Association between copy number variations in parkin (PRKN) and schizophrenia and autism spectrum disorder: A case-control study

AIM

The present study aimed to examine the association between copy number variations (CNVs) in parkin (PRKN) and schizophrenia (SCZ) and autism spectrum disorder (ASD) in a large case-control sample.

METHOD

Array comparative genomic hybridization was performed on 3111 cases with SCZ, 1236 cases with ASD, and 2713 controls. We systematically prioritized likely pathogenic CNVs (LP-CNVs) in PRKN and examined their association with SCZ and ASD.

RESULTS

In total, 3014 SCZ cases (96.9%), 1205 ASD cases (97.5%), and 2671 controls (98.5%) passed quality control. We found that monoallelic carriers of LP-CNVs in PRKN were common (70/6890, 1.02%) and were not at higher risk of SCZ (p = 0.29) or ASD (p = 0.72). We observed that the distribution pattern of LP-CNVs in the Japanese population was consistent with those in other populations. We also identified a patient diagnosed with SCZ and early-onset Parkinson's disease carrying biallelic pathogenic CNVs in PRKN. The absence of Parkinson's symptoms in 10 other monoallelic carriers of the same pathogenic CNV further reflects the lack of effect of monoallelic pathogenic variants in PRKN in the absence of a second hit.

CONCLUSION

The present findings suggest that monoallelic CNVs in PRKN do not confer a significant risk for SCZ or ASD. However, further studies to investigate the association between biallelic CNVs in PRKN and SCZ and ASD are warranted.

Effects of MAP4K inhibition on neurite outgrowth

Protein kinases are responsible for protein phosphorylation and are involved in important intracellular signal transduction pathways in various cells, including neurons; however, a considerable number of poorly characterized kinases may be involved in neuronal development. Here, we considered mitogen-activated protein kinase kinase kinase kinases (MAP4Ks), related to as candidate regulators of neurite outgrowth and synaptogenesis, by examining the effects of a selective MAP4K inhibitor PF06260933. PF06260933 treatments of the cultured neurons reduced neurite lengths, not the number of synapses, and phosphorylation of GAP43 and JNK, relative to the control. These results suggest that MAP4Ks are physiologically involved in normal neuronal development and that the resultant impaired neurite outgrowth by diminished MAP4Ks' activity, is related to psychiatric disorders.

Usefulness of the autism spectrum quotient (AQ) in screening for autism spectrum disorder and social communication disorder

BACKGROUND

In the Diagnostic and Statistical Manual and Mental Disorders, Fifth Edition (DSM-5), autism spectrum disorder (ASD) and social (pragmatic) communication disorder (SCD) were described as a new category of psychiatry nosography. SCD involves impairments in social communication and social interaction but not restricted, repetitive patterns of behavior, interests, or activities. The autism spectrum quotient (AQ) was developed to screen for autism tendencies in adults with normal intelligence. However, AQ cutoff scores for screening ASD and SCD in the DSM-5 have not been established. This study examined whether the Japanese version of the AQ (AQ-J) total scores could discriminate between an ASD group, an SCD group, and a neurotypical (NT) group.

METHODS

Participants were 127 ASD patients, 52 SCD patients, and 49 NT individuals. Receiver operating characteristic (ROC) analyses were used to examine AQ-J total score cutoff values to distinguish between ASD and NT groups, SCD and NT groups, and ASD and SCD groups.

RESULTS

In the ROC analysis for the ASD and NT groups, the area under the curve (AUC) was 0.96, and the optimum cutoff value was 23 points (sensitivity 92.9%, specificity 85.7%). The AUC for the SCD and NT groups was 0.89, and the optimum cutoff value was 22 points (sensitivity 84.6%, specificity 85.7%). The AUC for the ASD and SCD groups was 0.75; the optimum cutoff value was 32 points (sensitivity 67.7%, specificity 71.2%).

CONCLUSION

Our findings suggest the usefulness of the AQ-J in screening for ASD and SCD.

The three-factor structure of the Autism-Spectrum Quotient Japanese version in pregnant women

Background

There is a rising interest in perinatal mental health studies, and proper psychometric tools to assess autistic traits among this population in Japan are vital.

Objective

This study aimed to clarify the optimal factor structure of the AQ as part of a perinatal mental health research project.

Methods

We used the Japanese version of the AQ (AQ-J) to measure autistic-like traits in pregnant women. Participants were 4,287 Japanese women who were pregnant or who had given birth within the last month. We performed exploratory factor analysis (EFA) using the first sample group (n = 2,154) to obtain factor structures for the final item selections. We performed confirmatory factor analysis (CFA) using the second sample group (n = 2,133) to obtain a model with good fit, then compared the model to all previously proposed models to determine the best-fitting model.

Results

The EFA analysis identified a model consisting of 25 items distributed across three factors. Cronbach's alpha for the total 25-item AQ-J, 9-item "Social interaction" factor, 11-item "Non-verbal communication" factor, and 5-item "Restricted interest" factor was 0.829, 0.829, 0.755, and 0.576, respectively. McDonald's omega and its 95% confidence interval were 0.826 (0.821-0.836), 0.835 (0.821-0.837), 0.755 (0.744-0.766), and 0.603 (0.556-0.596), respectively. CFA confirmed that the three-factor structure had an acceptable fit (goodness of fit index: 0.900, comparative fit index: 0.860, root mean square error of approximation: 0.066). These findings indicated that the three-factor model was better than the 13 existing models.

Conclusion

The findings are discussed in relation to the adequacy of the AQ-J for assessing autistic traits in perinatal women. We recommend the use of this 25-item, three-factor AQ-J model for this population owing to its superiority to all previous models.

High care and low overprotection from both paternal and maternal parents predict a secure attachment style with a partner among perinatal Japanese women

This study aimed to determine how paternal and maternal parenting before adolescence affects adult attachment to a partner during the perinatal period, using three different models of attachment. We used the Parental Bonding Instrument (PBI) and the Relationship Questionnaire (RQ) to examine perceived parenting practices and adult attachment styles, respectively. The participants included 4586 Japanese women who were pregnant or who had given birth, up until one month after childbirth. We performed structural equation modeling analysis between PBI and RQ scores with three different category models, including the four-category model (secure, fearful, preoccupied, and dismissive attachment) as Model 1, the two-category model (model of the self and others) as Model 2, and the single-category model (total attachment style) as Model 3. Models 1 and 2 showed a good fit. Both path models showed a significant association between adult attachment style and perceived paternal and maternal parenting before adolescence, where high care and low overprotection from both paternal and maternal parents predicted adult attachment. Our findings indicate that attachment styles are best described using the four-category and two-category models, and suggest that both paternal and maternal overprotection and care influence adult attachment with a partner during the perinatal period.

Relationships among autistic traits, depression, anxiety, and maternal-infant bonding in postpartum women

BACKGROUND

Although several studies have found significant relationships between autistic traits and depression/anxiety, the relationships between autistic traits and postpartum depression/anxiety remain unclear. Moreover, few studies have examined the relationships between autistic traits and mother-infant bonding while considering depression or anxiety.

METHODS

This study used a cross-sectional data analysis design. Participants were 2692 women who completed the Autism-Spectrum Quotient (AQ), Hospital Anxiety and Depression Scale (HADS), and Mother-to-Infant Bonding Scale (MIBS) at 1 month postpartum. We performed path analysis that included parity, the five AQ subscales (social skills, attention switching, attention to detail, communication, and imagination), both HADS subscales (anxiety and depression), and the two MIBS subscales (lack of affection and anger and rejection).

RESULTS

Our path analysis revealed that higher scores for social skills, attention switching, communication, and imagination were associated with higher scores for depression. Higher scores for social skills, attention switching, attention to detail, and communication were associated with higher scores for anxiety. Moreover, difficulties in social skills and imagination were associated with failure of maternal-infant bonding. However, more attention to detail was associated with better maternal-infant bonding.

CONCLUSIONS

This study suggests that maternal autistic traits are related to anxiety and depression to a certain degree, but only slightly related to maternal-infant bonding at 1 month postpartum. To improve autistic women's quality of life and that of their newborns, perinatal mental health issues such as anxiety, depression, and maternal-fetal bonding difficulties should be appropriately addressed.

Case report: Methylphenidate improved chronic pain in an adult patient with attention deficit hyperactivity disorder

Introduction

Chronic pain remains a health problem that is difficult to treat adequately. Its unknown cause and complex comorbidity with other illnesses, including mental disorders, amplify the severity of symptoms, which consequently decreases the quality of life of patients long term. In our clinical practice, we coincidentally found evidence that methylphenidate (MPH) effectively managed chronic pain in an adult patient with attention deficit hyperactivity disorder (ADHD). The effectiveness of MPH in the treatment of ADHD is well-established; however, its utility in treating pain remains unclear.

Case presentation

We present a rare case of a 43-year-old male patient with 15 years of chronic idiopathic pain symptoms that did not adequately respond to standard pain management, such as acetaminophen, non-opioid analgesics, and muscle relaxers. Pain also persisted after treatments with antidepressants and an epidural block. Furthermore, symptoms worsened following several sessions of modified electroconvulsive therapy. After a thorough assessment at our child and adolescent psychiatric outpatient clinic, we confirmed a diagnosis of adult ADHD with a predominantly inattentive type. Considering this newly established diagnosis, we prescribed osmotic-release oral system (OROS) methylphenidate. Within 1 month of treatment at a dose of 18 mg/day of OROS-MPH, the patient’s chronic pain unexpectedly improved dramatically, and the patient no longer experienced pain symptoms. The dosage of OROS-MPH was titrated monthly, reaching 72 mg/day as a maintenance dose, and ADHD symptoms improved after 4 months of treatment. The patient was followed up regularly for 7 years during his OROS-MPH treatment. No adverse effects were reported, including stimulant addiction. He was stable overall and functioned well in his daily activities. His pain never recurred.

Conclusion

This case report suggests that MPH may be potentially effective in treating chronic pain. Further studies are needed to confirm whether MPH improved chronic pain simultaneously with or separately from the improvement in ADHD. Moreover, elucidating the anatomical sites and molecular pharmacological mechanisms related to the action of MPH in pain modulation and perception is essential. Such sites include the descending dopaminergic pain pathway and higher cortical areas. Furthering our understanding may reinforce the justification for treating chronic pain using MPH.

Theory of mind tested by implicit false belief: a simple and full-fledged mental state attribution

About 40 years have passed since 'theory of mind (ToM)' research started. The false-belief test is used as a litmus test for ToM ability. The implicit false-belief test has renewed views of ToM in several disciplines, including psychology, psychiatry, and neuroscience. Many important questions have been considered via the paradigm of implicit false belief. We recently addressed the phylogenetic and physiological aspects of ToM using a version of this paradigm combined with the chemogenetic technique on Old World monkeys. We sought to create animal models for autism that exhibit behavioral phenotypes similar to human symptoms. The simultaneous manipulation of neural circuits and assessments of changes in phenotypes can help identify the causal neural substrate of ToM.

Cross-Disorder Analysis of Genic and Regulatory Copy Number Variations in Bipolar Disorder, Schizophrenia, and Autism Spectrum Disorder

BACKGROUND

We aimed to determine the similarities and differences in the roles of genic and regulatory copy number variations (CNVs) in bipolar disorder (BD), schizophrenia (SCZ), and autism spectrum disorder (ASD).

METHODS

Based on high-resolution CNV data from 8708 Japanese samples, we performed to our knowledge the largest cross-disorder analysis of genic and regulatory CNVs in BD, SCZ, and ASD.

RESULTS

In genic CNVs, we found an increased burden of smaller (<100 kb) exonic deletions in BD, which contrasted with the highest burden of larger (>500 kb) exonic CNVs in SCZ/ASD. Pathogenic CNVs linked to neurodevelopmental disorders were significantly associated with the risk for each disorder, but BD and SCZ/ASD differed in terms of the effect size (smaller in BD) and subtype distribution of CNVs linked to neurodevelopmental disorders. We identified 3 synaptic genes (DLG2, PCDH15, and ASTN2) as risk factors for BD. Whereas gene set analysis showed that BD-associated pathways were restricted to chromatin biology, SCZ and ASD involved more extensive and similar pathways. Nevertheless, a correlation analysis of gene set results indicated weak but significant pathway similarities between BD and SCZ or ASD (r = 0.25-0.31). In SCZ and ASD, but not BD, CNVs were significantly enriched in enhancers and promoters in brain tissue.

CONCLUSIONS

BD and SCZ/ASD differ in terms of CNV burden, characteristics of CNVs linked to neurodevelopmental disorders, and regulatory CNVs. On the other hand, they have shared molecular mechanisms, including chromatin biology. The BD risk genes identified here could provide insight into the pathogenesis of BD.

The cyclin G-associated kinase (GAK) inhibitor SGC-GAK-1 inhibits neurite outgrowth and synapse formation

Protein kinases are responsible for protein phosphorylation and are involved in important signal transduction pathways; however, a considerable number of poorly characterized kinases may be involved in neuronal development. Here, we considered cyclin G-associated kinase (GAK) as a candidate regulator of neurite outgrowth and synaptogenesis by examining the effects of the selective GAK inhibitor SGC-GAK-1. SGC-GAK-1 treatment of cultured neurons reduced neurite length and decreased synapse number and phosphorylation of neurofilament 200-kDa subunits relative to the control. In addition, the related kinase inhibitor erlotinib, which has distinct specificity and potency from SGC-GAK-1, had no effect on neurite growth, unlike SGC-GAK-1. These results suggest that GAK may be physiologically involved in normal neuronal development, and that decreased GAK function and the resultant impaired neurite outgrowth and synaptogenesis may be related to neurodevelopmental disorders.

Novel missense SETD1A variants in Japanese patients with schizophrenia: Resequencing and association analysis

SETD1A has been identified as a substantial risk gene for schizophrenia. To further investigate the role of SETD1A in the genetic etiology of schizophrenia in the Japanese population, we performed resequencing and association analyses. First, we resequenced the SETD1A coding regions of 974 patients with schizophrenia. Then, we genotyped variants, prioritized via resequencing, in 2,027 patients with schizophrenia and 2,664 controls. Next, we examined the association between SETD1A and schizophrenia in 3,001 patients with schizophrenia and 2,664 controls. Finally, we performed a retrospective chart review of patients with prioritized SETD1A variants. We identified two novel missense variants (p.Ser575Pro and p.Glu857Gln) via resequencing. We did not detect these variants in 4,691 individuals via genotyping. These variants were not significantly associated with schizophrenia in the association analysis. Additionally, we found that a schizophrenia patient with the p.Glu857Gln variant had developmental delays. In conclusion, novel SETD1A missense variants were exclusively identified in Japanese patients with schizophrenia. However, our study does not provide evidence for the contribution of these variants to the genetic etiology of schizophrenia in the Japanese population.

Influence of Atomoxetine on Relationship Between ADHD Symptoms and Prefrontal Cortex Activity During Task Execution in Adult Patients

Objective: We conducted this non-randomized prospective interventional study to clarify the relationship between improved attention-deficit hyperactivity disorder (ADHD) symptoms and regional brain activity. Methods: Thirty-one adult patients underwent near-infrared spectroscopy examinations during a go/no-go task, both before and 8 weeks after atomoxetine administration. Results: Clinical symptoms, neuropsychological results of the go/no-go task, and bilateral lateral prefrontal activity significantly changed. A positive correlation was observed between right dorsolateral prefrontal cortex activity and Conners' Adult ADHD Rating Scales scores. Before atomoxetine administration, no correlations between prefrontal cortex activity and clinical symptoms were observed in all cases. When participants were divided into atomoxetine-responder and non-responder groups, a positive correlation was observed between prefrontal cortex activity and clinical symptoms in the non-responder group before treatment but not in the responder group, suggesting that non-responders can activate the prefrontal cortex without atomoxetine. Conclusions: Individuals with increased ADHD symptoms appear to recruit the right dorsolateral prefrontal cortex more strongly to perform the same task than those with fewer symptoms. In clinical settings, individuals with severe symptoms are often observed to perform more difficultly when performing the tasks which individuals with mild symptoms can perform easily. The atomoxetine-responder group was unable to properly activate the right dorsolateral prefrontal cortex when necessary, and the oral administration of atomoxetine enabled these patients to activate this region. In brain imaging studies of heterogeneous syndromes such as ADHD, the analytical strategy used in this study, involving drug-responsivity grouping, may effectively increase the signal-to-noise ratio.

Perceived parenting before adolescence and parity have direct and indirect effects via depression and anxiety on maternal-infant bonding in the perinatal period

AIM

This study was aimed towards detecting how perceived parenting practices before adolescence affect maternal-infant bonding in the perinatal period, considering factors such as depression, anxiety, and parity.

METHODS

We used the Parental Bonding Instrument (PBI) to examine perceived parenting practices. Participants included 1301 pregnant women who completed the Hospital Anxiety and Depression Scale (HADS) and Mother-to-Infant Bonding Scale (MIBS) at three time points: early pregnancy (approximately 12-15 weeks), late pregnancy (approximately 30-34 weeks) and postpartum (4 weeks after childbirth). We performed a path analysis with factors including parity, PBI subscales (paternal care, paternal overprotection, maternal care and maternal overprotection), HADS and MIBS.

RESULTS

Perceived paternal or maternal low care parenting predicted higher HADS and MIBS scores in early pregnancy. Moreover, perceived maternal low care parenting predicted higher HADS scores at postpartum and higher MIBS scores in late pregnancy. Perceived paternal or maternal overprotective parenting predicted higher HADS scores in the pregnancy period. Furthermore, perceived maternal overprotective parenting predicted higher MIBS scores in late pregnancy. Being primipara predicted higher HADS scores at postpartum and higher MIBS scores in early pregnancy and at postpartum. Being multipara predicted higher MIBS scores in late pregnancy.

CONCLUSION

This study suggests that perceived negative parenting before adolescence has indirect effects (via anxiety and depression) and direct effects on maternal-infant bonding in the perinatal period.

The lowest effective plasma concentration of atomoxetine in pediatric patients with attention deficit/hyperactivity disorder: A non-randomized prospective interventional study

BACKGROUND

Atomoxetine (ATX) is used as a first-line, non-stimulant treatment for attention-deficit/hyperactivity disorder (ADHD), although no studies have systematically examined the relationship between plasma concentration and clinical efficacy. We conducted this non-randomized prospective interventional study to examine the relationship between plasma concentration of ATX and clinical efficacy.

METHODS

Forty-three ADHD pediatric patients received ATX, and the steady-state through plasma concentration of the last daily dose that was maintained for at least 4 weeks were determined by high-performance liquid chromatography.

RESULTS

The receiver operating characteristic curve suggested that when plasma concentration exceeded 64.60 ng/mL, scores on the ADHD-Rating Scale improved by 50% or more (P = .14). Although 6 of the 8 final responders were unresponsive at the initial dose (.72 ± .04 mg/kg [mean ± standard deviation]), they responded after increasing the ATX dose to the final dose (1.52 ± .31 mg/kg). Excluding 7 outlier participants, the concentration was 83.3 ± 32.3 ng/mL in 7 responders and was significantly higher than 29.5 ± 23.9 ng/mL (P < .01) for the 29 non-responders.

CONCLUSIONS

These results suggest that a minimum effective plasma concentration of ATX is required to achieve sufficient clinical efficacy. We hypothesized a mechanism that results in the realization of a clinical effect when the plasma concentration exceeds a certain threshold in the potential response group, whereas will not improve even if the plasma concentration is increased in the unqualified non-responder group.

Macaques Exhibit Implicit Gaze Bias Anticipating Others' False-Belief-Driven Actions via Medial Prefrontal Cortex

The ability to infer others' mental states is essential to social interactions. This ability, critically evaluated by testing whether one attributes false beliefs (FBs) to others, has been considered to be uniquely hominid and to accompany the activation of a distributed brain network. We challenge the taxon specificity of this ability and identify the causal brain locus by introducing an anticipatory-looking FB paradigm combined with chemogenetic neuronal manipulation in macaque monkeys. We find spontaneous gaze bias of macaques implicitly anticipating others' FB-driven actions. Silencing of the medial prefrontal neuronal activity with inhibitory designer receptor exclusively activated by designer drugs (DREADDs) specifically eliminates the implicit gaze bias while leaving the animals' visually guided and memory-guided tracking abilities intact. Thus, neuronal activity in the medial prefrontal cortex could have a causal role in FB-attribution-like behaviors in the primate lineage, emphasizing the importance of probing the neuronal mechanisms underlying theory of mind with relevant macaque animal models.

Factor Structure and Measurement Invariance of the Hospital Anxiety and Depression Scale Across the Peripartum Period Among Pregnant Japanese Women

PURPOSE

The Hospital Anxiety and Depression Scale (HADS) is a self-report questionnaire widely used to assess anxiety and depression. To the best of our knowledge, only four studies have examined the factor structure of the HADS for assessing pregnant women, with conflicting results. This study aimed to assess the factor structure and measurement invariance of the HADS for use with pregnant Japanese women.

PARTICIPANTS AND METHODS

A total of 936 pregnant Japanese women completed the HADS questionnaire at three time points: the first and third trimester of pregnancy, and postpartum. We examined the factor structure of the HADS in Group 1 (n = 466) using exploratory factor analysis (EFA). We then compared the models identified in Group 1 with those from previous studies using confirmatory factor analysis (CFA) in Group 2 (n = 470). We performed multiple-group CFA for Group 2 to test the measurement invariance of the best-fit model across the three time points.

RESULTS

The EFA for the Group 1 data at the three time points revealed a two-factor model. In the CFA, the two-factor model from Group 1 showed the best fit with the data at the three time points. In the multiple-group CFA for Group 2, we confirmed the configural and metric invariance of the two-factor model across the three time points.

CONCLUSION

Our findings provide evidence for a two-factor structure and weak measurement invariance of the HADS in pregnant Japanese women during the peripartum period.

Identification of Bonding Difficulties in the Peripartum Period Using the Mother-to-Infant Bonding Scale-Japanese Version and Its Tentative Cutoff Points

PURPOSE

Identification of pregnant women with bonding difficulties is important to provide early intervention. However, few studies have examined the utility of self-report questionnaires that assess mother-infant bonding as screening tools for bonding difficulties. This longitudinal study aimed to identify pregnant women with bonding difficulties using the Japanese version of the Mother-to-Infant Bonding Scale (MIBS-J) and to estimate its optimal cutoff points in the peripartum period.

PATIENTS AND METHODS

A total of 1301 pregnant women completed the MIBS-J and Hospital Anxiety and Depression Scale (HADS) at three time points: first trimester (T1; approximately 12-15 weeks gestation), third trimester (T2; approximately 30-34 weeks gestation), and postpartum (T3; approximately 4 weeks postpartum). A two-step cluster analysis was conducted to classify pregnant women based on their MIBS-J subscale scores at the three time points. Based on the cluster analysis results, receiver operating characteristic curve analysis was performed to estimate the optimal cutoff scores for the MIBS-J total score at each time point.

RESULTS

The two-step cluster analysis produced two clusters: Cluster 1 (n = 824) and Cluster 2 (n = 477). Both the MIBS-J and HADS scores were significantly higher in Cluster 2 than in Cluster 1 at all time points. The MIBS-J tentative cutoff points were 3/4, 3/4, and 2/3 at T1, T2, and T3, respectively.

CONCLUSION

We identified two distinct groups across the perinatal period: pregnant women with bonding difficulties and pregnant women with normal bonding. Our findings suggest the usefulness of the MIBS-J as a screening tool to identify bonding difficulties during pregnancy.

Depression, Anxiety and Primiparity are Negatively Associated with Mother-Infant Bonding in Japanese Mothers

PURPOSE

Postpartum depression is a well-known risk factor, and postpartum anxiety and parity are potential risk factors, for mother-infant bonding disorder. However, few studies have focused on the relationships among these factors and mother-infant bonding. This cross-sectional study explored the associations between depression, anxiety and parity, and mother-infant bonding.

MATERIALS AND METHODS

Japanese mothers, both primiparas and multiparas, completed the Mother-to-Infant Bonding Scale (MIBS) and the Hospital Anxiety and Depression Scale (HADS) one month after childbirth. We performed a stepwise multiple regression analysis with the forward selection method to assess the effects of HADS anxiety and depression scores and parity as independent variables on mother-infant bonding as the dependent variable.

RESULTS

A total of 2379 Japanese mothers (1116 primiparas and 1263 multiparas) took part in the study. MIBS score (2.89 ± 2.68 vs 1.60 ± 2.11; p < 0.0001) was significantly higher in primiparas than in multiparas. HADS anxiety (6.55 ± 4.06 vs 4.63 ± 3.41; p < 0.0001) and depression (6.56 ± 3.43 vs 5.98 ± 3.20; p < 0.0001) scores were also significantly higher in primiparas than in multiparas. A stepwise multiple regression analysis with the forward selection method revealed that HADS depression and anxiety scores and parity were significantly associated with MIBS score (p = 0.003, 0.015 and 0.023).

CONCLUSION

Depression, anxiety and primiparity were negatively associated with mother-infant bonding one month after childbirth.

Rare genetic variants in the gene encoding histone lysine demethylase 4C (KDM4C) and their contributions to susceptibility to schizophrenia and autism spectrum disorder

Dysregulation of epigenetic processes involving histone methylation induces neurodevelopmental impairments and has been implicated in schizophrenia (SCZ) and autism spectrum disorder (ASD). Variants in the gene encoding lysine demethylase 4C (KDM4C) have been suggested to confer a risk for such disorders. However, rare genetic variants in KDM4C have not been fully evaluated, and the functional impact of the variants has not been studied using patient-derived cells. In this study, we conducted copy number variant (CNV) analysis in a Japanese sample set (2605 SCZ and 1141 ASD cases, and 2310 controls). We found evidence for significant associations between CNVs in KDM4C and SCZ (p = 0.003) and ASD (p = 0.04). We also observed a significant association between deletions in KDM4C and SCZ (corrected p = 0.04). Next, to explore the contribution of single nucleotide variants in KDM4C, we sequenced the coding exons in a second sample set (370 SCZ and 192 ASD cases) and detected 18 rare missense variants, including p.D160N within the JmjC domain of KDM4C. We, then, performed association analysis for p.D160N in a third sample set (1751 SCZ and 377 ASD cases, and 2276 controls), but did not find a statistical association with these disorders. Immunoblotting analysis using lymphoblastoid cell lines from a case with KDM4C deletion revealed reduced KDM4C protein expression and altered histone methylation patterns. In conclusion, this study strengthens the evidence for associations between KDM4C CNVs and these two disorders and for their potential functional effect on histone methylation patterns.

Rare single-nucleotide DAB1 variants and their contribution to Schizophrenia and autism spectrum disorder susceptibility

Disabled 1 (DAB1) is an intracellular adaptor protein in the Reelin signaling pathway and plays an essential role in correct neuronal migration and layer formation in the developing brain. DAB1 has been repeatedly reported to be associated with neurodevelopmental disorders including schizophrenia (SCZ) and autism spectrum disorders (ASD) in genetic, animal, and postmortem studies. Recently, increasing attention has been given to rare single-nucleotide variants (SNVs) found by deep sequencing of candidate genes. In this study, we performed exon-targeted resequencing of DAB1 in 370 SCZ and 192 ASD patients using next-generation sequencing technology to identify rare SNVs with a minor allele frequency <1%. We detected two rare missense mutations (G382C, V129I) and then performed a genetic association study in a sample comprising 1763 SCZ, 380 ASD, and 2190 healthy control subjects. Although no statistically significant association with the detected mutations was observed for either SCZ or ASD, G382C was found only in the case group, and in silico analyses and in vitro functional assays suggested that G382C alters the function of the DAB1 protein. The rare variants of DAB1 found in the present study should be studied further to elucidate their potential functional relevance to the pathophysiology of SCZ and ASD.

A rare mutation could affect nerve development in the brain, potentially increasing susceptibility to schizophrenia and autism spectrum disorder. Hiroki Kimura of Nagoya University Graduate School of Medicine and colleagues in Japan screened the protein-coding parts of the gene DAB1 in people with schizophrenia or autism for rare nucleotide variations. DAB1 is important for neurodevelopment and synaptic function, and has been associated with neurodevelopmental disorders. Their investigations revealed a mutation that can change the structure and stability of the protein coded by DAB1, potentially increasing susceptibility to neurodevelopmental disorders. The mutation was found in people with schizophrenia and autism, but not in healthy controls. Further research with larger patient samples and investigations on mice engineered to include the mutation could clarify its impact on the pathophysiology of schizophrenia and autism.

Functional characterization of rare NRXN1 variants identified in autism spectrum disorders and schizophrenia

Background

Rare genetic variants contribute to the etiology of both autism spectrum disorder (ASD) and schizophrenia (SCZ). Most genetic studies limit their focus to likely gene-disrupting mutations because they are relatively easier to interpret their effects on the gene product. Interpretation of missense variants is also informative to some pathophysiological mechanisms of these neurodevelopmental disorders; however, their contribution has not been elucidated because of relatively small effects. Therefore, we characterized missense variants detected in NRXN1, a well-known neurodevelopmental disease-causing gene, from individuals with ASD and SCZ.

Methods

To discover rare variants with large effect size and to evaluate their role in the shared etiopathophysiology of ASD and SCZ, we sequenced NRXN1 coding exons with a sample comprising 562 Japanese ASD and SCZ patients, followed by a genetic association analysis in 4273 unrelated individuals. Impact of each missense variant detected here on cell surface expression, interaction with NLGN1, and synaptogenic activity was analyzed using an in vitro functional assay and in silico three-dimensional (3D) structural modeling.

Results

Through mutation screening, we regarded three ultra-rare missense variants (T737M, D772G, and R856W), all of which affected the LNS4 domain of NRXN1α isoform, as disease-associated variants. Diagnosis of individuals with T737M, D772G, and R856W was 1ASD and 1SCZ, 1ASD, and 1SCZ, respectively. We observed the following phenotypic and functional burden caused by each variant. (i) D772G and R856W carriers had more serious social disabilities than T737M carriers. (ii) In vitro assay showed reduced cell surface expression of NRXN1α by D772G and R856W mutations. In vitro functional analysis showed decreased NRXN1α-NLGN1 interaction of T737M and D772G mutants. (iii) In silico 3D structural modeling indicated that T737M and D772G mutations could destabilize the rod-shaped structure of LNS2-LNS5 domains, and D772G and R856W could disturb N-glycan conformations for the transport signal.

Conclusions

The combined data suggest that missense variants in NRXN1 could be associated with phenotypes of neurodevelopmental disorders beyond the diagnosis of ASD and/or SCZ.

Non-Linear Pharmacokinetics of Atomoxetine in Adult Japanese Patients With ADHD

Objective: The objective was to reveal the relationship between dose and concentration of atomoxetine. Method: Fifty-five blood samples of 33 patients with ADHD were examined using high-performance liquid chromatography. Results: The plasma concentrations were 53.2 ± 67.0, 298.0 ± 390.5, and 639.3 ± 831.9 ng/mL at doses of 40 mg, 80 mg, and 120 mg, and the concentration/dose were 1.33 ± 1.67, 3.73 ± 4.88, and 5.33 ± 6.93 ng/mL/mg, respectively. Statistical analyses revealed a significant correlation between the concentration and the dose of atomoxetine (p = .004), and a trending toward significance in the difference in the concentration/dose in the three dosage groups (p = .064). The concentration/dose at 40 and 80 + 120 mg/day were 1.33 ± 1.67 and 4.22 ± 5.53 ng/mL/mg, the latter was significantly higher than the former (p = .006), which suggested non-linear pharmacokinetics. Conclusion: Clinicians should carefully titrate in high dose atomoxetine treatment.

Comparative Analyses of Copy-Number Variation in Autism Spectrum Disorder and Schizophrenia Reveal Etiological Overlap and Biological Insights

Compelling evidence in Caucasian populations suggests a role for copy-number variations (CNVs) in autism spectrum disorder (ASD) and schizophrenia (SCZ). We analyzed 1,108 ASD cases, 2,458 SCZ cases, and 2,095 controls in a Japanese population and confirmed an increased burden of rare exonic CNVs in both disorders. Clinically significant (or pathogenic) CNVs, including those at 29 loci common to both disorders, were found in about 8% of ASD and SCZ cases, which was significantly higher than in controls. Phenotypic analysis revealed an association between clinically significant CNVs and intellectual disability. Gene set analysis showed significant overlap of biological pathways in both disorders including oxidative stress response, lipid metabolism/modification, and genomic integrity. Finally, based on bioinformatics analysis, we identified multiple disease-relevant genes in eight well-known ASD/SCZ-associated CNV loci (e.g., 22q11.2, 3q29). Our findings suggest an etiological overlap of ASD and SCZ and provide biological insights into these disorders.

Rare compound heterozygous missense SPATA7 variations and risk of schizophrenia; whole-exome sequencing in a consanguineous family with affected siblings, follow-up sequencing and a case-control study

PURPOSE

Whole-exome sequencing (WES) of multiplex families is a promising strategy for identifying causative variations for common diseases. To identify rare recessive risk variations for schizophrenia, we performed a WES study in a consanguineous family with affected siblings. We then performed follow-up sequencing of SPATA7 in schizophrenia-affected families. In addition, we performed a case-control study to investigate association between SPATA7 variations and schizophrenia.

PATIENTS AND METHODS

WES was performed on two affected siblings and their unaffected parents, who were second cousins, of a multiplex schizophrenia family. Subsequently, we sequenced the coding region of SPATA7, a potential risk gene identified by the WES analysis, in 142 affected offspring from 137 families for whom parental DNA samples were available. We further tested rare recessive SPATA7 variations, identified by WES and sequencing, for associations with schizophrenia in 2,756 patients and 2,646 controls.

RESULTS

Our WES analysis identified rare compound heterozygous missense SPATA7 variations, p.Asp134Gly and p.Ile332Thr, in both affected siblings. Sequencing SPATA7 coding regions from 137 families identified no rare recessive variations in affected offspring. In the case-control study, we did not detect the rare compound heterozygous SPATA7 missense variations in patients or controls.

CONCLUSION

Our data does not support the role of the rare compound heterozygous SPATA7 missense variations p.Asp134Gly and p.Ile332Thr in conferring a substantial risk of schizophrenia.

Inhibition of RhoA reduces propofol-mediated growth cone collapse, axonal transport impairment, loss of synaptic connectivity, and behavioural deficits

BACKGROUND

Exposure of the developing brain to propofol results in cognitive deficits. Recent data suggest that inhibition of neuronal apoptosis does not prevent cognitive defects, suggesting mechanisms other than neuronal apoptosis play a role in anaesthetic neurotoxicity. Proper neuronal growth during development is dependent upon growth cone morphology and axonal transport. Propofol modulates actin dynamics in developing neurones, causes RhoA-dependent depolymerisation of actin, and reduces dendritic spines and synapses. We hypothesised that RhoA inhibition prevents synaptic loss and subsequent cognitive deficits. The present study tested whether RhoA inhibition with the botulinum toxin C3 (TAT-C3) prevents propofol-induced synapse and neurite loss, and preserves cognitive function.

METHODS

RhoA activation, growth cone morphology, and axonal transport were measured in neonatal rat neurones (5-7 days in vitro) exposed to propofol. Synapse counts (electron microscopy), dendritic arborisation (Golgi-Cox), and network connectivity were measured in mice (age 28 days) previously exposed to propofol at postnatal day 5-7. Memory was assessed in adult mice (age 3 months) previously exposed to propofol at postnatal day 5-7.

RESULTS

Propofol increased RhoA activation, collapsed growth cones, and impaired retrograde axonal transport of quantum dot-labelled brain-derived neurotrophic factor, all of which were prevented with TAT-C3. Adult mice previously treated with propofol had decreased numbers of total hippocampal synapses and presynaptic vesicles, reduced hippocampal dendritic arborisation, and infrapyramidal mossy fibres. These mice also exhibited decreased hippocampal-dependent contextual fear memory recall. All anatomical and behavioural changes were prevented with TAT-C3 pre-treatment.

CONCLUSION

Inhibition of RhoA prevents propofol-mediated hippocampal neurotoxicity and associated cognitive deficits.

Rare loss of function mutations in N-methyl-D-aspartate glutamate receptors and their contributions to schizophrenia susceptibility

In schizophrenia (SCZ) and autism spectrum disorder (ASD), the dysregulation of glutamate transmission through N-methyl-D-aspartate receptors (NMDARs) has been implicated as a potential etiological mechanism. Previous studies have accumulated evidence supporting NMDAR-encoding genes' role in etiology of SCZ and ASD. We performed a screening study for exonic regions of GRIN1, GRIN2A, GRIN2C, GRIN2D, GRIN3A, and GRIN3B, which encode NMDAR subunits, in 562 participates (370 SCZ and 192 ASD). Forty rare variants were identified including 38 missense, 1 frameshift mutation in GRIN2C and 1 splice site mutation in GRIN2D. We conducted in silico analysis for all variants and detected seven missense variants with deleterious prediction. De novo analysis was conducted if pedigree samples were available. The splice site mutation in GRIN2D is predicted to result in intron retention by minigene assay. Furthermore, the frameshift mutation in GRIN2C and splice site mutation in GRIN2D were genotyped in an independent sample set comprising 1877 SCZ cases, 382 ASD cases, and 2040 controls. Both of them were revealed to be singleton. Our study gives evidence in support of the view that ultra-rare variants with loss of function (frameshift, nonsense or splice site) in NMDARs genes may contribute to possible risk of SCZ.

Effects of deep sedation under mechanical ventilation on cognitive outcome in patients undergoing surgery for oral and maxillofacial cancer and microvascular reconstruction

OBJECTIVE

Cognitive impairment after intensive care unit (ICU) admission is becoming increasingly recognized. High-dose deep sedation has been suggested to play an important role in the development of cognitive impairment. However, the impact of heavy sedation as a single cause in the development of cognitive impairment in ICU patients remains unclear. In this study we investigated whether a three-day deep sedation protocol could reduce cognitive function in mechanically ventilated non-critical patients.

DESIGN

A prospective observational study was carried out.

PATIENTS

A total of 17 surgical patients were studied.

INTERVENTION

None.

VARIABLES OF INTEREST

Cognitive function before and after ICU admission.

RESULTS

Thirty-one patients requiring three days of sedation after microvascular reconstruction were initially enrolled in the study. Sedation in the ICU was maintained with propofol and dexmedetomidine combined with fentanyl. Cognitive function was assessed using a battery of 6 neuropsychological tests two days before surgery and three weeks after surgery. Finally, a total of 17 patients were included in the analysis. Cognitive impairment (defined as a decline of >20% from the pre-admission cognitive evaluation scores in at least two of 6 tests) was observed in 5 of the 17 patients (29%). However, there were no significant differences between the pre- and post-admission cognitive evaluations in 6 tests.

CONCLUSIONS

Middle-term cognitive function can be impaired in some patients subjected to deep sedation during several days following maxillary-mandibular oral surgery with microvascular reconstruction.

Rare PDCD11 variations are not associated with risk of schizophrenia in Japan

AIM

Rare gene variations are thought to confer substantial risk for schizophrenia. We performed a three-stage study to identify rare variations that have a strong impact on the risk of developing schizophrenia.

METHODS

In the first stage, we prioritized rare missense variations using whole-exome sequencing (WES) data from three families, consisting of a proband, an affected sibling, and parents. In the second stage, we performed targeted resequencing of the PDCD11 coding region in 96 patients. In the third stage, we conducted an association study of rare PDCD11 variations with schizophrenia in a total of 1357 patients and 1394 controls.

RESULTS

Via WES, we identified two rare missense PDCD11 variations, p.(Asp961Asn) and p.(Val1240Leu), shared by two affected siblings within families. Targeted resequencing of the PDCD11 coding region identified three rare non-synonymous variations: p.(Asp961Asn), p.(Phe1835del), and p.(Arg1837His). The case-control study demonstrated no significant associations between schizophrenia and four rare PDCD11 variations: p.(Asp961Asn), p.(Val1240Leu), p.(Phe1835del), and p.(Arg1837His).

CONCLUSION

Our data do not support the role of rare PDCD11 variations in conferring substantial risk for schizophrenia in the Japanese population.

Rare genetic variants in CX3CR1 and their contribution to the increased risk of schizophrenia and autism spectrum disorders

CX3CR1, a G protein-coupled receptor solely expressed by microglia in the brain, has been repeatedly reported to be associated with neurodevelopmental disorders including schizophrenia (SCZ) and autism spectrum disorders (ASD) in transcriptomic and animal studies but not in genetic studies. To address the impacts of variants in CX3CR1 on neurodevelopmental disorders, we conducted coding exon-targeted resequencing of CX3CR1 in 370 Japanese SCZ and 192 ASD patients using next-generation sequencing technology, followed by a genetic association study in a sample comprising 7054 unrelated individuals (2653 SCZ, 574 ASD and 3827 controls). We then performed in silico three-dimensional (3D) structural modeling and in vivo disruption of Akt phosphorylation to determine the impact of the detected variant on CX3CR1-dependent signal transduction. We detected a statistically significant association between the variant Ala55Thr in CX3CR1 with SCZ and ASD phenotypes (odds ratio=8.3, P=0.020). A 3D structural model indicated that Ala55Thr could destabilize the conformation of the CX3CR1 helix 8 and affect its interaction with a heterotrimeric G protein. In vitro functional analysis showed that the CX3CR1-Ala55Thr mutation inhibited cell signaling induced by fractalkine, the ligand for CX3CR1. The combined data suggested that the variant Ala55Thr in CX3CR1 might result in the disruption of CX3CR1 signaling. Our results strengthen the association between microglia-specific genes and neurodevelopmental disorders.

Rare FBXO18 variations and risk of schizophrenia: Whole-exome sequencing in two parent-affected offspring trios followed by resequencing and case-control studies

AIM

Rare variations are suggested to play a role in the genetic etiology of schizophrenia; to further investigate their role, we performed a three-stage study in a Japanese population.

METHODS

In the first stage, we performed whole-exome sequencing (WES) of two parent-affected offspring trios. In the second stage, we resequenced the FBXO18 coding region in 96 patients. In the third stage, we tested rare non-synonymous FBXO18 variations for association with schizophrenia in two independent populations comprising a total of 1376 patients and 1496 controls.

RESULTS

A rare frameshift variation (L116fsX) in the FBXO18 gene was recurrently identified by WES in both trios. Resequencing FBXO18 coding regions, we detected three rare non-synonymous variations (V15L, L116fsX, and V1006I). However, there were no significant associations between these rare FBXO18 variations and schizophrenia in the case-control study.

CONCLUSION

Our present study does not provide evidence for the contribution of rare non-synonymous FBXO18 variations to the genetic etiology of schizophrenia in the Japanese population. However, to draw a definitive conclusion, further studies should be performed using sufficiently large sample sizes.

Rare UNC13B variations and risk of schizophrenia: Whole-exome sequencing in a multiplex family and follow-up resequencing and a case-control study

Rare genomic variations inherited in multiplex schizophrenia families are suggested to play a role in the genetic etiology of the disease. To identify rare variations with large effects on the risk of developing schizophrenia, we performed whole-exome sequencing (WES) in two affected and one unaffected individual of a multiplex family with 10 affected individuals. We also performed follow-up resequencing of the unc-13 homolog B (Caenorhabditis elegans) (UNC13B) gene, a potential risk gene identified by WES, in the multiplex family and undertook a case-control study to investigate association between UNC13B and schizophrenia. UNC13B coding regions (39 exons) from 15 individuals of the multiplex family and 111 affected offspring for whom parental DNA samples were available were resequenced. Rare missense UNC13B variations identified by resequencing were further tested for association with schizophrenia in two independent case-control populations comprising a total of 1,753 patients and 1,602 controls. A rare missense variation (V1525M) in UNC13B was identified by WES in the multiplex family; this variation was present in five of six affected individuals, but not in eight unaffected individuals or one individual of unknown disease status. Resequencing UNC13B coding regions identified five rare missense variations (T103M, M813T, P1349T, I1362T, and V1525M). In the case-control study, there was no significant association between rare missense UNC13B variations and schizophrenia, although single-variant meta-analysis indicated that M813T was nominally associated with schizophrenia. These results do not support a contribution of rare missense UNC13B variations to the genetic etiology of schizophrenia in the Japanese population. © 2016 Wiley Periodicals, Inc.

Resequencing and Association Analysis of CLN8 with Autism Spectrum Disorder in a Japanese Population

Rare variations contribute substantially to autism spectrum disorder (ASD) liability. We recently performed whole-exome sequencing in two families with affected siblings and then carried out a follow-up study and identified ceroid-lipofuscinosis neuronal 8 (epilepsy, progressive with mental retardation) (CLN8) as a potential genetic risk factor for ASD. To further investigate the role of CLN8 in the genetic etiology of ASD, we performed resequencing and association analysis of CLN8 with ASD in a Japanese population. Resequencing the CLN8 coding region in 256 ASD patients identified five rare missense variations: g.1719291G>A (R24H), rs201670636 (F39L), rs116605307 (R97H), rs143701028 (T108M) and rs138581191 (N152S). These variations were genotyped in 568 patients (including the resequenced 256 patients) and 1017 controls. However, no significant association between these variations and ASD was identified. This study does not support a contribution of rare missense CLN8 variations to ASD susceptibility in the Japanese population.

Whole-exome sequencing in a family with a monozygotic twin pair concordant for autism spectrum disorder and a follow-up study

Two truncating variations (WDR90 V1125fs and EFCAB5 L1210fs), identified by whole-exome sequencing in a family with a monozygotic twin pair concordant for autism spectrum disorder (ASD), were not detected in 257 ASD patients, 677 schizophrenia patients or 667 controls in a follow-up study. Thus, these variations were exclusively identified in the family, suggesting that rare truncating variations may have a role in the genetic etiology of ASD, at least in a subset of ASD patients.

Rare heterozygous truncating variations and risk of autism spectrum disorder: Whole-exome sequencing of a multiplex family and follow-up study in a Japanese population

AIMS

Rare heterozygous truncating variations in multiplex families with autism spectrum disorder (ASD) are suggested to play a major role in the genetic etiology of ASD. To further investigate the role of rare heterozygous truncating variations, we performed whole-exome sequencing (WES) in a multiplex ASD family with four affected individuals (two siblings and two maternal cousins), and a follow-up case-control study in a Japanese population.

METHODS

WES was performed in four individuals (a proband, his affected and unaffected siblings, and their putative carrier mother) from the multiplex ASD family. Rare heterozygous truncating variations prioritized in WES were genotyped in 243 patients and 667 controls.

RESULTS

By WES of the multiplex family, we prioritized two rare heterozygous truncating variations, RPS24 Q191X and CD300LF P261fsX266. However, we did not identify these variations in patients or controls in the follow-up study.

CONCLUSIONS

Our findings suggest that two rare heterozygous truncating variations (RPS24 Q191X and CD300LF P261fsX266) are risk candidates for ASD.

Novel rare missense variations and risk of autism spectrum disorder: whole-exome sequencing in two families with affected siblings and a two-stage follow-up study in a Japanese population

Rare inherited variations in multiplex families with autism spectrum disorder (ASD) are suggested to play a major role in the genetic etiology of ASD. To further investigate the role of rare inherited variations, we performed whole-exome sequencing (WES) in two families, each with three affected siblings. We also performed a two-stage follow-up case-control study in a Japanese population. WES of the six affected siblings identified six novel rare missense variations. Among these variations, CLN8 R24H was inherited in one family by three affected siblings from an affected father and thus co-segregated with ASD. In the first stage of the follow-up study, we genotyped the six novel rare missense variations identified by WES in 241 patients and 667 controls (the Niigata sample). Only CLN8 R24H had higher mutant allele frequencies in patients (1/482) compared with controls (1/1334). In the second stage, this variation was further genotyped, yet was not detected in a sample of 309 patients and 350 controls (the Nagoya sample). In the combined Niigata and Nagoya samples, there was no significant association (odds ratio = 1.8, 95% confidence interval = 0.1–29.6). These results suggest that CLN8 R24H plays a role in the genetic etiology of ASD, at least in a subset of ASD patients.

Resequencing and association analysis of OXTR with autism spectrum disorder in a Japanese population

AIMS

The oxytocin receptor (OXTR) is implicated in the pathophysiology of autism spectrum disorder (ASD). A recent study found a rare non-synonymous OXTR gene variation, rs35062132 (R376G), associated with ASD in a Japanese population. In order to investigate the association between rare non-synonymous OXTR variations and ASD, we resequenced OXTR and performed association analysis with ASD in a Japanese population.

METHODS

We resequenced the OXTR coding region in 213 ASD patients. Rare non-synonymous OXTR variations detected by resequencing were genotyped in 213 patients and 667 controls.

RESULTS

We detected three rare non-synonymous variations: rs35062132 (R376G/C), rs151257822 (G334D), and g.8809426G>T (R150S). However, there was no significant association between these rare non-synonymous variations and ASD.

CONCLUSIONS

Our present study does not support the contribution of rare non-synonymous OXTR variations to ASD susceptibility in the Japanese population.

Altered activity of the primary visual area during gaze processing in individuals with high-functioning autistic spectrum disorder: a magnetoencephalography study

BACKGROUND

Individuals with autistic spectrum disorder (ASD) demonstrate an impaired ability to infer the mental states of others from their gaze. Thus, investigating the relationship between ASD and eye gaze processing is crucial for understanding the neural basis of social impairments seen in individuals with ASD. In addition, characteristics of ASD are observed in more comprehensive visual perception tasks. These visual characteristics of ASD have been well-explained in terms of the atypical relationship between high- and low-level gaze processing in ASD.

METHOD

We studied neural activity during gaze processing in individuals with ASD using magnetoencephalography, with a focus on the relationship between high- and low-level gaze processing both temporally and spatially. Minimum Current Estimate analysis was applied to perform source analysis of magnetic responses to gaze stimuli.

RESULTS

The source analysis showed that later activity in the primary visual area (V1) was affected by gaze direction only in the ASD group. Conversely, the right posterior superior temporal sulcus, which is a brain region that processes gaze as a social signal, in the typically developed group showed a tendency toward greater activation during direct compared with averted gaze processing.

CONCLUSION

These results suggest that later activity in V1 relating to gaze processing is altered or possibly enhanced in high-functioning individuals with ASD, which may underpin the social cognitive impairments in these individuals.

Interleukin 1 beta gene and risk of schizophrenia: detailed case-control and family-based studies and an updated meta-analysis

OBJECTIVE

Interleukin-1 beta (IL-1β) has been implicated in the pathophysiology of schizophrenia. To assess whether the IL1B gene confers increased susceptibility to schizophrenia, we conducted case-control and family-based studies and an updated meta-analysis.

METHODS

We tested the association between IL1B and schizophrenia in 1229 case-control and 112 trio samples using 12 markers, including common tagging single nucleotide variations (SNVs) and a rare non-synonymous variation detected by resequencing the coding regions. We also performed a meta-analysis of rs16944 using a total of 8724 case-control and 201 trio samples from 16 independent populations.

RESULTS

We found no significant associations between any of the 12 SNVs examined and schizophrenia in either case-control or trio samples. Moreover, our meta-analysis results showed no significant association between the common SNV, rs16944, and schizophrenia.

CONCLUSIONS

The present study does not support a role for IL1B in schizophrenia susceptibility.

Neural activity in the posterior superior temporal region during eye contact perception correlates with autistic traits

The present study investigated the relationship between neural activity associated with gaze processing and autistic traits in typically developed subjects using magnetoencephalography. Autistic traits in 24 typically developed college students with normal intelligence were assessed using the Autism Spectrum Quotient (AQ). The Minimum Current Estimates method was applied to estimate the cortical sources of magnetic responses to gaze stimuli. These stimuli consisted of apparent motion of the eyes, displaying direct or averted gaze motion. Results revealed gaze-related brain activations in the 150-250 ms time window in the right posterior superior temporal sulcus (pSTS), and in the 150-450 ms time window in medial prefrontal regions. In addition, the mean amplitude in the 150-250 ms time window in the right pSTS region was modulated by gaze direction, and its activity in response to direct gaze stimuli correlated with AQ score. pSTS activation in response to direct gaze is thought to be related to higher-order social processes. Thus, these results suggest that brain activity linking eye contact and social signals is associated with autistic traits in a typical population.

Resequencing and association analysis of MIR137 with schizophrenia in a Japanese population

MicroRNA may play a role in the pathophysiology of schizophrenia. A recent meta-analysis of genome-wide association studies indicated a significant association between schizophrenia and a common intronic variation in MIR137HG (microRNA 137 host gene) encoding the primary microRNA-137. To explore additional risk variations for schizophrenia, we resequenced MIR137 and performed an association analysis in 1321 Japanese individuals. By resequencing, we detected four sequence variations in the 5' and 3' flanking regions. There were no significant associations between these variations and schizophrenia. Our resequencing and association analysis of MIR137 failed to find additional risk variations for schizophrenia.