Sexually Dimorphic Alterations in the Transcriptome and Behavior with Loss of Histone Demethylase KDM5C

Abstract

Chromatin dysregulation has emerged as a major hallmark of neurodevelopmental disorders such as intellectual disability (ID) and autism spectrum disorders (ASD). The prevalence of ID and ASD is higher in males compared to females, with unknown mechanisms. Intellectual developmental disorder, X-linked syndromic, Claes-Jensen type (MRXSCJ), is caused by loss-of-function mutations of lysine demethylase 5C (KDM5C), a histone H3K4 demethylase gene. KDM5C escapes X-inactivation, thereby presenting at a higher level in females. Initially, MRXSCJ was exclusively reported in males, while it is increasingly evident that females with heterozygous KDM5C mutations can show cognitive deficits. The mouse model of MRXSCJ, male Kdm5c-hemizygous knockout animals, recapitulates key features of human male patients. However, the behavioral and molecular traits of Kdm5c-heterozygous female mice remain incompletely characterized. Here, we report that gene expression and behavioral abnormalities are readily detectable in Kdm5c-heterozygous female mice, demonstrating the requirement for a higher KDM5C dose in females. Furthermore, we found both shared and sex-specific consequences of a reduced KDM5C dose in social behavior, gene expression, and genetic interaction with the counteracting enzyme KMT2A. These observations provide an essential insight into the sex-biased manifestation of neurodevelopmental disorders and sex chromosome evolution.

Keywords: chromatin regulators; histone demethylase; learning and memory; neurodevelopmental disorders; x-linked intellectual disability.

Background: Fidelity, or the degree to which an intervention is implemented as designed, is essential for effective implementation. There has been a growing emphasis on assessing fidelity of evidence-based practices for autistic children in schools. Fidelity measurement should be multidimensional and focus on core intervention components and assess their link with program outcomes. This study evaluated the relation between intervention fidelity ratings from multiple sources, tested the relation between fidelity ratings and child outcomes, and determined the relations between core intervention components and child outcomes in a study of an evidence-based psychosocial intervention designed to promote inclusion of autistic children at school, Remaking Recess.

Method: This study extends from a larger randomized controlled trial examining the effect of implementation support on Remaking Recess fidelity and child outcomes. Schools were randomized to receive the intervention or the intervention plus implementation support. Observers, intervention coaches, and school personnel completed fidelity measures to rate completion and quality of intervention delivery. A measure of peer engagement served as the child outcome. Pearson correlation coefficients were calculated to determine concordance between raters. Two sets of hierarchical linear models were conducted using fidelity indices as predictors of peer engagement.

Results: Coach- and self-rated completion and quality scores, observer- and self-rated quality scores, and observer- and coach-rated quality fidelity scores were significantly correlated. Higher observer-rated completion and quality fidelity scores were predictors of higher peer engagement scores. No single intervention component emerged as a significant predictor of peer engagement.

Conclusions: This study demonstrates the importance of using a multidimensional approach for measuring fidelity, testing the link between fidelity and child outcomes, and examining how core intervention components may be associated with child outcomes. Future research should clarify how to improve multi-informant reports to provide “good enough” ratings of fidelity that provide meaningful information about outcomes in community settings.

Plain language summary: Fidelity is defined as how closely an intervention is administered in the way the creators intended. Fidelity is important because it allows researchers to determine what exactly is leading to changes. In recent years, there has been an interest in examining fidelity of interventions for autistic children who receive services in school. This study looked at the relationship between fidelity ratings from multiple individuals, the relationship between fidelity and child outcomes, and the relationship between individual intervention component and child changes in a study of Remaking Recess, an intervention for autistic children at school. Schools were randomly selected to receive the intervention only or the intervention plus implementation support from the research team. Observers, intervention coaches, and individuals delivering the intervention themselves completed fidelity measures. Child engagement with peers was measured before and after the intervention. Several measures of self-, coach-, and observer-report fidelity were associated with each other. Higher observer-reported fidelity was associated with higher child peer engagement scores. No single intervention step was linked to child peer engagement and both treatment groups had similar outcomes in terms of fidelity. This study shows the importance of having multiple raters assess different parts of intervention fidelity, looking at the link between fidelity and child outcomes, and seeing how individual intervention steps may be related to outcomes. Future research should aim to find out which types of fidelity ratings are “good enough” to lead to positive changes following treatment so that those aspects can be used and targeted in the future.

Keywords: autism spectrum disorder; fidelity; implementation; school-based; social engagement intervention.

Objectives: Autism spectrum disorder (autism) is a heterogeneous condition that poses challenges in describing the needs of individuals with autism and making prognoses about future outcomes. We applied a newly proposed definition of profound autism to surveillance data to estimate the percentage of children with autism who have profound autism and describe their sociodemographic and clinical characteristics.

Methods: We analyzed population-based surveillance data from the Autism and Developmental Disabilities Monitoring Network for 20 135 children aged 8 years with autism during 2000-2016. Children were classified as having profound autism if they were nonverbal, were minimally verbal, or had an intelligence quotient <50.

Results: The percentage of 8-year-old children with profound autism among those with autism was 26.7%. Compared with children with non-profound autism, children with profound autism were more likely to be female, from racial and ethnic minority groups, of low socioeconomic status, born preterm or with low birth weight; have self-injurious behaviors; have seizure disorders; and have lower adaptive scores. In 2016, the prevalence of profound autism was 4.6 per 1000 8-year-olds. The prevalence ratio (PR) of profound autism was higher among non-Hispanic Asian/Native Hawaiian/Other Pacific Islander (PR = 1.55; 95 CI, 1.38-1.73), non-Hispanic Black (PR = 1.76; 95% CI, 1.67-1.86), and Hispanic (PR = 1.50; 95% CI, 0.88-1.26) children than among non-Hispanic White children.

Conclusions: As the population of children with autism continues to change, describing and quantifying the population with profound autism is important for planning. Policies and programs could consider the needs of people with profound autism across the life span to ensure their needs are met.

Keywords: autism; public health; surveillance.

Best practice for the assessment of autism spectrum disorder (ASD) symptom severity relies on clinician ratings of the Autism Diagnostic Observation Schedule, 2nd Edition (ADOS-2), but the association of these ratings with objective measures of children’s social gaze and smiling is unknown. Sixty-six preschool-age children (49 boys, M = 39.97 months, SD = 10.58) with suspected ASD (61 confirmed ASD) were administered the ADOS-2 and provided social affect calibrated severity scores (SA CSS). Children’s social gaze and smiling during the ADOS-2, captured with a camera contained in eyeglasses worn by the examiner and parent, were obtained via a computer vision processing pipeline. Children who gazed more at their parents (p = .04) and whose gaze at their parents involved more smiling (p = .02) received lower social affect severity scores, indicating fewer social affect symptoms, adjusted R2 = .15, p = .003.

Keywords: Autism diagnostic observation schedule; Autism spectrum disorder; Objective measurement; Smiling; Social gaze.

Individuals diagnosed with autism spectrum disorder (ASD) present with a highly diverse set of challenges, disabilities, impairments and strengths. Recently, it has been suggested that researchers and practitioners avoid using certain words to describe the difficulties and impairments experienced by individuals with ASD to reduce stigma. The proposed limitations on terminology were developed by only a subset of the autism community, and the recommendations are already causing negative consequences that may be harmful to future scientific and clinical endeavors and, ultimately, to people with ASD. No one should have the power to censor language to exclude the observable realities of autism. Scientists and clinicians must be able to use any scientifically accurate terms necessary to describe the wide range of autistic people they study and support, without fear of censure or retribution.

Keywords: Vocabulary; autism spectrum disorder; bias; language.

Literature examining emotional regulation in infants with autism spectrum disorder (ASD) has focused on parent report. We examined behavioral and physiological responses during an emotion-evoking task designed to elicit emotional states in infants. Infants at an increased likelihood for ASD (IL; have an older sibling with ASD; 96 not classified; 29 classified with ASD at age two) and low likelihood (LL; no family history of ASD; n = 61) completed the task at 6, 12, and 18 months. The main findings were (1) the IL-ASD group displayed higher levels of negative affect during toy removal and negative tasks compared to the IL non-ASD and LL groups, respectively, (2) the IL-ASD group spent more time looking at the baseline task compared to the other two groups, and (3) the IL-ASD group showed a greater increase in heart rate from baseline during the toy removal and negative tasks compared to the LL group. These results suggest that IL children who are classified as ASD at 24 months show differences in affect, gaze, and heart rate during an emotion-evoking task, with potential implications for understanding mechanisms related to emerging ASD.

Keywords: ASD; affect; autism; baby sibling; gaze; heart rate; physiology.

Eye tracking has long been used to characterize differences in social attention between autistic and non-autistic children, but recent work has shown that these patterns may vary widely according to the biological sex of the participants and the social complexity and gender-typicality of the eye tracking stimuli (e.g., barbies vs. transformers). To better understand effects of sex, social complexity, and object gender-typicality on social and non-social gaze behavior in autism, we compared the visual attention patterns of 67 autistic (ASD) and non-autistic (NA) males (M) and females (F) (ASD M = 21; ASD F = 18; NA M = 14; NA F = 14) across four eye tracking paradigms varying in social complexity and object gender-typicality. We found consistency across paradigms in terms of overall attention and attention to social stimuli, but attention to objects varied when paradigms considered gender in their stimulus design. Children attended more to gendered objects, particularly when the gender-typicality of the object matched their assigned sex. These results demonstrate that visual social attention in autism is affected by interactions between a child’s biological sex, social scene complexity, and object gender-typicality and have broad implications for the design and interpretation of eye tracking studies.

Keywords: attention; eye movement; gender/female ASD; sex differences.

Defects in interneuron migration can disrupt the assembly of cortical circuits and lead to neuropsychiatric disease. Using forebrain assembloids derived by integration of cortical and ventral forebrain organoids, we have previously discovered a cortical interneuron migration defect in Timothy syndrome (TS), a severe neurodevelopmental disease caused by a mutation in the L-type calcium channel (LTCC) Cav1.2. Here, we find that acute pharmacological modulation of Cav1.2 can regulate the saltation length, but not the frequency, of interneuron migration in TS. Interestingly, the defect in saltation length is related to aberrant actomyosin and myosin light chain (MLC) phosphorylation, while the defect in saltation frequency is driven by enhanced γ-aminobutyric acid (GABA) sensitivity and can be restored by GABA-A receptor antagonism. Finally, we describe hypersynchronous hCS network activity in TS that is exacerbated by interneuron migration. Taken together, these studies reveal a complex role of LTCC function in human cortical interneuron migration and strategies to restore deficits in the context of disease.

Keywords: GABA; Timothy syndrome; assembloids; calcium; interneurons; organoids.

Background: Fragile X syndrome (FXS) is the most prevalent form of inherited intellectual disability and is commonly associated with autism. Previous studies have linked the structural and functional alterations in FXS with impaired sensory processing and sensory hypersensitivity, which may hinder the early development of cognitive functions such as language comprehension. In this study, we compared the P1 response of the auditory evoked potential and its habituation to repeated auditory stimuli in male children (2-7 years old) with and without FXS, and examined their association with clinical measures in these two groups.

Methods: We collected high-density electroencephalography (EEG) data in an auditory oddball paradigm from 12 male children with FXS and 11 age- and sex-matched typically developing (TD) children. After standardized EEG pre-processing, we conducted a spatial principal component (PC) analysis and identified two major PCs-a frontal PC and a temporal PC. Within each PC, we compared the P1 amplitude and inter-trial phase coherence (ITPC) between the two groups, and performed a series of linear regression analysis to study the association between these EEG measures and several clinical measures, including assessment scores for language abilities, non-verbal skills, and sensory hypersensitivity.

Results: At the temporal PC, both early and late standard stimuli evoked a larger P1 response in FXS compared to TD participants. For temporal ITPC, the TD group showed greater habituation than the FXS group. However, neither group showed significant habituation of the frontal or temporal P1 response. Despite lack of habituation, exploratory analysis of brain-behavior associations observed that within the FXS group, reduced frontal P1 response to late standard stimuli, and increased frontal P1 habituation were both associated with better language scores.

Conclusion: We identified P1 amplitude and ITPC in the temporal region as a contrasting EEG phenotype between the FXS and the TD groups. However, only frontal P1 response and habituation were associated with language measures. Larger longitudinal studies are required to determine whether these EEG measures could be used as biomarkers for language development in patients with FXS.

Keywords: EEG; ERP; Fragile X syndrome; autism; language; neural habituation; phase coherence.

Children’s ability to share attention with another person (i.e., achieve joint attention) is critical for learning about their environments in general1-3 and supporting language and object word learning in particular.1,4-14 While joint attention (JA) as it pertains to autism spectrum disorder (ASD) is often more narrowly operationalized as arising from eye gaze or explicit pointing cues alone,2,5,10,15-19 recent evidence demonstrates that JA in natural environments can be achieved more broadly through multiple other pathways beyond gaze and gestures.2,4,20-31 Here, we use dual head-mounted eye tracking to examine pathways into and characteristics of JA episodes during free-flowing parent-child toy play, comparing children with ASD to typically developing (TD) children. Moments of JA were defined objectively as both the child’s and parent’s gaze directed to the same object at the same time. Consistent with previous work in TD children,4,21,25,30-32 we found that both TD and ASD children rarely look at their parent’s face in this unstructured free play context. Nevertheless, both groups achieved similarly high rates of JA that far exceeded chance, suggesting the use of alternative pathways into JA. We characterize these alternate pathways, find they occur at similar levels across both groups, and achieve similar ends: namely, for both groups, targets of JA are named more frequently by parents in those moments than non-jointly attended objects. These findings broaden the conceptualization of JA abilities and impairment in ASD and raise questions regarding the mechanistic role of the face-gaze-mediated JA pathway in ASD.

Keywords: autism; development; dyadic interaction; eye tracking; joint attention; naturalistic play; social interaction.

Background: Canonical babbling-producing syllables with a mature consonant, full vowel, and smooth transition-is an important developmental milestone that typically occurs in the first year of life. Some studies indicate delayed or reduced canonical babbling in infants at high familial likelihood for autism spectrum disorder (ASD) or who later receive an ASD diagnosis, but evidence is mixed. More refined characterization of babbling in the first year of life in infants with high likelihood for ASD is needed.

Methods: Vocalizations produced at 6 and 12 months by infants (n = 267) taking part in a longitudinal study were coded for canonical and non-canonical syllables. Infants were categorized as low familial likelihood (LL), high familial likelihood diagnosed with ASD at 24 months (HL-ASD) or not diagnosed (HL-Neg). Language delay was assessed based on 24-month expressive and receptive language scores. Canonical babble ratio (CBR) was calculated by dividing the number of canonical syllables by the number of total syllables. Generalized linear (mixed) models were used to assess the relationship between group membership and CBR, controlling for site, sex, and maternal education. Logistic regression was used to assess whether canonical babbling ratios at 6 and 12 months predict 24-month diagnostic outcome.

Results: No diagnostic group differences in CBR were detected at 6 months, but HL-ASD infants produced significantly lower CBR than both the HL-Neg and LL groups at 12 months. HL-Neg infants with language delay also showed reduced CBR at 12 months. Neither 6- nor 12-month CBR was significant predictors of 24-month diagnostic outcome (ASD versus no ASD) in logistic regression.

Limitations: Small numbers of vocalizations produced by infants at 6 months may limit the reliability of CBR estimates. It is not known if results generalize to infants who are not at high familial likelihood, or infants from more diverse racial and socioeconomic backgrounds.

Conclusions: Lower canonical babbling ratios are apparent by the end of the first year of life in ASD regardless of later language delay, but are also observed for infants with later language delay without ASD. Canonical babbling may lack specificity as an early marker when used on its own.

Acquisition of pronominal forms by children with autism spectrum disorder (ASD) continues to garner significant attention due to the unusual ways that such children produce and comprehend them. In particular, pronoun reversal errors (e.g., using the 2nd-person pronoun “you” to refer to oneself) have been noted in the speech of children with ASD since the very first report of the disorder. In more recent years, investigations of the signing of deaf children with ASD have documented a different phenomenon: palm orientation reversals, such that signs typically produced with an outward-facing palm are produced with the palm towards the signer, or vice versa. At the same time, true pronoun reversals have yet to be documented in the signing of deaf children on the autism spectrum. These two curious facts have led us to ask if there is evidence that palm orientation reversals in signed languages and pronoun reversals in spoken languages could be surface manifestations of the same underlying differences present in ASD. In this paper we seek to establish whether there is evidence for such an analogy, by comparing the ages at which the two phenomena appear in both typically-developing (TD) children and those with ASD, the frequency and consistency with which they appear, and their relationships with other linguistic and cognitive skills. Data are presented from a fingerspelling task given to a sample of 17 native-signing children with ASD and 24 native-signing TD children. We conclude that there are provocative parallels between pronoun reversals in spoken languages and palm reversals in signed languages, though more research is needed to definitively answer these questions.

Keywords: ASL; autism spectrum disorder; fingerspelling; modality; pronouns.