GWAS defines pathogenic signaling pathways and prioritizes drug targets for IgA nephropathy

Background Syncope is a common condition in the general population causing frequent hospitalisation and visits to the emergency department. Family aggregation and twin studies have previously indicated that syncope and collapse has a heritable component. Purpose We investigated whether common genetic variants predispose to syncope and collapse. Methods We used genome-wide association data on syncope and collapse for 408,961 individuals with European ancestry from the UK Biobank study. In a replication study, the Integrative Psychiatric Research Consortium (iPSYCH) cohort (n=86,189) was used to investigate the risk of incident syncope stratified by genotype carrier status. Results We report on a genome-wide significant locus on chromosome 2q32.1 with the lead SNP rs12465214 (odds ratio [OR] = 1.13, 95% confidence interval [CI] = 1.10–1.17, P=5.8x10–15; Figure 1a). This association was replicated in the iPSYCH cohort, where homozygous carriers of the C allele conferred an increased hazard ratio (HR=1.30, CI: 1.15–1.46, P=1.68x10–5; Figure 1b). LD score regression demonstrated a significant genetic correlation (rg) with coronary artery disease (rg=0.41, P=6.99x10–15) and related phenotypes such as angina and hypertension (Figure 1c). Analyses of eQTL (P=4x10–8) and epigenetic chromatin states revealed that variation in this locus likely affects expression of the gene ZNF804A, which resides in its proximity (Figure 1d). A qPCR analysis showed that ZNF804A was mostly expressed in the brain. A lower level of ZNF804A expression was also detected in the cerebral arteries. ZNF804A was not expressed in heart tissue. Figure 1 Conclusion rs12465214 is associated with syncope and collapse. Variation in this locus likely modulates the expression of the nearby gene ZNF804A through eQTLs and chromatin interactions. ZNF804A is mainly expressed in the brain and cerebral arteries. However, the precise function of ZNF804A is unknown. Furthermore, syncope and collapse is a polygenetic trait and share a significant genetic overlap with coronary artery disease, angina and hypertension. Acknowledgement/Funding This work was supported by grants from The John and Birthe Meyer Foundation, The Research Foundation of the Heart Centre, Rigshospitalet, The Research

M25 - Investigation of Relationships Between Bipolar Disorder Phenotypes And Genome-Wide Significant Loci From PGC2 Schizophrenia

IgA antibodies against Klebsiella pneumoniae were measured by immunofluorescence in 84 Catalan patients with ankylosing spondylitis (AS), 41 patients with non-inflammatory arthropathies (NIA) and 22 patients with rheumatoid arthritis (RA). Patients with AS showed higher levels of anti-klebsiella IgA antibodies (IgA-Kp) than NIA and RA patients (4.7 +/- 1.6 U vs 3.7 +/- 1.5 U and 3.1 +/- 1.4 U respectively, p = 0.001). In AS patients a significant correlation between IgA-Kp and levels of C-reactive protein was observed. Although no clear correlation was found between IgA anti-klebsiella and total serum IgA levels, a significant correlation between IgA anti-klebsiella and serum levels of secretory IgA was detected (r: 0.43, p = 0.003). In conclusion, some patients with AS disclosed raised levels of Klebsiella antibodies in sera and this is related to an increase of secretory IgA level. Analysis about the relationship between response to klebsiella and the presence of gut inflammation in AS patients could be of interest.

In our study, BALB/c mice were orally administered multistrain probiotics or sterile water for 28 consecutive days. The total serum IgA and IgG antibody levels were significantly higher in the group of mice administered probiotics (p ＜ 0.05) than in the control group at the 4^(th) week. Consumption of multistrain probiotics for 28 days significantly increased (p ＜ 0.05) the fecal populations of Bifidobacterium spp. and Lactobacillus spp. In another animal model, the mice were orally administered for 14 consecutive days. On the 7th day, all the mice were orally challenged with Salmonella Typhimurium ISM 50. The mice were sacrificed after 6 days of infection, Salmonella counts in the spleen and liver of the mice administered probiotics significantly declined (p ＜ 0.001) as compared to the control group. We demonstrated that the probiotic mixture could be used to enhance the host serum IgA and IgG levels and prevent Salmonella infection.

The authors conducted a genome-wide association study of anorexia nervosa and calculated genetic correlations with a series of psychiatric, educational, and metabolic phenotypes. Following uniform quality control and imputation procedures using the 1000 Genomes Project (phase 3) in 12 case-control cohorts comprising 3,495 anorexia nervosa cases and 10,982 controls, the authors performed standard association analysis followed by a meta-analysis across cohorts. Linkage disequilibrium score regression was used to calculate genome-wide common variant heritability (single-nucleotide polymorphism [SNP]-based heritability [h2SNP]), partitioned heritability, and genetic correlations (rg) between anorexia nervosa and 159 other phenotypes. Results were obtained for 10,641,224 SNPs and insertion-deletion variants with minor allele frequencies >1% and imputation quality scores >0.6. The h2SNP of anorexia nervosa was 0.20 (SE=0.02), suggesting that a substantial fraction of the twin-based heritability arises from common genetic variation. The authors identified one genome-wide significant locus on chromosome 12 (rs4622308) in a region harboring a previously reported type 1 diabetes and autoimmune disorder locus. Significant positive genetic correlations were observed between anorexia nervosa and schizophrenia, neuroticism, educational attainment, and high-density lipoprotein cholesterol, and significant negative genetic correlations were observed between anorexia nervosa and body mass index, insulin, glucose, and lipid phenotypes. Anorexia nervosa is a complex heritable phenotype for which this study has uncovered the first genome-wide significant locus. Anorexia nervosa also has large and significant genetic correlations with both psychiatric phenotypes and metabolic traits. The study results encourage a reconceptualization of this frequently lethal disorder as one with both psychiatric and metabolic etiology.

Dogs display temperamental and behavioral variation between individuals, just as psychiatric, temperamental, and cognitive traits vary in humans. In both species, these traits are highly heritable, yet causal genes remain incompletely understood. We performed 14 genome-wide association studies (GWAS) for behavioral traits quantified using the Canine Behavioral Assessment and Research Questionnaire (C-BARQ) in ~1,000 golden retrievers, identifying 12 genome-wide significant loci (P < 2.97 × 10-6) for 8 traits and 9 additional loci exceeding a suggestive threshold (P < 1 × 10-5). A human phenome-wide association study (PheWAS) showed that most of the 18 canine positional candidate genes identified were associated with one or more of 190 psychiatric, temperamental, or cognitive traits in humans (7/12 genes at genome-wide loci and 5/9 at suggestive loci). For example, a genome-wide significant locus near PTPN1 (dog-directed aggression) overlapped with human measures of Intelligence, Educational attainment, and major depressive disorder. The gene ROMO1 was within a genome-wide significant locus for trainability in dogs and associated with intelligence, depression, irritability, and sensitivity/hurt feelings in humans. Other genes located at genome-wide significant loci associated with behavioral, psychiatric, temperamental, or cognitive traits in both species included PRDX1(dog-directed fear), VWA8 (touch sensitivity), ITPR2, and ADGRL2/LPHN2 (trainability), and ADD2 (stranger-directed fear). From suggestive loci we also found cross-species associations for HUNK, and ZC3H12C, (dog-directed fear), SLC35F6 and IGSF11 (separation-related problems). These results suggest that shared genetic and molecular mechanisms underlie complex behavioral and temperamental states across species and may inform our understanding of emotional states driving undesirable behaviors in dogs.

Long Term Humoral Immune Reconstitution Kinetics After Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) In Children

The aim of the research is to determine the effect of the probiotic preparation «Dialak» (dietary supplement), which includes the strain Lactobacillus casei IMV B-7280, on the vaginal microbiota and humoral immunity in women with bacterial vaginosis (BV). Methods. 40 female patients aged 20—45 years with disturbed vaginal microbiota and 10 healthy individuals were examined. The verification of 3 types of vaginal biocenosis states, namely normocenosis, intermediate type, and vaginal dysbiosis, was carried out on the basis of the Recommendations for the Treatment of Sexually Transmitted Infections Weekly Morbidity and Mortality Report (2021) and laboratory diagnostic methods according to the well-known criteria proposed by R. Amsel. Female patients with an intermediate type of BV (group 1) received suppositories and capsules of the probiotic (once daily) for 10 days. Women with vaginal dysbiosis (group 2) received metronidazole in a dosage of 500 mg twice a day for 7 days during the first stage, and then 1 suppository at night and oral capsules of the probiotic in the morning for 10 days during the second stage. The studied vaginal secretion was stained by the Gram method in the Kopeloff modification and also sown on nutrient media to determine facultatively anaerobic and obligately anaerobic microorganisms. Microorganism identification was carried out on the basis of morphological, cultural, biochemical, and antigenic properties according to the classification of D. H. Bergey (2009). The activity of humoral immunity was determined by evaluating the number of B-lymphocytes in the peripheral blood of patients using flow cytometry, as well as the levels of serum Ig A, M, and G before treatment and aft er 1 month using the immunoturbidimetric method and the Cobas 6000 test system from Roche Diagnostics (Switzerland). Results. When analyzing the vaginal microbiota in two groups of patients before treatment, a decrease in the number of Lactobacillus spp. and Bifidobacterium spp. and a significant increase in the number of obligate anaerobic microorganisms, including Gardnerella vaginalis, were found compared to the control group. Before treatment, the number of Lactobacillus spp. in women of group 2 was lower compared to group 1. In patients with vaginal dysbiosis before treatment, the number of obligate anaerobic microorganisms was higher than in patients with bacterial vaginosis, except for Eubacterium spp. At the same time, in women in both comparison groups, the indicators of the humoral immune response were partially disrupted, as evidenced by a decrease in the level of IgG and IgA (in women of group 2) in the serum against the normal level of B lymphocytes (CD19+ cells). However, these patients showed an increase in the IgM level in the serum, which may be due to the development of anaerobic microflora. After treatment, the number of Lactobacillus spp. and Bifidobacterium spp. in the vagina of women in both comparison groups increased compared to the indicators before treatment. However, the number of these bacteria in the vagina of patients with dysbiosis remained lower compared to patients with BV. In both groups, normalization of the number of obligate anaerobic microorganisms, including G. vaginalis, except for Veillonella spp., was also observed. After treatment, the humoral immune response indicators were normalized as well: the level of serum IgG and IgA increased, and the content of serum IgM decreased. Conclusions. In BV patients, the probiotic «Dialak» normalizes the vaginal microbiota, which was confirmed by increasing the number of Lactobacillus spp. and Bifidobacterium spp. along with decreasing the number of anaerobic microorganisms, including G. vaginalis, against the background of the dynamic disappearance of clinical signs of the disease, as well as restoration to the normal level of indicators of the immunity humoral link. The obtained data indicate the effective therapeutic effect of the probiotic «Dialak» on BV.

IgA nephropathy, the most prevalent glomerular disease in the world, requires a renal biopsy for diagnosis. Reliable biomarkers are needed for the non-invasive diagnosis of this disease and to more fully delineate its natural history and risk for progression. In this review, the authors examine serum levels of galactose-deficient IgA1 (Gd-IgA1) and glycan-specific IgG and IgA autoantibodies that are integral to pathogenesis of IgA nephropathy. They also explore biomarkers related to alternative and lectin pathways of complement activation and serum and urinary peptide biomarkers detected by mass spectrometric methods. The literature search included review of all publications having IgA nephropathy in the title that were cited in PubMed and Scopus over the past 10 years and a non-systematic review of abstracts published for the annual meetings of the American Society of Nephrology and the International Symposia on IgA Nephropathy. Serum Gd-IgA1 level and glycan-specific autoantibody levels are prime candidates to become diagnostic biomarkers for IgA nephropathy because of their central role in the earliest stages of disease pathogenesis. Assays for serum levels of complement proteins C3 and factor H are readily available in clinical practice and deserve continued study, either alone or in tandem with total serum IgA or serum Gd-IgA1 levels, as prognostic biomarkers for patients with IgA nephropathy. Urinary peptidomic data are also reviewed because this approach can successfully differentiate patients with IgA nephropathy from healthy controls and from patients with other forms of renal disease.

Schistosoma mansoni-infected subjects from the Gezira Irrigated Area of Sudan were studied for serum immunoglobulin levels, and specific antibody titres to larval, adult and egg stage antigens, by class and IgG subclass. The 276 subjects were adult chronic cases (frequently exposed male canal cleaners), primary school children, and hospital-referred cases with acute symptoms including hepatosplenomegaly. Chronic untreated cases were compared with a similar group of canal cleaners 3 months after successful chemotherapy with Praziquantel administered at the start of the non-transmission season. All cases, except those previously treated, were egg positive at the time of blood sampling. Data from infected and treated cases were compared with measurements of serum immunoglobulin in a panel of European blood donors. The major findings are as follows: There is a consistently elevated total serum IgG concentration in infected groups which is accounted for mainly by an increased IgG1 subclass (greatest in chronic cases) and by a remarkable 10- to 11-fold increase in IgG4 in the untreated chronically infected group and in the schoolchildren. All infected groups showed high IgG antibody responses to all life cycle stage antigens, and IgM titres were high to adult and egg antigens in untreated canal cleaners. Major differences were evident in the distribution of IgG subclass antibodies between the infected groups: the response to larval and adult antigens is poor or absent in IgG1, IgG2 and IgG3 in untreated chronic infections but is high in IgG4, whereas in acute cases with hepatosplenomegaly and in school-children IgG1, IgG2 and IgG3 antibodies to larval antigens are in high titre but IgG4 and IgM responses to larvae are low or absent, the response in these isotypes being restricted in these cases to adult and egg antigens. Comparing the treated and untreated canal cleaners, although these are separate groups, the data suggest that Praziquantel reduces total serum IgA and IgM levels but has little effect on the raised IgG component except for the IgG4 subclass. The treated chronic cases show a reversal in the ratio of IgG1, IgG2 and IgG3 to IgG4 antibodies to larval and adult antigens compared with the untreated chronic group-the IgG4 response being low by 3 months after treatment and the IgG1, IgG2 and IgG3 being high. These data are discussed in relation to the possible importance of antibody isotype selection in determining host susceptibility to infection, with reference to age, exposure and treatment of the host.

Primary immunoglobulin A nephropathy (IgAN) is characterized by IgA1-dominant or codominant glomerular deposits, postulated to be galactose deficient (Gd). However, glomerular IgA deposition can also occur in nonrenal diseases such as liver cirrhosis, psoriasis and inflammatory bowel disease ('secondary IgAN') or be an incidental finding in biopsies with other pathologies. A glomerulonephritis resembling IgAN can develop in patients with bacterial, mainly staphylococcal infections [staphylococcal infection-associated glomerulonephritis (SAGN)]. There are no specific histological features to distinguish between these, but differentiation is critical for appropriate management. The aim of this study was to investigate whether a recently described antibody to Gd-IgA1 (KM-55) could aid in differentiating primary IgAN from other conditions with glomerular IgA deposition, especially SAGN. We performed a retrospective cohort study of patients who underwent kidney biopsy for clinical indications and were found to have glomerular IgA deposits. We evaluated 100 biopsies, including primary IgAN (n = 44), secondary IgAN (n = 27), SAGN (n = 13), incidental IgA deposition (n = 8) and lupus nephritis (n = 8). There was no difference in Gd-IgA staining intensity or the proportion of positive cases between primary and secondary IgAN. SAGN and cases with incidental IgA deposits had significantly lower Gd-IgA staining intensity than primary IgAN, but up to 69% of SAGN cases were positive (albeit weaker). Gd-IgA staining is present not only in primary IgAN, but also in biopsies with secondary IgAN, SAGN and incidental IgA. Weak or negative staining may favor SAGN, especially in the setting of infection, or incidental IgA in the absence of nephritic symptoms or in the presence of other unrelated glomerular pathologies. However, positive staining for Gd-IgA alone is not specific enough for a diagnosis of primary IgAN.

The incidence of obesity has significantly increased worldwide. However, it is still unclear about the genetic susceptibility of obesity. Here we performed the largest European meta-analysis of genome-wide association study, including 98,421 obesity cases and 2,108,019 healthy controls. We identified 322 novel genome-wide significant obesity-associated loci and 23 of 32 known loci. SNP-based heritability analyses revealed that common variants explain 17.19 ± 0.59% of genetic risk for obesity, whereas MiXeR predicted an estimated 1.6 million effective sample sizes explaining 90% of obesity-associated phenotypic variance. Across 345 obesity-associated loci, 2000 likely causal genes are indicated, and 410 causal genes are prioritized. Tissue specificity enrichment analyses demonstrated that obesity-related causal genes mainly expressed in brain putamen basal ganglia, hippocampus, amygdala, substantia nigra, and caudate basal ganglia. The genetic correlation and gene-set analyses showed that apart from obesity-related diseases, some brain diseases and mood (e.g., broad depression, neuroticism, mood swings), inflammatory and allergic diseases diseases (e.g., asthma, spondyloarthritis, Hashimoto thyroiditis), cardiovascular diseases (e.g., hypertension, myocardial infarction, coronary artery disease), and lung disease (e.g., interstitial lung disease, chronic obstructive pulmonary disease, lung cancer) have the positive correlations with obesity. Gene-drug interaction analysis suggested that obesity-associated genes overlapped with targets of current medications for obesity. Finally, we used this meta-analysis to explore some potential targets (e.g., GLP1R, SIGMAR1, MC4R) and drug repurposing (e.g., iloprost, flunarizine, edrophonium chloride) for obesity. We identified 345 genome-wide significant loci, including 322 novel loci for obesity. Based on 345 loci, we provided new biological insights to the etiology of obesity. Of clinical interest, we provided some potential targets and drug repurposing for obesity.

Frozen shoulder is a painful condition that often requires surgery and affects up to 5% of individuals aged 40–60 years. Little is known about the causes of the condition, but diabetes is a strong risk factor. To begin to understand the biological mechanisms involved, we aimed to identify genetic variants associated with frozen shoulder and to use Mendelian randomization to test the causal role of diabetes. We performed a genome-wide association study (GWAS) of frozen shoulder in the UK Biobank using data from 10,104 cases identified from inpatient, surgical and primary care codes. We used data from FinnGen for replication and meta-analysis. We used one-sample and two-sample Mendelian randomization approaches to test for a causal association of diabetes with frozen shoulder. We identified five genome-wide significant loci. The most significant locus (lead SNP rs28971325; OR = 1.20, [95% CI: 1.16–1.24], p = 5x10-29) contained WNT7B. This variant was also associated with Dupuytren’s disease (OR = 2.31 [2.24, 2.39], p<1x10-300) as were a further two of the frozen shoulder associated variants. The Mendelian randomization results provided evidence that type 1 diabetes is a causal risk factor for frozen shoulder (OR = 1.03 [1.02–1.05], p = 3x10-6). There was no evidence that obesity was causally associated with frozen shoulder, suggesting that diabetes influences risk of the condition through glycemic rather than mechanical effects. We have identified genetic loci associated with frozen shoulder. There is a large overlap with Dupuytren’s disease associated loci. Diabetes is a likely causal risk factor. Our results provide evidence of biological mechanisms involved in this common painful condition.

Vitamin D is a steroid hormone precursor that is associated with a range of human traits and diseases. Previous GWAS of serum 25-hydroxyvitamin D concentrations have identified four genome-wide significant loci (GC, NADSYN1/DHCR7, CYP2R1, CYP24A1). In this study, we expand the previous SUNLIGHT Consortium GWAS discovery sample size from 16,125 to 79,366 (all European descent). This larger GWAS yields two additional loci harboring genome-wide significant variants (P = 4.7×10-9 at rs8018720 in SEC23A, and P = 1.9×10-14 at rs10745742 in AMDHD1). The overall estimate of heritability of 25-hydroxyvitamin D serum concentrations attributable to GWAS common SNPs is 7.5%, with statistically significant loci explaining 38% of this total. Further investigation identifies signal enrichment in immune and hematopoietic tissues, and clustering with autoimmune diseases in cell-type-specific analysis. Larger studies are required to identify additional common SNPs, and to explore the role of rare or structural variants and gene-gene interactions in the heritability of circulating 25-hydroxyvitamin D levels.

We recently conducted a large association analysis to compare the genetic profiles between patients with psoriatic arthritis (PsA) and cutaneous-only psoriasis (PsC). Despite including over 7,000 genotyped patients, only the MHC achieved genome-wide significance. In this study, we hypothesized that appropriate epigenomic elements (H3K27ac marks for active enhancers) can guide us to reveal valuable information about the loci with suggestive evidence of association. Our aim is to investigate these loci and explore how they may lead to the development of PsA. We evaluated this potential by investigating the genes connected with these loci from the perspective of pharmacogenomics and gene expression. We illustrated that markers with suggestive evidence of association outside the MHC region are enriched in H3K27ac marks for osteoblast and chondrogenic differentiated cells; using pharmacogenomics resources, we showed that genes near these markers are targeted by existing drugs used to treat psoriatic arthritis. Significantly, six of the ten suggestive significant loci overlapping the regulatory elements encompass genes differentially expressed (FDR < 5%) in differentiated osteoblasts, including genes participating in the Wnt signaling such as RUNX1, FUT8, and CTNNAL1. Our approach shows that epigenomic information can be used as cost-effective approach to enhance the inferences for GWAS results, especially in situations when few genome-wide significant loci are available. Our results also point the way to more directed investigations comparing the genetics of PsA and PsC.