Activity-Dependent Transcriptional Program in NGN2+ Neurons Enriched for Genetic Risk for Brain-Related Disorders.

BACKGROUND: Converging evidence from large-scale genetic and postmortem studies highlights the role of aberrant neurotransmission and genetic regulation in brain-related disorders. However, identifying neuronal activity-regulated transcriptional programs in the human brain and understanding how changes contribute to disease remain challenging. METHODS: To better understand how the activity-dependent regulome contributes to risk for brain-related disorders, we profiled the transcriptomic and epigenomic changes following neuronal depolarization in human induced pluripotent stem cell-derived glutamatergic neurons (NGN2) from 6 patients with schizophrenia and 5 control participants. RESULTS: Multiomic data integration associated global patterns of chromatin accessibility with gene expression and identified enhancer-promoter interactions in glutamatergic neurons. Within 1 hour of potassium chloride-induced depolarization, independent of diagnosis, glutamatergic neurons displayed substantial activity-dependent changes in the expression of genes regulating synaptic function. Depolarization-induced changes in the regulome revealed significant heritability enrichment for schizophrenia and Parkinson's disease, adding to mounting evidence that sequence variation within activation-dependent regulatory elements contributes to the genetic risk for brain-related disorders. Gene coexpression network analysis elucidated interactions among activity-dependent and disease-associated genes and pointed to a key driver (NAV3) that interacted with multiple genes involved in axon guidance. CONCLUSIONS: Overall, we demonstrated that deciphering the activity-dependent regulome in glutamatergic neurons reveals novel targets for advanced diagnosis and therapy.

Sleep neurophysiology in childhood onset schizophrenia.

Altered sleep neurophysiology has consistently been reported in adult patients with schizophrenia. Converging evidence suggests that childhood onset schizophrenia (COS), a rare but severe form of schizophrenia, is continuous with adult onset schizophrenia. The aim of the current study was to characterize sleep neurophysiology in COS. An overnight sleep electroencephalogram (EEG) was recorded in 17 children and adolescents with COS (16 years ± 6.6) and 17 age and gender-matched controls. Non-rapid eye movement (NREM) and rapid eye movement (REM) sleep EEG power and coherence for the frequency bands delta (1.6-4.8 Hz), theta (5-8.4 Hz), alpha (8.6-11 Hz), beta 1 (16.4-20.2 Hz) and beta 2 (20.4-24.2 Hz) were compared between COS patients and controls. COS patients exhibited significant and widespread deficits in beta power during NREM and REM sleep. With regard to coherence, we found increases in COS patients across brain regions, frequency bands and sleep states. This study demonstrates the utility of the sleep EEG for studying vulnerable populations and its potential to aid diagnosis.

Sleep spindle activity in childhood onset schizophrenia: Diminished and associated with clinical symptoms.

Neuroimaging studies of childhood onset schizophrenia (COS), a rare yet severe form of schizophrenia with an onset before the age of 13 years, have shown continuity with adult onset schizophrenia. Previous research in adult patients has shown reduced sleep spindle activity, transient oscillations in the sleep electroencephalogram (EEG) generated through thalamocortical loops. The current study examines sleep spindle activity in patients with COS. Seventeen children and adolescents with COS (16 years ±6.6) underwent overnight sleep EEG recordings. Sleep spindle activity was compared between patients with COS and age and gender matched controls and correlated with clinical symptom severity. We found pronounced deficits in sleep spindle amplitude, duration, density and frequency in patients with COS (effect size = 0.61 to 1.96; dependent on metric and EEG derivation). Non-rapid eye movement (NREM) sleep EEG power and coherence in the sigma band (11-16 Hz) corresponding to spindle activity were also markedly diminished in patients with COS as compared to controls. Furthermore, the degree of deficit in power and coherence of spindles was strongly associated with clinician rated hallucinations and positive symptoms over widespread cortical regions. Our finding of diminished spindle activity and its association with hallucinations likely reflect dysfunction of the thalamocortical circuits in children and adolescents with COS. Given the relative ease of sleep EEG recordings in vulnerable populations, this study highlights the potential of such recordings to characterize brain function in schizophrenia.

Neuronal impact of patient-specific aberrant NRXN1α splicing.

NRXN1 undergoes extensive alternative splicing, and non-recurrent heterozygous deletions in NRXN1 are strongly associated with neuropsychiatric disorders. We establish that human induced pluripotent stem cell (hiPSC)-derived neurons well represent the diversity of NRXN1α alternative splicing observed in the human brain, cataloguing 123 high-confidence in-frame human NRXN1α isoforms. Patient-derived NRXN1+/- hiPSC-neurons show a greater than twofold reduction in half of the wild-type NRXN1α isoforms and express dozens of novel isoforms from the mutant allele. Reduced neuronal activity in patient-derived NRXN1+/- hiPSC-neurons is ameliorated by overexpression of individual control isoforms in a genotype-dependent manner, whereas individual mutant isoforms decrease neuronal activity levels in control hiPSC-neurons. In a genotype-dependent manner, the phenotypic impact of patient-specific NRXN1+/- mutations can occur through a reduction in wild-type NRXN1α isoform levels as well as the presence of mutant NRXN1α isoforms.

Reduced Functional Brain Activation and Connectivity During a Working Memory Task in Childhood-Onset Schizophrenia.

OBJECTIVE: Working memory (WM) deficits are consistently reported in schizophrenia and are related to poor functional outcomes. Functional magnetic resonance imaging studies of adult-onset schizophrenia have reported decreased functional activations and connectivity in the WM network, but no prior functional magnetic resonance imaging study has examined WM in childhood-onset schizophrenia (COS). The aim of this study was to examine the neural correlates of WM in COS. METHOD: Adult patients with COS (n = 32, 21.3 ± 1.1 years), nonpsychotic siblings of patients with COS (n = 30, 19.4 ± 0.8 years), and healthy controls (n = 39, 20.0 ± 0.7 years) completed 1- and 2-back WM tasks during 3-T functional magnetic resonance imaging. Functional activation and connectivity analyses were conducted. A separate group of 23 younger patients with COS (17.9 ± 7.4 years) could not perform the tasks after twice completing a standard training and are not included in this report. RESULTS: Patients with COS who were included scored significantly lower than controls on all tasks (p < .001). Patients with COS showed significantly lower activations in the dorsolateral prefrontal cortices, posterior parietal cortices, cerebellum, and caudate and decreased frontoparietal and corticostriatal functional connectivity compared with controls (p < .05, corrected). Siblings had functional activations and connectivity intermediate between those of patients and controls in a similar set of regions (p < .05, corrected). In patients, functional connectivity strength in the left frontoparietal network correlated positively with accuracy scores during the 1-back task (p = .0023, corrected). CONCLUSION: Decreased functional activation and connectivity in the WM network in COS supports pathophysiologic continuity with adult-onset schizophrenia. The low participation rate and accuracy of the patients highlights the disease severity of COS. Hypo-activations and hypo-connectivity were shared by siblings of patients with COS, suggesting COS as a potential endophenotype. CLINICAL TRIAL REGISTRATION INFORMATION: Evaluating Genetic Risk Factors for Childhood-Onset Schizophrenia; http://ClinicalTrials.gov;NCT00001198.

Attenuated resting-state functional connectivity in patients with childhood- and adult-onset schizophrenia.

BACKGROUND: Childhood-onset schizophrenia (COS) is a rare, severe form of the adult-onset disorder (AOS). Our previous resting-state fMRI study identified attenuated functional connectivity in COS compared with controls. Here, we ask whether COS and AOS patients and their siblings exhibit similar abnormalities of functional connectivity. METHODS: A whole-brain, data-driven approach was used to assess resting-state functional connectivity differences in COS (patients/siblings/controls, n: 26/28/33) and AOS (n: 19/28/30). There were no significant differences in age, sex, or head motion across groups in each dataset and as designed, the COS dataset has a significantly lower age than the AOS. RESULTS: Both COS and AOS patients showed decreased functional connectivity relative to controls among a wide set of brain regions (P<0.05, corrected), but their siblings did not. Decreased connectivity in COS and AOS patients showed no amplitude differences and was not modulated by age-at-onset or medication doses. Cluster analysis revealed that these regions fell into two large-scale networks: one sensorimotor network and one centered on default-mode network regions, but including higher-order cognitive areas only in COS. Decreased connectivity between these two networks was notable (P<0.05, corrected) for both patient groups. CONCLUSIONS: A shared pattern of attenuated functional connectivity was found in COS and AOS, supporting the continuity of childhood-onset and adult-onset schizophrenia. Connections were altered between sensorimotor areas and default-mode areas in both COS and AOS, suggesting potential abnormalities in processes of self-monitoring and sensory prediction. The absence of substantial dysconnectivity in siblings indicates that attenuation is state-related.

Symptom dimensions and subgroups in childhood-onset schizophrenia.

OBJECTIVE: This study investigated symptom dimensions and subgroups in the National Institute of Mental Health (NIMH) childhood-onset schizophrenia (COS) cohort and their similarities to adult-onset schizophrenia (AOS) literature. METHOD: Scores from the Scales for the Assessment of Positive and Negative Symptoms (SAPS & SANS) from 125 COS patients were assessed for fit with previously established symptom dimensions from AOS literature using confirmatory factor analysis (CFA). K-means cluster analysis of each individual's scores on the best fitting set of dimensions was used to form patient clusters, which were then compared using demographic and clinical data. RESULTS: CFA showed the SAPS & SANS data was well suited to a 2-dimension solution, including positive and negative dimensions, out of five well established models. Cluster analysis identified three patient groups characterized by different dimension scores: (1) low scores on both dimensions, (2) high negative, low positive scores, and (3) high scores on both dimensions. These groups had different Full scale IQ, Children's Global Assessment Scale (CGAS) scores, ages of onset, and prevalence of some co-morbid behavior disorders (all p<3.57E-03). CONCLUSION: Our analysis found distinct symptom-based subgroups within the NIMH COS cohort using an established AOS symptom structure. These findings confirm the heterogeneity of COS and were generally consistent with AOS literature.

Transcriptional signatures of schizophrenia in hiPSC-derived NPCs and neurons are concordant with post-mortem adult brains.

The power of human induced pluripotent stem cell (hiPSC)-based studies to resolve the smaller effects of common variants within the size of cohorts that can be realistically assembled remains uncertain. We identified and accounted for a variety of technical and biological sources of variation in a large case/control schizophrenia (SZ) hiPSC-derived cohort of neural progenitor cells and neurons. Reducing the stochastic effects of the differentiation process by correcting for cell type composition boosted the SZ signal and increased the concordance with post-mortem data sets. We predict a growing convergence between hiPSC and post-mortem studies as both approaches expand to larger cohort sizes. For studies of complex genetic disorders, to maximize the power of hiPSC cohorts currently feasible, in most cases and whenever possible, we recommend expanding the number of individuals even at the expense of the number of replicate hiPSC clones.

Lack of Gender-Related Differences in Childhood-Onset Schizophrenia.

OBJECTIVE: Gender differences, including younger age of onset and greater premorbid deficits in men, have been reported in adult-onset schizophrenia. This study comprehensively evaluated gender differences in childhood-onset schizophrenia (COS), a rare variant of the disorder. METHOD: Demographic, premorbid, clinical, familial, and cognitive characteristics, presence of chromosomal abnormalities, and brain magnetic resonance imaging cortical volumes were evaluated in 133 patients with COS. Cortical analyses included age- and gender-matched healthy volunteers (n = 124). RESULTS: Males with COS (n = 72) had a slightly but significantly younger age of onset than females with COS (mean age 9.51 ± 2.28 versus 10.29 ± 1.63 years, t131 = 2.21, p = .03), higher verbal IQ scores (83.00 ± 15.97 versus 75.58 ± 15.10, t89 = 2.24, p = .03), and higher rates of comorbid pervasive developmental disorder (28.17% versus 6.90%, χ(2)1 = 9.54, p < .01) and attention-deficit/hyperactivity disorder (43.86% versus 21.43%, χ(2)1 = 5.40, p = .02). There were no significant gender differences across other demographic, IQ, or clinical measurements, frequency of chromosomal abnormalities, family clinical measurements, premorbid functioning, or in gender-by-disorder interactions for magnetic resonance imaging brain measurements. CONCLUSION: The present comprehensive examination found few remarkable gender differences in COS. Although less striking than that seen in adult-onset schizophrenia, males with COS had a younger age of onset. Attention-deficit/hyperactivity disorder and pervasive developmental disorder rates were high in COS overall, suggesting greater neurodevelopmental vulnerability in COS. However, the gender ratios of these comorbidities in COS mirror those of the general populations, indicating that these gender differences might be unrelated to COS.

Dysregulation of miRNA-9 in a Subset of Schizophrenia Patient-Derived Neural Progenitor Cells.

Converging evidence indicates that microRNAs (miRNAs) may contribute to disease risk for schizophrenia (SZ). We show that microRNA-9 (miR-9) is abundantly expressed in control neural progenitor cells (NPCs) but also significantly downregulated in a subset of SZ NPCs. We observed a strong correlation between miR-9 expression and miR-9 regulatory activity in NPCs as well as between miR-9 levels/activity, neural migration, and diagnosis. Overexpression of miR-9 was sufficient to ameliorate a previously reported neural migration deficit in SZ NPCs, whereas knockdown partially phenocopied aberrant migration in control NPCs. Unexpectedly, proteomic- and RNA sequencing (RNA-seq)-based analysis revealed that these effects were mediated primarily by small changes in expression of indirect miR-9 targets rather than large changes in direct miR-9 targets; these indirect targets are enriched for migration-associated genes. Together, these data indicate that aberrant levels and activity of miR-9 may be one of the many factors that contribute to SZ risk, at least in a subset of patients.

15q13.3 duplication in two patients with childhood-onset schizophrenia.

We report two cases of paternally inherited 15q13.3 duplications in carriers diagnosed with childhood-onset schizophrenia (COS), a rare neurodevelopmental disorder of proposed polygenic origin with onset in children before age 13. This study documents that the 15q13.3 deletion and duplication exhibit pathogenicity for COS, with both copy number variants (CNVs) sharing a disrupted CHRNA7 gene. CHRNA7 encodes the neuronal alpha7 nicotinic acetylcholine receptor (α7nAChR) and is a candidate gene that has been suggested as a pathophysiological process mediating adult-onset schizophrenia (AOS) and other neurodevelopmental disorders. These results support the incomplete penetrance and variable expressivity of this CNV and represent the first report of 15q13.3 duplication carriers exhibiting COS. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics published by Wiley Periodicals, Inc.

Strong Treatment Response and High Maintenance Rates of Clozapine in Childhood-Onset Schizophrenia.

OBJECTIVE: Childhood-onset schizophrenia (COS) is a rare but severe form of the disorder, which is often treatment refractory. Short-term studies have indicated a greater differential efficacy, evident through effect sizes, favoring clozapine over other agents in alleviating negative symptoms in COS patients compared with adult-onset patients (AOS). There have been no data for COS patients on long-term compliance with clozapine treatment. Therefore, we wanted to know, over a span of up to 24 years, how many of our COS cohort had remained on clozapine for at least 2 years. We review short-term treatment data and present updated long-term data on compliance and functioning for our patients. METHODS: We present the results for long-term medication maintenance over a 24 year observation period for our cohort of 131 patients. Of this cohort, 91.6% (120) were available for follow-up information from either in-person or telephone contact with the patient and/or family members. We defined clozapine compliance as ≥2 years receiving this medication and doing well. RESULTS: We were able to contact 120 of the 131 patients. In spite of the additional cost and inconvenience of regular blood monitoring, 87 patients (72.5%, 87/120) adhered to long-term clozapine maintenance therapy with dosages ranging from 50 to 900 mg, and a median dosage of 500 mg. This rate exceeds the long-term clozapine maintenance rates reported for AOS patients. CONCLUSIONS: Short-term data on differential efficacy and long-term maintenance data suggest a possibly greater efficacy of clozapine, relative to other antipsychotics, in COS than in AOS. Our overall findings indicate that very early-onset schizophrenic patients may be more responsive to clozapine. This extends other support for clozapine as an option in the treatment of early-onset schizophrenia.

Severity of Cortical Thinning Correlates With Schizophrenia Spectrum Symptoms.

OBJECTIVE: This study investigated the relationship between regional cortical gray matter thinning and symptoms of schizophrenia spectrum personality disorders (PDs) in siblings of patients with childhood-onset schizophrenia (COS). METHOD: A total of 66 siblings of patients with COS were assessed for symptoms of schizophrenia spectrum PDs (avoidant, paranoid, schizoid, schizotypal). Structural magnetic resonance images were obtained at approximately 2-year intervals from the siblings and from 62 healthy volunteers matched for age, sex, ethnicity, and handedness. Cortical thickness measures were extracted. Mixed effect regression models were used to test the relationship between symptoms and cortical gray matter thickness in siblings. Cortical thinning was also tested longitudinally in healthy volunteers and siblings. RESULTS: Cortical thinning was found to correlate with symptoms of schizotypal and, to a lesser extent, schizoid PDs. Thinning was most pronounced in the left temporal and parietal lobes and right frontal and parietal regions. Gray matter loss was found to be continuous with that measured in COS. Longitudinal thinning trajectories were found not to differ between siblings and healthy volunteers. CONCLUSION: The present investigation of cortical thinning in siblings of patients with COS indicates that symptoms of schizophrenia spectrum PDs correlate with regional gray matter loss. This finding supports the idea of cortical thinning as a schizophrenia endophenotype.

Looking for childhood-onset schizophrenia: diagnostic algorithms for classifying children and adolescents with psychosis.

OBJECTIVE: Among children <13 years of age with persistent psychosis and contemporaneous decline in functioning, it is often difficult to determine if the diagnosis of childhood onset schizophrenia (COS) is warranted. Despite decades of experience, we have up to a 44% false positive screening diagnosis rate among patients identified as having probable or possible COS; final diagnoses are made following inpatient hospitalization and medication washout. Because our lengthy medication-free observation is not feasible in clinical practice, we constructed diagnostic classifiers using screening data to assist clinicians practicing in the community or academic centers. METHODS: We used cross-validation, logistic regression, receiver operating characteristic (ROC) analysis, and random forest to determine the best algorithm for classifying COS (n=85) versus histories of psychosis and impaired functioning in children and adolescents who, at screening, were considered likely to have COS, but who did not meet diagnostic criteria for schizophrenia after medication washout and inpatient observation (n=53). We used demographics, clinical history measures, intelligence quotient (IQ) and screening rating scales, and number of typical and atypical antipsychotic medications as our predictors. RESULTS: Logistic regression models using nine, four, and two predictors performed well with positive predictive values>90%, overall accuracy>77%, and areas under the curve (AUCs)>86%. CONCLUSIONS: COS can be distinguished from alternate disorders with psychosis in children and adolescents; greater levels of positive and negative symptoms and lower levels of depression combine to make COS more likely. We include a worksheet so that clinicians in the community and academic centers can predict the probability that a young patient may be schizophrenic, using only two ratings.

Risk factors for neutropenia in clozapine-treated children and adolescents with childhood-onset schizophrenia.

OBJECTIVE: The purpose of this study was to retrospectively analyze rates of neutropenia and risk factors for neutropenia in hospitalized children and adolescents treated with clozapine. METHODS: A retrospective chart review was conducted for all patients who received clozapine at any time during a hospitalization at the National Institute of Mental Health (NIMH) between 1990 and 2011. All patients satisfied screening criteria for the NIMH childhood-onset schizophrenia study, including onset of psychosis before the age of 13 years. Absolute neutrophil count (ANC) values recorded during inpatient hospitalization were extracted for 87 eligible patients with a mean age of 13.35±2.46 years at hospitalization and a mean length of stay of 117±43 days. RESULTS: Mild neutropenia only (lowest ANC<2000/mm3 but>1500/mm3) was observed in 27 (31%) patients and moderate neutropenia (any ANC<1500/mm3) was observed in 17 (20%) patients. There were no cases of agranulocytosis or severe infection. Significant risk factors for mild neutropenia compared with no hematologic adverse effects (HAEs) were male gender (p=0.012) and younger age (p<0.001). Male gender was also a significant risk factor for moderate neutropenia compared with no HAEs (p=0.003). If a child of African American ethnicity developed neutropenia during hospitalization at all that child was significantly more likely to develop moderate neutropenia than mild neutropenia only (p=0.017). African American boys had the highest rate of moderate neutropenia at 47%. Sixteen of the 17 patients exhibiting moderate neutropenia were successfully treated with clozapine by the time of discharge; 8 of these 16 required adjunctive lithium carbonate administration to maintain ANC>2000/mm3. CONCLUSIONS: Our study shows that the rates of neutropenia in clozapine-treated children and adolescents are considerably higher than in the adult population. Younger age, African American ethnicity, and male gender were significant risk factors. These are also risk factors for benign neutropenia in healthy children and adolescents. Despite these high rates of neutropenia, all but one of the patients with neutropenia during hospitalization were successfully discharged on clozapine.

Childhood-onset schizophrenia: the challenge of diagnosis.

During the past two decades, the Child Psychiatry Branch at the National Institute of Mental Health has conducted a longitudinal study (including long-term prospective follow-up) of childhood-onset schizophrenia, a rare form of the disorder. Critical to this research has been accurate diagnosis. Outpatient screening has accurately diagnosed 55% of the 121 childhood-onset schizophrenia patients in the study to date. However, inpatient observation including drug-free observation has proven crucial to ruling out 96 children with alternative diagnoses who had been provisionally admitted for inpatient study. Standardized clinical ratings from outpatient screening only predicted 62% of these nonschizophrenia patients. Historically, medication-free observation was standard clinical care for difficult and unusual patients; this should be employed when possible in similar situations.

Remission status and cortical thickness in childhood-onset schizophrenia.

OBJECTIVE: Few studies have examined prediction of schizophrenia outcome in relation to brain magnetic resonance imaging measures. In this study, remission status at the time of discharge was examined in relation to admission cortical thickness for childhood-onset schizophrenia probands. We hypothesized that total, frontal, temporal, and parietal gray matter thickness would be greater in patients who subsequently remit. METHOD: The relation between admission cortical brain thickness on magnetic resonance imaging and remission status at the time of discharge an average of 3 months later was examined for 56 individuals (32 males) ages 6 to 19 diagnosed with childhood-onset schizophrenia. Cortical thickness was measured across the cerebral hemispheres at admission. Discharge remission criteria were adapted from the 2005 Remission in Schizophrenia Working Group criteria. RESULTS: Patients remitted at discharge (n = 16 [29%]) had thicker regional cortex in left orbitofrontal, left superior, and middle temporal gyri and bilateral postcentral and angular gyri (p < or = .008). CONCLUSIONS: Our results provide neuroanatomic correlates of clinical remission in schizophrenia and evidence that response to treatment may be mediated by these cortical brain regions.

Rare structural variants disrupt multiple genes in neurodevelopmental pathways in schizophrenia.

Schizophrenia is a devastating neurodevelopmental disorder whose genetic influences remain elusive. We hypothesize that individually rare structural variants contribute to the illness. Microdeletions and microduplications >100 kilobases were identified by microarray comparative genomic hybridization of genomic DNA from 150 individuals with schizophrenia and 268 ancestry-matched controls. All variants were validated by high-resolution platforms. Novel deletions and duplications of genes were present in 5% of controls versus 15% of cases and 20% of young-onset cases, both highly significant differences. The association was independently replicated in patients with childhood-onset schizophrenia as compared with their parents. Mutations in cases disrupted genes disproportionately from signaling networks controlling neurodevelopment, including neuregulin and glutamate pathways. These results suggest that multiple, individually rare mutations altering genes in neurodevelopmental pathways contribute to schizophrenia.