Index Single Nucleotide Polymorphisms Research Articles

A Multilayered Post-Genome-Wide Association Study Analysis Pipeline Defines Functional Variants and Target Genes for Systemic Lupus Erythematosus.

Systemic lupus erythematosus (SLE), an autoimmune disease with incompletely understood etiology, has a strong genetic component. Although genome-wide association studies (GWASs) have revealed multiple SLE susceptibility loci and associated single-nucleotide polymorphisms (SNPs), the precise causal variants, target genes, cell types, tissues, and mechanisms of action remain largely unknown. Here, we report a comprehensive post-GWAS analysis using extensive bioinformatics, molecular modeling, and integrative functional genomic and epigenomic analyses to optimize fine-mapping. We compile and cross-reference immune cell-specific expression quantitative trait loci (cis- and trans-expression quantitative trait loci) with promoter capture high-throughput capture chromatin conformation (PCHi-C), allele-specific chromatin accessibility, and massively parallel reporter assay data to define predisposing variants and target genes. We experimentally validate a predicted locus using CRISPR/Cas9 genome editing, quantitative polymerase chain reaction, and Western blot. Anchoring on 452 index SNPs, we selected 9,931 high linkage disequilibrium (r2 > 0.8) SNPs and defined 182 independent non-human leukocyte antigen (HLA) SLE loci. The 3,746 SNPs from 143 loci were identified as regulating 564 unique genes. Target genes are enriched in lupus-related tissues and associated with other autoimmune diseases. Of these, 329 SNPs (106 loci) showed significant allele-specific chromatin accessibility and/or enhancer activity, indicating regulatory potential. Using CRISPR/Cas9, we validated reference SNP identifier 57668933 (rs57668933) as a functional variant regulating multiple targets, including SLE-risk gene ELF1 in B cells. We demonstrate and validate post-GWAS strategies for using multidimensional data to prioritize likely causal variants with cognate gene targets underlying SLE pathogenesis. Our results provide a catalog of significantly SLE-associated SNPs and loci, target genes, and likely biochemical mechanisms to guide experimental characterization.

Evolution of human brain left-right asymmetry - Old genes with new functions.

The human brain is generally anatomically symmetrical, boasting mirror-like brain regions in the left and right hemispheres. Despite this symmetry, fine-scale structural asymmetries are prevalent and are believed to be responsible for distinct functional divisions within the brain. Prior studies propose that these asymmetric structures are predominantly primate-specific or even unique to humans, suggesting that the genes contributing to the structural asymmetry of the human brain might have evolved recently. In our study, we identified approximately 1,500 traits associated with human brain asymmetry by collecting paired brain MRI features from the UK Biobank. Each trait is measured in a specific region of one hemisphere and mirrored in the corresponding region of the other hemisphere. Conducting genome-wide association studies on these traits, we identified over 1,000 quantitative trait loci (QTLs). Around these index single nucleotide polymorphisms (SNPs), we found approximately 200 genes that are enriched in brain-related Gene Ontology terms and are predominantly up-regulated in brain tissues. Interestingly, most of these genes are evolutionarily old, originating just prior to the emergence of Bilateria (bilaterally symmetrical animals) and Euteleostomi (bony vertebrates with a brain), at a significantly higher ratio than expected. Further analyses of these genes reveal a brain-specific up-regulation in humans relative to other mammalian species. This suggests that the structural asymmetry of the human brain has been shaped by evolutionarily ancient genes that have assumed new functions over time.

Evaluating significance of European-associated index SNPs in the East Asian population for 31 complex phenotypes

BackgroundGenome-wide association studies (GWASs) have identified many single-nucleotide polymorphisms (SNPs) associated with complex phenotypes in the European (EUR) population; however, the extent to which EUR-associated SNPs can be generalized to other populations such as East Asian (EAS) is not clear.ResultsBy leveraging summary statistics of 31 phenotypes in the EUR and EAS populations, we first evaluated the difference in heritability between the two populations and calculated the trans-ethnic genetic correlation. We observed the heritability estimates of some phenotypes varied substantially across populations and 53.3% of trans-ethnic genetic correlations were significantly smaller than one. Next, we examined whether EUR-associated SNPs of these phenotypes could be identified in EAS using the trans-ethnic false discovery rate method while accounting for winner's curse for SNP effect in EUR and difference of sample sizes in EAS. We found on average 54.5% of EUR-associated SNPs were also significant in EAS. Furthermore, we discovered non-significant SNPs had higher effect heterogeneity, and significant SNPs showed more consistent linkage disequilibrium and allele frequency patterns between the two populations. We also demonstrated non-significant SNPs were more likely to undergo natural selection.ConclusionsOur study revealed the extent to which EUR-associated SNPs could be significant in the EAS population and offered deep insights into the similarity and diversity of genetic architectures underlying phenotypes in distinct ancestral groups.

GWAS Quality Score for Evaluating Associated Regions in GWAS Analyses.

The number of significantly associated regions reported in genome-wide association studies (GWAS) for polygenic traits typically increases with sample size. A traditional tool for quality control and identification of significant regions has been visual inspection of how significant and correlated genetic variants cluster within a region. However, while inspecting hundreds of regions, this subjective method can misattribute significance to some loci or neglect others that are significant. The GWAS quality score (GQS) identifies suspicious regions and prevents erroneous interpretations with an objective, quantitative and automated method. The GQS assesses all measured SNPs that are linked by inheritance to each other (linkage disequilibrium-LD) and compares the significance of trait association of each SNP to its LD value for the reported index SNP. A GQS value of 1.0 ascribes a high level of confidence to the entire region and its underlying gene(s), while GQS values less than 1.0 indicate the need to closely inspect the outliers. We applied the GQS to published and non-published genome-wide summary statistics and report suspicious regions requiring secondary inspection while supporting the majority of reported regions from large-scale published meta-analyses. The GQS code/scripts can be cloned from GitHub (https://github.com/Xswapnil/GQS/).The analyst can use whole genome summary statistics to estimate GQS for each defined region. We also provide an online tool (http://35.227.18.38/ ) that gives access to the GQS. The quantitative measure of quality attributes by GQS and its visualization is an objective method that enhances the confidence of each genomic hit. Supplementary data are available at Bioinformatics online.

HBB rs334, ABO Rs8176703 and Plasmodium Falciparum Positivity at Enrollment Are Independently Associated with Lower Risk for Endemic Burkitt Lymphoma in Uganda, Tanzania, Kenya, and Malawi

Background Burkitt lymphoma (BL) is an aggressive B-cell lymphoma that accounts for 50-75% of childhood cancers in sub-Saharan Africa. Recurrent infection with Plasmodium (P.) falciparum is hypothesized to be causally linked to BL, but the epidemiological evidence is limited because it is based on exposures measured after BL onset. The prolonged period before BL onset makes traditional cohort studies impractical. To circumvent this problem, it was proposed that genetic variants that confer genetic resistance to P falciparum, such as heterozygotes for the HBB sickle allele (rs334), could be used to demonstrate a causal link with malaria. However, results from six studies have been conflicting, perhaps, reflecting effects of small sample size, design flaws in the studies or confounding. For example, co-inheritance with other genetic variants, such as a-thalassemia, have been reported to confound the epidemiological associations of severe malaria with rs334. Additionally, resistance against P. falciparum due to "premunition", defined as anti-clinical and anti-parasite resistance due to acquired immunity, could confound genetic associations with BL. To address the hypothesis of whether resistance to malaria protects against BL, we investigated the associations between BL and rs334 and 31 other single nucleotide polymorphisms (SNPs) plus α-thalassemia (hereafter, index malaria resistance SNPs/variants), and premunition, defined as P. falciparum positivity at enrollment, in cases enrolled in Uganda, Tanzania, Kenya, and Malawi, all designated as high malaria burden countries by the World Health Organization. Methods The study cohort consisted of 800 children (<16 years) with BL and 3845 children without BL enrolled in the Epidemiology of Burkitt Lymphoma in East African Children and Minors (EMBLEM) study (2010-2016) and the Infections and Childhood Cancer case-control study conducted in Malawi (2005-2010). P falciparum status was determined by thick-film microscopy, malaria antigen (HRP2/pLDH) rapid diagnostic test, or PCR at enrollment. Malaria protective SNPs were extracted from genome-wide data measured using Infinium Omni5Exome-4 v1.3 BeadChip (Illumina, San Diego, CA, USA). Genotyping for α3.7-thalassemia deletions (/-α3.7)utilized droplet digital polymerase chain reaction. We tested for associations between BL and the malaria index SNPs, a genotypes, and P. falciparum positivity using generalized linear mixed models, controlling for age, sex, and the first 3 population-specific principal components as fixed effects and for genetic relatedness (calculated from genome-wide data) as a random effect. We considered a p-value < 0.05 for statistical significance for malaria index SNPs. Results The mean age was similar for BL cases and controls (7.19 years versus 7.43 years, p= 0.07), but BL cases were more likely to be males (63.2% versus 52.1%, p£0.0001). P. falciparum positivity was lower in BL cases than controls (35.2% versus 48.3%, p<0.0001). Figure 1 shows the associations between 32 malaria index SNPs with BL and with P. falciparum positivity. Odds of BL were significantly decreased in presence of HBB rs334 (odds ratio [OR]= 0·687, 95% CI 0·533-0·885; p=0·0037) and ABO rs8176703 (0·591, 0·379-0·922; p=0.0203). Results for α-genotypes included the normal genotype (αα/αα), triplication (ααα/αα), -α3.7/αα, -α3.7/-α3.7deletions and unknown. Using αα/αα as the reference, the ORs for BL were 1.82, p=0.06 for ααα/αα; 1.07, p=0.469 for -α3.7/αα; and 0.78, p=0.15 for -α3.7/-α3.7. The odds of BL were significantly decreased with P. falciparum positivity in analyses without the two significant index SNPs (OR= 0.526, 95% CI 0.428-0.633, p=9.64x10-12) and changed minimally when the two SNPs were included (OR= 0·524, 0·435-0·630, p=7·291x10-12) . Conclusion Based on 4,581 children in four high malaria burden countries, we found reduced odds of BL among carriers of malaria index variants in HBB and ABO genes which suggests that these variants may protect against BL as well. Additionally, our findings of decreased odds of BL with P. falciparum positivity at enrollment suggest premunition may be protective against BL, independent of the significant associations with SNPs in HBB and ABO. Together, our findings further enhance the evidence of a causal role of malaria in BL; coordination between malaria and BL programs in countries with high malaria/BL burden should be strengthened. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

RBFOX1 and Working Memory: From Genome to Transcriptome Revealed Posttranscriptional Mechanism Separate From Attention-Deficit/Hyperactivity Disorder

BackgroundMany psychiatric disorders share a working memory (WM) impairment phenotype, yet the genetic causes remain unclear. Here, we generated genetic profiles of WM deficits using attention-deficit/hyperactivity disorder samples and validated the results in zebrafish models. MethodsWe used 2 relatively large attention-deficit/hyperactivity disorder cohorts, 799 and 776 cases, respectively. WM impairment was assessed using the Rey Complex Figure Test. First, association analyses were conducted at single-variant, gene-based, and gene-set levels. Deeper insights into the biological mechanism were gained from further functional exploration by bioinformatic analyses and zebrafish models. ResultsGenomic analyses identified and replicated a locus with rs75885813 as the index single nucleotide polymorphism showing significant association with WM defects but not with attention-deficit/hyperactivity disorder. Functional feature exploration found that these single nucleotide polymorphisms may regulate the expression level of RBFOX1 through chromatin interaction. Further pathway enrichment analysis of potential associated single nucleotide polymorphisms revealed the involvement of posttranscription regulation that affects messenger RNA stability and/or alternative splicing. Zebrafish with functionally knocked down or genome-edited rbfox1 exhibited WM impairment but no hyperactivity. Transcriptome profiling of rbfox1-defective zebrafish indicated that alternative exon usages of snap25a might partially lead to reduced WM learning of larval zebrafish. ConclusionsThe locus with rs75885813 in RBFOX1 was identified as associated with WM. Rbfox1 regulates synaptic and long-term potentiation–related gene snap25a to adjust WM at the posttranscriptional level.

Common single-nucleotide polymorphisms combined with a genetic risk score provide new insights regarding the etiology of gestational diabetes mellitus.

Few studies have constructed a genetic risk score (GRS) to predict the risk of gestaional diabetes mellitus (GDM). We tested the hypothesis that single-nucleotide polymorphisms (SNPs) confirmed for diabetes and obesity and the GRS are associated with GDM. We conducted a case-control study comprising 971 GDM cases and 1682 controls from the University of Hong Kong Shenzhen Hospital. A total of 1448 SNPs reported with type 2 diabetes (T2D), type 1 diabetes (T1D), and obesity were selected and the GRS based on SNPs associated with GDM was created. We confirmed that rs10830963 (OR=1.41,95% CI=1.25, 1.59) in MTNR1B and rs2206734 (OR=1.38, 95% CI=1.22, 1.55) in CDKAL1 were strongly associated with the risk of GDM. Compared with participants with GRS based on T2D SNPs in the low tertile, the ORs of GDM across increasing GRS tertiles were 1.63 (95% CI 1.29, 2.06) and 2.72 (95% CI 2.18, 3.38) in the middle and high tertile, respectively. The positive associations between the GRS and the risk of GDM were also observed in GRS based on obesity/waist-to-hip ratio (WHR)/body mass index (BMI) SNPs. The resulting GRS for each allele increase was significantly associated with higher glycemic indices and lower HOMA-B values for GRS based on T2D SNPs, but not for GRS based on T1D SNPs and GRS based on obesity/WHR/BMI SNPs. These findings indicate that GDM may share a common genetic background with T2D and obesity and that SNPs associated with insulin secretion defects have a vital role in the development of GDM.

Meta-GWAS Reveals Novel Genetic Variants Associated with Urinary Excretion of Uromodulin.

Uromodulin, the most abundant protein excreted in normal urine, plays major roles in kidney physiology and disease. The mechanisms regulating the urinary excretion of uromodulin remain essentially unknown. We conducted a meta-analysis of genome-wide association studies for raw (uUMOD) and indexed to creatinine (uUCR) urinary levels of uromodulin in 29,315 individuals of European ancestry from 13 cohorts. We tested the distribution of candidate genes in kidney segments and investigated the effects of keratin-40 (KRT40) on uromodulin processing. Two genome-wide significant signals were identified for uUMOD: a novel locus (P 1.24E-08) over the KRT40 gene coding for KRT40, a type 1 keratin expressed in the kidney, and the UMOD-PDILT locus (P 2.17E-88), with two independent sets of single nucleotide polymorphisms spread over UMOD and PDILT. Two genome-wide significant signals for uUCR were identified at the UMOD-PDILT locus and at the novel WDR72 locus previously associated with kidney function. The effect sizes for rs8067385, the index single nucleotide polymorphism in the KRT40 locus, were similar for both uUMOD and uUCR. KRT40 colocalized with uromodulin and modulating its expression in thick ascending limb (TAL) cells affected uromodulin processing and excretion. Common variants in KRT40, WDR72, UMOD, and PDILT associate with the levels of uromodulin in urine. The expression of KRT40 affects uromodulin processing in TAL cells. These results, although limited by lack of replication, provide insights into the biology of uromodulin, the role of keratins in the kidney, and the influence of the UMOD-PDILT locus on kidney function.

Involvement of the long intergenic non-coding RNA LINC00461 in schizophrenia

ObjectiveLINC00461 is a highly conserved intergenic non-protein coding RNA that was implicated in schizophrenia at the genome-wide level. We aim to explore potential mechanisms underlying the involvement of LINC00461 in schizophrenia.MethodsWe performed a meta-analysis to investigate the association of LINC00461 rs410216 with schizophrenia, and evaluate the effects of the rs410216 on hippocampal volume and function using the functional magnetic resonance imaging (fMRI) analysis. We utilized the GTEx dataset to profile the expression distribution of LINC00461 across different brain regions, and to investigate the potential impact of the risk SNPs on the expression of LINC00461 and other nearby genes. We compared blood expression levels of LINC00461 between schizophrenia patients and controls.ResultsHere we show that single-nucleotide polymorphisms (SNPs) located in regulatory elements spanning the LINC00461 region are significantly associated with schizophrenia (index SNP rs410216, Pmeta = 1.43E-05); subjects carrying the risk allele of rs410216 showed decreased hippocampal volume. However, no significant association of the rs410216 variant with hippocampal activation was observed. Moreover, the expression level of LINC00461 mRNA was significantly lower in first-onset schizophrenia patients, and the risk allele also predicts a lower transcriptional level of LINC00461 in the hippocampus.ConclusionTogether, these convergent lines of evidence implicate inadequate LINC00461 expression in the hippocampus in the development of schizophrenia, providing novel insight into the genetic architecture and biological etiology of schizophrenia.

Factors associated with canine skin extensibility in toy poodles.

To assess factors for canine skin extensibility, our study investigated associations between the dogs’ skin extension index and the following factors, gender, age, neuter status, weight, coat color and six coat color related gene polymorphisms. Swab samples were collected from 69 toy poodles to extract DNA. The skin extension indices of the lower back and the neck were measured using the following formula: vertical height of the skin fold divided by body length multiplied by 100. The dogs’ age, weight, gender, neuter status and coat color were also recorded, as well as polymorphisms of the following six selected coat color related genes, Melanocortin 1 receptor, Tyrosinase-related protein 1, Melanophilin, Canine β-defensin-1, Major Facilitator Superfamily Domain Containing 12 and Agouti-signaling protein (ASIP). Univariable analysis showed there was a meaningful association between the lower back skin extension index and both gender and age (P<0.001 and P=0.048, respectively). Also, there was a possible association between the lower back skin extension index and ASIP Single nucleotide polymorphism (SNP) (R96C) (P=0.078). Linear model analysis showed there was a significant association between the lower back skin extension index and gender (P<0.001), and there was a tendency of the association between the lower back skin extension index and ASIP SNP (R96C) (P=0.098). In addition, there was an association between gender and age for the skin extension index. (P=0.048). Therefore, these results suggest that a greater risk of skin extensibility in toy poodle could be related to being female and the ASIP SNP (R96C), because these factors were associated with higher lower back skin extension index.

Abstract PO-179: Analysis of long-term exposures to cigarette smoking and female hormones jointly with risk alleles of glucose metabolism in African American hormone receptor positive breast cancer

Abstract Background: Breast cancer (BC) is the most common cancer diagnosis and cause of death related to cancer in women in the United States and worldwide and more than 80% of new cases and deaths occur in postmenopausal women ages 50 years and older. Whereas African American (AA) women have a lower BC incidence rate than white women (e.g., 126.7 vs. 130.8 cases per 100,000 during 2012–2016), AA women's incidence rates have more rapidly increased than those in white women (0.9% vs. 0.4% per year), contributing to a convergence in BC incidence rates in 2016. BC is also the top leading cause of cancer incidence and mortality in AA women. Glucose intolerance/insulin resistance (IR) is a well-established risk factor for invasive BC development in AA postmenopausal women. While obesity and IR are more prevalent in AA than white women, they are under-represented in genome-wide studies for systemic regulation of IR and the association with BC risk. Methods: By examining 780 genome-wide IR single-nucleotide polymorphisms (SNPs) available in the Women's Health Initiative Database for Genotypes and Phenotypes (WHI dbGaP) SNP Health Association Resource (SHARe), we tested 4,689 AA women for potential causal pathways of genetically determined IR and BC risk in a Mendelian randomization (MR) framework. By incorporating 37 BC-associated lifestyle factors, we further conducted a gene–environment interaction analysis to estimate risk prediction for the most influential genetic and lifestyle factors and evaluated their combined and joint effects on BC risk. Results: Our MR results analyzing 38 index SNPs were mixed. By accounting for variations of individual SNPs in BC risk in the prediction model, we detected 4 fasting glucose–associated SNPs in PCSK1, SPC25, ADCY5, and MTNR1B and 3 lifestyle factors (smoking, oral contraceptive use, and age at menopause) as the most predictive markers for BC risk. Our joint analysis of risk genotypes and lifestyles with smoking revealed a synergistic effect on increased risk of BC, particularly ER/PR+ BC, in a gene–lifestyle dose-dependent manner. The joint effect of smoking on ER/PR+ BC was more profound in women who had long-term exposure to cigarette smoking and a prolonged exposure to female hormones. Conclusion: Our finding may improve the prediction accuracy in BC subtypes and highlight genetically targeted preventive interventions (e.g., smoking cessation) for AA postmenopausal women who carry particular risk genotypes. Citation Format: Su Yon Jung, Jeanette C. Papp, Eric M. Sobel, Matteo Pellegrini, Herbert Yu. Analysis of long-term exposures to cigarette smoking and female hormones jointly with risk alleles of glucose metabolism in African American hormone receptor positive breast cancer [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-179.

Rare coding variants in 35 genes associate with circulating lipid levels—A multi-ancestry analysis of 170,000 exomes

Large-scale gene sequencing studies for complex traits have the potential to identify causal genes with therapeutic implications. We performed gene-based association testing of blood lipid levels with rare (minor allele frequency < 1%) predicted damaging coding variation by using sequence data from >170,000 individuals from multiple ancestries: 97,493 European, 30,025 South Asian, 16,507 African, 16,440 Hispanic/Latino, 10,420 East Asian, and 1,182 Samoan. We identified 35 genes associated with circulating lipid levels; some of these genes have not been previously associated with lipid levels when using rare coding variation from population-based samples. We prioritize 32 genes in array-based genome-wide association study (GWAS) loci based on aggregations of rare coding variants; three (EVI5, SH2B3, and PLIN1) had no prior association of rare coding variants with lipid levels. Most of our associated genes showed evidence of association among multiple ancestries. Finally, we observed an enrichment of gene-based associations for low-density lipoprotein cholesterol drug target genes and for genes closest to GWAS index single-nucleotide polymorphisms (SNPs). Our results demonstrate that gene-based associations can be beneficial for drug target development and provide evidence that the gene closest to the array-based GWAS index SNP is often the functional gene for blood lipid levels.

Cross-ancestry GWAS meta-analysis identifies six breast cancer loci in African and European ancestry women

Our study describes breast cancer risk loci using a cross-ancestry GWAS approach. We first identify variants that are associated with breast cancer at P < 0.05 from African ancestry GWAS meta-analysis (9241 cases and 10193 controls), then meta-analyze with European ancestry GWAS data (122977 cases and 105974 controls) from the Breast Cancer Association Consortium. The approach identifies four loci for overall breast cancer risk [1p13.3, 5q31.1, 15q24 (two independent signals), and 15q26.3] and two loci for estrogen receptor-negative disease (1q41 and 7q11.23) at genome-wide significance. Four of the index single nucleotide polymorphisms (SNPs) lie within introns of genes (KCNK2, C5orf56, SCAMP2, and SIN3A) and the other index SNPs are located close to GSTM4, AMPD2, CASTOR2, and RP11-168G16.2. Here we present risk loci with consistent direction of associations in African and European descendants. The study suggests that replication across multiple ancestry populations can help improve the understanding of breast cancer genetics and identify causal variants.

Common Genetic Polymorphisms Contribute to the Association between Non-Melanoma Skin Cancer and Chronic Lymphocytic Leukemia

Introduction: Genome-wide association studies (GWAS) have identified thousands of genetic variants associated with numerous traits and diseases. The analysis of shared genetic associations between diseases can help explain previously found epidemiological associations and provide better insight into disease etiology. Epidemiological studies have demonstrated a consistent positive association between chronic lymphocytic leukemia (CLL) and non-melanoma skin cancers (NMSC); however, the reasons for this association are not well understood. We explored the hypothesis that shared genetic risk factors between CLL and NMSC could contribute to the epidemiological association observed between these diseases.Methods: We identified established loci associated with CLL or NMSC with p<5x10-8 based on published results. Single nucleotide polymorphisms (SNPs) were considered independent if they were ≥500 kb apart and had r2<0.05. We examined the association between NMSC loci and CLL risk in a pooled GWAS of CLL including 3,100 cases and 7,667 controls of European ancestry. In parallel, we investigated the association between CLL loci and NMSC risk in a study of 4,242 basal cell carcinoma (BCC) cases and 12,802 controls and also 825 squamous cell carcinoma (SCC) cases and 11,518 controls. Weighted genetic risk scores (wGRS) were constructed separately for each disease. For each SNP, the odds ratios (OR) for the association with NMSC or CLL was extracted from existing literature. In the wGRS, the number of risk alleles was multiplied by the log-OR of that SNP as reported in the literature. We estimated the OR and 95% confidence interval (95% CI) for the associations with individual SNPs and with the wGRS for both CLL and NMSC using logistic regression, adjusting for age, sex, and principal components to account for population substructure.Results: Six of the established genetic loci for CLL and NMSC overlapped such that at least SNPs associated with CLL and NMSC were within a 1 Mb: 2q33.1, 3q28, 5p15, 6p21, 6p25 and 9q21.Of the reported NMSC loci, 4 index SNPs were nominally associated with CLL risk after adjustment for multiple testing (PFDR-adjusted≤0.05): rs12203592 and rs12210050 at 6p25 (IRF4/EXOC2), rs78378222 at 17p13.1 (TP53), and rs191177147 at 3q28 (LPP). The most significant associations were at 6p25.3 region in the IRF4/EXOC2 locus: rs12203592 (OR: 1.41, 95% CI: 1.29-1.54, P=7.34 x 10-14) and rs12210050 (OR=1.23, 95% CI: 1.12-1.35, P=1.97 x 10-5). Using the wGRS from SCC SNPs, we found a pattern of increasing risk of CLL with increasing quartile, reaching statistical significance for quartile 4 vs. quartile 1 (OR=1.26, 95% CI: 1.14-1.39, P=0.001). After excluding the IRF4 polymorphism rs12203592, the association between the wGRS and CLL was no longer significant (OR=1.02, 95% CI: 0.90-1.45, P=0.81).Of the reported CLL SNPs, five were associated with NMSC risk after adjustment for multiple testing (PFDR-adjusted≤0.05): rs9815073 at 3q28 (LPP), rs3769825 at 2q33 (CASP10/CASP8), rs17246404 at 7q31 (POT1), rs4368253 at 18q21 (PMAIP1) and rs872071 at 6p25 (IRF4/EXOC2). The wGRS based on the CLL SNPs was associated with BCC risk (P=0.004) but not with SCC risk (P=0.12), possibly due to a lack of statistical power. Of note, after exclusion of the IRF4 polymorphism, the association between the wGRS and BCC remained statistically significant (P=0.02).Conclusion: We report here a novel and statistically significant association between the genetic burden for risk of NMSC and of CLL. Finally, we uncovered that polymorphisms in the Interferon Regulatory Factor 4 (IRF4) gene appear to contribute to the association between CLL and NMSC. IRF4, also known as multiple myeloma oncogene-1 (MUM1), is a transcriptional regulator expressed in lymphocytes and in melanocytes. Further studies are needed to understand the common biological mechanisms that lead to this association. Overall, these findings highlight the pleiotropic effect of genes in the pathogeneses of these cancers and suggest that they have a partially shared genetic etiology. DisclosuresSmedby:Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding. Shanafelt:Genentech, Celgene, Pharamacyclics, Jansen, GlaxoSmithKline, AbbVie, Hospira, and Cephalon: Research Funding. Cerhan:Janssen: Other: Scientific Advisory Board (REMICADELYM4001); Janssen: Other: Multiple Myeloma Registry Steering.

Association of SUMOylation Pathway Genes With Stroke in a Genome-Wide Association Study in India.

To undertake a genome-wide association study (GWAS) to identify genetic variants for stroke in an Indian population. In a hospital-based case-control study, 8 teaching hospitals in India recruited 4,088 participants, including 1,609 stroke cases. Imputed genetic variants were tested for association with stroke subtypes using both single-marker and gene-based tests. Association with vascular risk factors was performed with logistic regression. Various databases were searched for replication, functional annotation, and association with related traits. Status of candidate genes previously reported in the Indian population was also checked. Associations of vascular risk factors with stroke were similar to previous reports and show modifiable risk factors such as hypertension, smoking, and alcohol consumption as having the highest effect. Single-marker-based association revealed 2 loci for cardioembolic stroke (1p21 and 16q24), 2 for small vessel disease stroke (3p26 and 16p13), and 4 for hemorrhagic stroke (3q24, 5q33, 6q13, and 19q13) at p < 5 × 10-8. The index single nucleotide polymorphism of 1p21 is an expression quantitative trait locus (p lowest = 1.74 × 10-58) for RWDD3 involved in SUMOylation and is associated with platelet distribution width (1.15 × 10-9) and 18-carbon fatty acid metabolism (p = 7.36 × 10-12). In gene-based analysis, we identified 3 genes (SLC17A2, FAM73A, and OR52L1) at p < 2.7 × 10-6. Eleven of 32 candidate gene loci studied in an Indian population replicated (p < 0.05), and 21 of 32 loci identified through previous GWAS replicated according to directionality of effect. This GWAS of stroke in an Indian population identified novel loci and replicated previously known loci. Genetic variants in the SUMOylation pathway, which has been implicated in brain ischemia, were identified for association with stroke.

Prioritization of schizophrenia risk genes from GWAS results by integrating multi-omics data

Schizophrenia (SCZ) is a polygenic disease with a heritability approaching 80%. Over 100 SCZ-related loci have so far been identified by genome-wide association studies (GWAS). However, the risk genes associated with these loci often remain unknown. We present a new risk gene predictor, rGAT-omics, that integrates multi-omics data under a Bayesian framework by combining the Hotelling and Box–Cox transformations. The Bayesian framework was constructed using gene ontology, tissue-specific protein–protein networks, and multi-omics data including differentially expressed genes in SCZ and controls, distance from genes to the index single-nucleotide polymorphisms (SNPs), and de novo mutations. The application of rGAT-omics to the 108 loci identified by a recent GWAS study of SCZ predicted 103 high-risk genes (HRGs) that explain a high proportion of SCZ heritability (Enrichment = 43.44 and p = 9.30 times 10^{ - 9}). HRGs were shown to be significantly (p_{mathrm{adj}} = 5.35 times 10^{ - 7}) enriched in genes associated with neurological activities, and more likely to be expressed in brain tissues and SCZ-associated cell types than background genes. The predicted HRGs included 16 novel genes not present in any existing databases of SCZ-associated genes or previously predicted to be SCZ risk genes by any other method. More importantly, 13 of these 16 genes were not the nearest to the index SNP markers, and them would have been difficult to identify as risk genes by conventional approaches while ten out of the 16 genes are associated with neurological functions that make them prime candidates for pathological involvement in SCZ. Therefore, rGAT-omics has revealed novel insights into the molecular mechanisms underlying SCZ and could provide potential clues to future therapies.

Brain Magnetic Resonance Imaging Phenome-Wide Association Study With Metal Transporter Gene SLC39A8.

The SLC39A8 gene encodes a divalent metal transporter, ZIP8. SLC39A8 is associated with pleiotropic effects across multiple tissues, including the brain. We determine the different brain magnetic resonance imaging (MRI) phenotypes associated with SLC39A8. We used a phenome-wide association study approach followed by joint and conditional association analysis. Using the summary statistics datasets from a brain MRI genome-wide association study on adult United Kingdom (UK) Biobank participants, we systematically selected all brain MRI phenotypes associated with single-nucleotide polymorphisms (SNPs) within 500 kb of the SLC39A8 genetic locus. For all significant brain MRI phenotypes, we used GCTA-COJO to determine the number of independent association signals and identify index SNPs for each brain MRI phenotype. Linkage equilibrium for brain phenotypes with multiple independent signals was confirmed by LDpair. We identified 24 brain MRI phenotypes that vary due to MRI type and brain region and contain a SNP associated with the SLC39A8 locus. Missense ZIP8 polymorphism rs13107325 was associated with 22 brain MRI phenotypes. Rare ZIP8 variants present in a published UK Biobank dataset are associated with 6 brain MRI phenotypes also linked to rs13107325. Among the 24 datasets, an additional 4 association signals were identified by GCTA-COJO and confirmed to be in linkage equilibrium with rs13107325 using LDpair. These additional association signals represent new probable causative SNPs in addition to rs13107325. This study provides leads into how genetic variation in SLC39A8, a trace mineral transport gene, is linked to brain structure differences and may affect brain development and nervous system function.

PICS2: next-generation fine mapping via probabilistic identification of causal SNPs.

The Probabilistic Identification of Causal SNPs (PICS) algorithm and web application was developed as a fine-mapping tool to determine the likelihood that each single nucleotide polymorphism (SNP) in LD with a reported index SNP is a true causal polymorphism. PICS is notable for its ability to identify candidate causal SNPs within a locus using only the index SNP, which are widely available from published GWAS, whereas other methods require full summary statistics or full genotype data. However, the original PICS web application operates on a single SNP at a time, with slow performance, severely limiting its usability. We have developed a next-generation PICS tool, PICS2, which enables performance of PICS analyses of large batches of index SNPs with much faster performance. Additional updates and extensions include use of LD reference data generated from 1000 Genomes phase 3; annotation of variant consequences; annotation of GTEx eQTL genes and downloadable PICS SNPs from GTEx eQTLs; the option of generating PICS probabilities from experimental summary statistics; and generation of PICS SNPs from all SNPs of the GWAS catalog, automatically updated weekly. These free and easy-to-use resources will enable efficient determination of candidate loci for biological studies to investigate the true causal variants underlying disease processes. PICS2 is available at https://pics2.ucsf.edu. Supplementary data are available at Bioinformatics online.

Genome-wide Association Analysis of Proinflammatory Cytokines and Gene-lifestyle Interaction for Invasive Breast Cancer Risk: The WHI dbGaP Study.

Immune-related etiologic pathways to influence invasive breast cancer risk may interact with lifestyle factors, but the interrelated molecular genetic pathways are incompletely characterized. We used data from the Women's Health Initiative Database for Genotypes and Phenotypes Study including 16,088 postmenopausal women, a population highly susceptible to inflammation, obesity, and increased risk for breast cancer. With 21,784,812 common autosomal single-nucleotide polymorphisms (SNP), we conducted a genome-wide association (GWA) gene-environment interaction (G × E) analysis in six independent GWA Studies for proinflammatory cytokines [IL6 and C-reactive protein (CRP)] and their gene-lifestyle interactions. Subsequently, we tested for the association of the GWA SNPs with breast cancer risk. In women overall and stratified by obesity status (body mass index, waist circumference, and waist-to-hip ratio) and obesity-related lifestyle factors (exercise and high-fat diet), 88 GWA SNPs in 10 loci were associated with proinflammatory cytokines: 3 associated with IL6 (1 index SNP in MAPK1 and 1 independent SNP in DEC1); 85 with CRP (3 index SNPs in CRPP1, CRP, RP11-419N10.5, HNF1A-AS1, HNF1A, and C1q2orf43; and two independent SNPs in APOE and APOC1). Of those, 27 in HNF1A-AS1, HNF1A, and C1q2orf43 displayed significantly increased risk for breast cancer. We found a number of novel top markers for CRP and IL6, which interacted with obesity factors. A substantial proportion of those SNPs' susceptibility influenced breast cancer risk. Our findings may contribute to better understanding of genetic associations between pro-inflammation and cancer and suggest intervention strategies for women who carry the risk genotypes, reducing breast cancer risk. PREVENTION RELEVANCE: The top GWA-SNPs associated with pro-inflammatory biomarkers have implications for breast carcinogenesis by interacting with obesity factors. Our findings may suggest interventions for women who carry the inflammatory-risk genotypes to reduce breast cancer risk.

A Meta-Analysis of the Transferability of Bone Mineral Density Genetic Loci Associations From European to African Ancestry Populations.

Genetic studies of bone mineral density (BMD) largely have been conducted in European populations. We therefore conducted a meta-analysis of six independent African ancestry cohorts to determine whether previously reported BMD loci identified in European populations were transferable to African ancestry populations. We included nearly 5000 individuals with both genetic data and assessments of BMD. Genotype imputation was conducted using the 1000G reference panel. We assessed single-nucleotide polymorphism (SNP) associations with femoral neck and lumbar spine BMD in each cohort separately, then combined results in fixed effects (or random effects if study heterogeneity was high, I2 index >60) inverse variance weighted meta-analyses. In secondary analyses, we conducted locus-based analyses of rare variants using SKAT-O. Mean age ranged from 12 to 68 years. One cohort included only men and another cohort included only women; the proportion of women in the other four cohorts ranged from 52% to 63%. Of 56 BMD loci tested, one locus, 6q25 (C6orf97, p = 8.87 × 10-4 ), was associated with lumbar spine BMD and two loci, 7q21 (SLC25A13, p = 2.84 × 10-4 ) and 7q31 (WNT16, p = 2.96 × 10-5 ), were associated with femoral neck BMD. Effects were in the same direction as previously reported in European ancestry studies and met a Bonferroni-adjusted p value threshold, the criteria for transferability to African ancestry populations. We also found associations that met locus-specific Bonferroni-adjusted p value thresholds in 11q13 (LRP5, p < 2.23 × 10-4 ), 11q14 (DCDC5, p < 5.35 × 10-5 ), and 17p13 (SMG6, p < 6.78 × 10-5 ) that were not tagged by European ancestry index SNPs. Rare single-nucleotide variants in AKAP11 (p = 2.32 × 10-2 ), MBL2 (p = 4.09 × 10-2 ), MEPE (p = 3.15 × 10-2 ), SLC25A13 (p = 3.03 × 10-2 ), STARD3NL (p = 3.35 × 10-2 ), and TNFRSF11A (p = 3.18 × 10-3 ) were also associated with BMD. The majority of known BMD loci were not transferable. Larger genetic studies of BMD in African ancestry populations will be needed to overcome limitations in statistical power and to identify both other loci that are transferable across populations and novel population-specific variants. © 2020 American Society for Bone and Mineral Research (ASBMR).