Top Variants Research Articles

Genetic loci associated with skin pigmentation in African Americans and their effects on vitamin D deficiency.

A recent genome-wide association study (GWAS) in African descent populations identified novel loci associated with skin pigmentation. However, how genomic variations affect skin pigmentation and how these skin pigmentation gene variants affect serum 25(OH) vitamin D variation has not been explored in African Americans (AAs). In order to further understand genetic factors that affect human skin pigmentation and serum 25(OH)D variation, we performed a GWAS for skin pigmentation with 395 AAs and a replication study with 681 AAs. Then, we tested if the identified variants are associated with serum 25(OH) D concentrations in a subset of AAs (n = 591). Skin pigmentation, Melanin Index (M-Index), was measured using a narrow-band reflectometer. Multiple regression analysis was performed to identify variants associated with M-Index and to assess their role in serum 25(OH)D variation adjusting for population stratification and relevant confounding variables. A variant near the SLC24A5 gene (rs2675345) showed the strongest signal of association with M-Index (P = 4.0 x 10−30 in the pooled dataset). Variants in SLC24A5, SLC45A2 and OCA2 together account for a large proportion of skin pigmentation variance (11%). The effects of these variants on M-Index was modified by sex (P for interaction = 0.009). However, West African Ancestry (WAA) also accounts for a large proportion of M-Index variance (23%). M-Index also varies among AAs with high WAA and high Genetic Score calculated from top variants associated with M-Index, suggesting that other unknown genomic factors related to WAA are likely contributing to skin pigmentation variation. M-Index was not associated with serum 25(OH)D concentrations, but the Genetic Score was significantly associated with vitamin D deficiency (serum 25(OH)D levels less than 12 ng/mL) (OR, 1.30; 95% CI, 1.04–1.64). The findings support the hypothesis suggesting that skin pigmentation evolved responding to increased demand for subcutaneous vitamin D synthesis in high latitude environments.

Genome-wide association study of prevalent and persistent cervical high-risk human papillomavirus (HPV) infection

BackgroundGenetic factors may influence the susceptibility to high-risk (hr) human papillomavirus (HPV) infection and persistence. We conducted the first genome-wide association study (GWAS) to identify variants associated with cervical hrHPV infection and persistence.MethodsParticipants were 517 Nigerian women evaluated at baseline and 6 months follow-up visits for HPV. HPV was characterized using SPF10/LiPA25. hrHPV infection was positive if at least one carcinogenic HPV genotype was detected in a sample provided at the baseline visit and persistent if at least one carcinogenic HPV genotype was detected in each of the samples provided at the baseline and follow-up visits. Genotyping was done using the Illumina Multi-Ethnic Genotyping Array (MEGA) and imputation was done using the African Genome Resources Haplotype Reference Panel. Association analysis was done for hrHPV infection (125 cases/392 controls) and for persistent hrHPV infection (51 cases/355 controls) under additive genetic models adjusted for age, HIV status and the first principal component (PC) of the genotypes.ResultsThe mean (±SD) age of the study participants was 38 (±8) years, 48% were HIV negative, 24% were hrHPV positive and 10% had persistent hrHPV infections. No single variant reached genome-wide significance (p < 5 X 10− 8). The top three variants associated with hrHPV infections were intronic variants clustered in KLF12 (all OR: 7.06, p = 1.43 × 10− 6). The top variants associated with cervical hrHPV persistence were in DAP (OR: 6.86, p = 7.15 × 10− 8), NR5A2 (OR: 3.65, p = 2.03 × 10− 7) and MIR365–2 (OR: 7.71, p = 2.63 × 10− 7) gene regions.ConclusionsThis exploratory GWAS yielded suggestive candidate risk loci for cervical hrHPV infection and persistence. The identified loci have biological annotation and functional data supporting their role in hrHPV infection and persistence. Given our limited sample size, larger discovery and replication studies are warranted to further characterize the reported associations.

Empirical assessment of case-based methods for identification of drugs associated with acute liver injury in the French National Healthcare System database (SNDS).

Drug induced acute liver injury (ALI) is a frequent cause of liver failure. Case-based designs were empirically assessed and calibrated in the French National claims database (SNDS), aiming to identify the optimum design for drug safety alert generation associated with ALI. All cases of ALI were extracted from SNDS (2009-2014) using specific and sensitive definitions. Positive and negative drug controls were used to compare 196 self-controlled case series (SCCS), case-control (CC), and case-population (CP) design variants, using area under the receiver operating curve (AUC), mean square error (MSE) and coverage probability. Parameters that had major impacts on results were identified through logistic regression. Using a specific ALI definition, AUCs ranged from 0.78 to 0.94, 0.64 to 0.92 and 0.48 to 0.85, for SCCS, CC and CP, respectively. MSE ranged from 0.12 to 0.40, 0.22 to 0.39 and 1.03 to 5.29, respectively. Variants adjusting for multiple drug use had higher coverage probabilities. Univariate regressions showed that high AUCs were achieved with SCCS using exposed time as the risk window. The top SCCS variant yielded an AUC = 0.93 and MSE = 0.22 and coverage = 86%, with 1/7 negative and 13/18 positive controls presenting significant estimates. SCCS adjusting for multiple drugs and using exposed time as the risk window performed best in generating ALI-related drug safety alert and providing estimates of the magnitude of the risk. This approach may be useful for ad-hoc pharmacoepidemiology studies to support regulatory actions.

Using genetic information to inform policy on cannabis

Using genetic information to inform policy on cannabis

GWAS of Post-Orthodontic Aggressive External Apical Root Resorption Identified Multiple Putative Loci at X-Y Chromosomes.

Personalized dental medicine requires from precise and customized genomic diagnostic. To conduct an association analysis over multiple putative loci and genes located at chromosomes 2, 4, 8, 12, 18, X, and Y, potentially implicated in an extreme type of external apical root resorption secondary to orthodontic forces (aEARR). A genome-wide association study of aEARR was conducted with 480 patients [ratio~1:3 case/control]. Genomic DNA was extracted and analyzed using the high-throughput Axiom platform with the GeneTitan® MC Instrument. Up to 14,377 single nucleotide polymorphisms (SNPs) were selected at candidate regions and clinical/diagnostic data were recorded. A descriptive analysis of the data along with a backward conditional binary logistic regression was used to calculate odds ratios, with 95% confidence intervals [p < 0.05]. To select the best SNP candidates, a logistic regression model was fitted assuming a log-additive genetic model using R software [p < 0.0001]. In this sample the top lead genetic variants associated with aEARR were two novel putative genes located in the X chromosome, specifically, STAG 2 gene, rs151184635 and RP1-30E17.2 gene, rs55839915. These variants were found to be associated with an increased risk of aEARR, particularly restricted to men [OR: 6.09; 95%CI: 2.6–14.23 and OR: 6.86; 95%CI: 2.65–17.81, respectively]. Marginal associations were found at previously studied variants such as SSP1: rs11730582 [OR: 0.54; 95%CI: 0.34–0.86; p = 0.008], P2RX7: rs1718119 [OR: 0.6; 95%CI: 0.36–1.01; p = 0.047], and TNFRSF11A: rs8086340 [OR: 0.6; 95%CI: 0.38–0.95; p = 0.024]), found solely in females. Multiple putative genetic variants located at chromosomes X and Y are potentially implicated in an extreme phenotype of aEARR. A gender-linked association was noted.

Association of GATA3 Polymorphisms With Minimal Residual Disease and Relapse Risk in Childhood Acute Lymphoblastic Leukemia.

Minimal residual disease (MRD) after induction therapy is one of the strongest prognostic factors in childhood acute lymphoblastic leukemia (ALL), and MRD-directed treatment intensification improves survival. Little is known about the effects of inherited genetic variants on interpatient variability in MRD. A genome-wide association study was performed on 2597 children on the Children's Oncology Group AALL0232 trial for high-risk B-cell ALL. Association between genotype and end-of-induction MRD levels was evaluated for 863370 single nucleotide polymorphisms (SNPs), adjusting for genetic ancestry and treatment strata. Top variants were further evaluated in a validation cohort of 491 patients from the Children's Oncology Group P9905 and 6 ALL trials. The independent prognostic value of single nucleotide polymorphisms was determined in multivariable analyses. All statistical tests were 2-sided. In the discovery genome-wide association study, we identified a genome-wide significant association at the GATA3 locus (rs3824662, odds ratio [OR] = 1.58, 95% confidence interval [CI] = 1.35 to 1.84; P = 1.15 × 10-8 as a dichotomous variable). This association was replicated in the validation cohort (P = .003, MRD as a dichotomous variable). The rs3824662 risk allele independently predicted ALL relapse after adjusting for age, white blood cell count, and leukemia DNA index (P = .04 and .007 in the discovery and validation cohort, respectively) and remained prognostic when the analyses were restricted to MRD-negative patients (P = .04 and .03 for the discovery and validation cohorts, respectively). Inherited GATA3 variant rs3824662 strongly influences ALL response to remission induction therapy and is associated with relapse. This work highlights the potential utility of germline variants in upfront risk stratification in ALL.

Validations of Top and Novel Susceptibility Variants in All-Age Chinese Patients With Acute Lymphoblastic Leukemia.

Through genome-wide association studies (GWAS), multiple inherited predispositions to acute lymphoblastic leukemia (ALL) have been identified in children. Most recently, a novel susceptibility locus at ERG was localized, exhibiting Hispanic-specific manner. In this study, we conducted a replication study to in all-age Chinese patients (N = 451), not only validating the novel ERG locus, but also systematically determining the impact of age on association status of the top GWAS signals. We found that single nucleotide polymorphisms at ARID5B, IKZF1, CEBPE, PIP4K2A were only significantly associated with ALL susceptibility in childhood patients with no BCR-ABL fusion, while GATA3 signal exhibited its significance in adults no matter carrying BCR-ABL fusion or not. Moreover, the novel ERG SNP can be validated in pediatric patients without both BCR-ABL and ETV6-RUNX1 fusion. Our finding suggests the modifying effects of age on genetic predisposition to ALL, and highlights the impact of ERG SNP in Chinese patients.

Abstract 37: Highly aggregated lung cancer families reveal a heterogeneous cause for a previous linkage signal on 6q

Abstract More Americans die every year of lung cancer than any other cancer. While the environmental risks for lung cancer are well understood, the genetic risk factors for this disease are not, even though it has been shown that lung cancer risk aggregates in families. Segregation analyses have confirmed the likelihood of rare, highly penetrant variants affecting lung cancer. Family studies offer a unique opportunity to identify such rare risk variants. We have previously identified a genome-wide significant risk locus for lung cancer using multipoint linkage analysis in highly aggregated lung cancer families. In this study, we performed targeted sequencing on this 6q23-6q27 region on 75 individuals from the 9 most strongly linked families. Parametric two-point linkage analysis using an autosomal dominant model with 10% penetrance for carriers and a 1% phenocopy rate and disease allele frequency of 1% was performed for each family. While we did not find any genome-wide significant results in any of the individual families, we did observe several interesting potential rare risk variants. First, we observed that the significant signal previously observed on 6q is recapitulated in these data but the location of the peak LOD is highly heterogeneous across families and it is likely that each family has a different risk gene. While most of the highest LOD scores were in noncoding variants, we did observe exonic variants with the highest LOD scores in two families (44 and 42). Both variants were rare, with a minor allele frequency (MAF) of approximately 1% and were in LPA and GPR126 respectively. Both these genes have been implicated somatically in lung cancer, however this is the first time that they have been implicated in the germline. While the other families have their highest LOD scores in noncoding variants, some of these genes are also good potential candidate genes including PARK2 (family 30), GRM1 (family 47), and PDE10A (family 102). All three genes have been implicated in lung cancer in some capacity, and this is the first time that GRM1 and PDE10A have been implicated as germline mutations. Again, all these variants are rare (MAF ⇐ 0.01) in the general population, which makes sense for a potential highly penetrant risk variant. In this study, we have elucidated that a previously identified risk locus on 6q25 is heterogeneous in the nine most strongly linked families, with different families appearing to be carrying different risk variants. Many of the top variants in each family are rare variants that are in good potential causal genes that have been identified for the first time here as germline risk variants for lung cancer. Further functional annotation is underway for these variants and some additional linkage analyses using other penetrance matrices may also be performed. Citation Format: Anthony M. Musolf, Claire L. Simpson, Bilal A. Moiz, Mariza de Andrade, Diptasri Mandal, Colette Gaba, Ping Yang, Ming You, Elena Y. Kupert, Marshall W. Anderson, Ann G. Schwartz, Susan M. Pinney, Christopher I. Amos, Joan E. Bailey-Wilson. Highly aggregated lung cancer families reveal a heterogeneous cause for a previous linkage signal on 6q [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 37.

Genetic variants and functional pathways associated with resilience to Alzheimer's disease.

Approximately 30% of older adults exhibit the neuropathological features of Alzheimer's disease without signs of cognitive impairment. Yet, little is known about the genetic factors that allow these potentially resilient individuals to remain cognitively unimpaired in the face of substantial neuropathology. We performed a large, genome-wide association study (GWAS) of two previously validated metrics of cognitive resilience quantified using a latent variable modelling approach and representing better-than-predicted cognitive performance for a given level of neuropathology. Data were harmonized across 5108 participants from a clinical trial of Alzheimer's disease and three longitudinal cohort studies of cognitive ageing. All analyses were run across all participants and repeated restricting the sample to individuals with unimpaired cognition to identify variants at the earliest stages of disease. As expected, all resilience metrics were genetically correlated with cognitive performance and education attainment traits (P-values < 2.5 × 10-20), and we observed novel correlations with neuropsychiatric conditions (P-values < 7.9 × 10-4). Notably, neither resilience metric was genetically correlated with clinical Alzheimer's disease (P-values > 0.42) nor associated with APOE (P-values > 0.13). In single variant analyses, we observed a genome-wide significant locus among participants with unimpaired cognition on chromosome 18 upstream of ATP8B1 (index single nucleotide polymorphism rs2571244, minor allele frequency = 0.08, P = 2.3 × 10-8). The top variant at this locus (rs2571244) was significantly associated with methylation in prefrontal cortex tissue at multiple CpG sites, including one just upstream of ATPB81 (cg19596477; P = 2 × 10-13). Overall, this comprehensive genetic analysis of resilience implicates a putative role of vascular risk, metabolism, and mental health in protection from the cognitive consequences of neuropathology, while also providing evidence for a novel resilience gene along the bile acid metabolism pathway. Furthermore, the genetic architecture of resilience appears to be distinct from that of clinical Alzheimer's disease, suggesting that a shift in focus to molecular contributors to resilience may identify novel pathways for therapeutic targets.

Regulation of melanocortin-4-receptor (MC4R) expression by SNP rs17066842 is dependent on glucose concentration

Melanocortin-4-receptor (MC4R) gene codes for a G-protein-coupled receptor that is highly expressed in the hypothalamus and involved in the regulation of appetite. Single-nucleotide polymorphisms (SNPs) in the MC4R gene region have been associated with obesity, type 2-diabetes (T2D) and with antipsychotic-induced weight gain. Of these, rs17066842 (G>A) in the MC4R promoter region is the top variant associated with obesity and diabetes. In this study, we investigated the effect of rs17066842 on MC4R expression at various glucose concentrations using reporter gene expression in the SH-SY5Y cell line and regulation of MC4R expression in human cerebral organoids. We observed that higher glucose concentrations significantly reduced MC4R mRNA expression in SH-SY5Y cells. In addition, at high glucose concentrations, the luciferase reporter plasmid containing the MC4R promoter insert with the G-allele of rs170066842 showed significantly reduced activity compared to the A-allele carrying plasmid. The immediate early gene product, early growth-response 1 (EGR-1), was identified to bind to the sequence containing the G-allele at rs17066842 but not to the A-allele-containing sequence. Interestingly, in human induced pluripotent stem cell (hiPSC)-derived cerebral organoids, we observed increased MC4R expression in response to high glucose exposure. These opposite observations might suggest that glucose regulation is complex and may be cell-specific.This study provides evidence that rs17066842 regulates MC4R gene expression through binding of EGR-1 and that this process is influenced by glucose concentration.

Contribution of exome sequencing to the identification of genes involved in the response to clopidogrel in cardiovascular patients

BackgroundOn‐clopidogrel platelet reactivity (PR) is associated with the risk of thrombotic or bleeding event in selected populations of high‐risk patients. PR is a highly heritable phenotype and a few variants of cytochrome genes, essentially CYP2C19, are associated with PR but only explain 5% to 12% of the variability. ObjectiveThe aim of this study is to delineate genetic determinants of on‐clopidogrel PR using high‐throughput sequencing. MethodsWe performed a whole exome sequencing of 96 low‐ and matched high‐PR patients in a discovery cohort. Exomes from genes with variants significantly associated with PR were sequenced in 96 low‐ and matched high‐PR patients from an independent replication cohort. ResultsWe identified 585 variants in 417 genes with an adjusted P value < .05. In the replication cohort, all top variants including CYP2C8, CYP2C18, and CYP2C19 from the discovery population were found again. An original network analysis identified several candidate genes of potential interest such as a regulator of PI3K, a key actor in the downstream signaling pathway of the P2Y12 receptor. ConclusionThis study emphasizes the role of CYP‐related genes as major regulators of clopidogrel response, including the poorly investigated CYP2C8 and CYP2C18.

Preliminary Comparison of Lactobacillus reuteri and Bifidobacterium longum Subspecies Infantis Probiotics Impact on Preterm Infant Gut Microbiome and Length Growth

Abstract Objectives The gut microbiome is associated with term infant growth. Here, we examine if use of a L. reuteri or a B. infantis probiotic in preterm infants is associated with changes in the gut microbiome and growth. Methods In this observational study, 26 preterm infants received L. reuteri and 13 infants received B. infantis. Infant length delta z-score was calculated by subtracting the birth length z-score (Fenton Growth Chart) from the discharge z-score value. Association between length delta z-score and probiotic was tested with a t-test. Gut microbiome was assessed by V4 sequencing using the first fecal sample collected in week 2 or 3 of life from each infant. Data analysis was done in QIIME2 and R. Alpha diversity (Shannon index) was compared by probiotic and length delta z-score using regression. Beta diversity (Bray-Curtis distance) was compared between probiotics and above/below median length delta z-score by PERMANOVA. Songbird was used for differential abundance testing. Results There was no association between length and the probiotic infants received, P = 0.34. There was no association between alpha diversity and probiotic, P = 0.58, or length, P = 0.43. There was an association between beta diversity and probiotic (P = 0.001), but not between beta diversity and length, P = 0.43. Songbird top and bottom ranked amplicon sequence variants (ASVs) are those most likely to be differentially abundant. For probiotic, top ranked ASVs (associated with L. reuteri) were Lactobacillus and L. reuteri. Bottom ranked ASVs (B. infantis) were Bifidobacterium and an Escherichia-Shigella. For length, top ranked ASVs (higher delta z-score) were Staphylococcus and probiotic associated Lactobacillus and L. reuteri. Bottom ranked ASVs (lower delta z-score) were Enterococcus, probiotic associated Escherchia-Shigella, Enterobacteriaceae, and Clostridium perfinigens. Conclusions Type of probiotic given was not associated with infant length growth, however, songbird identified ASVs that are likely to be differentially abundant by both probiotic and length. Additional work is needed to confirm the songbird results, and investigation into differences in probiotic administration methods and timing are on-going. Funding Sources F32HD093185 (DHT) and Peter J. Shields Endowed Chair in Dairy Food Science (DAM).

Whole-genome genotyping and resequencing reveal the association of a deletion in the complex interferon alpha gene cluster with hypothyroidism in dogs

BackgroundHypothyroidism is a common complex endocrinopathy that typically has an autoimmune etiology, and it affects both humans and dogs. Genetic and environmental factors are both known to play important roles in the disease development. In this study, we sought to identify the genetic risk factors potentially involved in the susceptibility to the disease in the high-risk Giant Schnauzer dog breed.ResultsBy employing genome-wide association followed by fine-mapping (top variant p-value = 5.7 × 10− 6), integrated with whole-genome resequencing and copy number variation analysis, we detected a ~ 8.9 kbp deletion strongly associated (p-value = 0.0001) with protection against development of hypothyroidism. The deletion is located between two predicted Interferon alpha (IFNA) genes and it may eliminate functional elements potentially involved in the transcriptional regulation of these genes. Remarkably, type I IFNs have been extensively associated to human autoimmune hypothyroidism and general autoimmunity. Nonetheless, the extreme genomic complexity of the associated region on CFA11 warrants further long-read sequencing and annotation efforts in order to ascribe functions to the identified deletion and to characterize the canine IFNA gene cluster in more detail.ConclusionsOur results expand the current knowledge on genetic determinants of canine hypothyroidism by revealing a significant link with the human counterpart disease, potentially translating into better diagnostic tools across species, and may contribute to improved canine breeding strategies.

A genome-wide association study of polycystic ovary syndrome identified from electronic health records

Polycystic ovary syndrome is the most common endocrine disorder affecting women of reproductive age. A number of criteria have been developed for clinical diagnosis of polycystic ovary syndrome, with theRotterdam criteria being the most inclusive. Evidence suggests that polycystic ovary syndrome is significantly heritable, and previous studies haveidentified genetic variants associated with polycystic ovary syndrome diagnosed using different criteria. The widely adopted electronic health record system provides an opportunity to identify patients with polycystic ovary syndrome using the Rotterdam criteria for genetic studies. To identify novel associated genetic variants under the same phenotype definition, we extracted polycystic ovary syndrome cases and unaffected controls based on the Rotterdam criteria from the electronic health records and performed a discovery-validation genome-wide association study. We developed a polycystic ovary syndrome phenotyping algorithm on the basis of the Rotterdam criteria and applied it to 3 electronic health record-linked biobanks to identify cases and controls for genetic study. In the discovery phase, we performed an individual genome-wide association study using the Geisinger MyCode and the Electronic Medical Records and Genomics cohorts, which were then meta-analyzed. We attempted validation of the significant association loci (P<1×10-6) in the BioVU cohort. All association analyses used logistic regression, assuming an additive genetic model, and adjusted for principal components to control for population stratification. An inverse-variance fixed-effect model was adopted for meta-analysis. In addition, we examined the top variants to evaluate their associations with each criterion in the phenotyping algorithm. We used the STRING database to characterize protein-protein interaction network. Using the same algorithm based on the Rotterdam criteria, we identified 2995 patients with polycystic ovary syndrome and 53,599 population controls in total (2742 cases and 51,438 controls from the discovery phase; 253 cases and 2161 controls in the validation phase). We identified 1 novel genome-wide significant variant rs17186366 (odds ratio [OR]=1.37 [1.23, 1.54], P=2.8×10-8) located near SOD2. In addition, 2 loci with suggestive association were also identified: rs113168128 (OR=1.72 [1.42, 2.10], P=5.2×10-8), an intronic variant of ERBB4 that is independent from the previously published variants, and rs144248326 (OR=2.13 [1.52, 2.86], P=8.45×10-7), a novel intronic variant in WWTR1. In the further association tests of the top 3 single-nucleotide polymorphisms with each criterion in the polycystic ovary syndrome algorithm, we found that rs17186366 (SOD2) was associated with polycystic ovaries and hyperandrogenism, whereas rs11316812 (ERBB4) and rs144248326 (WWTR1) were mainly associated with oligomenorrhea or infertility. We also validated the previously reported association with DENND1A1. Using the STRING database to characterize protein-protein interactions, we found both ERBB4 and WWTR1 can interact with YAP1, which has been previously associated with polycystic ovary syndrome. Through a discovery-validation genome-wide association study on polycystic ovary syndrome identified from electronic health records using an algorithm based on Rotterdam criteria, we identified and validated a novel genome-wide significant association with a variant near SOD2. We also identified a novel independent variant within ERBB4 and a suggestive association with WWTR1. With previously identified polycystic ovary syndrome gene YAP1, the ERBB4-YAP1-WWTR1 network suggests involvement of the epidermal growth factor receptor and the Hippo pathway in the multifactorial etiology of polycystic ovary syndrome.

A genome‐wide association study identifies FSHR rs2300441 associated with follicle‐stimulating hormone levels

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) play critical roles in female reproduction, while the underlying genetic basis is poorly understood. Genome-wide association studies (GWASs) of FSH and LH levels were conducted in 2590 Chinese females including 1882 polycystic ovary syndrome (PCOS) cases and 708 controls. GWAS for FSH level identified multiple variants at FSHR showing genome-wide significance with the top variant (rs2300441) located in the intron of FSHR. The A allele of rs2300441 led to a reduced level of FSH in the PCOS group (β = -.43, P = 6.70 × 10-14 ) as well as in the control group (β = -.35, P = 6.52 × 10-4 ). In the combined sample, this association was enhanced after adjusting for the PCOS status (before: β = -.38, P = 1.77 × 10-13 ; after: β = -.42, P = 3.33 × 10-16 ), suggesting the genetic effect is independent of the PCOS status. The rs2300441 explained sevenfold higher proportion of the FSH variance than the total variance explained by the two previously reported FSHR missense variants (rs2300441 R2 = 1.40% vs rs6166 R2 = 0.17%, rs6165 R2 = 0.03%). GWAS for LH did not identify any genome-wide significant associations. In conclusion, we identified genome-wide significant association between variants in FSHR and circulating FSH first, with the top associated variant rs2300441 might be a primary contributor at the population level.

Association of a Variant in VWA3A with Response to Anti-Vascular Endothelial Growth Factor Treatment in Neovascular AMD.

PurposeAnti–vascular endothelial growth factor (VEGF) therapy for neovascular AMD (nvAMD) obtains a variable outcome. We performed a genome-wide association study for anti-VEGF treatment response in nvAMD to identify variants potentially underlying such a variable outcome.MethodsIsraeli patients with nvAMD who underwent anti-VEGF treatment (n = 187) were genotyped on a whole exome chip containing approximately 500,000 variants. Genotyping was correlated with delta visual acuity (deltaVA) between baseline and after three injections of anti-VEGF. Top principal components, age, and baseline VA were included in the analysis. Two lead associated variants were genotyped in an independent validation set of patients with nvAMD (n = 108).ResultsLinear regression analysis on 5,353,842 variants revealed five exonic variants with an association P value of less than 6 × 10−5. The top variant in the gene VWA3A (P = 1.77 × 10−6) was tested in the validation cohort. The minor allele of the VWA3A variant was associated with worse response to treatment (P = 0.02). The average deltaVA of discovery plus validation was –0.214 logMAR (≈ a gain of 10.7 Early Treatment Diabetic Retinopathy Study letters) for homozygote for the major allele, 0.172 logMAR for heterozygotes (≈ a loss of 8.6 Early Treatment Diabetic Retinopathy Study letters), and 0.21 logMAR for homozygote for the minor allele (≈ a loss of 10.5 Early Treatment Diabetic Retinopathy Study letters). Minor allele carriers had a higher frequency of macular hemorrhage at baseline.ConclusionsAn VWA3A gene variant was associated with worse response to anti-VEGF treatment in Israeli patients with nvAMD. The VWA3A protein is a precursor of the multimeric von Willebrand factor which is involved in blood coagulation, a system previously associated with nvAMD.

Fine-Mapping of SNCA in Rapid Eye Movement Sleep Behavior Disorder and Overt Synucleinopathies.

Rapid eye movement sleep behavior disorder (RBD) is a prodromal synucleinopathy, as >80% will eventually convert to overt synucleinopathy. We performed an in-depth analysis of the SNCA locus to identify RBD-specific risk variants. Full sequencing and genotyping of SNCA was performed in isolated/idiopathic RBD (iRBD, n = 1,076), Parkinson disease (PD, n = 1,013), dementia with Lewy bodies (DLB, n = 415), and control subjects (n = 6,155). The iRBD cases were diagnosed with RBD prior to neurodegeneration, although some have since converted. A replication cohort from 23andMe of PD patients with probable RBD (pRBD) was also analyzed (n = 1,782 cases; n = 131,250 controls). Adjusted logistic regression models and meta-analyses were performed. Effects on conversion rate were analyzed in 432 RBD patients with available data using Kaplan-Meier survival analysis. A 5'-region SNCA variant (rs10005233) was associated with iRBD (odds ratio [OR] = 1.43, p = 1.1E-08), which was replicated in pRBD. This variant is in linkage disequilibrium (LD) with other 5' risk variants across the different synucleinopathies. An independent iRBD-specific suggestive association (rs11732740) was detected at the 3' of SNCA (OR = 1.32, p = 4.7E-04, not statistically significant after Bonferroni correction). Homozygous carriers of both iRBD-specific SNPs were at highly increased risk for iRBD (OR = 5.74, p = 2E-06). The known top PD-associated variant (3' variant rs356182) had an opposite direction of effect in iRBD compared to PD. There is a distinct pattern of association at the SNCA locus in RBD as compared to PD, with an opposite direction of effect at the 3' of SNCA. Several 5' SNCA variants are associated with iRBD and with pRBD in overt synucleinopathies. ANN NEUROL 2020;87:584-598.

Genetic Determinants of Electrocardiographic P-Wave Duration and Relation to Atrial Fibrillation.

The P-wave duration (PWD) is an electrocardiographic measurement that represents cardiac conduction in the atria. Shortened or prolonged PWD is associated with atrial fibrillation (AF). We used exome-chip data to examine the associations between common and rare variants with PWD. Fifteen studies comprising 64 440 individuals (56 943 European, 5681 African, 1186 Hispanic, 630 Asian) and ≈230 000 variants were used to examine associations with maximum PWD across the 12-lead ECG. Meta-analyses summarized association results for common variants; gene-based burden and sequence kernel association tests examined low-frequency variant-PWD associations. Additionally, we examined the associations between PWD loci and AF using previous AF genome-wide association studies. We identified 21 common and low-frequency genetic loci (14 novel) associated with maximum PWD, including several AF loci (TTN, CAND2, SCN10A, PITX2, CAV1, SYNPO2L, SOX5, TBX5, MYH6, RPL3L). The top variants at known sarcomere genes (TTN, MYH6) were associated with longer PWD and increased AF risk. However, top variants at other loci (eg, PITX2 and SCN10A) were associated with longer PWD but lower AF risk. Our results highlight multiple novel genetic loci associated with PWD, and underscore the shared mechanisms of atrial conduction and AF. Prolonged PWD may be an endophenotype for several different genetic mechanisms of AF.

79: Genetic variants at AGTR2 locus increase risk of preterm birth

Preterm birth (PTB) complicates approximately 10% of pregnancies in the U.S. While genetic factors contribute to PTB, there has been limited replication of specific genetic risk loci associated with PTB. Recently, we conducted the first large-scale, maternal genome-wide association study (GWAS), utilizing 43,568 women from 23andMe, that identified a locus of variants near the angiotensin II receptor type 2 receptor (AGTR2) gene associated with both PTB and gestational length. We hypothesized that a causative variant in this locus influences expression of AGTR2. We assessed genetic variants previously identified in our GWAS located near AGTR2 (combined analysis p-value of 7.2x10-16 in association with gestational length) to identify genotype-dependent regulation of AGTR2 expression. We computationally prioritized disease variants using available functional genomics data. Implicated variants were then evaluated for possible effects on transcription factor (TF) binding using protein-binding microarray data. Selected variants predicted to alter TF binding were analyzed using electrophoretic mobility shift assays (EMSAs). Luciferase reporter assays were performed to identify rs7889204 genotype-dependent regulation of the AGTR2 promoter. Our computational analyses identified rs7889204 as the top functional candidate variant. EMSA analysis confirmed predicted allele-dependent binding for the transcription factors CEBPB and HOXA10. Luciferase reporter assays revealed allele-dependent reporter activity for rs7889204, with decreased expression for the non-reference “C” allele. We identified candidate mechanisms in which rs7889204 at the AGTR2 locus differentially binds CEBPB and HOXA10. Reporter assays demonstrate decreased enhancer activity for the non-reference allele at rs7889204. These results are consistent with a previously established eQTL for AGTR2 in the uterus, suggesting decreased binding of CEBPB and HOXA10 to the preterm birth rs7889204 risk allele results in decreased AGTR2 expression and possible downstream decidual implantation abnormalities leading to PTB.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Male-specific association of the 2p25 region with suicide attempt in bipolar disorder

We previously conducted a genome-wide association study (GWAS) of attempted suicide within bipolar disorder, which implicated common variation in the 2p25 region primarily in males. The top association signal from our GWAS occurred in an intergenic region of 2p25 (p = 5.07 × 10−8) and was supported by two independent studies. In the current study, to better characterize the association of the 2p25 region with attempted suicide, we sequenced the entire 350kb 2p25 region in 476 bipolar suicide attempters and 473 bipolar non-attempters using targeted next-generation sequencing. This fine-mapping project identified 4,681 variants in the 2p25 region. We performed both gene-level and individual-variant tests on our sequencing results and identified 375 variants which were nominally significant (p < 0.05) and three common variants that were significantly associated with attempted suicide in males (corrected p = 0.035, odds ratio (OR) = 2.13). These three variants are in strong linkage disequilibrium with the top variant from our GWAS. Our top five variants are also predicted expression quantitative trait loci (eQTL) for three genes in the 2p25 region based on publicly available brain expression databases. Our sequencing and eQTL data implicate these three genes – SH3YL1, ACP1, and FAM150B – and three additional pathways – androgen receptor, Wnt signaling, and glutamatergic/GABAergic signaling – in the association of the 2p25 region with suicide. The current study provides additional support for an association of the 2p25 region with attempted suicide in males and identifies several candidate genes and pathways that warrant further investigation to understand their role in suicidal behavior.