of familial risk for autism

Background

Autism spectrum disorder (ASD) is characterized by high population-level heritability and a three-to-one male-to-female ratio that occurs independent of sex linkage. Prior research in a mixed-sex pediatric sample identified neural signatures of familial risk elicited by passive viewing of point light motion displays, suggesting the possibility that both resilience and risk of autism might be associated with brain responses to biological motion. To confirm a relationship between these signatures and inherited risk of autism, we tested them in families enriched for genetic loading through undiagnosed (“carrier”) females.

Methods

Using functional magnetic resonance imaging, we examined brain responses to passive viewing of point light displays—depicting biological versus non-biological motion—in a sample of undiagnosed adult females enriched for inherited susceptibility to ASD on the basis of affectation in their respective family pedigrees. Brain responses in carrier females were compared to responses in age-, SRS-, and IQ-matched non-carrier-females—i.e., females unrelated to individuals with ASD. We conducted a hypothesis-driven analysis focused on previously published regions of interest as well as exploratory, brain-wide analyses designed to characterize more fully the rich responses to this paradigm.

Results

We observed robust responses to biological motion. Notwithstanding, the 12 regions implicated by prior research did not exhibit the hypothesized interaction between group (carriers vs. controls) and point light displays (biological vs. non-biological motion). Exploratory, brain-wide analyses identified this interaction in three novel regions. Post hoc analyses additionally revealed significant variations in the time course of brain activation in 20 regions spanning occipital and temporal cortex, indicating group differences in response to point light displays (irrespective of the nature of motion) for exploration in future studies.

Limitations

We were unable to successfully eye-track all participants, which prevented us from being able to control for potential differences in eye gaze position.

Conclusions

These methods confirmed pronounced neural signatures that differentiate brain responses to biological and scrambled motion. Our sample of undiagnosed females enriched for family genetic loading enabled discovery of numerous contrasts between carriers and non-carriers of risk of ASD that may index variations in visual attention and motion processing related to genetic susceptibility and inform our understanding of mechanisms incurred by inherited liability for ASD.

Comparing Rates of Diagnosis Using DSM-IV-TR Versus DSM-5 Criteria for Autism Spectrum Disorder

With the publication of DSM-5, many changes were introduced regarding how Autism Spectrum Disorder (ASD) would be diagnosed. Changes from DSM-IV-TR were controversial, with many arguing that individuals would lose their diagnosis with the new criteria. The purpose of this study was to examine differences in the application of diagnostic criteria across both recent versions in a sample of infants and toddlers. Fewer individuals met criteria according to DSM-5; however, a larger proportion of individuals met criteria for both. Additionally, individuals with higher levels of symptoms were more likely to meet criteria for both versions as compared to either alone. Overall, results suggest that there are meaningful differences in how DSM criteria may apply to individuals with an ASD.

Evaluating heterogeneity in ASD symptomatology, cognitive ability, and adaptive functioning among 16p11.2 CNV carriers

Individuals with 16p11.2 copy number variant (CNV) show considerable phenotypic heterogeneity. Although autism spectrum disorder (ASD) is reported in approximately 20-23% of individuals with 16p11.2 CNVs, ASD-associated symptoms are observed in those without a clinical ASD diagnosis. Previous work has shown that genetic variation and prenatal and perinatal birth complications influence ASD risk and symptom severity. This study examined the impact of genetic and environmental risk factors on phenotypic heterogeneity among 16p11.2 CNV carriers. Participants included individuals with a 16p11.2 deletion (N = 96) or duplication (N = 77) with exome sequencing from the Simons VIP study. The presence of prenatal factors, perinatal events, additional genetic events, and gender was studied. Regression analyses examined the contribution of each risk factor on ASD symptomatology, cognitive functioning, and adaptive abilities. For deletion carriers, perinatal and additional genetic events were associated with increased ASD symptomatology and decrements in cognitive and adaptive functioning. For duplication carriers, secondary genetic events were associated with greater cognitive impairments. Being female sex was a protective factor for both deletion and duplication carriers. Our findings suggest that ASD-associated risk factors contribute to the variability in symptom presentation in individuals with 16p11.2 CNVs. LAY SUMMARY: There are a wide range of autism spectrum disorder (ASD) symptoms and abilities observed for individuals with genetic changes of the 16p11.2 region. Here, we found perinatal complications contributed to more severe ASD symptoms (deletion carriers) and additional genetic mutations contributed to decreased cognitive abilities (deletion and duplication carriers). A potential protective factor was also observed for females with 16p11.2 variations. Autism Res 2020, 13: 1300-1310. © 2020 International Society for Autism Research, Wiley Periodicals, Inc.

Self- vs Parent Reports of Generalised Anxiety Disorder Symptomatology in Mildly Impaired Girls with an Autism Spectrum Disorder

Previous data have suggested that parents of boys with autism spectrum disorder (ASD) may rate their sons' generalised anxiety disorder (GAD) more severely than the boys do themselves. However, no reports have been published to date which examine this issue in a girls-only sample. This study investigated the extent and nature of mother-daughter agreement on ratings of GAD in a sample of 53 girls with an ASD with mild impairment, aged 6 to 17 years. Mothers rated their daughters' GAD more severely than the girls did themselves, despite confounding effects from the girls' medication and menarche status. Suggestions are made for the valid assessment of GAD in girls with an ASD.

Intersection of Eating Disorders and the Female Profile of Autism

There is a moderate degree of comorbidity between autism and eating disorders, particularly anorexia nervosa in female individuals. Research indicates that up to 30% of patients with anorexia are autistic, or display high levels of autistic traits. Frequently, an autism diagnosis is secondary to an eating disorder diagnosis, which brings concomitant issues into treatment efficacy and outcomes for both conditions. Less is known about comorbidity with other eating disorder subtypes. Autistic traits can impede standard approaches to eating disorder treatment. Treatment options and settings may need to be modified to better accommodate autistic female individuals.

Understanding and recognising the female phenotype of autism spectrum disorder and the “camouflage” hypothesis: a systematic PRISMA review

Purpose

Females with autism spectrum disorder (ASD) may display superficial social skills which may mask their ASD symptomology impacting on the identification of the disorder – known as the “camouflage” hypothesis. Compared to males with ASD, it is increasingly recognised that females with ASD have a stronger ability to imitate behaviour which is socially acceptable, particularly those females who have higher cognitive abilities (i.e. intelligence considered to be within the normal range) (Ehlers and Gillberg, 1993). The paper aims to discuss this issue.

Design/methodology/approach

This paper will explore the literature on camouflaging or masking behaviour in females with ASD. A systematic PRISMA review was conducted.

Findings

The capacity to “camouflage” social difficulties in social situations is considered to be one of the main features of the female phenotype of ASD (e.g. Kenyon, 2014). Social imitation or camouflaging enables some level of success and coping, which results in some females never receiving a diagnosis of ASD. They typically may not exhibit any observable functional impairments. However, under the surface of the camouflage, females may experience high levels of subjective stress, anxiety and exhaustion and a need to re-charge or recuperate by withdrawing from any social interaction.

Research limitations/implications

There is relatively little understanding and knowledge of the female phenotype of ASD. This lack of understanding and knowledge impacts significantly on the ability to identify females with ASD (Laiet al., 2015; Bargielaet al., 2016), which can have a number of negative consequence (Adamouet al., 2018; National Collaborating Centre for Mental Health (UK), 2012).

Practical implications

There is a need for the development of a camouflaging measure.

Originality/value

There is a real need for further research exploring the positive and negative impact of the phenomenon of “camouflaging”, or “pretending to be normal” in females with ASD.

Early life exposure to particulate matter air pollution (PM1, PM2.5 and PM10) and autism in Shanghai, China: A case-control study

BACKGROUND

The evidence for adverse effects of ambient particulate matter (PM) pollution on mental health is limited. Studies in Western countries suggested higher risk of autism spectrum disorder (ASD) associated with PM air pollution, but no such study has been done in developing countries.

METHODS

A case-control study was performed in Shanghai with a multi-stage random sampling design. Children's exposures to PM₁, PM_2.5 and PM₁₀ (particulate matter with aerodynamic diameter < 1 μm, < 2.5 μm and < 10 μm, respectively) during the first three years after birth were estimated with satellite remote sensing data. Conditional logistic regression was used to examine the PM-ASD association.

RESULTS

In total, 124 ASD cases and 1240 healthy controls were included in this study. The median levels of PM₁, PM_2.5 and PM₁₀ exposures during the first three years of life were 48.8 μg/m³, 66.2 μg/m³ and 95.4 μg/m³, respectively, and the interquartile range (IQR) for these three pollutants were 4.8 μg/m³, 3.4 μg/m³ and 4.9 μg/m³, respectively. The adjusted odds ratios (and 95% confidence intervals) of ASD associated with an IQR increase for PM₁, PM_2.5 and PM₁₀ were 1.86 (1.09, 3.17), 1.78 (1.14, 2.76) and 1.68 (1.09, 2.59), respectively. Higher ORs of ASD associated with PM pollution were observed in the second and the third year after birth.

CONCLUSIONS

Exposures to PM₁, PM_2.5 and PM₁₀ during the first three years of life were associated with the increased risk of ASD and there appeared to be stronger effects of ambient PM pollution on ASD in the second and the third years after birth.

Whole-genome sequencing in a family with twin boys with autism and intellectual disability suggests multimodal polygenic risk

Over the past decade, a focus on de novo mutations has rapidly accelerated gene discovery in autism spectrum disorder (ASD), intellectual disability (ID), and other neurodevelopmental disorders (NDDs). However, recent studies suggest that only a minority of cases are attributable to de novo mutations, and instead these disorders often result from an accumulation of various forms of genetic risk. Consequently, we adopted an inclusive approach to investigate the genetic risk contributing to a case of male monozygotic twins with ASD and ID. At the time of the study, the probands were 7 yr old and largely nonverbal. Medical records indicated a history of motor delays, sleep difficulties, and significant cognitive deficits. Through whole-genome sequencing of the probands and their parents, we uncovered elevated common polygenic risk, a coding de novo point mutation in CENPE, an ultra-rare homozygous regulatory variant in ANK3, inherited rare variants in NRXN3, and a maternally inherited X-linked deletion situated in a noncoding regulatory region between ZNF81 and ZNF182 Although each of these genes has been directly or indirectly associated with NDDs, evidence suggests that no single variant adequately explains the probands' phenotype. Instead, we propose that the probands' condition is due to the confluence of multiple rare variants in the context of a high-risk genetic background. This case emphasizes the multifactorial nature of genetic risk underlying most instances of NDDs and aligns with the "female protective model" of ASD.

Brain Connectivity and Neuroimaging of Social Networks in Autism

Impairments in social communication (SC) predominate among the core diagnostic features of autism spectrum disorders (ASDs). Neuroimaging has revealed numerous findings of atypical activity and connectivity of 'social brain' networks, yet no consensus view on crucial developmental causes of SC deficits has emerged. Aside from methodological challenges, the deeper problem concerns the clinical label of ASD. While genetic studies have not comprehensively explained the causes of nonsyndromic ASDs, they highlight that the clinical label encompasses many etiologically different disorders. The question of how potential causes and etiologies converge onto a comparatively narrow set of SC deficits remains. Only neuroimaging designs searching for subtypes within ASD cohorts (rather than conventional group level designs) can provide translationally informative answers.

Neonatal Oxytocin Treatment Ameliorates Autistic-Like Behaviors and Oxytocin Deficiency in Valproic Acid-Induced Rat Model of Autism

Autism spectrum disorder (ASD) is characterized by impaired social communication and repetitive/stereotyped behaviors. The neuropeptide oxytocin (OXT) plays a critical role in regulating social behaviors in the central nervous system, as indicated in both human and animal studies. We hypothesized that central OXT deficit is one of causes of etiology of ASD, which may be responsible for the social impairments. To test our hypothesis, central OXT system was examined in valproic acid (VPA)-induced rat model of autism (VPA rat). Our results showed that adolescent VPA rats exhibited a lower level of OXT mRNA and fewer OXT-ir cells in the hypothalamus than control rats. Additionally, OXT concentration in cerebrospinal fluid (CSF) was reduced. The number of OXT-ir cells in the supraoptic nucleus (SON) of neonatal VPA rats was also lower. Autistic-like behaviors were observed in these animals as well. We found that an acute intranasal administration of exogenous OXT restored the social preference of adolescent VPA rats. Additionally, early postnatal OXT treatment had long-term effects ameliorating the social impairments and repetitive behaviors of VPA rats until adolescence. This was accompanied by an increase in OXT-ir cells. Taken together, we demonstrated there was central OXT deficiency in the VPA-induced rat model of autism, and showed evidence that early postnatal OXT treatment had a long-term therapeutic effect on the autistic-like behaviors in VPA rats.

The Prevalence of Autism Spectrum Disorders in Adult Psychiatric Inpatients: A Systematic Review

Background:

Whilst the prevalence of autism spectrum disorders in adults within the community setting is well-established, less is known about the prevalence among adults based within a psychiatric inpatient setting.

Objective:

To conduct a systematic literature review pertaining to the prevalence of autism spectrum disorders among the adult psychiatric inpatient population.

Method:

Eligibility criteria included: (a) investigation of the prevalence of autism spectrum disorders (b) adult psychiatric inpatient study population (c) published in English language. Electronic databases accessed included PubMed, Medline, CINAHL, PsycINFO and EMBASE. Additionally, the ancestry method was utilised for the references of eligible papers, as well as grey literature searches and consultation with experts in the field.

Results:

From the search, 4 studies were identified which satisfied the inclusion criteria, conducted in a variety of inpatient psychiatric settings, including secure forensic and intellectual disability units and a state psychiatric hospital. There were significant differences in methodological approaches, including the screening tests, diagnostic instruments and diagnostic criteria utilised. Autism spectrum disorder prevalence estimates varied considerably, from 2.4-9.9%.

Conclusion:

From the limited research data currently available, it appears that the prevalence of autism spectrum disorders is increased in inpatient psychiatric settings relative to the general population. There is a need for further high quality research in this patient group, to add to this limited evidence base, as well as in developing effective strategies to identify patients with a high likelihood of autism spectrum disorders within this setting.

Evaluating Sex and Age Differences in ADI-R and ADOS Scores in a Large European Multi-site Sample of Individuals with Autism Spectrum Disorder

Research on sex-related differences in Autism Spectrum Disorder (ASD) has been impeded by small samples. We pooled 28 datasets from 18 sites across nine European countries to examine sex differences in the ASD phenotype on the ADI-R (376 females, 1763 males) and ADOS (233 females, 1187 males). On the ADI-R, early childhood restricted and repetitive behaviours were lower in females than males, alongside comparable levels of social interaction and communication difficulties in females and males. Current ADI-R and ADOS scores showed no sex differences for ASD severity. There were lower socio-communicative symptoms in older compared to younger individuals. This large European ASD sample adds to the literature on sex and age variations of ASD symptomatology.

Autism Diagnostic Observation Schedule (ADOS) scores in males and females diagnosed with autism: a naturalistic study

Purpose

Many tools are available for assessing autism in an adult population; however, few have been studied for the effects of gender on diagnostic scores. The purpose of this paper is to evaluate the Autism Diagnostic Observation Schedule (ADOS) assessment for gender bias in a clinical population, specifically whether the ADOS favours a “male-type” of autism.

Design/methodology/approach

The ADOS scores of patients referred to an NHS specialist autism assessment service were retrospectively examined for significant gender differences. The combined ADOS scores and diagnostic outcome were grouped by gender for each participant. The data were analysed in SPSS using independent t-tests to look for significant gender differences between combined ADOS scores and diagnostic outcomes.

Findings

A significant difference was observed in the mean combined ADOS scores for those participants who later received an autism diagnosis (male=10, female=6, t (13)=3.34, p=10; 0.005). However, no significant difference was observed between mean scores of those who did not receive an autism diagnosis (t (26)=1.21, p=0.237).

Originality/value

The ADOS is a popular assessment used for autism diagnosis. These results provide support for a male gender bias. This could have clinical implications for autism assessment services, whereby lower diagnostic thresholds could be considered for female patients. This could allow more females with autism to receive a diagnosis, and access support services.

Feasibility Testing of a Wearable Behavioral Aid for Social Learning in Children with Autism

BACKGROUND

Recent advances in computer vision and wearable technology have created an opportunity to introduce mobile therapy systems for autism spectrum disorders (ASD) that can respond to the increasing demand for therapeutic interventions; however, feasibility questions must be answered first.

OBJECTIVE

We studied the feasibility of a prototype therapeutic tool for children with ASD using Google Glass, examining whether children with ASD would wear such a device, if providing the emotion classification will improve emotion recognition, and how emotion recognition differs between ASD participants and neurotypical controls (NC).

METHODS

We ran a controlled laboratory experiment with 43 children: 23 with ASD and 20 NC. Children identified static facial images on a computer screen with one of 7 emotions in 3 successive batches: the first with no information about emotion provided to the child, the second with the correct classification from the Glass labeling the emotion, and the third again without emotion information. We then trained a logistic regression classifier on the emotion confusion matrices generated by the two information-free batches to predict ASD versus NC.

RESULTS

All 43 children were comfortable wearing the Glass. ASD and NC participants who completed the computer task with Glass providing audible emotion labeling (n = 33) showed increased accuracies in emotion labeling, and the logistic regression classifier achieved an accuracy of 72.7%. Further analysis suggests that the ability to recognize surprise, fear, and neutrality may distinguish ASD cases from NC.

CONCLUSION

This feasibility study supports the utility of a wearable device for social affective learning in ASD children and demonstrates subtle differences in how ASD and NC children perform on an emotion recognition task.

Linguistic camouflage in girls with autism spectrum disorder

Background

Autism spectrum disorder (ASD) is diagnosed more frequently in boys than girls, even when girls are equally symptomatic. Cutting-edge behavioral imaging has detected “camouflaging” in girls with ASD, wherein social behaviors appear superficially typical, complicating diagnosis. The present study explores a new kind of camouflage based on language differences. Pauses during conversation can be filled with words like UM or UH, but research suggests that these two words are pragmatically distinct (e.g., UM is used to signal longer pauses, and may correlate with greater social communicative sophistication than UH). Large-scale research suggests that women and younger people produce higher rates of UM during conversational pauses than do men and older people, who produce relatively more UH. Although it has been argued that children and adolescents with ASD use UM less often than typical peers, prior research has not included sufficient numbers of girls to examine whether sex explains this effect. Here, we explore UM vs. UH in school-aged boys and girls with ASD, and ask whether filled pauses relate to dimensional measures of autism symptom severity.

Methods

Sixty-five verbal school-aged participants with ASD (49 boys, 16 girls, IQ estimates in the average range) participated, along with a small comparison group of typically developing children (8 boys, 9 girls). Speech samples from the Autism Diagnostic Observation Schedule were orthographically transcribed and time-aligned, with filled pauses marked. Parents completed the Social Communication Questionnaire and the Vineland Adaptive Behavior Scales.

Results

Girls used UH less often than boys across both diagnostic groups. UH suppression resulted in higher UM ratios for girls than boys, and overall filled pause rates were higher for typical children than for children with ASD. Higher UM ratios correlated with better socialization in boys with ASD, but this effect was driven by increased use of UH by boys with greater symptoms.

Conclusions

Pragmatic language markers distinguish girls and boys with ASD, mirroring sex differences in the general population. One implication of this finding is that typical-sounding disfluency patterns (i.e., reduced relative UH production leading to higher UM ratios) may normalize the way girls with ASD sound relative to other children, serving as “linguistic camouflage” for a naïve listener and distinguishing them from boys with ASD. This first-of-its-kind study highlights the importance of continued commitment to understanding how sex and gender change the way that ASD manifests, and illustrates the potential of natural language to contribute to objective “behavioral imaging” diagnostics for ASD.

Gender comparisons in children with ASD entering early intervention

BACKGROUND

Males are diagnosed with Autism Spectrum Disorder (ASD) approximately four times as often as females. This has led to interest in recent years of potential under-diagnosis of females, as well as negative consequences for females with ASD due to under-identification. A number of potential explanations for gender bias in diagnosis are discussed including that females and males may present differently despite showing the same core symptoms. Previous research has shown inconsistent findings in comparisons between genders in young children with ASD for whom early intervention is vital. Thus, the aim of the present study was to investigate the social, communication, and cognitive functioning, as well as level of ASD symptoms, in a cohort of children who presented for early intervention to inform understanding of gender differences in this population, as well as to inform understanding of the mechanisms by which gender bias may occur.

METHOD

Participants included 254 children (42 females) aged 29-74 months who completed measures of cognition, communication skills, adaptive behaviour, and ASD symptoms on entry to early intervention.

RESULTS

Consistent with hypotheses, no significant gender differences were found both overall, and when split by functioning level. However, a similar ratio of males and females was found in both high- and low-functioning groups contrary to predictions.

CONCLUSIONS

These results are consistent with some of the previous research that suggests gender differences may not be apparent in clinical samples at this young age. We highlight a need for further research that may use universal screening or longitudinal methods to understand the trajectory of development for females with ASD specifically. Such research could better inform timely and tailored intervention from the preschool years onwards.

The Early Origins of Autism

Autism spectrum disorders (ASDs) are neurodevelopmental disorders whose core features of impaired social communication and atypical repetitive behaviors and/or restrictions in range of interests emerge in toddlerhood and carry significant implications at successive stages of development. The ability to reliably identify most cases of the condition far earlier than the average age of diagnosis presents a novel opportunity for early intervention, but the availability of such an intervention is disparate across US communities, and its impact is imperfectly understood. New research may transform the clinical approach to these conditions in early childhood.

Sex differences in the reciprocal behaviour of children with autism

Differences in the social limitations of girls compared to boys on the autism spectrum are still poorly understood. Impaired social-emotional reciprocity is a core diagnostic criterion for an autism spectrum disorder. This study compares sex differences in reciprocal behaviour in children with autism spectrum disorder (32 girls, 114 boys) and in typically developing children (24 girls, 55 boys). While children with autism spectrum disorder showed clear limitations in reciprocal behaviour compared to typically developing children, sex differences were found only in the autism spectrum disorder group: girls with autism spectrum disorder had higher reciprocity scores than boys with autism spectrum disorder. However, compared to typically developing girls, girls with autism spectrum disorder showed subtle differences in reciprocal behaviour. The sex-specific response patterns in autism spectrum disorder can inform and improve the diagnostic assessment of autism in females.

Psychometric properties of the Autism-Spectrum Quotient in both clinical and non-clinical samples: Chinese version for mainland China

BACKGROUND

The Autism-Spectrum Quotient (AQ) is widely used to quantify autistic traits, which have been evaluated in the parents of individuals with autism spectrum disorders (ASD) and in the general population. This paper's objective was to investigate the AQ's psychometric properties of the Chinese version for mainland China and to establish whether the pattern of sex differences in the quantity of autistic traits exists. We also examined the usefulness of the AQ in differentiating between individuals with ASD, schizophrenia (SCH), obsessive-compulsive disorder (OCD) and healthy controls (HC).

METHODS

In this study, the psychometric properties of the AQ were assessed in 1037 parents of children with ASD and in 1040 parents of typically developing children (TDC). Additionally, 32 participants with ASD, 37 patients with SCH, 38 OCD patients and 38 healthy controls (matched for age, gender and IQ) were assessed with the AQ.

RESULTS

The internal consistency and test-retest reliability of the AQ and AQ subscales were within an acceptable range. Parents of ASD children scored higher than TDC parents on total AQ and AQ subscales, and TDC parents scored more than parents of ASD children on 2 items of 50. Fathers scored higher than did mothers on total AQ and four subscales, with the sole exception being the subscale attention to detail. The total AQ score of the ASD group was higher than that of the SCH, OCD and HC groups, and the total AQ score of the HC group was significantly lower than that of the SCH and OCD groups, with no differences being observed between the SCH and OCD groups.

CONCLUSIONS

The Mandarin AQ demonstrated promising psychometric properties and was a reliable instrument for quantifying autistic traits in both clinical and non-clinical samples in mainland China.

Data from the Baby Siblings Research Consortium confirm and specify the nature of the female protective effect in autism: A commentary on Messinger et al

Sibling recurrence data from the Baby Siblings Research Consortium (BSRC) recapitulate results from very large clinical family studies that demonstrate the absence of the Carter effect and provide clarification of the nature of the female protective effect in ASD. This legacy prospective data collection confirmed marked differences in the proportions of males versus females who lie along deviant trajectories of social development in the setting of inherited liability to autism—a phenomenon which defines the female protective effect—and demonstrate that among affected children, sex differences are modest and homologous to those observed among non-ASD children.

Rapid video-referenced ratings of reciprocal social behavior in toddlers: a twin study

BACKGROUND

Reciprocal social behavior (RSB) is a developmental prerequisite for social competency, and deficits in RSB constitute a core feature of autism spectrum disorder (ASD). Although clinical screeners categorically ascertain risk of ASD in early childhood, rapid methods for quantitative measurement of RSB in toddlers are not yet established. Such measurements are critical for tracking developmental trajectories and incremental responses to intervention.

METHODS

We developed and validated a 20-min video-referenced rating scale, the video-referenced rating of reciprocal social behavior (vrRSB), for untrained caregivers to provide standardized ratings of quantitative variation in RSB. Parents of 252 toddler twins [Monozygotic (MZ) = 31 pairs, Dizygotic (DZ) = 95 pairs] ascertained through birth records, rated their twins' RSB at two time points, on average 6 months apart, and completed two developmental measures, the Modified Checklist for Autism in Toddlers (M-CHAT) and the MacArthur Communicative Development Inventory Short Form (MCDI-s).

RESULTS

Scores on the vrRSB were fully continuously distributed, with excellent 6-month test-retest reliability ([intraclass correlation coefficient] ICC = 0.704, p < .000). MZ twins displayed markedly greater trait concordance than DZ twins, (MZ ICC = 0.863, p < .000, DZ ICC = 0.231, p < .012). VrRSB score distributions were highly distinct for children passing versus failing the M-CHAT (t = -8.588, df = 31, p < .000), incrementally improved from 18-24 months, and were inversely correlated with receptive and expressive vocabulary on the MCDI-s.

CONCLUSIONS

Like quantitative autistic trait ratings in school-aged children and adults, toddler scores on the vrRSB are continuously distributed and appear highly heritable. These ratings exhibited minimal measurement error, high inter-individual stability, and developmental progression in RSB as children matured from 18-24 months, supporting their potential utility for serially quantifying the severity of early autistic syndromes over time and in response to intervention. In addition, these findings inform the genetic-environmental structure of RSB in early typical development.

Distribution and Within-Family Specificity of Quantitative Autistic Traits in Patients with Neurofibromatosis Type I

OBJECTIVE

To examine the distribution of quantitative autistic traits (QATs) in an independent neurofibromatosis type I (NF1) sample, the relationships between QAT, sex, and attention deficit hyperactivity disorder (ADHD) symptomatology, and to explore evidence for QAT mutational specificity within families.

STUDY DESIGN

Age-appropriate versions of the Social Responsiveness Scale, second edition and the Conners Adult ADHD Rating Scales were completed for 103 patients with NF1 from the Washington University Neurofibromatosis Center.

RESULTS

Patients with NF1 exhibited a pathologically shifted unimodal distribution for QAT. Forty-four percent of the subjects exhibited a QAT burden at or above 1 SD from the population mean; 13% scored at or above the extreme first percentile of the general population distribution. Elevations in ADHD symptomatology exhibited a distinct bimodal distribution; however, mean ADHD index scores were equivalent in patients who had been diagnosed in the community with ADHD compared with those who had not. We observed striking within-family associations for QAT, reflected by an Social Responsiveness Scale, second edition intraclass correlation of 0.77 in pairings of first degree relatives with NF1.

CONCLUSIONS

Impairments in reciprocal social behavior and attention affect a large proportion of patients with NF1 throughout life and are often clinically unrecognized. Further exploration of genotype-phenotype correlation is strongly warranted for the purpose of gaining insights into mechanisms by which specific mutational variations in the NF1 gene may influence autistic trait severity.

Sex/gender differences and autism: setting the scene for future research

OBJECTIVE

The relationship between sex/gender differences and autism has attracted a variety of research ranging from clinical and neurobiological to etiological, stimulated by the male bias in autism prevalence. Findings are complex and do not always relate to each other in a straightforward manner. Distinct but interlinked questions on the relationship between sex/gender differences and autism remain underaddressed. To better understand the implications from existing research and to help design future studies, we propose a 4-level conceptual framework to clarify the embedded themes.

METHOD

We searched PubMed for publications before September 2014 using search terms "'sex OR gender OR females' AND autism." A total of 1,906 articles were screened for relevance, along with publications identified via additional literature reviews, resulting in 329 articles that were reviewed.

RESULTS

Level 1, "Nosological and diagnostic challenges," concerns the question, "How should autism be defined and diagnosed in males and females?" Level 2, "Sex/gender-independent and sex/gender-dependent characteristics," addresses the question, "What are the similarities and differences between males and females with autism?" Level 3, "General models of etiology: liability and threshold," asks the question, "How is the liability for developing autism linked to sex/gender?" Level 4, "Specific etiological-developmental mechanisms," focuses on the question, "What etiological-developmental mechanisms of autism are implicated by sex/gender and/or sexual/gender differentiation?"

CONCLUSIONS

Using this conceptual framework, findings can be more clearly summarized, and the implications of the links between findings from different levels can become clearer. Based on this 4-level framework, we suggest future research directions, methodology, and specific topics in sex/gender differences and autism.

Familiality of Quantitative Autism Traits

Background:

Autistic traits exist along a continuum that extends into social functioning in the general population, and they aggregate in the family members of children with autism spectrum disorder (ASD). Quantitative measures are therefore essential when investigating the patterns of familiality of these traits. Prior studies have suggested differential inheritance patterns of autistic traits that depend on the cognitive level of the child with ASD as well as the family type.

Objective:

Our goal was to examine the family patterns of quantitative autism traits (QAT) in a group of simplex autism families of high-functioning children with ASD.

Method:

We used the Social Responsiveness Scale (SRS) to evaluate QAT in 47 ASD families and 46 control families. SRS assessments (parental/spousal evaluations) were collected for the children with ASD, their siblings, and their parents as well as for the control children and their parents.

Results:

The SRS was able to distinguish individuals with ASD from the control children and from their unaffected siblings. Significant group differences were also found when comparing the fathers of ASD families to control fathers and when comparing the brothers of individuals with ASD to control boys, with male members of ASD families having higher SRS scores. Gender differences were observed in the group of siblings of children with ASD and the group of parents of children with ASD, with males having higher scores than females. In ASD families, a positive trend between child and father QAT was found, whereas mothers’ scores were not associated with child outcomes. By contrast, in control families, mothers’ QAT correlated more strongly with child QAT.

Conclusions:

Autistic traits aggregate in the fathers and brothers of children with ASD in simplex autism families. The QAT levels of the family members should be taken into consideration when planning the rehabilitation of the child or adolescent with ASD and when designing family interventions.

Parental social responsiveness and risk of autism spectrum disorder in offspring

IMPORTANCE

Although autism spectrum disorder (ASD) is known to be heritable, patterns of inheritance of subclinical autistic traits in nonclinical samples are poorly understood.

OBJECTIVE

To examine the familiality of Social Responsiveness Scale (SRS) scores of individuals with and without ASD.

DESIGN, SETTING, AND PARTICIPANTS

We performed a nested case-control study (pilot study: July 1, 2007, through June 30, 2009; full-scale study: September 15, 2008, through September 14, 2012) within a population-based longitudinal cohort. Participants were drawn from the Nurses' Health Study II, a cohort of 116,430 female nurses recruited in 1989. Case participants were index children with reported ASD; control participants were frequency matched by year of birth of case participants among those not reporting ASD. Of 3161 eligible participants, 2144 nurses (67.8%) returned SRS forms for a child and at least 1 parent and were included in these analyses.

EXPOSURE

The SRS scores, as reported by nurse mothers and their spouses, were examined in association with risk of ASD using crude and adjusted logistic regression analyses. The SRS scores of the children were examined in association with SRS scores of the parents using crude and adjusted linear regression analyses stratified by case status.

MAIN OUTCOMES AND MEASURES

Autism spectrum disorder, assessed by maternal report, validated in a subgroup with the Autism Diagnostic Interview-Revised.

RESULTS

A total of 1649 individuals were included in these analyses, including 256 ASD case participants, 1393 control participants, 1233 mothers, and 1614 fathers. Risk of ASD was increased by 85.0% among children whose parents had concordantly elevated SRS scores (odds ratio [OR], 1.85; 95% CI, 1.08-3.16) and by 52.0% when the score of either parent was elevated (OR, 1.52; 95% CI, 1.11-2.06). Elevated scores of the father significantly increased the risk of ASD in the child (OR, 1.94; 95% CI, 1.38-2.71), but no association was seen with elevated scores of the mother. Elevated parent scores significantly increased child scores in controls, corresponding to an increase in 23 points (P < .001).

CONCLUSIONS AND RELEVANCE

These findings support the role of additive genetic influences in concentrating inherited ASD susceptibility in successive generations and the potential role of preferential mating, and suggest that typical variation in parental social functioning can produce clinically significant differences in offspring social traits.

Attenuation of typical sex differences in 800 adults with autism vs. 3,900 controls

Sex differences have been reported in autistic traits and systemizing (male advantage), and empathizing (female advantage) among typically developing individuals. In individuals with autism, these cognitive-behavioural profiles correspond to predictions from the "extreme male brain" (EMB) theory of autism (extreme scores on autistic traits and systemizing, below average on empathizing). Sex differences within autism, however, have been under-investigated. Here we show in 811 adults (454 females) with autism and 3,906 age-matched typical control adults (2,562 females) who completed the Empathy Quotient (EQ), the Systemizing Quotient-Revised (SQ-R), and the Autism Spectrum Quotient (AQ), that typical females on average scored higher on the EQ, typical males scored higher on the SQ-R and AQ, and both males and females with autism showed a shift toward the extreme of the "male profile" on these measures and in the distribution of "brain types" (the discrepancy between standardized EQ and SQ-R scores). Further, normative sex differences are attenuated but not abolished in adults with autism. The findings provide strong support for the EMB theory of autism, and highlight differences between males and females with autism.

Gender differences in emotionality and sociability in children with autism spectrum disorders

Background

Four times as many males are diagnosed with high functioning autism compared to females. A growing body of research that focused on females with autism spectrum disorder (ASD) questions the assumption of gender invariance in ASD. Clinical observations suggest that females with ASD superficially demonstrate better social and emotional skills than males with ASD, which may camouflage other diagnostic features. This may explain the under-diagnosis of females with ASD.

Methods

We hypothesised that females with ASD would display better social skills than males with ASD on a test of friendship and social function. One hundred and one 10- to 16-year-olds (ASD females, n = 25; typically developing (TD) females, n = 25; ASD males, n = 25; TD males, n = 26) were interviewed (using the friendship questionnaire (FQ)) with high scores indicating the child has close, empathetic and supportive relationships. One parent of each child completed the FQ to assess whether there are differences in perception of friendships between parents and children.

Results

It was found that, independent of diagnosis, females demonstrated higher scores on the FQ than males. Further, regardless of gender, children with ASD demonstrated lower scores than TD children. Moreover, the effect of ASD was independent of gender. Interestingly, females with ASD and TD males displayed similar scores on the FQ.

Conclusions

This finding is supported by clinical reports that females with ASD have more developed social skills than males with ASD. Further research is now required to examine the underlying causes for this phenomenon in order to develop gender-appropriate diagnostic criteria and interventions for ASD.

Disentangling the heterogeneity of autism spectrum disorder through genetic findings

Autism spectrum disorder (ASD) represents a heterogeneous group of disorders, which presents a substantial challenge to diagnosis and treatment. Over the past decade, considerable progress has been made in the identification of genetic risk factors for ASD that define specific mechanisms and pathways underlying the associated behavioural deficits. In this Review, we discuss how some of the latest advances in the genetics of ASD have facilitated parsing of the phenotypic heterogeneity of this disorder. We argue that only through such advances will we begin to define endophenotypes that can benefit from targeted, hypothesis-driven treatments. We review the latest technologies used to identify and characterize the genetics underlying ASD and then consider three themes-single-gene disorders, the gender bias in ASD, and the genetics of neurological comorbidities-that highlight ways in which we can use genetics to define the many phenotypes within the autism spectrum. We also present current clinical guidelines for genetic testing in ASD and their implications for prognosis and treatment.

Autistic traits in male and female students and individuals with high functioning autism spectrum disorders measured by the Polish version of the Autism-Spectrum Quotient

So far no standardized screening instrument for autism spectrum disorders for adults has been developed in Poland. The main aim of the study was to explore the properties of the Polish version of the Autism-Spectrum Quotient (AQ), especially its reliability and discriminating power. The second purpose was to establish whether the pattern of sex and area of study differences in the amount of autistic traits found in other countries also exist in Poland. The groups in the study included students (n = 2819), adults with ASD (n = 60) and a non-clinical sample (n = 60) matched with the ASD group for age, sex, education and place of residence. The Polish version of AQ proved to be reliable, although - as in studies conducted in other countries - the internal consistency coefficients for subscales (with exception for social skill) were low. ASD diagnosis was the most powerful determinant of AQ scores. Sex differences in autistic traits and a relationship between autistic traits and area of study were found.

Confirmatory factor analytic structure and measurement invariance of quantitative autistic traits measured by the social responsiveness scale-2

Understanding the factor structure of autistic symptomatology is critical to the discovery and interpretation of causal mechanisms in autism spectrum disorder. We applied confirmatory factor analysis and assessment of measurement invariance to a large (N = 9635) accumulated collection of reports on quantitative autistic traits using the Social Responsiveness Scale, representing a broad diversity of age, severity, and reporter type. A two-factor structure (corresponding to social communication impairment and restricted, repetitive behavior) as elaborated in the updated Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5) criteria for autism spectrum disorder exhibited acceptable model fit in confirmatory factor analysis. Measurement invariance was appreciable across age, sex, and reporter (self vs other), but somewhat less apparent between clinical and nonclinical populations in this sample comprised of both familial and sporadic autism spectrum disorders. The statistical power afforded by this large sample allowed relative differentiation of three factors among items encompassing social communication impairment (emotion recognition, social avoidance, and interpersonal relatedness) and two factors among items encompassing restricted, repetitive behavior (insistence on sameness and repetitive mannerisms). Cross-trait correlations remained extremely high, that is, on the order of 0.66-0.92. These data clarify domains of statistically significant factoral separation that may relate to partially-but not completely-overlapping biological mechanisms, contributing to variation in human social competency. Given such robust intercorrelations among symptom domains, understanding their co-emergence remains a high priority in conceptualizing common neural mechanisms underlying autistic syndromes.

Male-biased autosomal effect of 16p13.11 copy number variation in neurodevelopmental disorders

Copy number variants (CNVs) at chromosome 16p13.11 have been associated with a range of neurodevelopmental disorders including autism, ADHD, intellectual disability and schizophrenia. Significant sex differences in prevalence, course and severity have been described for a number of these conditions but the biological and environmental factors underlying such sex-specific features remain unclear. We tested the burden and the possible sex-biased effect of CNVs at 16p13.11 in a sample of 10,397 individuals with a range of neurodevelopmental conditions, clinically referred for array comparative genomic hybridisation (aCGH); cases were compared with 11,277 controls. In order to identify candidate phenotype-associated genes, we performed an interval-based analysis and investigated the presence of ohnologs at 16p13.11; finally, we searched the DECIPHER database for previously identified 16p13.11 copy number variants. In the clinical referral series, we identified 46 cases with CNVs of variable size at 16p13.11, including 28 duplications and 18 deletions. Patients were referred for various phenotypes, including developmental delay, autism, speech delay, learning difficulties, behavioural problems, epilepsy, microcephaly and physical dysmorphisms. CNVs at 16p13.11 were also present in 17 controls. Association analysis revealed an excess of CNVs in cases compared with controls (OR = 2.59; p = 0.0005), and a sex-biased effect, with a significant enrichment of CNVs only in the male subgroup of cases (OR = 5.62; p = 0.0002), but not in females (OR = 1.19, p = 0.673). The same pattern of results was also observed in the DECIPHER sample. Interval-based analysis showed a significant enrichment of case CNVs containing interval II (OR = 2.59; p = 0.0005), located in the 0.83 Mb genomic region between 15.49-16.32 Mb, and encompassing the four ohnologs NDE1, MYH11, ABCC1 and ABCC6. Our data confirm that duplications and deletions at 16p13.11 represent incompletely penetrant pathogenic mutations that predispose to a range of neurodevelopmental disorders, and suggest a sex-limited effect on the penetrance of the pathological phenotypes at the 16p13.11 locus.