Genome-wide association study identifies 30 obsessive-compulsive disorder associated loci

Obsessive-compulsive disorder (OCD) affects ∼1% of the population and exhibits a high SNP-heritability, yet previous genome-wide association studies (GWAS) have provided limited information on the genetic etiology and underlying biological mechanisms of the disorder. We conducted a GWAS meta-analysis combining 53,660 OCD cases and 2,044,417 controls from 28 European-ancestry cohorts revealing 30 independent genome-wide significant SNPs and a SNP-based heritability of 6.7%. Separate GWAS for clinical, biobank, comorbid, and self-report sub-groups found no evidence of sample ascertainment impacting our results. Functional and positional QTL gene-based approaches identified 249 significant candidate risk genes for OCD, of which 25 were identified as putatively causal, highlighting WDR6, DALRD3, CTNND1 and genes in the MHC region. Tissue and single-cell enrichment analyses highlighted hippocampal and cortical excitatory neurons, along with D1- and D2-type dopamine receptor-containing medium spiny neurons, as playing a role in OCD risk. OCD displayed significant genetic correlations with 65 out of 112 examined phenotypes. Notably, it showed positive genetic correlations with all included psychiatric phenotypes, in particular anxiety, depression, anorexia nervosa, and Tourette syndrome, and negative correlations with a subset of the included autoimmune disorders, educational attainment, and body mass index.. This study marks a significant step toward unraveling its genetic landscape and advances understanding of OCD genetics, providing a foundation for future interventions to address this debilitating disorder.

Genome-wide association study identifies new loci associated with OCD

To date, four genome-wide association studies (GWAS) of obsessive-compulsive disorder (OCD) have been published, reporting a high single-nucleotide polymorphism (SNP)-heritability of 28% but finding only one significant SNP. A substantial increase in sample size will likely lead to further identification of SNPs, genes, and biological pathways mediating the susceptibility to OCD. We conducted a GWAS meta-analysis with a 2-3-fold increase in case sample size (OCD cases: N = 37,015, controls: N = 948,616) compared to the last OCD GWAS, including six previously published cohorts (OCGAS, IOCDF-GC, IOCDF-GC-trio, NORDiC-nor, NORDiC-swe, and iPSYCH) and unpublished self-report data from 23andMe Inc. We explored the genetic architecture of OCD by conducting gene-based tests, tissue and celltype enrichment analyses, and estimating heritability and genetic correlations with 74 phenotypes. To examine a potential heterogeneity in our data, we conducted multivariable GWASs with MTAG. We found support for 15 independent genome-wide significant loci (14 new) and 79 protein-coding genes. Tissue enrichment analyses implicate multiple cortical regions, the amygdala, and hypothalamus, while cell type analyses yielded 12 cell types linked to OCD (all neurons). The SNP-based heritability of OCD was estimated to be 0.08. Using MTAG we found evidence for specific genetic underpinnings characteristic of different cohort-ascertainment and identified additional significant SNPs. OCD was genetically correlated with 40 disorders or traits-positively with all psychiatric disorders and negatively with BMI, age at first birth and multiple autoimmune diseases. The GWAS meta-analysis identified several biologically informative genes as important contributors to the aetiology of OCD. Overall, we have begun laying the groundwork through which the biology of OCD will be understood and described.

Autonomic responses during gambling: the effect of outcome type and sex in a large community sample of young adults

Introduction

Autonomic arousal is believed to be an underlying reinforcer for problematic gambling behavior. Theories suggests that near-misses (outcomes falling just short of a true win) are structural characteristics affecting emotion and motivation while increasing gambling persistence.

Objectives

Psychophysiological responses to different outcomes in gambling were investigated in a community-based sample of young adults. Furthermore, sex differences in responses to different gambling outcomes were investigated.

Methods

Young adults (n=270) performed a simplified virtual slot machine producing wins, two types of near-misses (before/after payline) and full-misses, with simultaneous measurements of heart rate (HR) and skin conductance responses (SCR). Self-reports of perceived chance of winning, pleasure and motivation to play were given by the participants on each trial.

Results

Near-misses were associated with the largest HR acceleration compared to wins and full-misses, and larger HR deceleration and SCRs compared to full-misses. Differential autonomic and subjective reports were observed for near-misses subtypes, suggesting that near-misses are processed differently depending on their position before or after payline. Females showed larger SCR responses and increased motivation following wins compared to males.

Conclusions

Slot machine gambling outcomes elicit differential physiological and subjective responses in young adults. Specifically, near-misses produce larger autonomic responses compared to regular full-misses. However, near-misses are complex, multifaceted events producing various emotional responses depending on their characterization. Males and females respond differently to wins, highlighting the importance of considering sex differences in experimental research on autonomic responses in gambling.

Disclosure

No significant relationships.

Lack of Support for the Genes by Early Environment Interaction Hypothesis in the Pathogenesis of Schizophrenia

Ursini et al reported recently that the liability of schizophrenia explained by a polygenic risk score (PRS) derived from the variants most associated with schizophrenia was increased 5-fold in individuals who experienced complications during pregnancy or birth. Follow-up gene expression analysis showed that the genes mapping to the most associated genetic variants are highly expressed in placental tissues. If confirmed, these findings will have major implications in our understanding of the joint effect of genes and environment in the pathogenesis of schizophrenia. We examined the interplay between PRS and obstetric complications (OCs) in 5 independent samples (effective N = 2110). OCs were assessed with the full or modified Lewis-Murray scale, or with birth weight < 2.5 kg as a proxy. In a large cohort we tested whether the pathways from placenta-relevant variants in the original report were associated with case-control status. Unlike in the original study, we did not find significant effect of PRS on the presence of OCs in cases, nor a substantial difference in the association of PRS with case-control status in samples stratified by the presence of OCs. Furthermore, none of the PRS by OCs interactions were significant, nor were any of the biological pathways, examined in the Swedish cohort. Our study could not support the hypothesis of a mediating effect of placenta biology in the pathway from genes to schizophrenia. Methodology differences, in particular the different scales measuring OCs, as well as power constraints for interaction analyses in both studies, may explain this discrepancy.

AB0859 IMPROVEMENTS IN PHYSICAL FUNCTION IN PATIENTS WITH OSTEOARTHRITIS RECEIVING SUBCUTANEOUS TANEZUMAB IN 3 RANDOMIZED CONTROLLED TRIALS

Background:

Tanezumab, a monoclonal antibody against nerve growth factor, is in development for the treatment of the signs and symptoms of osteoarthritis (OA).

Objectives:

To assess the improvement in physical function following treatment with subcutaneous (SC) tanezumab in three Phase 3 OA studies.

Methods:

All three randomized, double-blind, controlled studies enrolled patients (pts) with radiographically-confirmed OA of the hip or knee, who had inadequate response or could not tolerate standard of care analgesics. Study 1 was a dose-titration study (NCT02697773), where pts received two SC doses of: placebo at baseline/week (wk) 8; tanezumab 2.5 mg at baseline/wk 8; or tanezumab 2.5 mg at baseline/5 mg at wk 81. In Study 2 (NCT02709486), pts received three SC doses of placebo, tanezumab 2.5 mg, or 5 mg (at baseline/wk 8/wk 16). In Study 3 (NCT02528188), pts received a stable dose of nonsteroidal anti-inflammatory drugs (NSAIDs) before randomization to double-dummy tanezumab 2.5 mg or 5 mg (at baseline and every 8 wks during a 56 wk treatment period) or twice daily oral NSAIDs. Pts completed Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Physical Function subscale questionnaires in clinic. The least squares (LS) mean (standard error (SE)) change from baseline was calculated for each timepoint up to wk 16 and significance was calculated versus placebo (Studies 1 and 2) or NSAID (Study 3).

Results:

A total of 4541 pts were evaluated (n=696 in Study 1, n=849 in Study 2 and n=2996 in Study 3). In Studies 1 and 2, there were statistically significant improvements from baseline for all tanezumab treated groups versus placebo at wks 2, 4, 8, 12 and 16 (Table 1).In Study 3, the tanezumab 2.5 mg group showed a significant improvement from baseline at wk 2, compared with the NSAID group (Table 2).At wk 4, both tanezumab treatment groups showed a significant improvement from baseline compared with the NSAID group (Table 2). The tanezumab 5 mg group showed a significant improvement from baseline compared with the NSAID group at wks 8 and 16 (Table 2).

Table 1.

Change from baseline in WOMAC Physical Function: Study 1 and 2

Study 1Study 2Tanezumab 2.5 mg n=231Tanezumab 2.5/5 mg n=233Placebon=232Tanezumab 2.5 mg n=283Tanezumab5 mgn=284Placebon=282Wk 2LS mean (SE)-2.89 (0.21)-3.05 (0.21)-2.14 (0.21)-1.95 (0.14)-1.69 (0.14)-1.26 (0.14)p vs placebo0.0004<0.001<.00010.0014Wk 4LS mean (SE)-3.30 (0.21)-3.38 (0.21)-2.28 (0.21)-2.52 (0.15)-2.50 (0.15)-1.71 (0.15)p vs placebo<.0001<.0001<.0001<.0001Wk 8LS mean (SE)-3.17 (0.21)-3.12 (0.21)-2.55 (0.21)-2.38 (0.15)-2.52 (0.15)-1.76 (0.15)p vs placebo0.00570.0114<.0001<.0001Wk 12LS mean (SE)-3.61 (0.22)-3.80 (0.22)-2.75 (0.22)-2.83 (0.16)-2.87 (0.16)-2.04 (0.16)p vs placebo0.0004<.0001<.0001<.0001Wk 16LS mean (SE)-3.22 (0.22)-3.45 (0.22)-2.56 (0.22)-2.68 (0.16)-2.69 (0.16)-2.02 (0.17)p vs placebo0.00650.0002<.0001<.0001Table 2.

Change from baseline in WOMAC Physical Function in Study 3

Tanezumab 2.5 mg n=1002Tanezumab 5 mg n=998NSAID n=996Wk 2LS mean (SE)-1.76 (0.08)-1.64 (0.08)-1.55 (0.08)p vs NSAID0.01500.3286Wk 4LS mean (SE)-2.29 (0.09)-2.31 (0.09)-1.96 (0.09)p vs NSAID0.00040.0001Wk 8LS mean (SE)-2.46 (0.10)-2.69 (0.10)-2.27 (0.10)p vs NSAID0.0517<.0001Wk 16LS mean (SE)-3.27 (0.11)-3.39 (0.11)-3.08 (0.11)p vs NSAID0.06910.0030

Conclusion:

Consistent improvements in WOMAC Physical Function were seen across the first 16 wks for all dose groups of tanezumab-treated pts versus placebo in Study 1 and 2. The tanezumab 5 mg group in Study 3 showed a significant improvement at wks 4, 8 and 16 compared with the NSAID group. Improving physical function could help OA pts attain treatment goals beyond pain relief, improving their ability to perform important daily activities.

References:

[1]Schnitzer, T. J.et al. JAMA 2019

Disclosure of Interests:

Steven P Stanos Consultant of: Pfizer, Sanofi, Scilex, Salix, Speakers bureau: Scilex, Wilson J Chang: None declared, Cory Hultman Employee of: Eli Lilly and Co., Mojgan Sadrarhami Shareholder of: Pfizer Inc., Employee of: Pfizer Inc., Takaharu Yamabe Shareholder of: Pfizer, Employee of: Pfizer, Peter Park Shareholder of: Pfizer Inc., Employee of: Pfizer Inc.

Inherited DNA Repair Gene Mutations in Men with Lethal Prostate Cancer

Germline variants in DNA repair genes are associated with aggressive prostate cancer (PrCa). The aim of this study was to characterize germline variants in DNA repair genes associated with lethal PrCa in Finnish and Swedish populations. Whole-exome sequencing was performed for 122 lethal and 60 unselected PrCa cases. Among the lethal cases, a total of 16 potentially damaging protein-truncating variants in DNA repair genes were identified in 15 men (12.3%). Mutations were found in six genes with CHEK2 (4.1%) and ATM (3.3%) being most frequently mutated. Overall, the carrier rate of truncating variants in DNA repair genes among men with lethal PrCa significantly exceeded the carrier rate of 0% in 60 unselected PrCa cases (p = 0.030), and the prevalence of 1.6% (p < 0.001) and 5.4% (p = 0.040) in Swedish and Finnish population controls from the Exome Aggregation Consortium. No significant difference in carrier rate of potentially damaging nonsynonymous single nucleotide variants between lethal and unselected PrCa cases was observed (p = 0.123). We confirm that DNA repair genes are strongly associated with lethal PrCa in Sweden and Finland and highlight the importance of population-specific assessment of variants contributing to PrCa aggressiveness.

Association of Genetic and Environmental Factors With Autism in a 5-Country Cohort

IMPORTANCE

The origins and development of autism spectrum disorder (ASD) remain unresolved. No individual-level study has provided estimates of additive genetic, maternal, and environmental effects in ASD across several countries.

OBJECTIVE

To estimate the additive genetic, maternal, and environmental effects in ASD.

DESIGN, SETTING, AND PARTICIPANTS

Population-based, multinational cohort study including full birth cohorts of children from Denmark, Finland, Sweden, Israel, and Western Australia born between January 1, 1998, and December 31, 2011, and followed up to age 16 years. Data were analyzed from September 23, 2016 through February 4, 2018.

MAIN OUTCOMES AND MEASURES

Across 5 countries, models were fitted to estimate variance components describing the total variance in risk for ASD occurrence owing to additive genetics, maternal, and shared and nonshared environmental effects.

RESULTS

The analytic sample included 2 001 631 individuals, of whom 1 027 546 (51.3%) were male. Among the entire sample, 22 156 were diagnosed with ASD. The median (95% CI) ASD heritability was 80.8% (73.2%-85.5%) for country-specific point estimates, ranging from 50.9% (25.1%-75.6%) (Finland) to 86.8% (69.8%-100.0%) (Israel). For the Nordic countries combined, heritability estimates ranged from 81.2% (73.9%-85.3%) to 82.7% (79.1%-86.0%). Maternal effect was estimated to range from 0.4% to 1.6%. Estimates of genetic, maternal, and environmental effects for autistic disorder were similar with ASD.

CONCLUSIONS AND RELEVANCE

Based on population data from 5 countries, the heritability of ASD was estimated to be approximately 80%, indicating that the variation in ASD occurrence in the population is mostly owing to inherited genetic influences, with no support for contribution from maternal effects. The results suggest possible modest differences in the sources of ASD risk between countries.

Increased neutrophil extracellular trap formation promotes thrombosis in myeloproliferative neoplasms

Thrombosis is a major cause of morbidity and mortality in Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), clonal disorders of hematopoiesis characterized by activated Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling. Neutrophil extracellular trap (NET) formation, a component of innate immunity, has been linked to thrombosis. We demonstrate that neutrophils from patients with MPNs are primed for NET formation, an effect blunted by pharmacological inhibition of JAK signaling. Mice with conditional knock-in of Jak2^V617F, the most common molecular driver of MPN, have an increased propensity for NET formation and thrombosis. Inhibition of JAK-STAT signaling with the clinically available JAK2 inhibitor ruxolitinib abrogated NET formation and reduced thrombosis in a deep vein stenosis murine model. We further show that expression of PAD4, a protein required for NET formation, is increased in JAK2^V617F-expressing neutrophils and that PAD4 is required for Jak2^V617F-driven NET formation and thrombosis in vivo. Finally, in a population study of more than 10,000 individuals without a known myeloid disorder, JAK2^V617F-positive clonal hematopoiesis was associated with an increased incidence of thrombosis. In aggregate, our results link JAK2^V617F expression to NET formation and thrombosis and suggest that JAK2 inhibition may reduce thrombosis in MPNs through cell-intrinsic effects on neutrophil function.

Recurrence Risk of Autism in Siblings and Cousins: A Multinational, Population-Based Study

OBJECTIVE

Familial recurrence risk is an important population-level measure of the combined genetic and shared familial liability of autism spectrum disorder (ASD). Objectives were to estimate ASD recurrence risk among siblings and cousins by varying degree of relatedness and by sex.

METHOD

This is a population-based cohort study of livebirths from 1998 to 2007 in California, Denmark, Finland, Israel, Sweden and Western Australia followed through 2011 to 2015. Subjects were monitored for an ASD diagnosis in their older siblings or cousins (exposure) and for their ASD diagnosis (outcome). The relative recurrence risk was estimated for different sibling and cousin pairs, for each site separately and combined, and by sex.

RESULTS

During follow-up, 29,998 cases of ASD were observed among the 2,551,918 births used to estimate recurrence in ASD and 33,769 cases of childhood autism (CA) were observed among the 6,110,942 births used to estimate CA recurrence. Compared with the risk in unaffected families, there was an 8.4-fold increase in the risk of ASD following an older sibling with ASD and a 17.4-fold increase in the risk of CA following an older sibling with CA. A 2-fold increase in the risk for cousin recurrence was observed for the 2 disorders. There also was a significant difference in sibling ASD recurrence risk by sex.

CONCLUSION

The present estimates of relative recurrence risks for ASD and CA will assist clinicians and families in understanding autism risk in the context of other families in their population. The observed variation by sex underlines the need to deepen the understanding of factors influencing ASD familial risk.

Quantifying the Impact of Rare and Ultra-rare Coding Variation across the Phenotypic Spectrum

There is a limited understanding about the impact of rare protein-truncating variants across multiple phenotypes. We explore the impact of this class of variants on 13 quantitative traits and 10 diseases using whole-exome sequencing data from 100,296 individuals. Protein-truncating variants in genes intolerant to this class of mutations increased risk of autism, schizophrenia, bipolar disorder, intellectual disability, and ADHD. In individuals without these disorders, there was an association with shorter height, lower education, increased hospitalization, and reduced age at enrollment. Gene sets implicated from GWASs did not show a significant protein-truncating variants burden beyond what was captured by established Mendelian genes. In conclusion, we provide a thorough investigation of the impact of rare deleterious coding variants on complex traits, suggesting widespread pleiotropic risk.

Integrated Bayesian analysis of rare exonic variants to identify risk genes for schizophrenia and neurodevelopmental disorders

BACKGROUND

Integrating rare variation from trio family and case-control studies has successfully implicated specific genes contributing to risk of neurodevelopmental disorders (NDDs) including autism spectrum disorders (ASD), intellectual disability (ID), developmental disorders (DDs), and epilepsy (EPI). For schizophrenia (SCZ), however, while sets of genes have been implicated through the study of rare variation, only two risk genes have been identified.

METHODS

We used hierarchical Bayesian modeling of rare-variant genetic architecture to estimate mean effect sizes and risk-gene proportions, analyzing the largest available collection of whole exome sequence data for SCZ (1,077 trios, 6,699 cases, and 13,028 controls), and data for four NDDs (ASD, ID, DD, and EPI; total 10,792 trios, and 4,058 cases and controls).

RESULTS

For SCZ, we estimate there are 1,551 risk genes. There are more risk genes and they have weaker effects than for NDDs. We provide power analyses to predict the number of risk-gene discoveries as more data become available. We confirm and augment prior risk gene and gene set enrichment results for SCZ and NDDs. In particular, we detected 98 new DD risk genes at FDR < 0.05. Correlations of risk-gene posterior probabilities are high across four NDDs (ρ>0.55), but low between SCZ and the NDDs (ρ<0.3). An in-depth analysis of 288 NDD genes shows there is highly significant protein-protein interaction (PPI) network connectivity, and functionally distinct PPI subnetworks based on pathway enrichment, single-cell RNA-seq cell types, and multi-region developmental brain RNA-seq.

CONCLUSIONS

We have extended a pipeline used in ASD studies and applied it to infer rare genetic parameters for SCZ and four NDDs ( https://github.com/hoangtn/extTADA ). We find many new DD risk genes, supported by gene set enrichment and PPI network connectivity analyses. We find greater similarity among NDDs than between NDDs and SCZ. NDD gene subnetworks are implicated in postnatally expressed presynaptic and postsynaptic genes, and for transcriptional and post-transcriptional gene regulation in prenatal neural progenitor and stem cells.

Mutation intolerant genes and targets of FMRP are enriched for nonsynonymous alleles in schizophrenia

Risk of schizophrenia is conferred by alleles occurring across the full spectrum of frequencies from common SNPs of weak effect through to ultra rare alleles, some of which may be moderately to highly penetrant. Previous studies have suggested that some of the risk of schizophrenia is attributable to uncommon alleles represented on Illumina exome arrays. Here, we present the largest study of exomic variation in schizophrenia to date, using samples from the United Kingdom and Sweden (10,011 schizophrenia cases and 13,791 controls). Single variants, genes, and gene sets were analyzed for association with schizophrenia. No single variant or gene reached genome-wide significance. Among candidate gene sets, we found significant enrichment for rare alleles (minor allele frequency [MAF] < 0.001) in genes intolerant of loss-of-function (LoF) variation and in genes whose messenger RNAs bind to fragile X mental retardation protein (FMRP). We further delineate the genetic architecture of schizophrenia by excluding a role for uncommon exomic variants (0.01 ≤ MAF ≥ 0.001) that confer a relatively large effect (odds ratio [OR] > 4). We also show risk alleles within this frequency range exist, but confer smaller effects and should be identified by larger studies.

The Heritability of Autism Spectrum Disorder

This study reanalyzes Swedish cohort data to assess the stability under alternative assumptions and models of a previous estimate of the heritability of autism spectrum disorder.

Waiting time for cancer treatment and mental health among patients with newly diagnosed esophageal or gastric cancer: a nationwide cohort study

Background

Except for overall survival, whether or not waiting time for treatment could influences other domains of cancer patients’ overall well-being is to a large extent unknown. Therefore, we performed this study to determine the effect of waiting time for cancer treatment on the mental health of patients with esophageal or gastric cancer.

Methods

Based on the Swedish National Quality Register for Esophageal and Gastric Cancers (NREV), we followed 7,080 patients diagnosed 2006–2012 from the time of treatment decision. Waiting time for treatment was defined as the interval between diagnosis and treatment decision, and was classified into quartiles. Mental disorders were identified by either clinical diagnosis through hospital visit or prescription of psychiatric medications. For patients without any mental disorder before treatment, the association between waiting time and subsequent onset of mental disorders was assessed by hazard ratios (HRs) with 95% confidence interval (CI), derived from multivariable-adjusted Cox model. For patients with a preexisting mental disorder, we compared the rate of psychiatric care by different waiting times, allowing for repeated events.

Results

Among 4,120 patients without any preexisting mental disorder, lower risk of new onset mental disorders was noted for patients with longer waiting times, i.e. 18–29 days (HR 0.86; 95% CI 0.74-1.00) and 30–60 days (HR 0.79; 95% CI 0.67-0.93) as compared with 9–17 days. Among 2,312 patients with preexisting mental disorders, longer waiting time was associated with more frequent psychiatric hospital care during the first year after treatment (37.5% higher rate per quartile increase in waiting time; p for trend = 0.0002). However, no such association was observed beyond one year nor for the prescription of psychiatric medications.

Conclusions

These data suggest that waiting time to treatment for esophageal or gastric cancer may have different mental health consequences for patients depending on their past psychiatric vulnerabilities. Our study sheds further light on the complexity of waiting time management, and calls for a comprehensive strategy that takes into account different domains of patient well-being in addition to the overall survival.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-3013-7) contains supplementary material, which is available to authorized users.

Genome-wide association study identifies SESTD1 as a novel risk gene for lithium-responsive bipolar disorder

This corrects the article DOI: 10.1038/mp.2015.165.

Implication of LRRC4C and DPP6 in neurodevelopmental disorders

We performed whole-genome sequencing on an individual from a family with variable psychiatric phenotypes that had a sensory processing disorder, apraxia, and autism. The proband harbored a maternally inherited balanced translocation (46,XY,t(11;14)(p12;p12)mat) that disrupted LRRC4C, a member of the highly specialized netrin G family of axon guidance molecules. The proband also inherited a paternally derived chromosomal inversion that disrupted DPP6, a potassium channel interacting protein. Copy Number (CN) analysis in 14,077 cases with neurodevelopmental disorders and 8,960 control subjects revealed that 60% of cases with exonic deletions in LRRC4C had a second clinically recognizable syndrome associated with variable clinical phenotypes, including 16p11.2, 1q44, and 2q33.1 CN syndromes, suggesting LRRC4C deletion variants may be modifiers of neurodevelopmental disorders. In vitro, functional assessments modeling patient deletions in LRRC4C suggest a negative regulatory role of these exons found in the untranslated region of LRRC4C, which has a single, terminal coding exon. These data suggest that the proband's autism may be due to the inheritance of disruptions in both DPP6 and LRRC4C, and may highlight the importance of the netrin G family and potassium channel interacting molecules in neurodevelopmental disorders. © 2016 Wiley Periodicals, Inc.

Variants in ELL2 influencing immunoglobulin levels associate with multiple myeloma

Multiple myeloma (MM) is characterized by an uninhibited, clonal growth of plasma cells. While first-degree relatives of patients with MM show an increased risk of MM, the genetic basis of inherited MM susceptibility is incompletely understood. Here we report a genome-wide association study in the Nordic region identifying a novel MM risk locus at ELL2 (rs56219066T; odds ratio (OR)=1.25; P=9.6 × 10(-10)). This gene encodes a stoichiometrically limiting component of the super-elongation complex that drives secretory-specific immunoglobulin mRNA production and transcriptional regulation in plasma cells. We find that the MM risk allele harbours a Thr298Ala missense variant in an ELL2 domain required for transcription elongation. Consistent with a hypomorphic effect, we find that the MM risk allele also associates with reduced levels of immunoglobulin A (IgA) and G (IgG) in healthy subjects (P=8.6 × 10(-9) and P=6.4 × 10(-3), respectively) and, potentially, with an increased risk of bacterial meningitis (OR=1.30; P=0.0024).

An inherited duplication at the gene p21 Protein-Activated Kinase 7 (PAK7) is a risk factor for psychosis

Identifying rare, highly penetrant risk mutations may be an important step in dissecting the molecular etiology of schizophrenia. We conducted a gene-based analysis of large (>100 kb), rare copy-number variants (CNVs) in the Wellcome Trust Case Control Consortium 2 (WTCCC2) schizophrenia sample of 1564 cases and 1748 controls all from Ireland, and further extended the analysis to include an additional 5196 UK controls. We found association with duplications at chr20p12.2 (P = 0.007) and evidence of replication in large independent European schizophrenia (P = 0.052) and UK bipolar disorder case-control cohorts (P = 0.047). A combined analysis of Irish/UK subjects including additional psychosis cases (schizophrenia and bipolar disorder) identified 22 carriers in 11 707 cases and 10 carriers in 21 204 controls [meta-analysis Cochran-Mantel-Haenszel P-value = 2 × 10(-4); odds ratio (OR) = 11.3, 95% CI = 3.7, ∞]. Nineteen of the 22 cases and 8 of the 10 controls carried duplications starting at 9.68 Mb with similar breakpoints across samples. By haplotype analysis and sequencing, we identified a tandem ~149 kb duplication overlapping the gene p21 Protein-Activated Kinase 7 (PAK7, also called PAK5) which was in linkage disequilibrium with local haplotypes (P = 2.5 × 10(-21)), indicative of a single ancestral duplication event. We confirmed the breakpoints in 8/8 carriers tested and found co-segregation of the duplication with illness in two additional family members of one of the affected probands. We demonstrate that PAK7 is developmentally co-expressed with another known psychosis risk gene (DISC1) suggesting a potential molecular mechanism involving aberrant synapse development and plasticity.

Allelic differences between Europeans and Chinese for CREB1 SNPs and their implications in gene expression regulation, hippocampal structure and function, and bipolar disorder susceptibility

Bipolar disorder (BD) is a polygenic disorder that shares substantial genetic risk factors with major depressive disorder (MDD). Genetic analyses have reported numerous BD susceptibility genes, while some variants, such as single-nucleotide polymorphisms (SNPs) in CACNA1C have been successfully replicated, many others have not and subsequently their effects on the intermediate phenotypes cannot be verified. Here, we studied the MDD-related gene CREB1 in a set of independent BD sample groups of European ancestry (a total of 64,888 subjects) and identified multiple SNPs significantly associated with BD (the most significant being SNP rs6785[A], P=6.32 × 10(-5), odds ratio (OR)=1.090). Risk SNPs were then subjected to further analyses in healthy Europeans for intermediate phenotypes of BD, including hippocampal volume, hippocampal function and cognitive performance. Our results showed that the risk SNPs were significantly associated with hippocampal volume and hippocampal function, with the risk alleles showing a decreased hippocampal volume and diminished activation of the left hippocampus, adding further evidence for their involvement in BD susceptibility. We also found the risk SNPs were strongly associated with CREB1 expression in lymphoblastoid cells (P<0.005) and the prefrontal cortex (P<1.0 × 10(-6)). Remarkably, population genetic analysis indicated that CREB1 displayed striking differences in allele frequencies between continental populations, and the risk alleles were completely absent in East Asian populations. We demonstrated that the regional prevalence of the CREB1 risk alleles in Europeans is likely caused by genetic hitchhiking due to natural selection acting on a nearby gene. Our results suggest that differential population histories due to natural selection on regional populations may lead to genetic heterogeneity of susceptibility to complex diseases, such as BD, and explain inconsistencies in detecting the genetic markers of these diseases among different ethnic populations.

CNV analysis in a large schizophrenia sample implicates deletions at 16p12.1 and SLC1A1 and duplications at 1p36.33 and CGNL1

Large and rare copy number variants (CNVs) at several loci have been shown to increase risk for schizophrenia. Aiming to discover novel susceptibility CNV loci, we analyzed 6882 cases and 11 255 controls genotyped on Illumina arrays, most of which have not been used for this purpose before. We identified genes enriched for rare exonic CNVs among cases, and then attempted to replicate the findings in additional 14 568 cases and 15 274 controls. In a combined analysis of all samples, 12 distinct loci were enriched among cases with nominal levels of significance (P < 0.05); however, none would survive correction for multiple testing. These loci include recurrent deletions at 16p12.1, a locus previously associated with neurodevelopmental disorders (P = 0.0084 in the discovery sample and P = 0.023 in the replication sample). Other plausible candidates include non-recurrent deletions at the glutamate transporter gene SLC1A1, a CNV locus recently suggested to be involved in schizophrenia through linkage analysis, and duplications at 1p36.33 and CGNL1. A burden analysis of large (>500 kb), rare CNVs showed a 1.2% excess in cases after excluding known schizophrenia-associated loci, suggesting that additional susceptibility loci exist. However, even larger samples are required for their discovery.

A nationwide study of the association between celiac disease and the risk of autistic spectrum disorders

IMPORTANCE

Most case reports suggest an association between autistic spectrum disorders (ASDs) and celiac disease (CD) or positive CD serologic test results, but larger studies are contradictory.

OBJECTIVE

To examine the association between ASDs and CD according to small intestinal histopathologic findings.

DESIGN AND SETTING

Nationwide case-control study in Sweden.

MAIN OUTCOMES AND MEASURES

Through 28 Swedish biopsy registers, we collected data about 26,995 individuals with CD (equal to villous atrophy, Marsh stage 3), 12,304 individuals with inflammation (Marsh stages 1-2), and 3719 individuals with normal mucosa (Marsh stage 0) but positive CD serologic test results (IgA/IgG gliadin, endomysium, or tissue transglutaminase) and compared them with 213,208 age- and sex-matched controls. Conditional logistic regression estimated odds ratios (ORs) for having a prior diagnosis of an ASD according to the Swedish National Patient Register. In another analysis, we used the Cox proportional hazards regression model to estimate hazard ratios (HRs) for future ASDs in individuals undergoing small intestinal biopsy.

RESULTS

A prior ASD was not associated with CD (OR, 0.93; 95% CI, 0.51-1.68) or inflammation (OR 1.03; 95% CI, 0.40-2.64) but was associated with a markedly increased risk of having a normal mucosa but a positive CD serologic test result (OR, 4.57; 95% CI, 1.58-13.22). Restricting our data to individuals without a diagnosis of an ASD at the time of biopsy, CD (HR, 1.39; 95% CI, 1.13-1.71) and inflammation (HR, 2.01; 95% CI, 1.29-3.13) were both associated with moderate excess risks of later ASDs, whereas the HR for later ASDs in individuals with normal mucosa but positive CD serologic test results was 3.09 (95% CI, 1.99-4.80).

CONCLUSIONS AND RELEVANCE

Although this study found no association between CD or inflammation and earlier ASDs, there was a markedly increased risk of ASDs in individuals with normal mucosa but a positive CD serologic test result.

Poor school performance in offspring of patients with schizophrenia: what are the mechanisms?

BACKGROUND

Offspring of patients with schizophrenia exhibit poorer school performance compared with offspring of non-schizophrenic parents. We aimed to elucidate the mechanisms behind this association.

METHOD

We linked longitudinal national population registers in Sweden and compared school performance among offspring of schizophrenic parents with offspring of non-schizophrenic parents (1 439 215 individuals with final grades from compulsory school 1988-2006). To investigate the mechanisms, we studied offspring of schizophrenic patients and controls within the same extended families. We investigated genetic effects by stratifying analyses of parent-child associations according to genetic relatedness (half-cousins, full cousins and half-siblings). Environmental effects were investigated by comparing school performance of offspring of schizophrenic fathers and of schizophrenic mothers, respectively, and by stratifying the analyses according to environmental relatedness while controlling genetic relatedness (paternal and maternal half-cousins, paternal and maternal half-siblings).

RESULTS

Offspring of parents with schizophrenia had poorer overall school performance than unrelated offspring of non-schizophrenic parents (-0.31 s.d.). Variability in genetic relatedness greatly moderated the strength of the within-family association (β=-0.23 within exposure-discordant half-cousins, β=-0.13 within exposure-discordant full cousins, β=0.04 within exposure-discordant half-siblings), while no evidence was found that the environment affected offspring school performance.

CONCLUSIONS

Genetic factors account for poorer school performance in children of parents with schizophrenia. This supports that cognitive deficits found in individuals with schizophrenia and their relatives might be genetically inherited. Early detection of prodromal signs and impaired functioning of offspring of patients with schizophrenia could lead to earlier and better tailored interventions.

Creativity and mental disorder: family study of 300,000 people with severe mental disorder

BACKGROUND

There is a long-standing belief that creativity is coupled with psychopathology.

AIMS

To test this alleged association and to investigate whether any such association is the result of environmental or genetic factors.

METHOD

We performed a nested case-control study based on Swedish registries. The likelihood of holding a creative occupation in individuals who had received in-patient treatment for schizophrenia, bipolar disorder or unipolar depression between 1973 and 2003 and their relatives without such a diagnosis was compared with that of controls.

RESULTS

Individuals with bipolar disorder and healthy siblings of people with schizophrenia or bipolar disorder were overrepresented in creative professions. People with schizophrenia had no increased rate of overall creative professions compared with controls, but an increased rate in the subgroup of artistic occupations. Neither individuals with unipolar depression nor their siblings differed from controls regarding creative professions.

CONCLUSIONS

A familial cosegregation of both schizophrenia and bipolar disorder with creativity is suggested.

Genetic differences between five European populations

AIMS

We sought to examine the magnitude of the differences in SNP allele frequencies between five European populations (Scotland, Ireland, Sweden, Bulgaria and Portugal) and to identify the loci with the greatest differences.

METHODS

We performed a population-based genome-wide association analysis with Affymetrix 6.0 and 5.0 arrays. We used a 4 degrees of freedom χ(2) test to determine the magnitude of stratification for each SNP. We then examined the genes within the most stratified regions, using a highly conservative cutoff of p < 10(-45).

RESULTS

We found 40,593 SNPs which are genome-wide significantly (p ≤ 10(-8)) stratified between these populations. The largest differences clustered in gene ontology categories for immunity and pigmentation. Some of the top loci span genes that have already been reported as highly stratified: genes for hair color and pigmentation (HERC2, EXOC2, IRF4), the LCT gene, genes involved in NAD metabolism, and in immunity (HLA and the Toll-like receptor genes TLR10, TLR1, TLR6). However, several genes have not previously been reported as stratified within European populations, indicating that they might also have provided selective advantages: several zinc finger genes, two genes involved in glutathione synthesis or function, and most intriguingly, FOXP2, implicated in speech development.

CONCLUSION

Our analysis demonstrates that many SNPs show genome-wide significant differences within European populations and the magnitude of the differences correlate with the geographical distance. At least some of these differences are due to the selective advantage of polymorphisms within these loci.

Familial factors confound the association between maternal smoking during pregnancy and young adult offspring overweight

BACKGROUND

Smoking during pregnancy has been shown to increase the risks of several adverse birth outcomes. Associations with overweight and/or obesity in the offspring have also been suggested. We aim to investigate whether familial factors confound the association between maternal smoking during pregnancy and overweight in early adulthood in young Swedish males born 1983-88.

METHODS

In a population-based Swedish cohort comprising 124 203 singleton males born to Nordic mothers between 1983 and 1988, we examined the association between maternal smoking during pregnancy and the risk of overweight in the offspring at age ∼18 years. We also investigated the association within siblings, controlling for common genes and shared environment.

RESULTS

In the cohort analyses, the risk of overweight was increased in sons of smoking mothers compared with sons of non-smokers: adjusted odds ratios 1.41, 95% confidence interval (CI) 1.34-1.49, and 1.56, 95% CI 1.46-1.66, for one to nine cigarettes per day, and >10 cigarettes per day, respectively. Stratifying for maternal smoking habits across two subsequent male pregnancies, there was an increased risk of overweight for the second son only if the mother was smoking in both male pregnancies. The effect of smoking during pregnancy on the offspring's body mass index was not present when the association was evaluated within full and half sibling pairs.

CONCLUSION

The association between maternal smoking during pregnancy and offspring's risk of overweight appears to be confounded by familial factors.

Maternal smoking during pregnancy and intellectual performance in young adult Swedish male offspring

Smoking during pregnancy has been linked to an increased risk of several adverse birth outcomes. Associations with deficits in cognitive development have also been suggested. It is unclear whether these associations are due to genetic and/or environmental confounding. In a population-based Swedish cohort study on 205,777 singleton males born to Nordic mothers between 1983 and 1988, we examined the association between maternal smoking during pregnancy and the risk of poor intellectual performance in young adult male offspring. In the cohort analyses, the risk of poor intellectual performance was increased in sons of smoking mothers compared with sons of non-smokers. Stratifying for maternal smoking habits across two pregnancies, there was an increased risk of poor intellectual performance for both sons if the mother was only smoking in the first pregnancy, but in neither son if the mother was only smoking in the second pregnancy. The effect of smoking during pregnancy on intellectual performance was not present when the association was evaluated within sibling pairs. Thus, the association between prenatal smoking exposure and offspring risk of low intellectual performance appears to be completely confounded by familial (genetic and early environmental) factors.

Suicide among patients with amyotrophic lateral sclerosis

Studies on the suicide risk among patients with amyotrophic lateral sclerosis (ALS) in countries without legalized euthanasia or assisted suicide are important additions to data on the wish to die of these patients. We conducted a population-based cohort study in Sweden between 1965 and 2004, which comprised of 6,642 patients with incident ALS identified from the Swedish Inpatient Register. We calculated the standardized mortality ratios (SMRs) of suicide among the patients using the suicide rates of the general Swedish population as a reference. In total, 21 patients committed suicide during follow-up, compared to the predicted 3.6 suicides. Thus, we noted an almost 6-fold increased risk for suicide among ALS patients [SMR 5.8, 95% confidence interval (CI) 3.6-8.8]. Patients who committed suicide were, on average, around 7 years younger at the time of their first period of hospitalization than patients who did not commit suicide. The highest relative risk for suicide was observed within the first year after the patient's first period of hospitalization (SMR 11.2, 95% CI 5.8-19.6). After that, the relative risks decreased with time after hospitalization (P-value for trend = 0.006), but remained elevated 3 years later. The relative risks of suicide among ALS patients did not show a clear trend over time in contrast to the decreasing trend of relative risks for suicide among patients with cancer during the same period. Patients with ALS are at excess risk of suicide in Sweden and the relative risk is higher during the earlier stage of the disease.

Combining data from 2 nested case-control studies of overlapping cohorts to improve efficiency

Researchers subject to time and budget constraints may conduct small nested case-control studies with individually matched controls to help optimize statistical power. In this paper, we show how precision can be improved considerably by combining data from a small nested case-control study with data from a larger nested case-control study of a different outcome in the same or overlapping cohort. Our approach is based on the inverse probability weighting concept, in which the log-likelihood contribution of each individual observation is weighted by the inverse of its probability of inclusion in either study. We illustrate our approach using simulated data and an application where we combine data sets from 2 nested case-control studies to investigate risk factors for anorexia nervosa in a cohort of young women in Sweden.

Maternal smoking during pregnancy and school performance at age 15

BACKGROUND

Smoking during pregnancy has been suggested to have long-term consequences for neuropsychologic development in the offspring, including behavioral problems, attention deficit disorders, and antisocial behavior. Also, findings from several studies indicate an association with impaired cognitive function in the children.

METHODS

In a population-based Swedish cohort study, we examined possible associations between maternal smoking in pregnancy and educational achievement in the offspring at age 15 years among more than 400,000 male and female students born 1983 through 1987. Generalized estimating equation models were used to evaluate associations of maternal smoking, other maternal characteristics, and birth characteristics with school performance. Odds ratios (ORs) were used as a measure of risk.

RESULTS

In a model adjusted for maternal characteristics, maternal smoking compared with no tobacco use during pregnancy was associated with an increased risk of poor scholastic achievement: for 1-9 cigarettes per day, the OR was 1.59 (95% confidence interval = 1.59-1.63) and for 10 or more cigarettes per day, the OR was 1.92 (1.86-1.98). These risks remained unchanged when we also adjusted for smoking-related pregnancy outcomes such as fetal growth restriction and preterm birth. However, if the mother had smoked in her first pregnancy, but not in her second pregnancy, the younger sibling was also at increased risk of poor school performance.

CONCLUSION

Observed associations between maternal smoking during pregnancy and poor cognitive performance in the offspring might not be causal. We suggest that associations reported in earlier studies may instead reflect the influence of unmeasured characteristics that differ between smokers and nonsmokers.

Maternal smoking during pregnancy and school performance at age 15

BACKGROUND

Smoking during pregnancy has been suggested to have long-term consequences for neuropsychologic development in the offspring, including behavioral problems, attention deficit disorders, and antisocial behavior. Also, findings from several studies indicate an association with impaired cognitive function in the children.

METHODS

In a population-based Swedish cohort study, we examined possible associations between maternal smoking in pregnancy and educational achievement in the offspring at age 15 years among more than 400,000 male and female students born 1983 through 1987. Generalized estimating equation models were used to evaluate associations of maternal smoking, other maternal characteristics, and birth characteristics with school performance. Odds ratios (ORs) were used as a measure of risk.

RESULTS

In a model adjusted for maternal characteristics, maternal smoking compared with no tobacco use during pregnancy was associated with an increased risk of poor scholastic achievement: for 1-9 cigarettes per day, the OR was 1.59 (95% confidence interval = 1.59-1.63) and for 10 or more cigarettes per day, the OR was 1.92 (1.86-1.98). These risks remained unchanged when we also adjusted for smoking-related pregnancy outcomes such as fetal growth restriction and preterm birth. However, if the mother had smoked in her first pregnancy, but not in her second pregnancy, the younger sibling was also at increased risk of poor school performance.

CONCLUSION

Observed associations between maternal smoking during pregnancy and poor cognitive performance in the offspring might not be causal. We suggest that associations reported in earlier studies may instead reflect the influence of unmeasured characteristics that differ between smokers and nonsmokers.

Glycemic control with Humalog Mix25 in type 2 diabetes inadequately controlled with glyburide

BACKGROUND

Humalog Mix25 (Mix25) is a premixed insulin mixture of 25% insulin lispro and 75% neutral protamine lispro.

OBJECTIVE

The aim of this study was to quantitate the improvement in glycemic control achieved with Mix25 versus the maximum dose of glyburide (GB) in patients with type 2 diabetes inadequately controlled with GB.

METHODS

In this randomized, parallel, open-label comparative study, patients with type 2 diabetes received either Mix25 before the morning and evening meals for 4 months or GB 15 mg daily for 4 months. Glycemic control was assessed by glycosylated hemoglobin (HbA1c) measurements, 4-point self-monitored blood glucose profiles, and patient-reported hypoglycemia. Patients also completed a treatment satisfaction questionnaire at the end of the study.

RESULTS

All 172 patients were white; 85 were randomized to receive Mix25. The mean age was 59.5 +/- 8.2 years, and 35.5% (61/172) were men. The mean body mass index was 27.2 kg/m2. The mean duration of type 2 diabetes was 10.2 +/- 6.6 years, and the mean duration of sulfonylurea treatment was 5.8 +/- 5.9 years. The mean HbA1c and fasting blood glucose levels were 10.07% +/- 1.4% and 11.6 +/- 2.8 mmol/L, respectively, in the glyburide group and 9.85% +/- 1.2% and 12.2 +/- 2.9 mmol/L, respectively, in the Mix25 group. There were no statistically significant differences between the treatment groups at baseline for any of the demographic or efficacy variables. At end point, mean HbA1c was significantly lower in the Mix25 group than in the GB group (Mix25, 8.5% +/- 1.3%; GB, 9.4% +/- 1.8%; P = 0.001). A larger decrease from baseline in HbA1c and in all self-monitored blood glucose values was observed in the Mix25 group: -1.4% versus -0.7% for HbA1c, P = 0.004; -2.8 mmol/L versus -1.1 mmol/L for fasting blood glucose, P < 0.01; -5.1 mmol/L versus -1.7 mmol/L for the morning 2-hour postprandial blood glucose, P < 0.001; -2.2 mmol/L versus -0.8 mmol/L for the evening preprandial blood glucose, P < 0.05; and -4.4 mmol/L versus -1.5 mmol/L for the evening 2-hour postprandial blood glucose, P < 0.001. Patients expressed more satisfaction with Mix25 than with GB, as measured by the weighted combined score on a treatment satisfaction questionnaire (2.0 +/- 1.3 vs 0.7 +/- 1.3). The mean hypoglycemia rate (events per patient per 30 days) was significantly higher in the Mix25 group at end point (Mix25, 0.30 +/- 0.53; GB, 0.05 +/- 0.20; P < 0.001).

CONCLUSIONS

Compared with maximum-dose GB, twice-daily injections of Mix25 resulted in improved glycemic control and treatment satisfaction, and were associated with a predictably higher rate of hypoglycemia in this group of patients with type 2 diabetes who were inadequately controlled with maximum-dose GB. Although the inclusion of patients who were inadequately controlled with GB was intended to allow a comparison of the 2 treatments with respect to efficacy and tolerability in a real-life setting, a double-blind comparison in treatment-naive individuals may have resulted in a different outcome.

Dose accuracy testing of the humalog/ humulin insulin pen device

The primary purpose of the study was to determine whether pen users would challenge the insufficient remaining dose (IRD) stop mechanism with sufficient force to affect the dose accuracy of the final dose. The secondary purpose was to determine the participant's positive and negative impressions of the Humalog/Humulin pen and the likelihood of using the new prefilled pen. Three different modifications to the prefilled pen's IRD stop feature were made. These three pen models then underwent environmental dose accuracy testing at various temperatures and humidities, and user dose accuracy testing by 64 patients with diabetes. Evaluation also involved challenging the IRD stop at various dialing torques. Thirty pens from each model were tested to failure of the IRD stop. A model of the prefilled pen was selected for commercialization that met the dose accuracy targets of +/- 1 unit (U) for insulin doses less than 20 U and +/- 5% of dose volume for doses equal to or over 20 U. The selected pen model was superior at the minimum (1 unit), median (30 unit) and maximum (60 unit) dose volumes. Also 92% (n = 59) of patients interviewed felt that the stop mechanism for the final dose was clear. Extensive testing in the development of a prefilled insulin delivery device demonstrates an accurate and reliable medical device.

Normative F wave values and the number of recorded F waves

F waves were recorded from the right abductor pollicis brevis of 11 normal subjects following 100 supramaximal stimuli. F wave data from sequential groups of 10 stimuli were analyzed. "True" values were considered those based on the results following all 100 stimuli. The F wave data evaluated were: minimal, mean, and median latencies; persistences (the percentage of F waves present in a series of stimuli); chronodispersion (CD) (the difference between minimal and maximal F latencies); mean F/M wave (mF/M) amplitudes; and repeater waves. F latencies appear normally distributed, and there is no statistical justification for using either median latencies or amplitudes. Following 10 stimuli, however, mean latencies are more reproducible than minimal values. In these normal data, results following 10 stimuli give latency measurements within 1 ms of "true" as well as for persistences; 20 stimuli will provide mean latencies within 0.5 ms of "true" as well as probable reasonable values (i.e., 80% of "true" or greater, for mF/M and the percentage of repeater waves; for CDs 80% of "true" or greater, 50-60 stimuli are needed; for the number of individual repeater waves, data from all 100 stimuli would be required. Analysis of repeater waves amplitudes would support a preferential activation of larger motor units in F waves.