Selective Serotonin Reuptake Inhibitor Treatment Post Gene Therapy for an Ultrarare Neurometabolic Disorder (AADC Deficiency)

Aromatic L-amino acid decarboxylase (AADC) deficiency is an ultrarare genetic disorder affecting 1 in 500,000 individuals. It causes complete absence of monoamine neurotransmitter synthesis, profound motor impairment, and developmental delays. Treatment guidelines recommend against selective serotonin re-uptake inhibitors (SSRIs) in AADC deficiency, given reports of movement-related side effects and no benefits. Newly developed disease modifying gene therapy for this condition substantially improves motor symptoms. Herein, we describe a case of beneficial treatment response to SSRIs for anxiety in a child post AADC gene therapy. The child was diagnosed with AADC deficiency in infancy during investigations for hypotonia. Between 6 months and 5 years of age, she experienced severe irritability and sleep disturbance, severe hypotonia (no voluntary motor movements or head control, g-tube fed), and several hours of dystonic episodes weekly. At age 5 years, she received gene therapy that delivered an adeno-associated viral gene vector (AAV2-AADC) to the midbrain, resulting in marked improvements in motor function. At age 6 and 7 years, standardized developmental assessment estimated cognitive skills in the 10-month range, and she was diagnosed with autism spectrum disorder and an anxiety disorder. A cautious trial of sertraline 12.5 mg titrated to 75 mg over 4 months was well tolerated and substantially reduced anxiety and emotional lability, without adverse effects. This report is illustrative of the challenges and opportunities posed by genetic therapies, including a need to systematically revisit existing evidence and treatment guidelines in the emerging era of genomic medicine.

Developmental cascades between insistence on sameness behaviour and anxiety symptoms in autism spectrum disorder

Autistic children experience high rates of anxiety. Insistence on sameness behaviour (IS) is a core feature of autism that appears correlated with anxiety severity. The objective of this study was to examine the longitudinal relations between anxiety and IS in autistic children using a developmental cascade model. A longitudinal cohort of 421 autistic children was followed between 4 and 11 years of age. Anxiety was quantified using items from the Anxiety Problems subscale of the Child Behavior Checklist; sameness behaviours were measured using the Repetitive Behavior Scale-Revised, Ritualistic/sameness subscale (both parent-report measures). Structural equation modelling was used to examine the longitudinal and directional associations between anxiety and IS at four time-points, through cross-lagged panel models (CLPM) with and without a random-intercepts component (RI-CLPM). Both the CLPM and the RI-CLPM had good fit. Significant directional associations were detected whereby elevated or increasing IS preceded elevated or increasing anxiety symptoms 1-2 years later, respectively. Stable baseline tendencies towards anxiety and IS as between-person traits (intercepts) were strongly associated (standardized estimate = 0.69, p < 0.001). The magnitude of the cross-sectional associations between anxiety and IS appeared to lessen with age. IS and anxiety symptoms in autism are closely related. They appear to be shared traits that mirror each other particularly in younger children. Increasing IS may be a sign of emerging future anxiety. Interventions that target IS to reduce or prevent anxiety amongst school-aged autistic children merit further study.

Linkage of whole genome sequencing and administrative health data in autism: A proof of concept study

Whether genetic testing in autism can help understand longitudinal health outcomes and health service needs is unclear. The objective of this study was to determine whether carrying an autism-associated rare genetic variant is associated with differences in health system utilization by autistic children and youth. This retrospective cohort study examined 415 autistic children/youth who underwent genome sequencing and data collection through a translational neuroscience program (Province of Ontario Neurodevelopmental Disorders Network). Participant data were linked to provincial health administrative databases to identify historical health service utilization, health care costs, and complex chronic medical conditions during a 3-year period. Health administrative data were compared between participants with and without a rare genetic variant in at least 1 of 74 genes associated with autism. Participants with a rare variant impacting an autism-associated gene (n = 83, 20%) were less likely to have received psychiatric care (at least one psychiatrist visit: 19.3% vs. 34.3%, p = 0.01; outpatient mental health visit: 66% vs. 77%, p = 0.04). Health care costs were similar between groups (median: $5589 vs. $4938, p = 0.4) and genetic status was not associated with odds of being a high-cost participant (top 20%) in this cohort. There were no differences in the proportion with complex chronic medical conditions between those with and without an autism-associated genetic variant. Our study highlights the feasibility and potential value of genomic and health system data linkage to understand health service needs, disparities, and health trajectories in individuals with neurodevelopmental conditions.

Differential symptom cluster responses to repetitive transcranial magnetic stimulation treatment in depression

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) can target specific neural circuits, which may allow for personalized treatment of depression. Treatment outcome is typically determined using sum scores from validated measurement scales; however, this may obscure differential improvements within distinct symptom domains. The objectives for this work were to determine: (1) whether a standard depression measure can be represented using a four symptom cluster model and (2) whether these symptom clusters had a differential response to rTMS treatment.

METHODS

Data were obtained from two multi-centre randomized controlled trials of rTMS delivered to the left dorsolateral prefrontal cortex (DLPFC) for participants with treatment-resistant depression (TRD) conducted in Canada (THREE-D [Conducted between Sept 2013, and Oct 2016] and CARTBIND [Conducted between Apr 2016 and Feb 2018]). The first objective used confirmatory factor analytic techniques, and the second objective used a linear mixed effects model. Trial Registration: NCT01887782, NCT02729792.

FINDINGS

In the total sample of 596 participants with TRD, we found a model consisting of four symptom clusters adequately fit the data. The primary analysis using the THREE-D treatment trial found that symptom clusters demonstrated a differential response to rTMS treatment (F(3,5984) = 31.92, p < 0.001). The anxiety symptom cluster was significantly less responsive to treatment than other symptom clusters (t(6001) = -8.02, p < 0.001). These findings were replicated using data from the CARTBIND trial.

INTERPRETATION

There are distinct symptom clusters experienced by individuals with TRD that have a differential response to rTMS. Future work will determine whether differing rTMS treatment targets have distinct patterns of symptom cluster responses with the eventual goal of personalizing rTMS protocols based on an individual's clinical presentation.

FUNDING

Canadian Institutes of Health Research, Brain Canada.

Developmental implications of genetic testing for physical indications

In children undergoing genetic testing for physical health concerns, we examined how often the results also revealed information about their risk for neurodevelopmental disorders. The study sample consisted of 3056 genetic tests (1686 chromosomal microarrays--CMAs, and 1378 next-generation sequencing--NGS panels) ordered at a tertiary pediatric hospital because of a physical/congenital health problem. Tests ordered to investigate developmental concerns were excluded. Pathogenic, or likely pathogenic variants were manually reviewed for diagnostic likelihood, and for evidence of an association with a neurodevelopmental disorder (e.g., autism or intellectual disability). A total of 169 CMAs (10%) and 232 NGS panels (17%) had likely diagnostic results. More than half (52%) of all diagnostic results had established evidence of a neurodevelopmental disorder association. In summary, there is a high prevalence of neurodevelopmental implications from genetic tests ordered for physical/congenital indications. This broad clinical utility suggests a growing need for genetics-first developmental care pathways.

Application of Transactional (Cross-lagged panel) Models in Mental Health Research: An Introduction and Review of Methodological Considerations

Transactional models employing cross-lagged panels have been used for over 40 years to examine the longitudinal relations and directional associations between variables of interest to child and adolescent mental health. Through a narrative synthesis of the literature, we provide an accessible overview of cross-lagged panels with attention to developing a research question, study design and assumptions, dynamic effects (including the random-intercept cross-lagged panel model), and reporting and interpretation of results. Implications and critical appraisal guidelines for readers are discussed throughout. Overall, several key points are highlighted, with particular emphasis on the intended level of inference, model and measure selection, and timing of assessments. Despite limitations in establishing causation, cross-lagged panel models are fundamental to non-experimental epidemiologic research in child mental health and development.

Co-occurring trajectories of anxiety and insistence on sameness behaviour in autism spectrum disorder

BACKGROUND

Children with autism spectrum disorder (ASD) have increased susceptibility to anxiety disorders. Variation in a common ASD symptom, insistence on sameness behaviour, may predict future anxiety symptoms.

AIMS

To describe the joint heterogeneous longitudinal trajectories of insistence on sameness and anxiety in children with ASD and to characterise subgroups at higher risk for anxiety.

METHOD

In a longitudinal ASD cohort (n = 421), insistence on sameness behaviour was measured using the Autism Diagnostic Interview-Revised at approximately ages 3, 6 and 11 years. Anxiety was quantified at 8 time points between ages 3 and 11 years using the Child Behavior Checklist (CBCL) (parent report). Clusters of participants following similar trajectories were identified using group-based and joint trajectory modelling.

RESULTS

Three insistence on sameness trajectories were identified: (a) 'low-stable' (41.7% of participants), (b) 'moderate-increasing' (52.0%) and (c) 'high-peaking' (i.e. increasing then stabilising/decreasing behaviour) (6.3%). Four anxiety trajectories were identified: (a) 'low-increasing' (51.0%), (b) 'moderate-decreasing' (16.2%), (c) 'moderate-increasing' (19.6%) and (d) 'high-stable' (13.1%). Of those assigned to the 'high-peaking' insistence on sameness trajectory, 95% jointly followed an anxiety trajectory that surpassed the threshold for clinical concern (T-score >65) by middle childhood (anxiety trajectories 3 or 4). Insistence on sameness and anxiety trajectories were similar in severity and direction for 64% of the sample; for 36%, incongruous patterns were seen (e.g. decreasing anxiety and increasing insistence on sameness).

CONCLUSIONS

The concurrent assessment of insistence on sameness behaviour and anxiety in ASD may help in understanding current symptom profiles and anticipating future trajectories. High preschool insistence on sameness in particular may be associated with elevated current or future anxiety symptoms.

Repetitive Behavior Severity as an Early Indicator of Risk for Elevated Anxiety Symptoms in Autism Spectrum Disorder

OBJECTIVE

A significant proportion of children with autism spectrum disorder (ASD) will develop an anxiety disorder during childhood. Restricted and repetitive behavior severity in ASD positively correlates with anxiety severity in cross-sectional surveys. The longitudinal relationship between restricted/repetitive behavior and future anxiety symptoms is unclear.

METHOD

In a longitudinal cohort of children with ASD (n = 421), restricted/repetitive behavior severity at enrollment (age 2-5 years) was categorized as "mild," "moderate," or "severe" using the Autism Diagnostic Interview-Revised. Elevated anxiety symptoms were defined by a Child Behavior Checklist (parent report) Anxiety subscale T-score of >65 at ages 8 to 11 years. Multivariable logistic regression with multiple imputation for missing data was used to examine the association between restricted/repetitive behavior severity and elevated anxiety symptoms while adjusting for age, sex, adaptive functioning, baseline anxiety, income, and parenting stress, generating adjusted odds ratios (aORs) and 95% CIs.

RESULTS

Approximately 58% of children with severe restricted/repetitive behavior at enrollment had elevated anxiety symptoms by age 11, compared to 41% of those with moderate, and 20% of those with mild restricted/repetitive behavior, respectively. Moderate and severe restricted/repetitive behavior were both associated with increased odds of elevated anxiety (moderate aOR: 2.5 [1.2-5.3]; severe aOR: 3.2 (1.4-7.5]).

CONCLUSION

Restricted/repetitive behavior severity at time of ASD diagnosis indicates risk for future anxiety symptoms. This finding increases our understanding of which children with ASD will develop anxiety disorders and may guide research concerning early interventions and etiological mechanisms.

Rare copy number variations affecting the synaptic gene DMXL2 in neurodevelopmental disorders

Background

Ultra-rare genetic variants, including non-recurrent copy number variations (CNVs) affecting important dosage-sensitive genes, are important contributors to the etiology of neurodevelopmental disorders (NDDs). Pairing family-based whole-genome sequencing (WGS) with detailed phenotype data can enable novel gene associations in NDDs.

Methods

We performed WGS of six members from a three-generation family, where three individuals each had a spectrum of features suggestive of a NDD. CNVs and sequence-level variants were identified and further investigated in disease and control databases.

Results

We identified a novel 252-kb deletion at 15q21 that overlaps the synaptic gene DMXL2 and the gene GLDN. The microdeletion segregated in NDD-affected individuals. Additional rare inherited and de novo sequence-level variants were found that may also be involved, including a missense change in GRIK5. Multiple CNVs and loss-of-function sequence variants affecting DMXL2 were discovered in additional unrelated individuals with a range of NDDs.

Conclusions

Disruption of DMXL2 may predispose to NDDs including autism spectrum disorder. The robust interpretation of private variants requires a multifaceted approach that incorporates multigenerational pedigrees and genome-wide and population-scale data.

Genomic Disorders in Psychiatry-What Does the Clinician Need to Know?

PURPOSE OF REVIEW

The purpose of this review is to summarize the role of genomic disorders in various psychiatric conditions and to highlight important recent advances in the field that are of potential clinical relevance.

RECENT FINDINGS

Genomic disorders are caused by large rare recurrent deletions and duplications at certain chromosomal "hotspots" (e.g., 22q11.2, 16p11.2, 15q11-q13, 1q21.1, 15q13.3) across the genome. Most overlap multiple genes, affect development, and are associated with variable cognitive and other neuropsychiatric expression. Although individually rare, genomic disorders collectively account for a significant minority of intellectual disability, autism spectrum disorder, and schizophrenia. Genome-wide chromosomal microarray analysis is capable of detecting all genomic disorders in a single test, offering the first opportunity for routine clinical genetic testing in psychiatric practice.

Oxytocin Receptor Polymorphisms are Differentially Associated with Social Abilities across Neurodevelopmental Disorders

Oxytocin is a pituitary neuropeptide that affects social behaviour. Single nucleotide polymorphisms (SNPs) in the oxytocin receptor gene (OXTR) have been shown to explain some variability in social abilities in control populations. Whether these variants similarly contribute to the severity of social deficits experienced by children with neurodevelopmental disorders is unclear. Social abilities were assessed in a group of children with autism spectrum disorder (ASD, n = 341) or attention deficit hyperactivity disorder (ADHD, n = 276) using two established social measures. Scores were compared by OXTR genotype (rs53576, rs237887, rs13316193, rs2254298). Unexpectedly, the two most frequently studied OXTR SNPs in the general population (rs53576 and rs2254298) were associated with an increased severity of social deficits in ASD (p < 0.0001 and p = 0.0005), yet fewer social deficits in ADHD (p = 0.007 and p < 0.0001). We conclude that these genetic modifier alleles are not inherently risk-conferring with respect to their impact on social abilities; molecular investigations are greatly needed.

Oxytocin and vasopressin: linking pituitary neuropeptides and their receptors to social neurocircuits

Oxytocin and vasopressin are pituitary neuropeptides that have been shown to affect social processes in mammals. There is growing interest in these molecules and their receptors as potential precipitants of, and/or treatments for, social deficits in neurodevelopmental disorders, including autism spectrum disorder. Numerous behavioral-genetic studies suggest that there is an association between these peptides and individual social abilities; however, an explanatory model that links hormonal activity at the receptor level to complex human behavior remains elusive. The following review summarizes the known associations between the oxytocin and vasopressin neuropeptide systems and social neurocircuits in the brain. Following a micro- to macro- level trajectory, current literature on the synthesis and secretion of these peptides, and the structure, function and distribution of their respective receptors is first surveyed. Next, current models regarding the mechanism of action of these peptides on microcircuitry and other neurotransmitter systems are discussed. Functional neuroimaging evidence on the acute effects of exogenous administration of these peptides on brain activity is then reviewed. Overall, a model in which the local neuromodulatory effects of pituitary neuropeptides on brainstem and basal forebrain regions strengthen signaling within social neurocircuits proves appealing. However, these findings are derived from animal models; more research is needed to clarify the relevance of these mechanisms to human behavior and treatment of social deficits in neuropsychiatric disorders.

An update on medication management of behavioral disorders in autism

Autism spectrum disorder is often comorbid with behavioral disturbances such as irritability, aggression and hyperactivity. Throughout the mid 2000s, several large-scale controlled clinical trials were published leading to the approval of two medications (aripiprazole and risperidone) for treatment of irritability in this condition. This review serves as an update regarding new research findings regarding psychopharmacology for children and adolescents with ASD. In summary, the past five years have yielded no further approved medications with ASD as a primary indication. Important new research results include 1) long-term safety and efficacy data (52 week) regarding treatment with aripiprazole for irritability, 2) consensus regarding potential harm from SSRIs for treatment of repetitive behaviors in children/ adolescents with ASD, 3) a randomized controlled trial showing modest benefits from atomoxetine on hyperactivity, 4) many novel agents currently under investigation.

Social Communication is an Emerging Target for Pharmacotherapy in Autism Spectrum Disorder - A Review of the Literature on Potential Agents

OBJECTIVE

To review the published literature and registered clinical trials on pharmacologic interventions targeting social communication impairment in Autism Spectrum Disorder (ASD).

METHODS

A comprehensive search of several databases (PubMed, MEDLINE, PsycINFO, Clinical trials.gov) was conducted to identify pharmacologic agents that have been, or will be, tested as treatments for social communication impairment in individuals with ASD. Evidence from basic science research supporting rational drug discovery is surveyed.

RESULTS

Data from animal models and early clinical trials suggest that novel and existing compounds, including N-methyl-D-aspartate (NMDA) modulators, γ-aminobutyric acid (GABA) agonists, metabotropic glutamate receptor (mGluR) antagonists and neuropeptides, may enhance social communication/function in ASD. Results from numerous Phase 2 and Phase 3 clinical trials are expected in the near future.

CONCLUSIONS

Recent evidence suggests that social communication may be an appropriate target for pharmacologic manipulation. It is hoped that, in combination with behavioural interventions, novel therapeutics may soon be clinically available to help improve social outcomes.

A comparison of neuroimaging findings in childhood onset schizophrenia and autism spectrum disorder: a review of the literature

BACKGROUND

Autism spectrum disorder (ASD) and childhood onset schizophrenia (COS) are pediatric neurodevelopmental disorders associated with significant morbidity. Both conditions are thought to share an underlying genetic architecture. A comparison of neuroimaging findings across ASD and COS with a focus on altered neurodevelopmental trajectories can shed light on potential clinical biomarkers and may highlight an underlying etiopathogenesis.

METHODS

A comprehensive review of the medical literature was conducted to summarize neuroimaging data with respect to both conditions in terms of structural imaging (including volumetric analysis, cortical thickness and morphology, and region of interest studies), white matter analysis (include volumetric analysis and diffusion tensor imaging) and functional connectivity.

RESULTS

In ASD, a pattern of early brain overgrowth in the first few years of life is followed by dysmaturation in adolescence. Functional analyses have suggested impaired long-range connectivity as well as increased local and/or subcortical connectivity in this condition. In COS, deficits in cerebral volume, cortical thickness, and white matter maturation seem most pronounced in childhood and adolescence, and may level off in adulthood. Deficits in local connectivity, with increased long-range connectivity have been proposed, in keeping with exaggerated cortical thinning.

CONCLUSION

The neuroimaging literature supports a neurodevelopmental origin of both ASD and COS and provides evidence for dynamic changes in both conditions that vary across space and time in the developing brain. Looking forward, imaging studies which capture the early post natal period, which are longitudinal and prospective, and which maximize the signal to noise ratio across heterogeneous conditions will be required to translate research findings into a clinical environment.

Outcomes of her2-positive early-stage breast cancer in the trastuzumab era: a population-based study of Canadian patients

Breast cancer is heterogenous, with variable expression of the estrogen receptor (er), progesterone receptor (pr), and human epidermal growth factor receptor 2 (her2). Overexpression of her2 is generally considered a negative prognostic feature, but whether outcomes for her2-positive early breast cancer remain different from those for other subtypes in the era of trastuzumab-based adjuvant therapy is unknown.

METHODS

Using a retrospective chart review, we compared overall survival (os) and relapse-free survival (rfs) in 3 groups of patients with early-stage breast cancer: er-positive or pr-positive (or both) and her2-negative ["hormone receptor-positive" (hr+)]; her2-positive (her2+); and er-negative, pr-negative, and her2-negative ["triple-negative" (tn)].

RESULTS

In the 503 charts analyzed (332 hr+, 94 her2+, 77 tn), the 5-year os and rfs were, respectively, 94.2% and 87.2% for hr+ patients, 88.6% and 74.9% for her2+ patients, and 85.4% and 76.2% for tn patients. On multivariate analysis, the os for the her2+ subtype was similar to that for the hr+ subtype (hazard ratio:1.07; 95% confidence interval: 0.31 to 3.67 with hr+ as reference), but os was significantly worse for tn patients than for hr+ patients (hazard ratio: 4.37; 95% confidence interval: 1.56 to 12.24). In her2+ patients, the 5-year os and rfs trended better for patients with er+ or pr+ disease than for patients with er-negative and pr-negative disease (5-year os: 92.1% vs. 86.9%; 5-year rfs: 79.8% vs. 71.4%). Of her2+ patients, just 80.9% received trastuzumab, including 33.3% of her2+ patients with sub-centimetre tumours.

CONCLUSIONS

In the trastuzumab era, patients with her2+ and hr+ early breast cancer have similar outcomes, while tn patients experience a significantly worse os than either of the foregoing groups. Outcomes for her2+ patients may differ by er and pr status. Trastuzumab was underutilized in this cohort.

Using an objective structured video exam to identify differential understanding of aspects of communication skills

BACKGROUND

Effective communication in health care is associated with patient satisfaction and improved clinical outcomes. Professional schools increasingly incorporate communication training into their curricula. The objective structured video exam (OSVE) is a video-based examination that provides an economical way of assessing students' knowledge of communication skills. This study presents a scoring strategy that enables blueprinting of an OSVE to consensus guidelines, to determine which aspects of communication skills create the most difficulty for students to understand and to what degree understanding improves through experiential communication skills training.

METHODS

Five interactions between a healthcare professional and client were scripted and filmed using standardized patients. The dialogues were mapped onto the Kalamazoo consensus statement by having five communication experts view each video and identify effective and ineffective use of communication skills. Undergraduate students enrolled in a communications course completed an OSVE on three occasions.

RESULTS

A total of 79 students completed at least one testing session. The scores assigned supported the validity of the scoring strategy as an indication of knowledge growth. Considerable variability was observed across Kalamazoo sub-domains.

CONCLUSION

With further refining, this scoring approach may prove useful for educators to tailor their education and assessment practices to specific consensus guidelines.