GWAS and meta-analysis identifies 49 genetic variants underlying critical COVID-19.

Critical illness in COVID-19 is an extreme and clinically homogeneous disease phenotype that we have previously shown1 to be highly efficient for discovery of genetic associations2. Despite the advanced stage of illness at presentation, we have shown that host genetics in patients who are critically ill with COVID-19 can identify immunomodulatory therapies with strong beneficial effects in this group3. Here we analyse 24,202 cases of COVID-19 with critical illness comprising a combination of microarray genotype and whole-genome sequencing data from cases of critical illness in the international GenOMICC (11,440 cases) study, combined with other studies recruiting hospitalized patients with a strong focus on severe and critical disease: ISARIC4C (676 cases) and the SCOURGE consortium (5,934 cases). To put these results in the context of existing work, we conduct a meta-analysis of the new GenOMICC genome-wide association study (GWAS) results with previously published data. We find 49 genome-wide significant associations, of which 16 have not been reported previously. To investigate the therapeutic implications of these findings, we infer the structural consequences of protein-coding variants, and combine our GWAS results with gene expression data using a monocyte transcriptome-wide association study (TWAS) model, as well as gene and protein expression using Mendelian randomization. We identify potentially druggable targets in multiple systems, including inflammatory signalling (JAK1), monocyte-macrophage activation and endothelial permeability (PDE4A), immunometabolism (SLC2A5 and AK5), and host factors required for viral entry and replication (TMPRSS2 and RAB2A).

CARTAR: a comprehensive web tool for identifying potential targets in chimeric antigen receptor therapies using TCGA and GTEx data.

Chimeric antigen receptor (CAR) therapy has emerged as a ground-breaking advancement in cancer treatment, harnessing the power of engineered human immune cells to target and eliminate cancer cells. The escalating interest and investment in CAR therapy in recent years emphasize its profound significance in clinical research, positioning it as a rapidly expanding frontier in the field of personalized cancer therapies. A crucial step in CAR therapy design is choosing the right target as it determines the therapy's effectiveness, safety and specificity against cancer cells, while sparing healthy tissues. Herein, we propose a suite of tools for the identification and analysis of potential CAR targets leveraging expression data from The Cancer Genome Atlas and Genotype-Tissue Expression Project, which are implemented in CARTAR website. These tools focus on pinpointing tumor-associated antigens, ensuring target selectivity and assessing specificity to avoid off-tumor toxicities and can be used to rationally designing dual CARs. In addition, candidate target expression can be explored in cancer cell lines using the expression data for the Cancer Cell Line Encyclopedia. To our best knowledge, CARTAR is the first website dedicated to the systematic search of suitable candidate targets for CAR therapy. CARTAR is publicly accessible at https://gmxenomica.github.io/CARTAR/.

HLA alleles: important pieces to the COVID-19 puzzle.

Research on human leukocyte antigen (HLA) molecules in coronavirus disease 2019 (COVID-19) raised high expectations but has yielded limited results. Augusto et al.'s recent study in Nature unveils a strong association of HLA-B*15:01 with asymptomatic COVID-19, representing an important contribution to genetics in COVID-19.

BMPR2 as a Novel Predisposition Gene for Hereditary Colorectal Polyposis.

BACKGROUND & AIMS: Colorectal cancer (CRC) is one of the most prevalent tumors worldwide, with incidence quickly increasing (particularly in the context of early-onset cases), despite important prevention efforts, mainly in the form of population-wide screening programs. Although many cases present a clear familial component, the current list of hereditary CRC genes leaves a considerable proportion of the cases unexplained. METHODS: In this work, we used whole-exome sequencing approaches on 19 unrelated patients with unexplained colonic polyposis to identify candidate CRC predisposition genes. The candidate genes were then validated in an additional series of 365 patients. CRISPR-Cas9 models were used to validate BMPR2 as a potential candidate for CRC risk. RESULTS: We found 8 individuals carrying 6 different variants in the BMPR2 gene (approximately 2% of our cohort of patients with unexplained colonic polyposis). CRISPR-Cas9 models of 3 of these variants showed that the p.(Asn442Thrfs∗32) truncating variant completely abrogated BMP pathway function in a similar way to the BMPR2 knockout. Missense variants p.(Asn565Ser), p.(Ser967Pro) had varying effects on cell proliferation levels, with the former impairing cell control inhibition via noncanonical pathways. CONCLUSIONS: Collectively, these results support loss-of-function BMPR2 variants as candidates to be involved in CRC germline predisposition.

Is There a Bias Towards Males in the Diagnosis of Autism? A Systematic Review and Meta-Analysis.

Autism is more frequently diagnosed in males, with evidence suggesting that females are more likely to be misdiagnosed or underdiagnosed. Possibly, the male/female ratio imbalance relates to phenotypic and camouflaging differences between genders. Here, we performed a comprehensive approach to phenotypic and camouflaging research in autism addressed in two studies. First (Study 1 - Phenotypic Differences in Autism), we conducted a systematic review and meta-analysis of gender differences in autism phenotype. The electronic datasets Pubmed, Scopus, Web of Science, and PsychInfo were searched. We included 67 articles that compared females and males in autism core symptoms, and in cognitive, socioemotional, and behavioural phenotypes. Autistic males exhibited more severe symptoms and social interaction difficulties on standard clinical measures than females, who, in turn, exhibited more cognitive and behavioural difficulties. Considering the hypothesis of camouflaging possibly underlying these differences, we then conducted a meta-analysis of gender differences in camouflaging (Study 2 - Camouflaging Differences in Autism). The same datasets as the first study were searched. Ten studies were included. Females used more compensation and masking camouflage strategies than males. The results support the argument of a bias in clinical procedures towards males and the importance of considering a 'female autism phenotype'-potentially involving camouflaging-in the diagnostic process.

Evaluation of Genetic Variants Associated with the Risk of Thiopurine-Related Pancreatitis: A Case Control Study from ENEIDA Registry.

INTRODUCTION: Risk factors for developing pancreatitis due to thiopurines in patients with inflammatory bowel disease (IBD) are not clearly identified. Our aim was to evaluate the predictive pharmacogenetic risk of pancreatitis in IBD patients treated with thiopurines. METHODS: We conducted an observational pharmacogenetic study of acute pancreatitis events in a cohort study of IBD patients treated with thiopurines from the prospectively maintained ENEIDA registry biobank of GETECCU. Samples were obtained and the CASR, CEL, CFTR, CDLN2, CTRC, SPINK1, CPA1, and PRSS1 genes, selected based on their known association with pancreatitis, were fully sequenced. RESULTS: Ninety-five cases and 105 controls were enrolled; a total of 57% were women. Median age at pancreatitis diagnosis was 39 years. We identified 81 benign variants (50 in cases and 67 in controls) and a total of 35 distinct rare pathogenic and unknown significance variants (10 in CEL, 21 in CFTR, 1 in CDLN2, and 3 in CPA1). None of the cases or controls carried pancreatitis-predisposing variants within the CASR, CPA1, PRSS1, and SPINK1 genes, nor a pathogenic CFTR mutation. Four different variants of unknown significance were detected in the CDLN and CPA1 genes; one of them was in the CDLN gene in a single patient with pancreatitis and 3 in the CPA1 gene in 5 controls. After the analysis of the variants detected, no significant differences were observed between cases and controls. CONCLUSION: In patients with IBD, genes known to cause pancreatitis seem not to be involved in thiopurine-related pancreatitis onset.

A genome-wide association study meta-analysis in a European sample of stage III/IV grade C periodontitis patients ≤35 years of age identifies new risk loci.

AIM: Few genome-wide association studies (GWAS) have been conducted for severe forms of periodontitis (stage III/IV grade C), and the number of known risk genes is scarce. To identify further genetic risk variants to improve the understanding of the disease aetiology, a GWAS meta-analysis in cases with a diagnosis at ≤35 years of age was performed. MATERIALS AND METHODS: Genotypes from German, Dutch and Spanish GWAS studies of III/IV-C periodontitis diagnosed at age ≤35 years were imputed using TopMed. After quality control, a meta-analysis was conducted on 8,666,460 variants in 1306 cases and 7817 controls with METAL. Variants were prioritized using FUMA for gene-based tests, functional annotation and a transcriptome-wide association study integrating eQTL data. RESULTS: The study identified a novel genome-wide significant association in the FCER1G gene (p = 1.0 × 10-9 ), which was previously suggestively associated with III/IV-C periodontitis. Six additional genes showed suggestive association with p < 10-5 , including the known risk gene SIGLEC5. HMCN2 showed the second strongest association in this study (p = 6.1 × 10-8 ). CONCLUSIONS: This study expands the set of known genetic loci for severe periodontitis with an age of onset ≤35 years. The putative functions ascribed to the associated genes highlight the significance of oral barrier tissue stability, wound healing and tissue regeneration in the aetiology of these periodontitis forms and suggest the importance of tissue regeneration in maintaining oral health.

Worldwide distribution of genetic factors related to severity of COVID-19 infection.

BACKGROUND: Genome-wide association studies of COVID-19 severity have been carried out mostly on European or East Asian populations with small representation of other world regions. Here we explore the worldwide distribution and linkage disequilibrium (LD) patterns of genetic variants previously associated with COVID-19 severity. METHODS: We followed up the results of a large Spanish genome-wide meta-analysis on 26 populations from the 1000 Genomes Project by calculating allele frequencies and LD scores of the nine most significant SNPs. We also used the entire set of summary statistics to compute polygenic risk scores (PRSs) and carried out comparisons at the population and continental level. RESULTS: We observed the strongest differences among continental regions for the five top SNPs in chromosome 3. European, American, and South Asian populations showed similar LD patterns. Average PRSs in South Asian and American populations were consistently higher than those observed in Europeans. While PRS distributions were similar among South Asians, the American populations showed striking differences among them. CONCLUSIONS: Considering the caveats of PRS transferability across ethnicities, our analysis showed that American populations present the highest genetic risk score, hence potentially higher propensity, for COVID-19 severity. Independent validation is warranted with additional summary statistics and phenotype data.

A genome-wide gene-environment interaction study of breast cancer risk for women of European ancestry.

BACKGROUND: Genome-wide studies of gene-environment interactions (G×E) may identify variants associated with disease risk in conjunction with lifestyle/environmental exposures. We conducted a genome-wide G×E analysis of ~ 7.6 million common variants and seven lifestyle/environmental risk factors for breast cancer risk overall and for estrogen receptor positive (ER +) breast cancer. METHODS: Analyses were conducted using 72,285 breast cancer cases and 80,354 controls of European ancestry from the Breast Cancer Association Consortium. Gene-environment interactions were evaluated using standard unconditional logistic regression models and likelihood ratio tests for breast cancer risk overall and for ER + breast cancer. Bayesian False Discovery Probability was employed to assess the noteworthiness of each SNP-risk factor pairs. RESULTS: Assuming a 1 × 10-5 prior probability of a true association for each SNP-risk factor pairs and a Bayesian False Discovery Probability < 15%, we identified two independent SNP-risk factor pairs: rs80018847(9p13)-LINGO2 and adult height in association with overall breast cancer risk (ORint = 0.94, 95% CI 0.92-0.96), and rs4770552(13q12)-SPATA13 and age at menarche for ER + breast cancer risk (ORint = 0.91, 95% CI 0.88-0.94). CONCLUSIONS: Overall, the contribution of G×E interactions to the heritability of breast cancer is very small. At the population level, multiplicative G×E interactions do not make an important contribution to risk prediction in breast cancer.

Prenatal environmental exposures associated with sex differences in childhood obesity and neurodevelopment.

BACKGROUND: Obesity and neurodevelopmental delay are complex traits that often co-occur and differ between boys and girls. Prenatal exposures are believed to influence children's obesity, but it is unknown whether exposures of pregnant mothers can confer a different risk of obesity between sexes, and whether they can affect neurodevelopment. METHODS: We analyzed data from 1044 children from the HELIX project, comprising 93 exposures during pregnancy, and clinical, neuropsychological, and methylation data during childhood (5-11 years). Using exposome-wide interaction analyses, we identified prenatal exposures with the highest sexual dimorphism in obesity risk, which were used to create a multiexposure profile. We applied causal random forest to classify individuals into two environments: E1 and E0. E1 consists of a combination of exposure levels where girls have significantly less risk of obesity than boys, as compared to E0, which consists of the remaining combination of exposure levels. We investigated whether the association between sex and neurodevelopmental delay also differed between E0 and E1. We used methylation data to perform an epigenome-wide association study between the environments to see the effect of belonging to E1 or E0 at the molecular level. RESULTS: We observed that E1 was defined by the combination of low dairy consumption, non-smokers' cotinine levels in blood, low facility richness, and the presence of green spaces during pregnancy (ORinteraction = 0.070, P = 2.59 × 10-5). E1 was also associated with a lower risk of neurodevelopmental delay in girls, based on neuropsychological tests of non-verbal intelligence (ORinteraction = 0.42, P = 0.047) and working memory (ORinteraction = 0.31, P = 0.02). In line with this, several neurodevelopmental functions were enriched in significant differentially methylated probes between E1 and E0. CONCLUSIONS: The risk of obesity can be different for boys and girls in certain prenatal environments. We identified an environment combining four exposure levels that protect girls from obesity and neurodevelopment delay. The combination of single exposures into multiexposure profiles using causal inference can help determine populations at risk.

Expanding the clinical and molecular spectrum of FOXG1- and ZBTB18-associated neurodevelopmental disorders.

Introduction The zinc finger BTB domain-containing protein ZBTB18 binds to FOXG1 to form a transcriptional repressive complex involved in neuronal differentiation. Disruption of the components of this complex results in chromosome 1q43-q44 deletion syndrome/intellectual developmental disorder 22 or in FOXG1 syndrome. Case presentation This study reports on five patients with cognitive and behavioral impairment, seizures, microcephaly, and/or congenital brain abnormalities. Whole exome sequencing identified deleterious ZBTB18 variants in three patients and deleterious FOXG1 variants in the remaining patients. We have detected a missense variant within the BTB domain of ZBTB18 in two affected monozygotic twins. In addition, we observed agenesis of the septum pellucidum in a missense FOXG1 carrier with a severe FOXG1 syndrome. Conclusion Although the ZBTB18 zinc finger domains harbor the majority of known deleterious variants, we report a novel de novo rare missense variant within the BTB domain. The agenesis of the septum pellucidum observed in a missense FOXG1 carrier could be considered as a novel clinical feature associated with FOXG1 syndrome. The severe FOXG1 syndrome in this patient contrasts with the milder phenotype expected for a missense. Genetic or environmental factors may explain this phenotypic variability in FOXG1 syndrome.

RSPO4 is a potential risk gene of stages III-IV, grade C periodontitis through effects on innate immune response and oral barrier integrity.

AIM: R-spondin 4 (RSPO4) is a suggestive risk gene of stage III-IV, grade C periodontitis and upregulated in gingiva of mice resistant to bacteria-induced alveolar bone loss. We aimed to replicate the association, identify and characterize the putative causal variant(s) and molecular effects, and understand the downstream effects of RSPO4 upregulation. MATERIALS AND METHODS: We performed a two-step association study for RSPO4 with imputed genotypes of a German-Dutch (896 stage III-IV, grade C periodontitis cases, 7104 controls) and Spanish sample (441 cases and 1141 controls). We analysed the allelic effects on transcription factor binding sites with reporter gene and antibody electrophoretic mobility shift assays. We used CRISPR/dCas9 activation and RNA sequencing to pinpoint RSPO4 as the target gene and to analyse downstream effects. RESULTS: RSPO4 was associated with periodontitis (rs6056178, pmeta  = 4.6 × 10-5 ). rs6056178 contains a GATA-binding motif. The rs6056178 T-allele abolished reporter activity (p = .004) and reduced GATA binding (-14.5%). CRISPRa of the associated region increased RSPO4 expression (25.8 ± 6.5-fold, p = .003). RSPO4 activation showed strongest induction of Gliomedin (439-fold) and Mucin 21 (178-fold) and of the gene set "response to interferon-alpha" (area under the curve [AUC] = 0.8, p < 5 × 10-6 ). The most repressed gene set was "extracellular matrix interactions" (AUC = 0.8, padj  = .00016). CONCLUSION: RSPO4 is a potential periodontitis risk gene and modifies host defence and barrier integrity.

DNA polymorphisms associated with lactase persistence, self-perceived symptoms of lactose intolerance, milk and dairy consumption, and ancestry, in the Uruguayan population.

Uruguay has one of the highest per capita milk intakes worldwide, even with a limited supply of lactose-free products; furthermore, the admixed nature of its population is well known, and various frequencies of lactase persistence (LP) are observed in the source populations. We aimed to contribute to the understanding of the relation between allelic variants associated with LP, milk consumption, digestive symptoms, and genetic ancestry in the Uruguayan population. Samples of saliva or peripheral blood were collected from 190 unrelated individuals from two regions of Uruguay, genotypes for polymorphic sites in a fragment within the LCT enhancer were determined and allelic frequencies calculated in all of them. Data were collected on frequency of milk and dairy consumption and self-reported symptoms in a subsample of 153 individuals. Biparental and maternal ancestry was determined by analyzing individual ancestry markers and mitochondrial DNA. Twenty-nine percentage of individuals reported symptoms attributed to the ingestion of fresh milk, with abdominal pain, bloating and flatulence being the most frequent. European LP-associated allele T-13910 showed a frequency of 33%, while other LP-associated alleles like G-13915 and T-14011 were observed in very low frequencies. Associations between self-reported symptoms, fresh milk intake, and C/T-13910 genotype were statistically significant. No evidence of association between genetic ancestry and C/T-13910 was found, although individuals carrying one T-13910 allele appeared to have more European ancestry. In conclusion, the main polymorphism capable of predicting lactose intolerance in Uruguayans is C/T-13910, although more studies are required to unravel the relation between genotype and lactase activity, especially in heterozygotes.

CSVS, a crowdsourcing database of the Spanish population genetic variability.

The knowledge of the genetic variability of the local population is of utmost importance in personalized medicine and has been revealed as a critical factor for the discovery of new disease variants. Here, we present the Collaborative Spanish Variability Server (CSVS), which currently contains more than 2000 genomes and exomes of unrelated Spanish individuals. This database has been generated in a collaborative crowdsourcing effort collecting sequencing data produced by local genomic projects and for other purposes. Sequences have been grouped by ICD10 upper categories. A web interface allows querying the database removing one or more ICD10 categories. In this way, aggregated counts of allele frequencies of the pseudo-control Spanish population can be obtained for diseases belonging to the category removed. Interestingly, in addition to pseudo-control studies, some population studies can be made, as, for example, prevalence of pharmacogenomic variants, etc. In addition, this genomic data has been used to define the first Spanish Genome Reference Panel (SGRP1.0) for imputation. This is the first local repository of variability entirely produced by a crowdsourcing effort and constitutes an example for future initiatives to characterize local variability worldwide. CSVS is also part of the GA4GH Beacon network. CSVS can be accessed at: http://csvs.babelomics.org/.

Mendelian Randomisation Confirms the Role of Y-Chromosome Loss in Alzheimer's Disease Aetiopathogenesis in Men.

Mosaic loss of chromosome Y (mLOY) is a common ageing-related somatic event and has been previously associated with Alzheimer's disease (AD). However, mLOY estimation from genotype microarray data only reflects the mLOY degree of subjects at the moment of DNA sampling. Therefore, mLOY phenotype associations with AD can be severely age-confounded in the context of genome-wide association studies. Here, we applied Mendelian randomisation to construct an age-independent mLOY polygenic risk score (mloy-PRS) using 114 autosomal variants. The mloy-PRS instrument was associated with an 80% increase in mLOY risk per standard deviation unit (p = 4.22 × 10-20) and was orthogonal with age. We found that a higher genetic risk for mLOY was associated with faster progression to AD in men with mild cognitive impairment (hazard ratio (HR) = 1.23, p = 0.01). Importantly, mloy-PRS had no effect on AD conversion or risk in the female group, suggesting that these associations are caused by the inherent loss of the Y chromosome. Additionally, the blood mLOY phenotype in men was associated with increased cerebrospinal fluid levels of total tau and phosphorylated tau181 in subjects with mild cognitive impairment and dementia. Our results strongly suggest that mLOY is involved in AD pathogenesis.

CIBERER: Spanish national network for research on rare diseases: A highly productive collaborative initiative.

CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research.

Genome-wide meta-analysis for Alzheimer's disease cerebrospinal fluid biomarkers.

Amyloid-beta 42 (Aß42) and phosphorylated tau (pTau) levels in cerebrospinal fluid (CSF) reflect core features of the pathogenesis of Alzheimer's disease (AD) more directly than clinical diagnosis. Initiated by the European Alzheimer & Dementia Biobank (EADB), the largest collaborative effort on genetics underlying CSF biomarkers was established, including 31 cohorts with a total of 13,116 individuals (discovery n = 8074; replication n = 5042 individuals). Besides the APOE locus, novel associations with two other well-established AD risk loci were observed; CR1 was shown a locus for Aß42 and BIN1 for pTau. GMNC and C16orf95 were further identified as loci for pTau, of which the latter is novel. Clustering methods exploring the influence of all known AD risk loci on the CSF protein levels, revealed 4 biological categories suggesting multiple Aß42 and pTau related biological pathways involved in the etiology of AD. In functional follow-up analyses, GMNC and C16orf95 both associated with lateral ventricular volume, implying an overlap in genetic etiology for tau levels and brain ventricular volume.

Evidence, and replication thereof, that molecular-genetic and environmental risks for psychosis impact through an affective pathway.

BACKGROUND: There is evidence that environmental and genetic risk factors for schizophrenia spectrum disorders are transdiagnostic and mediated in part through a generic pathway of affective dysregulation. METHODS: We analysed to what degree the impact of schizophrenia polygenic risk (PRS-SZ) and childhood adversity (CA) on psychosis outcomes was contingent on co-presence of affective dysregulation, defined as significant depressive symptoms, in (i) NEMESIS-2 (n = 6646), a representative general population sample, interviewed four times over nine years and (ii) EUGEI (n = 4068) a sample of patients with schizophrenia spectrum disorder, the siblings of these patients and controls. RESULTS: The impact of PRS-SZ on psychosis showed significant dependence on co-presence of affective dysregulation in NEMESIS-2 [relative excess risk due to interaction (RERI): 1.01, p = 0.037] and in EUGEI (RERI = 3.39, p = 0.048). This was particularly evident for delusional ideation (NEMESIS-2: RERI = 1.74, p = 0.003; EUGEI: RERI = 4.16, p = 0.019) and not for hallucinatory experiences (NEMESIS-2: RERI = 0.65, p = 0.284; EUGEI: -0.37, p = 0.547). A similar and stronger pattern of results was evident for CA (RERI delusions and hallucinations: NEMESIS-2: 3.02, p < 0.001; EUGEI: 6.44, p < 0.001; RERI delusional ideation: NEMESIS-2: 3.79, p < 0.001; EUGEI: 5.43, p = 0.001; RERI hallucinatory experiences: NEMESIS-2: 2.46, p < 0.001; EUGEI: 0.54, p = 0.465). CONCLUSIONS: The results, and internal replication, suggest that the effects of known genetic and non-genetic risk factors for psychosis are mediated in part through an affective pathway, from which early states of delusional meaning may arise.

A replication study of JTC bias, genetic liability for psychosis and delusional ideation.

BACKGROUND: This study attempted to replicate whether a bias in probabilistic reasoning, or 'jumping to conclusions'(JTC) bias is associated with being a sibling of a patient with schizophrenia spectrum disorder; and if so, whether this association is contingent on subthreshold delusional ideation. METHODS: Data were derived from the EUGEI project, a 25-centre, 15-country effort to study psychosis spectrum disorder. The current analyses included 1261 patients with schizophrenia spectrum disorder, 1282 siblings of patients and 1525 healthy comparison subjects, recruited in Spain (five centres), Turkey (three centres) and Serbia (one centre). The beads task was used to assess JTC bias. Lifetime experience of delusional ideation and hallucinatory experiences was assessed using the Community Assessment of Psychic Experiences. General cognitive abilities were taken into account in the analyses. RESULTS: JTC bias was positively associated not only with patient status but also with sibling status [adjusted relative risk (aRR) ratio : 4.23 CI 95% 3.46-5.17 for siblings and aRR: 5.07 CI 95% 4.13-6.23 for patients]. The association between JTC bias and sibling status was stronger in those with higher levels of delusional ideation (aRR interaction in siblings: 3.77 CI 95% 1.67-8.51, and in patients: 2.15 CI 95% 0.94-4.92). The association between JTC bias and sibling status was not stronger in those with higher levels of hallucinatory experiences. CONCLUSIONS: These findings replicate earlier findings that JTC bias is associated with familial liability for psychosis and that this is contingent on the degree of delusional ideation but not hallucinations.