Genome-wide association study implicates lipid pathway dysfunction in antipsychotic-induced weight gain: multi-ancestry validation.

Antipsychotic-induced weight gain (AIWG) is a common side effect of antipsychotic medication and may contribute to diabetes and coronary heart disease. To expand the unclear genetic mechanism underlying AIWG, we conducted a two-stage genome-wide association study in Han Chinese patients with schizophrenia. The study included a discovery cohort of 1936 patients and a validation cohort of 534 patients, with an additional 630 multi-ancestry patients from the CATIE study for external validation. We applied Mendelian randomization (MR) analysis to investigate the relationship between AIWG and antipsychotic-induced lipid changes. Our results identified two novel genome-wide significant loci associated with AIWG: rs10422861 in PEPD (P = 1.373 × 10-9) and rs3824417 in PTPRD (P = 3.348 × 10-9) in Chinese Han samples. The association of rs10422861 was validated in the European samples. Fine-mapping and functional annotation revealed that PEPD and PTPRD are potentially causal genes for AIWG, with their proteins being prospective therapeutic targets. Colocalization analysis suggested that AIWG and type 2 diabetes (T2D) shared a causal variant in PEPD. Polygenic risk scores (PRSs) for AIWG and T2D significantly predicted AIWG in multi-ancestry samples. Furthermore, MR revealed a risky causal effect of genetically predicted changes in low-density lipoprotein cholesterol (P = 7.58 × 10-4) and triglycerides (P = 2.06 × 10-3) caused by acute-phase of antipsychotic treatment on AIWG, which had not been previously reported. Our model, incorporating antipsychotic-induced lipid changes, PRSs, and clinical predictors, significantly predicted BMI percentage change after 6-month antipsychotic treatment (AUC = 0.79, R2 = 0.332). Our results highlight that the mechanism of AIWG involves lipid pathway dysfunction and may share a genetic basis with T2D through PEPD. Overall, this study provides new insights into the pathogenesis of AIWG and contributes to personalized treatment of schizophrenia.

Two subtypes of schizophrenia identified by an individual-level atypical pattern of tensor-based morphometric measurement.

Difficulties in parsing the multiaspect heterogeneity of schizophrenia (SCZ) based on current nosology highlight the need to subtype SCZ using objective biomarkers. Here, utilizing a large-scale multisite SCZ dataset, we identified and validated 2 neuroanatomical subtypes with individual-level abnormal patterns of the tensor-based morphometric measurement. Remarkably, compared with subtype 1, which showed moderate deficits of some subcortical nuclei and an enlarged striatum and cerebellum, subtype 2, which showed cerebellar atrophy and more severe subcortical nuclei atrophy, had a higher subscale score of negative symptoms, which is considered to be a core aspect of SCZ and is associated with functional outcome. Moreover, with the neuroimaging-clinic association analysis, we explored the detailed relationship between the heterogeneity of clinical symptoms and the heterogeneous abnormal neuroanatomical patterns with respect to the 2 subtypes. And the neuroimaging-transcription association analysis highlighted several potential heterogeneous biological factors that may underlie the subtypes. Our work provided an effective framework for investigating the heterogeneity of SCZ from multilevel aspects and may provide new insights for precision psychiatry.

GFAP hyperpalmitoylation exacerbates astrogliosis and neurodegenerative pathology in PPT1-deficient mice.

The homeostasis of protein palmitoylation and depalmitoylation is essential for proper physiological functions in various tissues, in particular the central nervous system (CNS). The dysfunction of PPT1 (PPT1-KI, infantile neuronal ceroid lipofuscinosis [INCL] mouse model), which catalyze the depalmitoylation process, results in serious neurodegeneration accompanied by severe astrogliosis in the brain. Endeavoring to determine critical factors that might account for the pathogenesis in CNS by palm-proteomics, glial fibrillary acidic protein (GFAP) was spotted, indicating that GFAP is probably palmitoylated. Questions concerning if GFAP is indeed palmitoylated in vivo and how palmitoylation of GFAP might participate in neural pathology remain unexplored and are waiting to be investigated. Here we show that GFAP is readily palmitoylated in vitro and in vivo; specifically, cysteine-291 is the unique palmitoylated residue in GFAP. Interestingly, it was found that palmitoylated GFAP promotes astrocyte proliferation in vitro. Furthermore, we showed that PPT1 depalmitoylates GFAP, and the level of palmitoylated GFAP is overwhelmingly up-regulated in PPT1-knockin mice, which lead us to speculate that the elevated level of palmitoylated GFAP might accelerate astrocyte proliferation in vivo and ultimately led to astrogliosis in INCL. Indeed, blocking palmitoylation by mutating cysteine-291 into alanine in GFAP attenuate astrogliosis, and remarkably, the concurrent neurodegenerative pathology in PPT1-knockin mice. Together, these findings demonstrate that hyperpalmitoylated GFAP plays critical roles in regulating the pathogenesis of astrogliosis and neurodegeneration in the CNS, and most importantly, pinpointing that cysteine-291 in GFAP might be a valuable pharmaceutical target for treating INCL and other potential neurodegenerative diseases.

Proteome-wide Mendelian randomization reveals the causal effects of immune-related plasma proteins on psychiatric disorders.

Immune dysregulation has been consistently reported in psychiatric disorders, however, the causes and mechanisms underlying immune dysregulation in psychiatric disorders remain largely unclear. Here we conduct a Mendelian randomization study by integrating plasma proteome and GWASs of schizophrenia, bipolar disorder and depression. The primate-specific immune-related protein BTN3A3 showed the most significant associations with all three psychiatric disorders. In addition, other immune-related proteins, including AIF1, FOXO3, IRF3, CFHR4, IGLON5, FKBP2, and PI3, also showed significant associations with psychiatric disorders. Our study showed that a proportion of psychiatric risk variants may contribute to disease risk by regulating immune-related plasma proteins, providing direct evidence that connect the genetic risk of psychiatric disorders to immune system.

Functional variant rs2270363 on 16p13.3 confers schizophrenia risk by regulating NMRAL1.

Recent genome-wide association studies have reported multiple schizophrenia risk loci, yet the functional variants and their roles in schizophrenia remain to be characterized. Here we identify a functional single nucleotide polymorphism (rs2270363: G>A) at the schizophrenia risk locus 16p13.3. rs2270363 lies in the E-box element of the promoter of NMRAL1 and disrupts binding of the basic helix-loop-helix leucine zipper family proteins, including USF1, MAX and MXI1. We validated the regulatory effects of rs2270363 using reporter gene assays and electrophoretic mobility shift assay. Besides, expression quantitative trait loci analysis showed that the risk allele (A) of rs2270363 was significantly associated with elevated NMRAL1 expression in the human brain. Transcription factors knockdown and CRISPR-Cas9-mediated editing further confirmed the regulatory effects of the genomic region containing rs2270363 on NMRAL1. Intriguingly, NMRAL1 was significantly downregulated in the brain of schizophrenia patients compared with healthy subjects, and knockdown of Nmral1 expression affected proliferation and differentiation of mouse neural stem cells, as well as genes and pathways associated with brain development and synaptic transmission. Of note, Nmral1 knockdown resulted in significant decrease of dendritic spine density, revealing the potential pathophysiological mechanisms of NMRAL1 in schizophrenia. Finally, we independently confirmed the association between rs2270363 and schizophrenia in the Chinese population and found that the risk allele of rs2270363 was the same in European and Chinese populations. These lines of evidence suggest that rs2270363 may confer schizophrenia risk by regulating NMRAL1, a gene whose expression dysregulation might be involved in the pathogenesis of schizophrenia by affecting neurodevelopment and synaptic plasticity.

Association of CTNND2 gene polymorphism with schizophrenia: Two-sample case-control study in Chinese Han population.

OBJECTIVES: Genetic factors play an important role in the etiology of schizophrenia (SZ). Catenin Delta 2 (CTNND2) is one of the genes regulating neuronal development in the brain. It is unclear whether CTNND2 is involved in SZ. With the hypothesis that CTNND2 may be a risk gene for SZ, we performed a case-control association analysis to investigate if CTNND2 gene single nucleotide polymorphisms (SNPs) are implicated in SZ in a Han Chinese population. MATERIALS AND METHODS: We recruited subjects from 2010 to 2022 from the Han population of northern Henan and divided them into two case-control samples, including a discovery sample (SZ = 528 and controls = 528) and replication sample (SZ = 2458 and controls = 6914). Twenty-one SNPs were genotyped on the Illumina BeadStation 500G platform using GoldenGate technology and analyzed by PLINK. The Positive and Negative Syndrome Scale (PANSS) was used to assess clinical symptoms. RESULTS: Rs16901943, rs7733427, and rs2168878 SNPs were associated with SZ (Chi2 = 7.484, 11.576, and 5.391, respectively, df = 1; p = 0.006, 0.00067, and 0.02, respectively) in the two samples. Rs10058868 was associated with SZ in male patients in the discovery sample (Chi2 = 6.264, df = 1, p = .044). Only the relationship with rs7733427 survived Bonferroni correction. Linkage disequilibrium block three haplotypes were associated with SZ in the discovery and total sample. PANSS analysis of the four SNPs implicated rs10058868 and rs2168878 in symptoms of depression and excitement, respectively, in the patients with SZ. CONCLUSION: Four SNPs of the CTNND2 gene were identified as being correlated with SZ. This gene may be involved in susceptibility to SZ.

Consistent brain structural abnormalities and multisite individualised classification of schizophrenia using deep neural networks.

BACKGROUND: Previous analyses of grey and white matter volumes have reported that schizophrenia is associated with structural changes. Deep learning is a data-driven approach that can capture highly compact hierarchical non-linear relationships among high-dimensional features, and therefore can facilitate the development of clinical tools for making a more accurate and earlier diagnosis of schizophrenia. AIMS: To identify consistent grey matter abnormalities in patients with schizophrenia, 662 people with schizophrenia and 613 healthy controls were recruited from eight centres across China, and the data from these independent sites were used to validate deep-learning classifiers. METHOD: We used a prospective image-based meta-analysis of whole-brain voxel-based morphometry. We also automatically differentiated patients with schizophrenia from healthy controls using combined grey matter, white matter and cerebrospinal fluid volumetric features, incorporated a deep neural network approach on an individual basis, and tested the generalisability of the classification models using independent validation sites. RESULTS: We found that statistically reliable schizophrenia-related grey matter abnormalities primarily occurred in regions that included the superior temporal gyrus extending to the temporal pole, insular cortex, orbital and middle frontal cortices, middle cingulum and thalamus. Evaluated using leave-one-site-out cross-validation, the performance of the classification of schizophrenia achieved by our findings from eight independent research sites were: accuracy, 77.19-85.74%; sensitivity, 75.31-89.29% and area under the receiver operating characteristic curve, 0.797-0.909. CONCLUSIONS: These results suggest that, by using deep-learning techniques, multidimensional neuroanatomical changes in schizophrenia are capable of robustly discriminating patients with schizophrenia from healthy controls, findings which could facilitate clinical diagnosis and treatment in schizophrenia.

A missense variant in NDUFA6 confers schizophrenia risk by affecting YY1 binding and NAGA expression.

Genome-wide association studies (GWASs) have revealed that genetic variants at the 22q13.2 risk locus were robustly associated with schizophrenia. However, the causal variants at this risk locus and their roles in schizophrenia remain elusive. Here we identify the risk missense variant rs1801311 (located in the 1st exon of NDUFA6 gene) as likely causal for schizophrenia at 22q13.2 by disrupting binding of YY1, TAF1, and POLR2A. We systematically elucidated the regulatory mechanisms of rs1801311 and validated the regulatory effect of this missense variant. Intriguingly, rs1801311 physically interacted with NAGA (encodes the alpha-N-acetylgalactosaminidase, which is mainly involved in regulating metabolisms of glycoproteins and glycolipids in lysosome) and showed the most significant association with NAGA expression in the human brain, with the risk allele (G) associated with higher NAGA expression. Consistent with eQTL analysis, expression analysis showed that NAGA was significantly upregulated in brains of schizophrenia cases compared with controls, further supporting that rs1801311 may confer schizophrenia risk by regulating NAGA expression. Of note, we found that NAGA regulates important neurodevelopmental processes, including proliferation and differentiation of neural stem cells. Transcriptome analysis corroborated that NAGA regulates pathways associated with neuronal differentiation. Finally, we independently confirmed the association between rs1801311 and schizophrenia in a large Chinese cohort. Our study elucidates the regulatory mechanisms of the missense schizophrenia risk variant rs1801311 and provides mechanistic links between risk variant and schizophrenia etiology. In addition, this study also revealed the novel role of coding variants in gene regulation and schizophrenia risk, i.e., genetic variant in coding region of a specific gene may confer disease risk through regulating distal genes (act as regulatory variant for distal genes).

Convergent lines of evidence support NOTCH4 as a schizophrenia risk gene.

The association between NOTCH4 and schizophrenia has been repeatedly reported. However, the results from different genetic studies are inconsistent, and the role of NOTCH4 in schizophrenia pathogenesis remains unknown. Here, we provide convergent lines of evidence that support NOTCH4 as a schizophrenia risk gene. We first performed a meta-analysis and found that a genetic variant (rs2071287) in NOTCH4 was significantly associated with schizophrenia (a total of 125 848 subjects, p=8.31×10-17), with the same risk allele across all tested samples. Expression quantitative trait loci (eQTL) analysis showed that rs2071287 was significantly associated with NOTCH4 expression (p=1.08×10-14) in human brain tissues, suggesting that rs2071287 may confer schizophrenia risk through regulating NOTCH4 expression. Sherlock integrative analysis using a large-scale schizophrenia GWAS and eQTL data from human brain tissues further revealed that NOTCH4 was significantly associated with schizophrenia (p=4.03×10-7 in CMC dataset and p=3.06×10-6 in xQTL dataset), implying that genetic variants confer schizophrenia risk through modulating NOTCH4 expression. Consistently, we found that NOTCH4 was significantly downregulated in brains of schizophrenia patients compared with controls (p=2.53×10-3), further suggesting that dysregulation of NOTCH4 may have a role in schizophrenia. Finally, we showed that NOTCH4 regulates proliferation, self-renewal, differentiation and migration of neural stem cells, suggesting that NOTCH4 may confer schizophrenia risk through affecting neurodevelopment. Our study provides convergent lines of evidence that support the involvement of NOTCH4 in schizophrenia. In addition, our study also elucidates a possible mechanism for the role of NOTCH4 in schizophrenia pathogenesis.

Progressive Changes in Brain Regional Homogeneity Induced by Electroconvulsive Therapy Among Patients With Schizophrenia.

OBJECTIVES: Electroconvulsive therapy (ECT) has significant effects on improving psychotic symptoms in schizophrenia (SZ), but the changes of brain function induced by it are unclear. The purpose of the study was to explore progressive ECT-induced changes in regional homogeneity (ReHo) at multiple time points before, during, and after a course of ECT. METHODS: The 27 in-patients with SZ (SZ group) who met the recruitment criteria accepted clinical evaluations and resting-state functional magnetic resonance imaging scans before the first ECT (pre-ECT), after the first ECT (ECT1), and after the eighth ECT (ECT8), all conducted within 10 to 12 hours. Forty-three healthy controls (HCs; HC group) who matched well with the patients for age, sex, and years of education were recruited. For Positive and Negative Syndrome Scale (PANSS) and ReHo, progressive changes were examined. RESULTS: Pair-wise comparisons of patient pre-ECT, ECT1, and ECT8 ReHo values with HC ReHo values revealed that ECT normalized the ReHo values in bilateral superior occipital gyrus (SOG), right lingual gyrus (LG), left medial prefrontal cortex. Furthermore, improved ReHo in bilateral SOG and right LG appeared after the first ECT application. The ReHo values in right middle occipital gyrus, right middle temporal gyrus, and right inferior parietal lobule were not significantly altered by ECT. The total PANSS score was lower even after the first ECT application (mean ΔPANSSECT1, 11.7%; range, 2%-32.8%) and markedly reduced after the eighth application (mean ΔPANSSECT8, 86.3%; range, 72.5%-97.9%). CONCLUSIONS: The antipsychotic effects of ECT may be achieved through regulating synchronization of some regions such as bilateral SOG, right LG, and left medial prefrontal cortex. Furthermore, the enhanced synchronizations also take place in other regions.

Genome-wide association study followed by trans-ancestry meta-analysis identify 17 new risk loci for schizophrenia.

BACKGROUND: Over 200 schizophrenia risk loci have been identified by genome-wide association studies (GWASs). However, the majority of risk loci were identified in populations of European ancestry (EUR), potentially missing important biological insights. It is important to perform 5 GWASs in non-European populations. METHODS: To identify novel schizophrenia risk loci, we conducted a GWAS in Han Chinese population (3493 cases and 4709 controls). We then performed a large-scale meta-analysis (a total of 143,438 subjects) through combining our results with previous GWASs conducted in EAS and EUR. In addition, we also carried out comprehensive post-GWAS analysis, including heritability partitioning, enrichment of schizophrenia associations in tissues and cell types, trancscriptome-wide association study (TWAS), expression quantitative trait loci (eQTL) and differential expression analysis. RESULTS: We identified two new schizophrenia risk loci, including associations in SHISA9 (rs7192086, P = 4.92 × 10-08) and PES1 (rs57016637, P = 2.33 × 10-11) in Han Chinese population. A fixed-effect meta-analysis (a total of 143,438 subjects) with summary statistics from EAS and EUR identifies 15 novel genome-wide significant risk loci. Heritability partitioning with linkage disequilibrium score regression (LDSC) reveals a significant enrichment of schizophrenia heritability in conserved genomic regions, promoters, and enhancers. Tissue and cell-type enrichment analyses show that schizophrenia associations are significantly enriched in human brain tissues and several types of neurons, including cerebellum neurons, telencephalon inhibitory, and excitatory neurons. Polygenic risk score profiling reveals that GWAS summary statistics from trans-ancestry meta-analysis (EAS + EUR) improves prediction performance in predicting the case/control status of our sample. Finally, transcriptome-wide association study (TWAS) identifies risk genes whose cis-regulated expression change may have a role in schizophrenia. CONCLUSIONS: Our study identifies 17 novel schizophrenia risk loci and highlights the importance and necessity of conducting genetic study in different populations. These findings not only provide new insights into genetic etiology of schizophrenia, but also facilitate to delineate the pathophysiology of schizophrenia and develop new therapeutic targets.

Chronic developmental exposure to low-dose ([C8mim][PF6]) induces neurotoxicity and behavioural abnormalities in rats.

Ionic liquids (ILs) are widely used for their physical and chemical properties. Toxicological assessments of ILs could help to avoid their threat to human health, but these are rarely reported, and no assessments of IL neurotoxicity in mammals have been performed. Here, we aimed to evaluate the neurotoxicity of chronic 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim][PF6]) (0, 1 mg/kg) exposure during development on rats. Our results indicated that chronic exposure to low-dose ([C8mim][PF6]) induces behavioural abnormalities, including cognitive deficits, social communication disorders, and sensory gating function impairment. Moreover, rats subjected to chronic ([C8mim][PF6]) exposure showed hypofunction of glutamatergic excitatory synapses, including increased expression of NMDA receptor subunits, increased density and immaturity of dendritic spines, and increased expression of PSD95. Additionally, ([C8mim][PF6]) exposure resulted in hippocampal-specific inflammatory activation, indicated by increased levels of proinflammatory factors, elevated nuclear localisation of NF-κB, and activation of microglia and astrocytes. In conclusion, chronic exposure to low-dose ([C8mim][PF6]) induced neurotoxicity, including damage to glutamatergic excitatory synapses and inflammatory activation, which may illuminate the associated behavioural abnormalities. The results presented here may be helpful for the safe use of ILs in the future.

Polygenic effects of schizophrenia on hippocampal grey matter volume and hippocampus-medial prefrontal cortex functional connectivity.

BACKGROUND: Schizophrenia is a complex mental disorder with high heritability and polygenic inheritance. Multimodal neuroimaging studies have also indicated that abnormalities of brain structure and function are a plausible neurobiological characterisation of schizophrenia. However, the polygenic effects of schizophrenia on these imaging endophenotypes have not yet been fully elucidated. AIMS: To investigate the effects of polygenic risk for schizophrenia on the brain grey matter volume and functional connectivity, which are disrupted in schizophrenia. METHOD: Genomic and neuroimaging data from a large sample of Han Chinese patients with schizophrenia (N = 509) and healthy controls (N = 502) were included in this study. We examined grey matter volume and functional connectivity via structural and functional magnetic resonance imaging, respectively. Using the data from a recent meta-analysis of a genome-wide association study that comprised a large number of Chinese people, we calculated a polygenic risk score (PGRS) for each participant. RESULTS: The imaging genetic analysis revealed that the individual PGRS showed a significantly negative correlation with the hippocampal grey matter volume and hippocampus-medial prefrontal cortex functional connectivity, both of which were lower in the people with schizophrenia than in the controls. We also found that the observed neuroimaging measures showed weak but similar changes in unaffected first-degree relatives of patients with schizophrenia. CONCLUSIONS: These findings suggested that genetically influenced brain grey matter volume and functional connectivity may provide important clues for understanding the pathological mechanisms of schizophrenia and for the early diagnosis of schizophrenia.

Age-related changes in neuroinflammation and prepulse inhibition in offspring of rats treated with Poly I:C in early gestation.

BACKGROUND: Maternal immune activation (MIA) during gestation can increase the later risk of schizophrenia in adult offspring. Neuroinflammation is believed to underlie this process. Postmortem brain studies have found changes in the neuroimmune systems of patients with schizophrenia. However, little is known about the dynamic changes in cerebral inflammation and behavior during the course of the disease. METHODS: Here, the prepulse inhibition (PPI) test was conducted in adolescent and adult Sprague-Dawley rats prenatally challenged with polyriboinosinic-polyribocytidylic acid (Poly I:C) on gestational day 9 to determine the behavioral trajectory triggered by early exposure to Poly I:C. Brain immune changes were determined in the prefrontal cortex (PFC) and hippocampus (HC) at both ages. The status of the microglia and astrocytes was determined with immunohistochemical staining. The levels of IL-6, IL-1ß, and TNF-α in both brain regions were evaluated with enzyme-linked immunosorbent assays. RESULTS: Disrupted PPI, the core phenotype of schizophrenia, only emerged in adulthood. Behavioral changes during puberty and adulthood were both accompanied by the activation of microglia (PFC and HC). Astrocytes were only activated at PN60. The levels of proinflammatory cytokines (IL-1ß, IL-6, and TNF-α) in the offspring of the Poly I:C-exposed mothers differed with brain region and time, with more cytokines elevated during periadolescence than during adulthood. CONCLUSIONS: Our findings indicate that immune activation emerged before symptom manifestation in the offspring of MIA rats. We conclude that early prenatal Poly I:C challenge can lead to age-related behavioral and neuroinflammatory changes. These data provide new insight into the neuroinflammatory and neuropathological mechanisms underlying the development of schizophrenia. They also suggest that periadolescence could be more important than adulthood in the prevention and treatment of schizophrenia.

Association of SYNE1 locus with bipolar disorder in Chinese population.

OBJECTIVES: Genome-wide association studies (GWAS) suggest that rs9371601 in the SYNE1 gene is a risk SNP for bipolar disorder (BPD) in populations of European ancestry, but further replication analyses across distinct populations are needed. METHODS: We analyzed the association between rs9371601 and BPD in a Han Chinese sample of 1315 BPD cases and 1956 controls. RESULTS: We observed a significant association between rs9371601 and BPD in Han Chinese (p = 0.0121, OR = 0.859). However, further examinations revealed that the Europeans and Chinese subjects had different BPD risk alleles at the locus. We then found that rs9371601 had different "minor alleles" and distinct linkage disequilibrium (LD) patterns surrounding itself in Europeans and Han Chinese, which might be the explanation of the observed inconsistent association signals for this locus in different populations. Our explorative analyses of the biological impact of rs9371601 suggested that this SNP was significantly associated with the methylation of a CpG site (cg01844274, p = 5.05⨯10- 6) within SYNE1 in human dorsal lateral prefrontal cortex (DLPFC) tissues. CONCLUSIONS: Our data confirms the association between rs9371601 and BPD, but the underlying biological mechanism remains to be fully elucidated in further studies.

Decreased Resting-State Interhemispheric Functional Connectivity Correlated with Neurocognitive Deficits in Drug-Naive First-Episode Adolescent-Onset Schizophrenia.

Background: Given that adolescence is a critical epoch in the onset of schizophrenia, studying aberrant brain changes in adolescent-onset schizophrenia, particularly in patients with drug-naive first-episode schizophrenia, is important to understand the biological mechanism of this disorder. Previous resting-state functional magnetic resonance imaging studies have shown abnormal functional connectivity in separate hemispheres in patients with adult-onset schizophrenia. Our aim to study adolescent-onset schizophrenia can provide clues for the early aetiology of schizophrenia. Method: A total of 48 drug-naïve, first-episode, adolescent-onset schizophrenia outpatients and 31 healthy controls underwent resting-state functional magnetic resonance imaging scans. Data were subjected to voxel-mirrored homotopic connectivity and support vector machine analyses. Results: Compared with the healthy controls, the adolescent-onset schizophrenia group showed significantly lower voxel-mirrored homotopic connectivity values in different brain regions, including the fusiform gyrus, superior temporal gyrus/insula, precentral gyrus, and precuneus. Decreased voxel-mirrored homotopic connectivity values in the superior temporal gyrus/insula were significantly correlated with Trail-Making Test: Part A performance (r = -0.437, P = .002). A combination of the voxel-mirrored homotopic connectivity values in the precentral gyrus and precuneus may be used to discriminate patients with adolescent-onset schizophrenia from controls with satisfactory classification results, which showed sensitivity of 100%, specificity of 87.09%, and accuracy of 94.93%. Conclusion: Our findings highlight resting-state interhemispheric FC abnormalities within the sensorimotor network of patients with adolescent-onset schizophrenia and confirm the relationship between adolescent-onset schizophrenia and adult-onset schizophrenia. These findings suggest that reduced interhemispheric connectivity within the sensorimotor network has a pivotal role in the pathogenesis of schizophrenia.

Association between cerebral dopamine neurotrophic factor (CDNF) 2 polymorphisms and schizophrenia susceptibility and symptoms in the Han Chinese population.

BACKGROUND: Schizophrenia (SZ) is a complex polygenic psychiatric disorder caused in part by abnormal dopamine levels. Cerebral dopamine neurotrophic factor (CDNF) 2 is known to protect and repair the dopaminergic system. Dopamine dysfunction is one of the pathogenesis of SZ. However, the relationship between CDNF2 and SZ has not been previously investigated. We speculated that CDNF2 may be a susceptibility factor for SZ. METHODS: To address this issue, we carried out a study to investigate the association between CDNF2 and SZ in the total sample 1371 (670 SZ patients and 701 healthy controls) Han Chinese population. Stage 1 included 528 SZ patients and 528 healthy controls; and stage 2 included 142 SZ patients and 173 healthy controls. The allele and genotype frequencies of five single nucleotide polymorphisms (rs2577074, rs2577075, rs2249810, rs6506891, and rs2118343) of CDNF2 were compared between patients and controls. RESULTS: We found a significant association in allele and genotype frequencies between the two groups at rs2249810 (χ2 = 4.38 and 6.45, respectively; P = 0.03 and 0.04, respectively). An association was also observed in males at rs2249810 (χ2 = 8.76; P = 0.03). Haplotype TGATC differed between SZ and controls in stage 2 samples (χ2 = 6.38; P = 0.01), and rs2118343 genotypes were associated with negative factor scores (F = 4.396; P = 0.01). CONCLUSIONS: These results suggest that rs2249810 and haplotype TGATC of CDNF2 are an SZ susceptibility locus and factor, respectively, and that rs2118343 genotypes are associated with negative symptoms of SZ in the Han Chinese population.

Abnormal functional connectivity strength in patients with adolescent-onset schizophrenia: a resting-state fMRI study.

Structural and functional abnormalities were reported in the brain of patients with adolescent-onset schizophrenia (AOS). However, evidence of abnormal functional connectivity of the brain in AOS patients is limited. Thus, we analyzed the resting-state functional magnetic resonance scans of 48 drug-naive AOS patients and 31 healthy controls to determine their functional connectivity strength (FCS) and examined if FCS abnormalities were correlated with clinical characteristics. Compared with healthy controls, AOS patients showed significantly increased FCS in the left cerebellum VI and right inferior frontal gyrus/insula. A positive correlation was observed between FCS values in the right inferior frontal gyrus/insula and general psychopathology scores of positive and negative syndrome scale. Results suggest that functional connectivity pattern is disrupted in drug-naive AOS patients. The FCS values in this abnormal region have potential for evaluating the disease severity.

A2BP1 gene polymorphisms association with olanzapine-induced weight gain.

The ataxin-2 binding protein 1 (A2BP1) gene is reported to be one of the susceptibility genes in schizophrenia, autism, and obesity. The aim of this study was to explore the association of A2BP1 gene polymorphisms with antipsychotic induced weight gain (AIWG) in Chinese Han population. Three hundred and twenty-eight patients with schizophrenia were followed-up for an 8-week period of treatment with olanzapine. The fasting weights of 328 patients were measured before and after the 8-week course of treatment. Four single nucleotide polymorphisms (SNPs: rs8048076, rs1478697, rs10500331, and rs4786847) of the A2BP1 gene were genotyped by polymerase chain reaction (PCR). We analyzed putative association of A2BP1 polymorphisms with AIWG of olanzapine using linear regression analysis and found that SNP rs1478697 was significantly associated with AIWG caused by olanzapine (p=0.0012; Bonferroni corrected p=0.0048). The association was replicated in another independent sample including 208 first-episode and drug-naïve patients presenting with schizophrenia after a 4-week treatment with olanzapine (p=0.0092; Bonferroni corrected p=0.0368; meta p=5.33×10(-5)). To explore the biological plausibility of A2BP1 in the pathogenesis of AIWG, we made expression analyses and eQTL analyses; these analyses showed that A2BP1 was highly expressed in whole brain tissues using the HBT database, and that rs1478697 has an expression quantitative trait locus effect in human cerebellar cortex tissues using the BRAINEAC database (p=2.50E-04). In conclusion, the rs1478697 in A2BP1 may be associated with AIWG induced by 8-week treatment with olanzapine.