Delineation of behavioral phenotypes in genetic syndromes: characteristics of autism spectrum disorder, affect and hyperactivity

X- vs. Y-chromosome influences on human behavior: a deep phenotypic comparison of psychopathology in XXY and XYY syndromes

BACKGROUND

Do different genetic disorders impart different psychiatric risk profiles? This question has major implications for biological and translational aspects of psychiatry, but has been difficult to tackle given limited access to shared batteries of fine-grained clinical data across genetic disorders.

METHODS

Using a new suite of generalizable analytic approaches, we examine gold-standard diagnostic ratings, scores on 66 dimensional measures of psychopathology, and measures of cognition and functioning in two different sex chromosome aneuploidies (SCAs)-Klinefelter (XXY/KS) and XYY syndrome (n = 102 and 64 vs. n = 74 and 60 matched XY controls, total n = 300). We focus on SCAs for their high collective prevalence, informativeness regarding differential X- vs. Y-chromosome effects, and potential relevance for normative sex differences.

RESULTS

We show that XXY/KS elevates rates for most psychiatric diagnoses as previously reported for XYY, but disproportionately so for anxiety disorders. Fine-mapping across all 66 traits provides a detailed profile of psychopathology in XXY/KS which is strongly correlated with that of XYY (r = .75 across traits) and robust to ascertainment biases, but reveals: (i) a greater penetrance of XYY than KS/XXY for most traits except mood/anxiety problems, and (ii) a disproportionate impact of XYY vs. XXY/KS on social problems. XXY/KS and XYY showed a similar coupling of psychopathology with adaptive function and caregiver strain, but not IQ.

CONCLUSIONS

This work provides new tools for deep-phenotypic comparisons of genetic disorders in psychiatry and uses these to detail unique and shared effects of the X- and Y-chromosome on human behavior.

Exploring an objective measure of overactivity in children with rare genetic syndromes

BACKGROUND

Overactivity is prevalent in several rare genetic neurodevelopmental syndromes, including Smith-Magenis syndrome, Angelman syndrome, and tuberous sclerosis complex, although has been predominantly assessed using questionnaire techniques. Threats to the precision and validity of questionnaire data may undermine existing insights into this behaviour. Previous research indicates objective measures, namely actigraphy, can effectively differentiate non-overactive children from those with attention-deficit hyperactivity disorder. This study is the first to examine the sensitivity of actigraphy to overactivity across rare genetic syndromes associated with intellectual disability, through comparisons with typically-developing peers and questionnaire overactivity estimates.

METHODS

A secondary analysis of actigraphy data and overactivity estimates from The Activity Questionnaire (TAQ) was conducted for children aged 4-15 years with Smith-Magenis syndrome (N=20), Angelman syndrome (N=26), tuberous sclerosis complex (N=16), and typically-developing children (N=61). Actigraphy data were summarized using the M10 non-parametric circadian rhythm variable, and 24-hour activity profiles were modelled via functional linear modelling. Associations between actigraphy data and TAQ overactivity estimates were explored. Differences in actigraphy-defined activity were also examined between syndrome and typically-developing groups, and between children with high and low TAQ overactivity scores within syndromes.

RESULTS

M10 and TAQ overactivity scores were strongly positively correlated for children with Angelman syndrome and Smith-Magenis syndrome. M10 did not substantially differ between the syndrome and typically-developing groups. Higher early morning activity and lower evening activity was observed across all syndrome groups relative to typically-developing peers. High and low TAQ group comparisons revealed syndrome-specific profiles of overactivity, persisting throughout the day in Angelman syndrome, occurring during the early morning and early afternoon in Smith-Magenis syndrome, and manifesting briefly in the evening in tuberous sclerosis complex.

DISCUSSION

These findings provide some support for the sensitivity of actigraphy to overactivity in children with rare genetic syndromes, and offer syndrome-specific temporal descriptions of overactivity. The findings advance existing descriptions of overactivity, provided by questionnaire techniques, in children with rare genetic syndromes and have implications for the measurement of overactivity. Future studies should examine the impact of syndrome-related characteristics on actigraphy-defined activity and overactivity estimates from actigraphy and questionnaire techniques.

Behavioral and Psychiatric Disorders in Syndromic Autism

Syndromic autism refers to autism spectrum disorder diagnosed in the context of a known genetic syndrome. The specific manifestations of any one of these syndromic autisms are related to a clinically defined genetic syndrome that can be traced to certain genes and variants, genetic deletions, or duplications at the chromosome level. The genetic mutations or defects in single genes associated with these genetic disorders result in a significant elevation of risk for developing autism relative to the general population and are related to recurrence with inheritance patterns. Additionally, these syndromes are associated with typical behavioral characteristics or phenotypes as well as an increased risk for specific behavioral or psychiatric disorders and clinical findings. Knowledge of these associations helps guide clinicians in identifying potentially treatable conditions that can help to improve the lives of affected patients and their families.

Psychiatric and neurological manifestations in adults with Smith-Magenis syndrome: A scoping review

Smith-Magenis syndrome (SMS) is a neurodevelopmental disorder caused by a 17p11.2 deletion or a pathogenic variant of the RAI1 gene, which lies within the 17p11.2 region. Various psychiatric and neurological disorders have been reported in SMS, with most literature focusing on children and adolescents. To provide an overview of the current knowledge on this topic in adults with SMS, we performed a comprehensive scoping review of the relevant literature. Our findings suggest that many manifestations that are common in childhood persist into adulthood. Neuropsychiatric manifestations in adults with SMS include intellectual disability, autism spectrum- and attention deficit hyperactivity disorder-related features, self-injurious and physical aggressive behaviors, sleep-wake disorders, and seizures. Findings of this review may facilitate optimization of management strategies in adults with SMS, and may guide future studies exploring late-onset psychiatric and neurological comorbidities in SMS.

The developmental trajectory of sleep in children with Smith-Magenis syndrome compared to typically developing peers: a 3-year follow-up study

Study Objectives

To determine the trajectory of: (i) objective sleep parameters and (ii) caregiver-reported sleep questionnaire scores over 3 years in children with Smith-Magenis syndrome (SMS) compared to age-matched typically developing (TD) controls. We also aimed to (iii) describe individual profiles of change in sleep parameters over time.

Methods

Week-long, overnight actigraphy and questionnaire data from 13 children with SMS and 13 age-matched TD children were collected at Time 1 and Time 2 (3 years later). Independent samples t-tests, paired samples t-tests, and Bayesian analyses were used to compare sleep parameters and sleep questionnaire scores between groups at each time point and compare data within groups to assess change over time.

Results

Sleep parameters were consistently more disrupted in the SMS group than the TD group, with significantly reduced sleep efficiency, increased wake after sleep onset and earlier get up times at both time points. This was mirrored in the questionnaire data, with children with SMS evidencing higher scores for overall sleep disturbance, night waking, and daytime sleepiness. While TD sleep parameters demonstrated expected developmental changes over 3 years, in the SMS group sleep parameters and variability between and within children remained largely stable. However, some children with SMS showed substantial variation in sleep parameters over time. Questionnaire scores remained stable over 3 years in both groups.

Conclusions

Overall, sleep disturbance appears to be a stable feature of SMS, indicative of a divergent sleep trajectory compared to TD peers. Proactive intervention approaches should be considered for poor sleep in SMS.

Behavioural and physiological indicators of anxiety reflect shared and distinct profiles across individuals with neurogenetic syndromes

Anxiety is heightened in individuals with intellectual disability, particularly in those with specific neurogenetic syndromes. Assessment of anxiety for these individuals is hampered by a lack of appropriate measures that cater for communication impairment, differences in presentation, and overlapping features with co-occurring conditions. Here, we adopt a multi-method approach to identify fine-grained behavioural and physiological (via salivary cortisol) responses to anxiety presses in people with fragile X (FXS; n = 27; Mage = 20.11 years; range 6.32 - 47.04 years) and Cornelia de Lange syndromes (CdLS; n = 27; Mage = 18.42 years; range 4.28 - 41.08 years), two neurogenetic groups at high risk for anxiety, compared to neurotypical children (NT; n = 21; Mage = 5.97 years; range 4.34 - 7.30 years). Results indicate that physical avoidance of feared stimuli and proximity seeking to a familiar adult are prominent behavioural indicators of anxiety/stress in FXS and CdLS. Heightened pervasive physiological arousal was identified in these groups via salivary cortisol. An association between autistic characteristics and anxiety was evident in the FXS group but not in the CdLS group pointing to syndrome-specific nuances in the association between anxiety and autism. This study furthers understanding of the behavioural and physiological presentation of anxiety in individuals with intellectual disability and progresses theoretical developments regarding the development and maintenance of anxiety at the intersection of autism.

X- vs. Y-Chromosome Influences on Human Behavior: A Deep Phenotypic Comparison of Psychopathology in XXY and XYY Syndromes

Do different genetic disorders impart different psychiatric risk profiles? This question has major implications for biological and translational aspects of psychiatry, but has been difficult to tackle given limited access to shared batteries of fine-grained clinical data across genetic disorders. Using a new suite of generalizable analytic approaches, we examine gold-standard diagnostic ratings, scores on 66 dimensional measures of psychopathology, and measures of cognition and functioning in two different sex chromosome aneuploidies (SCAs) - Klinefelter (XXY/KS) and XYY syndrome (n=102 and 64 vs. n=74 and 60 matched XY controls, total n=300). We focus on SCAs for their high collective prevalence, informativeness regarding differential X- vs. Y-chromosome effects, and potential relevance for normative sex differences. We show that XXY/KS elevates rates for most psychiatric diagnoses as previously reported for XYY, but disproportionately so for anxiety disorders. Fine-mapping across all 66 traits provides a detailed profile of psychopathology in XXY/KS which is strongly correlated with that of XYY (r=.75 across traits) and robust to ascertainment biases, but reveals: (i) a greater penetrance of XYY than KS/XXY for most traits except mood/anxiety problems, and (ii) a disproportionate impact of XYY vs. XXY/KS on social problems. XXY/KS and XXY showed a similar coupling of psychopathology with adaptive function and caregiver strain, but not IQ. This work provides new tools for deep-phenotypic comparisons of genetic disorders in psychiatry and uses these to detail unique and shared effects of the X- and Y-chromosome on human behavior.

The effect of emotion regulation on emotional eating among undergraduate students in China: The chain mediating role of impulsivity and depressive symptoms

This study aimed to examine the relationship between difficulties in emotion regulation and emotional eating and the role of impulsivity and depressive symptoms in mediating this chain. Four hundred ninety-four undergraduate students participated in the study. A self-designed questionnaire was used in the survey from February 6 to 13, 2022, to finish our purpose, including the Emotional Eating Scale (EES-R), Depression Scale (CES-D), Short Version of the Impulsivity Behavior Scale (UPPS-P) and Difficulties in Emotion Regulation Scale (DERS). The results showed that 1) difficulties in emotion regulation, impulsivity, depressive symptoms, and emotional eating were correlated; 2) impulsivity and depressive symptoms separately mediated the relationship between difficulties in emotion regulation and emotional eating; 3) impulsivity and depressive symptoms played a chain mediating role between difficulties in emotion regulation and emotional eating. The current study provided a better understanding of the psychologically related pathway of emotional eating. The results would be helpful for prevention and intervention of emotional eating among undergraduate students.

The developmental trajectories of the behavioral phenotype and neuropsychiatric functioning in Cornelia de Lange and Rubinstein Taybi syndromes: A longitudinal study

Several changes in the behavioral phenotype arise with the growth of children affected by Cornelia de Lange Syndrome (CdLS) and Rubinstein-Taybi Syndrome (RSTS). However, previous research relied on a cross-sectional study design turning into age-related comparisons of different syndromic cohorts to explore age-dependent changes. We aim to outline the variating pathways of the neuropsychiatric functioning across the lifespan in CdLS and RSTS, through the setting up of a longitudinal study design. The sample included 14 patients with CdLS and 15 with RSTS. The assessments were carried out in two different timepoints. Our findings highlight that the cognitive profile of CdLS is subjected to a worsening trend with decreasing Intellectual Quotient (IQ) scores from T0 to T1, whereas RSTS shows a stable IQ over time. Patients affected by RSTS show greater improvements compared to CdLS in communication, daily living skills, social abilities, and motor skills across the lifespan. Both syndromes report an upward trend in behavioral and emotional difficulties even if CdLS exhibit a significant and major deterioration compared to individuals with RSTS. Being aware of the early dysfunctional patterns which might pave the way for later neuropsychiatric impairments is the first step for planning preventive interventions.

Profiles of autism characteristics in thirteen genetic syndromes: a machine learning approach

BACKGROUND

Phenotypic studies have identified distinct patterns of autistic characteristics in genetic syndromes associated with intellectual disability (ID), leading to diagnostic uncertainty and compromised access to autism-related support. Previous research has tended to include small samples and diverse measures, which limits the generalisability of findings. In this study, we generated detailed profiles of autistic characteristics in a large sample of > 1500 individuals with rare genetic syndromes.

METHODS

Profiles of autistic characteristics based on the Social Communication Questionnaire (SCQ) scores were generated for thirteen genetic syndrome groups (Angelman n = 154, Cri du Chat n = 75, Cornelia de Lange n = 199, fragile X n = 297, Prader-Willi n = 278, Lowe n = 89, Smith-Magenis n = 54, Down n = 135, Sotos n = 40, Rubinstein-Taybi n = 102, 1p36 deletion n = 41, tuberous sclerosis complex n = 83 and Phelan-McDermid n = 35 syndromes). It was hypothesised that each syndrome group would evidence a degree of specificity in autistic characteristics. To test this hypothesis, a classification algorithm via support vector machine (SVM) learning was applied to scores from over 1500 individuals diagnosed with one of the thirteen genetic syndromes and autistic individuals who did not have a known genetic syndrome (ASD; n = 254). Self-help skills were included as an additional predictor.

RESULTS

Genetic syndromes were associated with different but overlapping autism-related profiles, indicated by the substantial accuracy of the entire, multiclass SVM model (55% correctly classified individuals). Syndrome groups such as Angelman, fragile X, Prader-Willi, Rubinstein-Taybi and Cornelia de Lange showed greater phenotypic specificity than groups such as Cri du Chat, Lowe, Smith-Magenis, tuberous sclerosis complex, Sotos and Phelan-McDermid. The inclusion of the ASD reference group and self-help skills did not change the model accuracy.

LIMITATIONS

The key limitations of our study include a cross-sectional design, reliance on a screening tool which focuses primarily on social communication skills and imbalanced sample size across syndrome groups.

CONCLUSIONS

These findings replicate and extend previous work, demonstrating syndrome-specific profiles of autistic characteristics in people with genetic syndromes compared to autistic individuals without a genetic syndrome. This work calls for greater precision of assessment of autistic characteristics in individuals with genetic syndromes associated with ID.

Endocrine and behavioural features of Lowe syndrome and their potential molecular mechanisms

BACKGROUND

Lowe syndrome (LS) is an X linked disease caused by pathogenic variants in the OCRL gene that impacts approximately 1 in 500 000 children. Classic features include congenital cataract, cognitive/behavioural impairment and renal tubulopathy.

METHODS

This study is a retrospective review of clinical features reported by family based survey conducted by Lowe Syndrome Association. Frequency of non-ocular clinical feature(s) of LS and their age of onset was summarised. An LS-specific therapy effectiveness scale was used to assess the response to the administered treatment. Expression of OCRL and relevant neuropeptides was measured in postmortem human brain by qPCR. Gene expression in the mouse brain was determined by reanalysis of publicly available bulk and single cell RNA sequencing.

RESULTS

A total of 137 individuals (1 female, 89.1% white, median age 14 years (range 0.8-56)) were included in the study. Short stature (height <3rd percentile) was noted in 81% (n=111) individuals, and 15% (n=20) received growth hormone therapy. Undescended testis was reported in 47% (n=64), and median age of onset of puberty was 15 years. Additional features were dental problems (n=77, 56%), bone fractures (n=63, 46%), hypophosphataemia (n=60, 44%), developmental delay and behavioural issues. OCRL is expressed in human and mouse hypothalami, and in hypothalamic cell clusters expressing Ghrh, Sst, Oxt, Pomc and pituitary cells expressing Gh and Prl.

CONCLUSIONS

There is a wide spectrum of the clinical phenotype of LS. Some of the features may be partly driven by the loss of function of OCRL in the hypothalamus and the pituitary.

Relationships between food-related behaviors, obesity, and medication use in individuals with Smith-Magenis syndrome

BACKGROUND

Smith-Magenis syndrome (SMS) is a complex neurodevelopmental disorder that includes obesity and food-seeking/satiety-related behaviors.

AIMS

This study examined associations between food-related/hyperphagic behaviors, weight, and medication use in individuals with SMS.

METHODS/PROCEDURES

Caregivers of individuals with SMS in the Parents and Researchers Interested in SMS (PRISMS) Patient Registry completed a demographic/medication questionnaire, the Hyperphagia Questionnaire for Clinical Trials, and the Food Related Problems Questionnaire.

OUTCOMES/RESULTS

Among 49 participants (M_age = 16.41 ± 12.73 years, range = 4-69 years, 55% girls/women), individuals with SMS with overweight/obesity (n = 22) had worse overall food-related problems including greater impaired satiety (p < 0.05), maladaptive eating behaviors (p < 0.05), inappropriate response (p < 0.01), and hyperphagia (p < 0.01) compared to individuals of normal/underweight (n = 27). Those taking anti-depressants/anxiolytics (n = 16) had greater maladaptive eating behaviors (p < 0.05), hyperphagic behaviors (p < 0.05), and hyperphagic severity (p < 0.05) than those not taking anti-depressants/anxiolytics (n = 33). Boys/men with SMS had greater maladaptive eating behaviors (p < 0.05), inappropriate response (p < 0.05), and hyperphagic drive (p < 0.01) than girls/women with SMS.

CONCLUSIONS/IMPLICATIONS

Maladaptive food-related behaviors were higher in individuals with SMS with overweight/obesity, taking anti-depressants/anxiolytics, or who were male. Medications in this population should be chosen with weight-related side effects in mind.

Convergence and Divergence of Rare Genetic Disorders on Brain Phenotypes: A Review

IMPORTANCE

Rare genetic disorders modulating gene expression-as exemplified by gene dosage disorders (GDDs)-represent a collectively common set of high-risk factors for neuropsychiatric illness. Research on GDDs is rapidly expanding because these variants have high effect sizes and a known genetic basis. Moreover, the prevalence of recurrent GDDs (encompassing aneuploidies and certain copy number variations) enables genetic-first phenotypic characterization of the same GDD across multiple individuals, thereby offering a unique window into genetic influences on the human brain and behavior. However, the rapid growth of GDD research has unveiled perplexing phenotypic convergences and divergences across genomic loci; while phenotypic profiles may be specifically associated with a genomic variant, individual behavioral and neuroimaging traits appear to be nonspecifically influenced by most GDDs.

OBSERVATIONS

This complexity is addressed by (1) providing an accessible survey of genotype-phenotype mappings across different GDDs, focusing on psychopathology, cognition, and brain anatomy, and (2) detailing both methodological and mechanistic sources for observed phenotypic convergences and divergences. This effort yields methodological recommendations for future comparative phenotypic research on GDDs as well as a set of new testable hypotheses regarding aspects of early brain patterning that might govern the complex mapping of genetic risk onto phenotypic variation in neuropsychiatric disorders.

CONCLUSIONS AND RELEVANCE

A roadmap is provided to boost accurate measurement and mechanistic interrogation of phenotypic convergence and divergence across multiple GDDs. Pursuing the questions posed by GDDs could substantially improve our taxonomical, neurobiological, and translational understanding of neuropsychiatric illness.

Direct assessment of overnight parent-child proximity in children with behavioral insomnia: Extending models of operant and classical conditioning

INTRODUCTION

Explanatory models of behavioral insomnia typically draw on operant learning theory with behavioral techniques focused on altering parent-child interactions to improve sleep. However, there are no data describing parent-child interactions overnight beyond parent report. In this study we used radio frequency identification technology to quantify parent-child proximity overnight in two groups at elevated risk of behavioral insomnia, Angelman syndrome (AS) and Smith-Magenis syndrome (SMS).

MATERIALS AND METHODS

Nineteen children aged 4-15 years (8 with AS, 11 with SMS) participated in a week-long at-home assessment of sleep and overnight parent-child proximity. Sleep parameters were recorded using the Philips Actiwatch 2 and proximity data were recorded using custom-built radio frequency identification watches.

RESULTS

Three patterns of proximity data between parent-child dyads overnight were evident: "checking" (six with AS, five with SMS), "co-sleeping" (four with SMS) and those who had "no proximity" overnight (two with AS, two with SMS). In the AS group, 25.45% of actigraphy-defined wakes resulted in a parent-child interaction. In the SMS group, 39.34% of wakes resulted in a parent-child interaction. Children who interacted with their parents when settling to sleep were not significantly more likely to interact at waking.

DISCUSSION

The novel application of radio frequency identification technology is a feasible method for studying overnight parent-child proximity. Profiles of proximity between participants that are not closely aligned with operant models of behavioral insomnia were evident. These results have significant implications for the etiology of poor sleep and the application of behavioral sleep interventions.

Prevalence of anxiety symptomatology and diagnosis in syndromic intellectual disability: A systematic review and meta-analysis

Individuals with syndromic intellectual disability are at increased risk of experiencing anxiety. Comparing prevalence estimates of anxiety will allow the identification of at-risk groups and inform causal pathways of anxiety. No known study has explored estimates of anxiety symptomatology and diagnosis, including specific anxiety profiles, across groups whilst accounting for methodological quality of studies. This systematic review and meta-analysis aimed to fill this gap. Prior to review completion, methodology and analysis plans were registered and documented in a protocol (CRD42019123561). Data from 83 papers, involving a pooled sample of 13,708 across eight syndromes were synthesised using a random effects model. Anxiety prevalence ranged from 9 % (95 % CI: 4-14) in Down syndrome to 73% in Rett syndrome (95 % CI: 70-77). Anxiety prevalence across syndromic intellectual disability was higher than for intellectual disability of mixed aetiology and general population estimates. Substantial variability between syndromes identified groups at higher risk than others. The identification of high-risk groups is crucial for early intervention, allowing us to refine models of risk and identify divergent profiles.

Variegation of autism related traits across seven neurogenetic disorders

Gene dosage disorders (GDDs) constitute a major class of genetic risks for psychopathology, but there is considerable debate regarding the extent to which different GDDs induce different psychopathology profiles. The current research speaks to this debate by compiling and analyzing dimensional measures of several autism-related traits (ARTs) across seven diverse GDDs. The sample included 350 individuals with one of 7 GDDs, as well as reference idiopathic autism spectrum disorder (ASD; n = 74) and typically developing control (TD; n = 171) groups. The GDDs were: Down, Williams-Beuren, and Smith-Magenis (DS, WS, SMS) syndromes, and varying sex chromosome aneuploidies ("plusX", "plusXX", "plusY", "plusXY"). The Social Responsiveness Scale (SRS-2) was used to measure ARTs at different levels of granularity-item, subscale, and total. General linear models were used to examine ART profiles in GDDs, and machine learning was used to predict genotype from SRS-2 subscales and items. These analyses were completed with and without covariation for cognitive impairment. Twelve of all possible 21 pairwise GDD group contrasts showed significantly different ART profiles (7/21 when co-varying for IQ, all Bonferroni-corrected). Prominent GDD-ART associations in post hoc analyses included relatively preserved social motivation in WS and relatively low levels of repetitive behaviors in plusX. Machine learning revealed that GDD group could be predicted with plausible accuracy (~60-80%) even after controlling for IQ. GDD effects on ARTs are influenced by GDD subtype and ART dimension. This observation has consequences for mechanistic, clinical, and translational aspects of psychiatric neurogenetics.

The behavioural phenotype of SATB2-associated syndrome: a within-group and cross-syndrome analysis

Background

SATB2-associated syndrome (SAS) is a multisystem neurodevelopmental disorder characterised by intellectual disability, speech delay, and craniofacial anomalies. Although the clinical presentation of SAS is well-delineated, behaviours associated with SAS are less well-defined. Given the varied social profile reported in SAS of a ‘jovial’ predisposition and autistic behaviours, there may be phenotypic overlap with both Angelman syndrome (AS) and non-syndromal autism. This study aimed to describe behaviours in SAS in relation to chronological age and level of ability and contrast aspects of the behavioural phenotype with AS and non-syndromal autism.

Methods

Informant report questionnaire measures of behaviour, emotion, and autism characteristics were completed for 81 individuals with SAS (aged 1–36 years; 43 male). Within-group associations were analysed, and categorical data were compared between pre-school (1–5 years), school-age (6–15 years), and adolescent and adult SAS sub-groups (16 years and over). Cross-syndrome subscale and item-level analyses were conducted for 63 individuals with SAS (aged 1–27 years; 31 male), who were matched according to age and level of ability to 63 individuals with AS (aged 2–25 years; 32 male) and 63 individuals with non-syndromal autism (aged 3–26 years; 53 male).

Results

In SAS, higher rates of overactivity were moderately associated with lower self-help ability, and higher general anxiety scores were reported for males compared with females. Cross-syndrome subscale analyses uncovered several significant differences (p < .01), with comparatively low rates of stereotyped behaviour, overactivity, insistence on sameness and positive affect, and comparatively greater interest and pleasure and compulsive behaviour in individuals with SAS. Item-level analyses revealed a distinct profile of repetitive and autistic behaviours.

Limitations

Developmental analysis was based on a cross-sectional rather than a longitudinal research design, the contribution of pain and sleep to behaviour was not explored, and molecular genetic testing to determine genotype–phenotype behavioural relationships was not possible.

Conclusions

This study highlights the importance of behavioural comparisons to well-delineated groups and the utility of fine-grained item-level analyses to elucidate aspects of behaviour that might be syndrome related or shared across neurodevelopmental disorders. Future research is needed to further describe the distinctive repetitive and autistic behavioural phenotype in SAS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09426-0.

Executive function, repetitive behaviour and restricted interests in neurodevelopmental disorders

BACKGROUND

Individuals with genetic syndromes show unique profiles of repetitive behaviours and restricted interests (RRBs). The executive dysfunction account of RRBs suggests that in autistic (AUT) individuals executive function impairments underpin RRBs, but not communication and social interaction autistic characteristics.

AIMS

To 1) describe profiles of behavioural manifestations of executive function (EF behaviours) and 2) explore the relationship between EF behaviours and autistic traits across individuals with Cornelia de Lange (CdLS), fragile X (FXS) and Rubinstein-Taybi syndromes (RTS), and AUT individuals.

METHOD

Carers completed the Behavior Rating Inventory of Executive Function - Preschool Version and the Social Communication Questionnaire. Data reporting on 25 individuals with CdLS (Mage = 18.60, SD = 8.94), 25 with FXS (Mage = 18.48, SD = 8.80), 25 with RTS (Mage = 18.60, SD = 8.65) and 25 AUT individuals (Mage = 18.52, SD = 8.65) matched on chronological age and adaptive ability were included in analyses.

RESULTS

All groups showed impairments across EF behaviours compared to two-to-three-year-old typically developing normative samples with no differences between groups. Different EF behaviours predicted RRBs in the syndrome groups with no associations found in the AUT group.

CONCLUSIONS

Syndrome related differences should be considered when developing targeted interventions that focus on EF behaviours and/or RRBs in these groups.

Caregivers' experience of sleep management in Smith-Magenis syndrome: a mixed-methods study

BACKGROUND

Smith-Magenis syndrome (SMS) is a rare genetic syndrome associated with a unique profile of early morning waking and daytime sleepiness. Children with SMS evidence high rates of self-injury and aggression and have a preference for adult over peer attention, with strong motivation to interact with a particular caregiver. In addition, people with SMS have lower adaptive functioning skills relative to cognitive abilities and demonstrate high levels of impulsivity. Taken together, these factors may result in individuals being awake overnight requiring vigilant caregiver supervision. Despite these complexities, no study has described the strategies caregivers take to keep their children with SMS safe overnight or considered the impact of these experiences on caregivers or the wider family.

METHODS

The current study used a mixed-methods approach to consider sleep management strategies and challenges for caregivers of people with SMS at different ages. Caregivers completed an international online survey about sleep management and related difficulties, use of interventions and access to services and support. Semi-structured interviews were conducted with 14 caregivers in the UK to increase understanding of caregiver experiences and priorities for change in the UK context. Interviews were transcribed verbatim and coded using thematic analysis.

RESULTS

Evidence from the online survey (n = 40) revealed wide-ranging impacts of poor sleep on the person with SMS and the wider family. Only 5% of caregivers reported that the sleep problems had no impact on their child, and 76% reported a moderately or extremely significant impact on themselves. For some individual caregivers, sleep management difficulties improved over time whereas for others no change was reported. Weekly respite emerged as the ideal provision for 49% of caregivers, although only 14% had access to this. The majority of caregivers (54%) received no respite. Thematic analysis of qualitative interviews revealed interactions between aspects of the behavioural phenotype of SMS which may contribute to complex and unusual presentations in relation to sleep management and safety.

CONCLUSIONS

Caregivers' priorities for sleep management and support were delineated, with key implications for services in terms of the use of SMS-sensitive strategies and respite provision.

Psychotropic Drug Treatment Patterns in Persons with Fragile X Syndrome

Objective: Psychiatric comorbidity is common in fragile X syndrome (FXS) and often addressed through pharmacological management. Here we examine data in the Fragile X Online Registry With Accessible Research Database (FORWARD) to characterize specific symptoms being treated with psychotropic medication, patterns of medication use, as well as the influence of gender, intellectual disability (ID), age, and autism spectrum disorder (ASD) diagnosis. Methods: Data were drawn from the 975 participants who have a completed clinician form. We explored the frequency of psychotropic medication use for the following symptom clusters: attention, hyperactivity, anxiety, hypersensitivity, obsessive-compulsive disorder (OCD), mood swings, irritability/agitation, aggression, and self-injury (IAAS). Results: A majority of participants (617 or 63.3%) were taking a psychotropic medication, including investigational drugs. Medications were often targeting multiple symptoms. Psychotropic medication use was more common in males, adolescents, and those with comorbid ID and ASD. Anxiety was the most frequently targeted symptom, followed by attention-deficit/hyperactivity disorder symptoms and IAAS. Selective serotonin reuptake inhibitors (SSRIs) were the most frequently prescribed medication class among all patients (n = 266, 43%), followed by stimulants (n = 235, 38%), each with no gender difference. Antipsychotics were the third most frequently prescribed medication class (n = 205, 33%), and were more frequently prescribed to males and those with ID and ASD. Conclusions: Anxiety, attention and hyperactivity were the most common symptom targets for psychopharmacologic intervention in FXS. Our results support clinical knowledge that males with comorbid ASD and ID have a more severe presentation requiring more intervention including medications. These results highlight the need for examination of symptom overlap and interaction.

An ethical analysis of divergent clinical approaches to the application of genetic testing for autism and schizophrenia

Genetic testing to identify genetic syndromes and copy number variants (CNVs) via whole genome platforms such as chromosome microarray (CMA) or exome sequencing (ES) is routinely performed clinically, and is considered by a variety of organizations and societies to be a "first-tier" test for individuals with developmental delay (DD), intellectual disability (ID), or autism spectrum disorder (ASD). However, in the context of schizophrenia, though CNVs can have a large effect on risk, genetic testing is not typically a part of routine clinical care, and no clinical practice guidelines recommend testing. This raises the question of whether CNV testing should be similarly performed for individuals with schizophrenia. Here we consider this proposition in light of the history of genetic testing for ID/DD and ASD, and through the application of an ethical analysis designed to enable robust, accountable and justifiable decision-making. Using a systematic framework and application of relevant bioethical principles (beneficence, non-maleficence, autonomy, and justice), our examination highlights that while CNV testing for the indication of ID has considerable benefits, there is currently insufficient evidence to suggest that overall, the potential harms are outweighed by the potential benefits of CNV testing for the sole indications of schizophrenia or ASD. However, although the application of CNV tests for children with ASD or schizophrenia without ID/DD is, strictly speaking, off-label use, there may be clinical utility and benefits substantive enough to outweigh the harms. Research is needed to clarify the harms and benefits of testing in pediatric and adult contexts. Given that genetic counseling has demonstrated benefits for schizophrenia, and has the potential to mitigate many of the potential harms from genetic testing, any decisions to implement genetic testing for schizophrenia should involve high-quality evidence-based genetic counseling.

Low speech rate but high gesture rate during conversational interaction in people with Cornelia de Lange syndrome

BACKGROUND

Cornelia de Lange syndrsome (CdLS) is a rare genetic syndrome with notable impaired expressive communication characterised by reduced spoken language. We examined gesture use to refine the description of expressive communication impairments in CdLS.

METHODS

During conversations, we compared gesture use in people with CdLS to peers with Down syndrome (DS) matched for receptive language and adaptive ability, and typically developing (TD) individuals of similar chronological age.

RESULTS

As anticipated the DS and CdLS groups used fewer words during conversation than TD peers (P < .001). However, the CdLS group used twice the number of gestures per 100 words compared with the DS and TD groups (P = .003).

CONCLUSIONS

Individuals with CdLS have a significantly higher gesture rate than expected given their level of intellectual disability and chronological age. This result indicates the cause of reduced use of spoken language does not extend to all forms of expressive communication.

Behaviour across the lifespan in Cornelia de Lange syndrome

PURPOSE OF REVIEW

While previous reviews have extended descriptions of the behavioural phenotype of Cornelia de Lange syndrome (CdLS) significantly, potential changes with age across the lifespan have been neglected. Age-related difference in the behavioural phenotype constitutes preliminary evidence of change with age. Documenting and understanding the developmental trajectories of behaviours is informative as it enables identification of risk periods for behavioural challenges and compromised mental health.

RECENT FINDINGS

Recent cross sectional, longitudinal and mixed design studies report differing presentations of the behavioural phenotype across the lifespan. Of particular interest are autistic characteristics and behaviours consistent with compromised mental health, particularly anxiety and negative affect, which are reported to be more common and severe in older individuals. Preliminary evidence for identified causal pathways with consideration of biological, cognitive and environmental factors are discussed.

SUMMARY

Older individuals with CdLS appear to be at greater risk of poorer psychological wellbeing than younger peers with significant implications for risk informed preventive and early interventions. Further work is required to document the behavioural phenotype across the lifespan with consideration of multiple factors that may influence the trajectory and extent of negative outcomes.

Refining the Behavioral Phenotype of Angelman Syndrome: Examining Differences in Motivation for Social Contact Between Genetic Subgroups

Angelman syndrome (AS) is caused by loss of information from the 15q11.2-13 region on the maternal chromosome with striking phenotypic difference from Prader–Willi syndrome in which information is lost from the same region on the paternal chromosome. Motivation for social contact and sensory seeking behaviors are often noted as characteristics of the phenotype of AS and it has been argued that the strong drive for social contact supports a kinship theory interpretation of genomic imprinting. In this study we developed an experimental paradigm for quantifying the motivation for social contact in AS and examined differences across the genetic subtypes that cause AS [deletion, imprinting centre defect (ICD), uniparental disomy and UBE3A mutation]. Using single case experimental designs we examined the rate of acquisition of behavioral responses using operant learning paradigms for 21 children with AS whilst systematically varying the nature of social and sensory reinforcement. Variability in rates of acquisition was influenced by the nature of rewarding stimuli. Across the total sample both sensory stimuli and social contact could increase the rate of rewarded behavior with difference between children in the most effective reward. A striking difference in the rewarding properties of social contact across genetic subtypes was evidenced by non-deletion genetic causes of AS showing significantly higher rates of responding than the deletion cause in the social reinforcement paradigm. The results indicate that reinforcer assessment can beneficially inform behavioral interventions and that within syndrome variability in the behavioral phenotype of AS is likely driven by genetic difference. The non-deletion cause of AS, and particularly the ICD group, may be the optimal group for further study of genomic imprinting.

The Relationship between Autism and Ehlers-Danlos Syndromes/Hypermobility Spectrum Disorders

Considerable interest has arisen concerning the relationship between hereditary connective tissue disorders such as the Ehlers-Danlos syndromes (EDS)/hypermobility spectrum disorders (HSD) and autism, both in terms of their comorbidity as well as co-occurrence within the same families. This paper reviews our current state of knowledge, as well as highlighting unanswered questions concerning this remarkable patient group, which we hope will attract further scientific interest in coming years. In particular, patients themselves are demanding more research into this growing area of interest, although science has been slow to answer that call. Here, we address the overlap between these two spectrum conditions, including neurobehavioral, psychiatric, and neurological commonalities, shared peripheral neuropathies and neuropathologies, and similar autonomic and immune dysregulation. Together, these data highlight the potential relatedness of these two conditions and suggest that EDS/HSD may represent a subtype of autism.

An Observational Study of Social Interaction Skills and Behaviors in Cornelia de Lange, Fragile X and Rubinstein-Taybi Syndromes

We directly assessed the broader aspects of sociability (social enjoyment, social motivation, social interaction skills and social discomfort) in individuals with Cornelia de Lange (CdLS), fragile X (FXS) and Rubinstein-Taybi syndromes (RTS), and their association with autism characteristics and chronological age in these groups. Individuals with FXS (p < 0.01) and RTS (p < 0.01) showed poorer quality of eye contact compared to individuals with CdLS. Individuals with FXS showed less person and more object attention than individuals with CdLS (p < 0.01). Associations between sociability and autism characteristics and chronological age differed between groups, which may indicate divergence in the development and aetiology of different components of sociability across these groups. Findings indicate that individuals with CdLS, FXS and RTS show unique profiles of sociability.

Dosage-sensitive genes in autism spectrum disorders: From neurobiology to therapy

Autism spectrum disorders (ASDs) are a group of heterogenous neurodevelopmental disorders affecting 1 in 59 children. Syndromic ASDs are commonly associated with chromosomal rearrangements or dosage imbalance involving a single gene. Many of these genes are dosage-sensitive and regulate transcription, protein homeostasis, and synaptic function in the brain. Despite vastly different molecular perturbations, syndromic ASDs share core symptoms including social dysfunction and repetitive behavior. However, each ASD subtype has a unique pathogenic mechanism and combination of comorbidities that require individual attention. We have learned a great deal about how these dosage-sensitive genes control brain development and behaviors from genetically-engineered mice. Here we describe the clinical features of eight monogenic neurodevelopmental disorders caused by dosage imbalance of four genes, as well as recent advances in using genetic mouse models to understand their pathogenic mechanisms and develop intervention strategies. We propose that applying newly developed quantitative molecular and neuroscience technologies will advance our understanding of the unique neurobiology of each disorder and enable the development of personalized therapy.

Rho GTPase Regulators and Effectors in Autism Spectrum Disorders: Animal Models and Insights for Therapeutics

The Rho family GTPases are small G proteins that act as molecular switches shuttling between active and inactive forms. Rho GTPases are regulated by two classes of regulatory proteins, guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Rho GTPases transduce the upstream signals to downstream effectors, thus regulating diverse cellular processes, such as growth, migration, adhesion, and differentiation. In particular, Rho GTPases play essential roles in regulating neuronal morphology and function. Recent evidence suggests that dysfunction of Rho GTPase signaling contributes substantially to the pathogenesis of autism spectrum disorder (ASD). It has been found that 20 genes encoding Rho GTPase regulators and effectors are listed as ASD risk genes by Simons foundation autism research initiative (SFARI). This review summarizes the clinical evidence, protein structure, and protein expression pattern of these 20 genes. Moreover, ASD-related behavioral phenotypes in animal models of these genes are reviewed, and the therapeutic approaches that show successful treatment effects in these animal models are discussed.

Profiles of atypical sensory processing in Angelman, Cornelia de Lange and Fragile X syndromes

BACKGROUND

There is growing evidence to suggest that children with neurodevelopmental disorders may evidence differences in their sensory processing. The aim of this study was to compare sensory processing patterns in three genetic syndromes associated with sensory difference.

METHODS

Sensory processing in Angelman syndrome (n = 91), Cornelia de Lange syndrome (n = 28) and Fragile X syndrome (n = 40) was examined using the informant report measure the Sensory Experiences Questionnaire (SEQ).

RESULTS

All three groups were associated with a heightened prevalence of unusual sensory processing in comparison with normative data, evidenced in over 80% of all participants. Cross-syndrome comparisons highlighted syndrome-specific sensory processing profiles, with heightened hypo responsivity in Cornelia de Lange syndrome and sensory seeking in Angelman syndrome.

CONCLUSIONS

The results have important implications for the understanding of sensory processing in genetic syndromes and the development of tailored behavioural interventions.

Behavioural and psychological characteristics in Pitt-Hopkins syndrome: a comparison with Angelman and Cornelia de Lange syndromes

Background

Pitt-Hopkins syndrome (PTHS) is a genetic neurodevelopmental disorder associated with intellectual disability. Although the genetic mechanisms underlying the disorder have been identified, description of its behavioural phenotype is in its infancy. In this study, reported behavioural and psychological characteristics of individuals with PTHS were investigated in comparison with the reported behaviour of age-matched individuals with Angelman syndrome (AS) and Cornelia de Lange syndrome (CdLS).

Methods

Questionnaire data were collected from parents/caregivers of individuals with PTHS (n = 24), assessing behaviours associated with autism spectrum disorder (ASD), sociability, mood, repetitive behaviour, sensory processing, challenging behaviours and overactivity and impulsivity. For most measures, data were compared to data for people with AS (n = 24) and CdLS (n = 24) individually matched by adaptive ability, age and sex.

Results

Individuals with PTHS evidenced significantly higher levels of difficulties with social communication and reciprocal social interaction than individuals with AS, with 21 of 22 participants with PTHS meeting criteria indicative of ASD on a screening instrument. Individuals with PTHS were reported to be less sociable with familiar and unfamiliar people than individuals with AS, but more sociable with unfamiliar people than individuals with CdLS. Data also suggested areas of atypicality in sensory experiences. Challenging behaviours were reported frequently in PTHS, with self-injury (70.8%) occurring at significantly higher rates than in AS (41.7%) and aggression (54.2%) occurring at significantly higher rates than in CdLS (25%). Individuals with PTHS also evidenced lower reported mood than individuals with AS.

Conclusions

Behaviours which may be characteristic of PTHS include those associated with ASD, including deficits in social communication and reciprocal social interaction. High rates of aggression and self-injurious behaviour compared to other genetic syndrome groups are of potential clinical significance and warrant further investigation. An atypical sensory profile may also be evident in PTHS. The specific aetiology of and relationships between different behavioural and psychological atypicalities in PTHS, and effective clinical management of these, present potential topics for future research.

Lifespan trajectory of affect in Cornelia de Lange syndrome: towards a neurobiological hypothesis

Background

Depressive symptomology and low affect are comparatively common in individuals with genetic disorders such as Cornelia de Lange syndrome. However, lifespan trajectories and associated person characteristics have not been examined. In this study, the trajectories for affect and associated behavioural characteristics were investigated in individuals with Cornelia de Lange syndrome with individuals with fragile X syndrome (FXS) comparable for chronological age and total number of behavioural indicators of ASD included for the purpose of contrast.

Methods

A 7-year longitudinal study of affect (mood, interest and pleasure) was conducted in individuals with CdLS (n = 44) and FXS (n = 95). The trajectories of low affect were explored, as well as associations between Time 1 behavioural characteristics and affect at Time 1 and Time 3 (7 years later).

Results

The CdLS group were lower in mood than the FXS group overall (p < .001). Interest and pleasure scores showed a significant decline over the lifespan for individuals with CdLS (p < .001) but not the FXS group. Lower level of ability at Time 1 was associated with lower mood at Time 1 and Time 3 in the FXS group only. Higher levels of ASD symptomology at Time 1 were associated with low mood and interest and pleasure in both syndrome groups at Time 1 and Time 3. Greater insistence on sameness at Time 1 was associated with lower mood at Time 1 in the FXS group and lower interest and pleasure at Time 1 and Time 3 in the CdLS group.

Conclusions

Low affect in specific genetic syndromes may be associated with differing lifespan trajectories and behavioural profiles. Specifically, individuals with CdLS appear at risk for experiencing declines in levels of interest and pleasure whereas individuals with FXS show no significant change in the level of affect with age.

Age-related Behavioural Change in Cornelia de Lange and Cri du Chat Syndromes: A Seven Year Follow-up Study

Age-related behavioural change in Cornelia de Lange syndrome is poorly understood. We report a 7 year follow-up study of adaptive behaviour, autism spectrum disorder symptomatology, language skills and behavioural characteristics in 30 individuals with Cornelia de Lange syndrome, compared with 18 individuals with Cri du Chat syndrome. The proportion of individuals with Cornelia de Lange syndrome meeting criteria for autism spectrum disorder on the Autism Diagnostic Observation Schedule increased, although patterns of change were complex. For both syndrome groups, absolute levels of adaptive ability were stable and receptive language improved, suggesting that changes over time do not result from an overall decline in ability. Reliable change index scores indicate heterogeneity within both groups in the occurrence of improvement or decline.

The Influence of Hyperactivity, Impulsivity, and Attention Problems on Social Functioning in Adolescents and Young Adults With Fragile X Syndrome

OBJECTIVE

Individuals with fragile X syndrome (FXS) present primarily with cognitive and social deficits in addition to symptoms of ADHD. The relationship between symptoms of ADHD, cognitive functioning, and social skills has never been explicitly studied.

METHOD

Here, we analyzed both longitudinal ( n = 70; Time 1: ages 6-18; Time 2: ages 15-26) and cross-sectional ( n = 73; Time 2 only) data using hierarchical linear regression to assess how global intellectual functioning (IQ) and symptoms of ADHD influence social functioning in individuals with FXS.

RESULTS

We found that ADHD symptoms at Times 1 and 2 consistently predict social functioning in both males and females with FXS at Time 2.

CONCLUSION

Our results suggest that addressing ADHD symptoms in childhood may have positive, long-term effects on the social functioning of adolescents and young adults with FXS.

Diagnosis and management of Cornelia de Lange syndrome: first international consensus statement

Cornelia de Lange syndrome (CdLS) is an archetypical genetic syndrome that is characterized by intellectual disability, well-defined facial features, upper limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in any one of seven genes, all of which have a structural or regulatory function in the cohesin complex. Although recent advances in next-generation sequencing have improved molecular diagnostics, marked heterogeneity exists in clinical and molecular diagnostic approaches and care practices worldwide. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria, both for classic CdLS and non-classic CdLS phenotypes, molecular investigations, long-term management and care planning.

Overactivity, impulsivity and repetitive behaviour in males with fragile X syndrome: contrasting developmental trajectories in those with and without elevated autism symptoms

BACKGROUND

Hyperactivity and repetitive behaviour are characteristic features of fragile X syndrome (FXS). However, little is known about the influence of autism symptomatology on how these characteristics develop over time. We investigate the profiles and developmental trajectories of overactivity, impulsivity and repetitive behaviour, in males with FXS over three time points spanning 8 years.

METHOD

Participants formed two subgroups, those who displayed elevated symptoms of autism at Time 1 (n = 37; M_age  = 16.32; age range = 6.61-43.51) and those who did not (n = 32; M_age  = 8.43; age range = 8.94-47.49).

RESULTS

Participants without elevated symptoms of autism showed a reduction in impulsivity and repetitive questioning over time, whereas those with elevated symptoms of autism did not. Differences between the two subgroups in several topographies of repetitive behaviour emerged at Time 3 only.

CONCLUSIONS

These results further understanding of the relationship between autistic phenomenology and behavioural characteristics in FXS.

Brief Report: Contrasting Profiles of Everyday Executive Functioning in Smith-Magenis Syndrome and Down Syndrome

Everyday executive function (EF) was examined in Smith-Magenis syndrome (SMS), associated with high risk of behaviour disorder, and Down syndrome (DS), associated with relatively low risk of behaviour disorder. Caregivers of 13 children with SMS and 17 with DS rated everyday EF using the Behavioral Rating Inventory of Executive Functioning-Preschool. Greater everyday EF deficits relative to adaptive ability were evident in SMS than in DS. The SMS profile of everyday EF abilities was relatively uniform; in DS emotional control strengths and working memory weaknesses were evident. Findings implicate broad everyday EF difficulties in SMS compared to DS, corresponding with increased rates of behaviour disorder in SMS. Findings further suggest that everyday EF profiles may, in part, be syndrome related.

The behavioural phenotype of Potocki-Lupski syndrome: a cross-syndrome comparison

Background

Potocki-Lupski syndrome (PTLS) and Smith-Magenis syndrome (SMS) are related genomic disorders, as duplication 17p11.2 (associated with PTLS) is the reciprocal recombination product of the SMS microdeletion. While SMS has a relatively well-delineated behavioural phenotype, the behavioural profile in PTLS is less well defined, despite purported associations with autism spectrum disorder (ASD) and the suggestion that some behaviours may be diametric to those seen in SMS.

Methods

Caregivers of individuals with PTLS (N = 34; M age = 12.43, SD = 6.78) completed online behavioural questionnaires, including the Challenging Behaviour Questionnaire (CBQ), the Activity Questionnaire (TAQ), the Repetitive Behaviour Questionnaire (RBQ), the Mood, Interest and Pleasure Questionnaire-Short Form (MIPQ-S) and the Social Communication Questionnaire (SCQ), which assesses behaviours associated with ASD. Individuals with PTLS were matched on age and adaptive functioning to individuals with SMS (N = 31; M age = 13.61, SD = 6.85) and individuals with idiopathic ASD (N = 33; M age = 12.04, SD = 5.85) from an existing dataset.

Results

Individuals with PTLS and SMS were less impaired than those with idiopathic ASD on the communication and reciprocal social interaction subscales of the SCQ, but neither syndrome group differed from idiopathic ASD on the restricted, repetitive and stereotyped behaviours subscale. On the repetitive behaviour measure, individuals with PTLS and idiopathic ASD scored higher than individuals with SMS on the compulsive behaviour subscale. Rates of self-injury and property destruction were significantly lower in PTLS and idiopathic ASD than in SMS. No between-syndrome differences were found in relation to overactivity or mood; however, impulsivity was greater in SMS than in PTLS.

Conclusions

Findings suggest some overlap in the behavioural phenotype of PTLS and features of ASD symptomatology; however, the overall profile of behaviours in PTLS appears to be divergent from both idiopathic ASD and SMS. Relative to idiopathic ASD, PTLS is not characterised by communication or social interaction deficits. However, restricted and repetitive behaviours were evident in PTLS, and these may be characterised specifically by compulsive behaviours. While several behavioural differences were identified between PTLS and SMS, there was little evidence of diametric behavioural phenotypes, particularly in relation to social behaviour.

Reversed gender ratio of autism spectrum disorder in Smith-Magenis syndrome

Background

A substantial amount of research shows a higher rate of autistic type of problems in males compared to females. The 4:1 male to female ratio is one of the most consistent findings in autism spectrum disorder (ASD).

Lately, the interest in studying ASD in genetic disorders has increased, and research has shown a higher prevalence of ASD in some genetic disorders than in the general population.

Smith-Magenis syndrome (SMS) is a rare and complex genetic syndrome caused by an interstitial deletion of chromosome 17p11.2 or a mutation on the retinoic acid induced 1 gene. The disorder is characterised by intellectual disability, multiple congenital anomalies, obesity, neurobehavioural abnormalities and a disrupted circadian sleep-wake pattern.

Methods

Parents of 28 persons with SMS between 5 and 50 years old participated in this study. A total of 12 of the persons with SMS were above the age of 18 at the time of the study. A total of 11 came from Sweden and 17 were from Norway.

We collected information regarding the number of autism spectrum symptoms using the Social Communication Questionnaire (SCQ) and the Social Responsiveness Scale (SRS). Adaptive behaviour was also measured using the Vineland Adaptive Behavior Scale II. The level of intellectual disability was derived from a review of the medical chart.

Results

We found significant gender differences in ASD symptomatology using the SCQ and SRS questionnaires. We found approximately three females per male above the SCQ cutoff. The same differences were not found in the intellectual level and adaptive behaviour or for behavioural and emotional problems.

Gender had an independent contribution in a regression model predicting the total SCQ score, and neither the Vineland Adaptive Behavior Scale II nor the Developmental Behaviour Checklist had an independent contribution to the SCQ scores.

Conclusion

We found a clear reversed gender difference in ASD symptomatology in persons with SMS. This may be relevant in the search for female protective factors assumed to explain the male bias in ASD.

Prospective study of autism phenomenology and the behavioural phenotype of Phelan-McDermid syndrome: comparison to fragile X syndrome, Down syndrome and idiopathic autism spectrum disorder

Background

The limited behavioural phenotype literature on Phelan–McDermid syndrome (PMS) indicates atypically high levels of activity, impulsivity and autism spectrum disorder (ASD) behaviours. Divergent profiles of ASD in PMS are also reported, with some studies demonstrating similarities to idiopathic ASD and others indicating an uneven profile of social and communication impairments and repetitive behaviours. An evaluation of the behavioural phenotype of PMS and the prevalence and phenomenology of ASD is warranted, particularly given the causal involvement of the SHANK3 gene in the aetiology of PMS.

Methods

Carers of individuals with PMS (N = 30; mean age = 10.55, SD = 7.08) completed questionnaires relating to impulsivity, overactivity, mood, interest and pleasure, repetitive behaviour and ASD phenomenology. These data were compared to data from matched samples of individuals with fragile X and Down syndromes and idiopathic ASD. In order to evaluate the profile of ASD phenomenology in PMS, two comparisons were made: first, including the total sample with PMS, and second, including only those who met the threshold indicative of autism on an ASD screening measure.

Results

The results revealed lower mood in individuals with PMS, but no differences in impulsivity and overactivity. Compulsive and routine-driven repetitive behaviours were less common in the total sample with PMS; however, motor-based stereotyped behaviours were more common. ASD phenomenology was highly prevalent, with 87% of the sample meeting the cutoff score for ASD and 57% meeting the cutoff for autism. The profile of ASD phenomenology in the total sample with PMS differed from those with idiopathic ASD across impairments in communication and social interaction and repetitive behaviour. However, the profile of those who met the threshold for autism was commensurate to those with idiopathic ASD.

Conclusions

ASD phenomenology is common within PMS. Whilst the total sample may display an atypical profile of ASD behaviour, the profile in those who met the threshold for autism was very similar to those with idiopathic ASD. These results are discussed in relation to the wider behavioural phenotype and the emerging evidence of an autism endophenotype in PMS.

Executive functioning in Cornelia de Lange syndrome: domain asynchrony and age-related performance

BACKGROUND

The aim of this study was to examine executive functioning in adolescents and adults with Cornelia de Lange syndrome (CdLS) to identify a syndrome and age-related profile of cognitive impairment.

METHODS

Participants were 24 individuals with CdLS aged 13-42 years (M = 22; SD = 8.98), and a comparable contrast group of 21 individuals with Down syndrome (DS) aged 15-33 years (M = 24; SD = 5.82). Measures were selected to test verbal and visual fluency, inhibition, perseverance/flexibility, and working memory and comprised both questionnaire and performance tests.

RESULTS

Individuals with CdLS showed significantly greater impairment on tasks requiring flexibility and inhibition (rule switch) and on forwards span capacity. These impairments were also reported in the parent/carer-rated questionnaire measures. Backwards Digit Span was significantly negatively correlated with chronological age in CdLS, indicating increased deficits with age. This was not identified in individuals with DS.

CONCLUSIONS

The relative deficits in executive functioning task performance are important in understanding the behavioural phenotype of CdLS. Prospective longitudinal follow-up is required to examine further the changes in executive functioning with age and if these map onto observed changes in behaviour in CdLS. Links with recent research indicating heightened responses to oxidative stress in CdLS may also be important.

Genotype-phenotype correlations in Cornelia de Lange syndrome: Behavioral characteristics and changes with age

Cornelia de Lange syndrome (CdLS) is a multisystem genetic disorder associated with unusual facial features, limb abnormalities, a wide range of health conditions, and intellectual disability. Mutations in five genes that encode (SMC1A, SMC3, RAD21) or regulate (NIPBL, HDAC8) the cohesin complex have been identified in up to 70% of individuals. Genetic cause remains unknown for a proportion of individuals. There is substantial heterogeneity in all aspects of CdLS but very little is known about what predicts phenotypic heterogeneity. In this study, we evaluated genotype-phenotype associations in 34 individuals with CdLS. Participants with NIPBL mutations had significantly lower self help skills and were less likely to have verbal skills relative to those who were negative for the NIPBL mutation. No significant differences were identified between the groups in relation to repetitive behavior, mood, interest and pleasure, challenging behavior, activity, impulsivity, and characteristics of autism spectrum disorder whilst controlling differences in self help skills. Significant correlations indicating lower mood, interest and pleasure, and increased insistence on sameness with older age were identified for those who were NIPBL mutation positive. The findings suggest similarities in the behavioral phenotype between those with and without the NIPBL mutation once differences in self help skills are controlled for. However, there may be subtle differences in the developmental trajectory of these behaviors according to genetic mutation status in CdLS.

A Comparative Study of Sociability in Angelman, Cornelia de Lange, Fragile X, Down and Rubinstein Taybi Syndromes and Autism Spectrum Disorder

Few comparative studies have evaluated the heterogeneity of sociability across a range of neurodevelopmental disorders. The Sociability Questionnaire for People with Intellectual Disability (SQID) was completed by caregivers of individuals with Cornelia de Lange (n = 98), Angelman (n = 66), Fragile X (n = 142), Down (n = 117) and Rubinstein Taybi (n = 88) syndromes and autism spectrum disorder (ASD; n = 107). Between groups and age-band (<12yrs; 12-18yrs; >18yrs) comparisons of SQID scores were conducted. Rates of behaviors indicative of selective mutism were also examined. Fragile X syndrome achieved the lowest SQID scores. Cornelia de Lange, ASD, and Fragile X groups scored significantly lower than Angelman, Down and Rubinstein Taybi groups. Selective mutism characteristics were highest in Cornelia de Lange (40%) followed by Fragile X (17.8%) and ASD (18.2%). Age-band differences were identified in Cornelia de Lange and Down syndrome.

Genes with high penetrance for syndromic and non-syndromic autism typically function within the nucleus and regulate gene expression

BACKGROUND

Intellectual disability (ID), autism, and epilepsy share frequent yet variable comorbidities with one another. In order to better understand potential genetic divergence underlying this variable risk, we studied genes responsible for monogenic IDs, grouped according to their autism and epilepsy comorbidities.

METHODS

Utilizing 465 different forms of ID with known molecular origins, we accessed available genetic databases in conjunction with gene ontology (GO) to determine whether the genetics underlying ID diverge according to its comorbidities with autism and epilepsy and if genes highly penetrant for autism or epilepsy share distinctive features that set them apart from genes that confer comparatively variable or no apparent risk.

RESULTS

The genetics of ID with autism are relatively enriched in terms associated with nervous system-specific processes and structural morphogenesis. In contrast, we find that ID with highly comorbid epilepsy (HCE) is modestly associated with lipid metabolic processes while ID without autism or epilepsy comorbidity (ID only) is enriched at the Golgi membrane. Highly comorbid autism (HCA) genes, on the other hand, are strongly enriched within the nucleus, are typically involved in regulation of gene expression, and, along with IDs with more variable autism, share strong ties with a core protein-protein interaction (PPI) network integral to basic patterning of the CNS.

CONCLUSIONS

According to GO terminology, autism-related gene products are integral to neural development. While it is difficult to draw firm conclusions regarding IDs unassociated with autism, it is clear that the majority of HCA genes are tightly linked with general dysregulation of gene expression, suggesting that disturbances to the chronology of neural maturation and patterning may be key in conferring susceptibility to autism spectrum conditions.

A structured assessment of motor function and behavior in patients with Kleefstra syndrome

The present study aimed to further our understanding of Kleefstra syndrome, especially regarding motor function and behavioral characteristics. In total, four males and four females between two and 27 years of age with a genetically confirmed diagnosis of Kleefstra syndrome and their parents participated in this study. Four patients had 9q34.3 deletions that caused Euchromatin Histone Methyl Transferase 1 (EHMT1) haplo-insufficiency, and four patients harbored EHMT1 mutations. The motor function was evaluated via systematic observation. Standardized assessments such as the Vineland Adapted Behavior Scales II (VABS II), the Social Communication Questionnaire (SCQ) and the Child or Adult Behavior Checklist (CBCL, ABCL) were used for the behavioral assessment. All patients showed a delayed developmental status. Muscular hypotonia and its manifestations were present in all patients, regardless of their age. The mean values for all VABS II domains (communication, socialization, daily living skills, and motor skills) were significantly lower than the mean of the reference population (p < 0.001), but similar to other rare intellectual disabilities such as Smith-Magenis syndrome and Angelman syndrome. The results from the SCQ indicated that all patient values exceeded the cut-off value, suggesting the possibility of autism spectrum disorder. The behavioral and emotional problems assessed by CBCL and ABCL were less frequent. In conclusion, patients with Kleefstra syndrome present with a broad range of clinical problems in all age groups and are therefore in need of a multidisciplinary follow-up also after their transition into adulthood.

Autism spectrum disorder profile in neurofibromatosis type I

Neurofibromatosis Type 1 (NF1) is a common autosomal dominant single-gene disorder, in which the co-occurrence of autism spectrum disorder (ASD) has attracted considerable research interest recently with prevalence estimates of 21-40%. However, detailed characterization of the ASD behavioral phenotype in NF1 is still lacking. This study characterized the phenotypic profile of ASD symptomatology presenting in 4-16 year old children with NF1 (n = 36) using evidence from parent-rated Social Responsiveness Scale and researcher autism diagnostic observation Scale-2. Compared to IQ-matched reference groups of children with autism and ASD, the NF1 profile shows overall similarity but improved eye contact, less repetitive behaviors and better language skills.

The relationship between challenging behaviours, mood and interest/pleasure in adults with severe and profound intellectual disabilities

BACKGROUND

We investigated whether current mood and interest/pleasure ratings in adults with moderate to profound intellectual disabilities were predictive of challenging behaviour [self-injurious behaviour (SIB), aggressive/destructive behaviour and stereotypic behaviour] and vice versa.

METHOD

In this combined cross-sectional and longitudinal study, staff members of a Hungarian residential facility completed translated versions of the Behaviour Problems Inventory-Short Form (BPI-S), the Challenging Behaviour Interview (CBI) and the Mood, Interest and Pleasure Questionnaire-Short Form (MIPQ-S) for 50 participants at two time points, approximately 4 to 5 months apart.

RESULTS

Bivariate correlations from data concurrently assessed at Time-1 showed significant linear relationships between the SIB (both frequency and severity scores) and Interest/Pleasure sub-scales, and the Aggressive/Destructive Behaviour (severity scores) and the MIPQ-S Mood sub-scales (unadjusted for multiple correlations). All of these effects were found with the BPI-S data, but not with the CBI. Multiple regression analyses revealed that (1) low interest/pleasure assessed at Time-1 predicted high SIB (frequency and severity) at Time-2. (2) Interest/pleasure was not predictive of aggressive or stereotypic behaviour. (3) Mood at Time-1 did not predict any of the three types of behaviour problems at Time-2. (4) In reverse, high SIB (frequency and severity) at Time-1 predicted low interest/pleasure ratings at Time-2. (5) Surprisingly, frequent aggressive/destructive behaviour predicted high interest/pleasure. (6) Stereotypic behaviour scores at Time-1 did not predict interest/pleasure ratings at Time-2. Again, all of these effects were only found with the BPI-S data, but not with the CBI. Internal consistency, test-retest reliability and concurrent validity of the Hungarian versions of all three questionnaires had generally satisfactory outcomes.

DISCUSSION

The fact that increasingly frequent and severe SIB was predicted by declining measures of interest/pleasure is consistent with previous studies. Contrary to those earlier studies, however, we found that SIB was not predicted by mood and that aggressive/destructive behaviour actually predicted future elevated mood. Implications for future research regarding the directional relationship between affective states such as mood and interest and pleasure, on the one hand, and challenging behaviour, on the other, were discussed.

Prevalence of autism spectrum disorder phenomenology in genetic disorders: a systematic review and meta-analysis

BACKGROUND

Autism spectrum disorder (ASD) phenomenology is reported to be more common in individuals with some genetic syndromes than in the general population; however, no meta-analysis has provided prevalence data within and between syndromes. In this systematic review and meta-analysis, we aimed to synthesise data from a wide range of papers to provide accurate estimates about ASD phenomenology in genetic and metabolic syndromes.

METHODS

We identified syndromes reported as most likely to be associated with ASD. We searched Ovid PsycINFO, Ovid MEDLINE, Ovid Embase, and PubMed Central for English-language papers published from database creation up to early 2014 with use of syndrome-specific keywords and a set of ASD keywords. We screened and extracted papers that had ASD prevalence data for ten or more people within a genetic syndrome. With use of a prespecified set of reliable criteria, we applied quality weighting to papers and estimated a quality-effects prevalence of ASD phenomenology for each syndrome. We then calculated relative risks to compare ASD between all syndromes and also calculated odds ratios to compare prevalence with the general population taking the current estimate of one in 68 people.

RESULTS

We identified 168 papers reporting the prevalence of ASD phenomenology and found widely varying methods and quality of data. Quality-weighted effect prevalence estimates of ASD phenomenology were established for Rett's syndrome (female individuals only 61%), Cohen's syndrome (54%), Cornelia de Lange syndrome (43%), tuberous sclerosis complex (36%), Angelman's syndrome (34%), CHARGE syndrome (30%), fragile X syndrome (male individuals only 30%; mixed sex 22%), neurofibromatosis type 1 (18%), Down's syndrome (16%), Noonan's syndrome (15%), Williams' syndrome (12%), and 22q11.2 deletion syndrome (11%). Relative risks and the odds ratio compared with the general population were highest for Rett's syndrome and Cohen's syndrome. In all syndromes, odds ratios showed ASD phenomenology to be significantly more likely than in the general population.

INTERPRETATION

ASD phenomenology varied between syndromes, but was consistently more likely than in the general population. Further research is needed in these populations, including how ASD in genetic and metabolic syndromes differs from idiopathic autism and what that can tell us about the mechanisms underlying ASD.

FUNDING

Cerebra.