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Aims/hypothesis: Type 2 diabetes is a growing global public health challenge. Investigating quantitative traits, including fasting glucose, fasting insulin and HbA1c, that serve as early markers of type 2 diabetes progression may lead to a deeper understanding of the genetic aetiology of type 2 diabetes development. Previous genome-wide association studies (GWAS) have identified over 500 loci associated with type 2 diabetes, glycaemic traits and insulin-related traits. However, most of these findings were based only on populations of European ancestry. To address this research gap, we examined the genetic basis of fasting glucose, fasting insulin and HbA1c in participants of the diverse Population Architecture using Genomics and Epidemiology (PAGE) Study. Methods: We conducted a GWAS of fasting glucose (n = 52,267), fasting insulin (n = 48,395) and HbA1c (n = 23,357) in participants without diabetes from the diverse PAGE Study (23% self-reported African American, 46% Hispanic/Latino, 40% European, 4% Asian, 3% Native Hawaiian, 0.8% Native American), performing transethnic and population-specific GWAS meta-analyses, followed by fine-mapping to identify and characterise novel loci and independent secondary signals in known loci. Results: Four novel associations were identified (p < 5 × 10−9), including three loci associated with fasting insulin, and a novel, low-frequency African American-specific locus associated with fasting glucose. Additionally, seven secondary signals were identified, including novel independent secondary signals for fasting glucose at the known GCK locus and for fasting insulin at the known PPP1R3B locus in transethnic meta-analysis. Conclusions/interpretation: Our findings provide new insights into the genetic architecture of glycaemic traits and highlight the continued importance of conducting genetic studies in diverse populations. Data availability: Full summary statistics from each of the population-specific and transethnic results are available at NHGRI-EBI GWAS catalog (https://www.ebi.ac.uk/gwas/downloads/summary-statistics).

Many common and rare variants associated with hematologic traits have been discovered through imputation on large-scale reference panels. However, the majority of genome-wide association studies (GWASs) have been conducted in Europeans, and determining causal variants has proved challenging. We performed a GWAS of total leukocyte, neutrophil, lymphocyte, monocyte, eosinophil, and basophil counts generated from 109,563,748 variants in the autosomes and the X chromosome in the Trans-Omics for Precision Medicine (TOPMed) program, which included data from 61,802 individuals of diverse ancestry. We discovered and replicated 7 leukocyte trait associations, including (1) the association between a chromosome X, pseudo-autosomal region (PAR), noncoding variant located between cytokine receptor genes (CSF2RA and CLRF2) and lower eosinophil count; and (2) associations between single variants found predominantly among African Americans at the S1PR3 (9q22.1) and HBB (11p15.4) loci and monocyte and lymphocyte counts, respectively. We further provide evidence indicating that the newly discovered eosinophil-lowering chromosome X PAR variant might be associated with reduced susceptibility to common allergic diseases such as atopic dermatitis and asthma. Additionally, we found a burden of very rare FLT3 (13q12.2) variants associated with monocyte counts. Together, these results emphasize the utility of whole-genome sequencing in diverse samples in identifying associations missed by European-ancestry-driven GWASs.

Several studies have found associations between higher pancreatic fat content and adverse health outcomes, such as diabetes and the metabolic syndrome, but investigations into the genetic contributions to pancreatic fat are limited. This genome-wide association study, comprised of 804 participants with MRI-assessed pancreatic fat measurements, was conducted in the ethnically diverse Multiethnic Cohort-Adiposity Phenotype Study (MEC-APS). Two genetic variants reaching genome-wide significance, rs73449607 on chromosome 13q21.2 (Beta = −0.67, P = 4.50×10-8) and rs7996760 on chromosome 6q14 (Beta = −0.90, P = 4.91×10-8) were associated with percent pancreatic fat on the log scale. Rs73449607 was most common in the African American population (13%) and rs79967607 was most common in the European American population (6%). Rs73449607 was also suggestively associated with lower risk of type 2 diabetes (OR = 0.95, 95% CI = 0.89-1.00, P = 0.047) in the Population Architecture Genomics and Epidemiology (PAGE) Study and the DIAbetes Genetics Replication and Meta-analysis (DIAGRAM), which included substantial numbers of non-European ancestry participants (53,102 cases and 193,679 controls). Rs73449607 is located in an intergenic region between GSX1 and PLUT, and rs79967607 is in intron 1 of EPM2A. PLUT, a linkRNA, regulates transcription of an adjacent gene, PDX1, that controls beta-cell function in the mature pancreas, and EPM2A encodes the protein laforin, which plays a critical role in regulating glycogen production. If validated, these variants may suggest a genetic component for pancreatic fat and a common etiologic link between pancreatic fat and type 2 diabetes.

Background The epidemiologic evidence from observational studies on breast cancer risk and phthalates, endocrine disrupting chemicals, has been inconsistent. In the only previous study based on pre-diagnostic urinary phthalates and risk of breast cancer, results were null in mostly white women. Methods We examined the association between pre-diagnostic urinary phthalates and breast cancer in a nested case-control study within the Multiethnic Cohort (MEC) study, presenting the first data from five major racial/ethnic groups in the USA. We measured 10 phthalate metabolites and phthalic acid, using a sensitive liquid chromatography mass spectrometry assay on 1032 women with breast cancer (48 African Americans, 77 Latinos, 155 Native Hawaiians, 478 Japanese Americans, and 274 Whites) and 1030 matched controls. Conditional logistic regression was used to examine risk with individual metabolites and ratios of primary (MEHP, mono-2-ethylhexyl-phthalate) to secondary (MEHHP, mono(2-ethyl-5-hydroxyhexyl); MEOHP, mono(2-ethyl-5-oxohexy)) metabolites of di-2-ethylhexyl phthalate (DEHP), a widely used plasticizer. In addition, we investigated risk associations with high (∑HMWP) and low molecular weight (∑LMWP) phthalates, as well as total phthalates which included high and low molecular weight phthalates with phthalic acid (∑LMHMPA) or without phthalic acid in molar ratios (∑LMHMmolar) and adjusted for creatinine and potential confounders. Results Among all women, breast cancer risk was higher for those in tertile 2 and tertile 3 of primary to secondary metabolites of DEHP (MEHP/(MEHHP + MEOHP)) in comparison to those in tertile 1; the respective odds ratios were 1.32 (95% CI 1.04–1.68) and 1.26 (95% CI 0.96–1.66) (Ptrend = 0.05). Risk among Native Hawaiian women increased with exposures to eight of ten individual phthalates and total phthalates (∑LMHMPA ORT3 vs T1 = 2.66, 95% CI 1.39–5.12, Ptrend = 0.001). In analysis by hormone receptor (HR) status, exposure above the median of ∑LMWP was associated with an increased risk of HR-positive breast cancer (OR = 1.30, 95% CI 1.05–1.60) while above the median exposure to phthalic acid was associated with an increased risk of HR-negative breast cancer (ORabove vs below median = 1.59, 95% CI 1.01–2.48). Conclusions Further investigations of suggestive associations of elevated breast cancer risk with higher ratios of primary to secondary metabolites of DEHP, and differences in risk patterns by race/ethnicity and HR status are warranted.

A shared genetic susceptibility underlies diabetes, adiposity, and kidney phenotypes, yet few studies have leveraged this common genetic architecture in an attempt to clarify molecular functions, identify mechanistic common denominators, and prioritize variants for functional interrogation. We systematically interrogated evidence of a shared genetic architecture across adiposity (BMI [N=90,813], waist circumference[N=68,389], and waist to hip ratio [WHR, N=63,747]), type 2 diabetes (T2D, [N=98,686, Ncase=26,440], fasting glucose [FG, N=52,211], HbA1c [N=23,357], and fasting insulin [FI, N=48,395]), and kidney (eGFR [N=52,555] and chronic kidney disease [CKD, N=91,382, Ncase=10,883]) phenotypes in an ancestrally diverse study population (28% African American, 31% European ancestry, 28% Hispanic; 69% female; average age 56.9 (range 18-90)) within PAGE. We conducted a cross-trait meta-analysis using Adaptive Sum of Powered Score Tests (aSPU). We have identified 42 loci associated across these traits, (P Disclosure H.M. Highland: None. C. Downie: None. S.F. Dimos: None. M. Graff: None. L.M. Polfus: None. B.F. Darst: None. A.R.M. Baldassari: None. C. Sitlani: None. A. Howard: None. C.L. Kooperberg: None. R. Loos: None. T. Matise: None. A.K. Mottl: None. K.E. North: None. C.L. Avery: Research Support; Self; Amgen. Funding American Diabetes Association (1-19-PDF-045 to H.M.M.); National Institutes of Health (T32HL007055, T32HL129982, R01HL142825)

TO THE EDITOR: Vitamin B12 (VB12), or cobalamin, is a water-soluble vitamin. It serves as an enzyme cofactor in the 1-carbon metabolism pathway, which plays a key role in a wide range of biological processes, including red blood cell (RBC) formation, DNA synthesis, and myelination of the central

Background and aims Results from prospective studies evaluating the relationship between elevated lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and incident peripheral arterial disease (PAD) have been mixed. We investigated whether higher Lp-PLA2 levels are associated with increased risk of incident PAD and whether PLA2G7 gene variants, which result in lower Lp-PLA2 levels, are associated with reduced risk of incident PAD. Methods Our analysis included 9922 participants (56% female; 21% African-American; mean age 63 years) without baseline PAD at ARIC Visit 4 (1996–1998), who had Lp-PLA2 activity measured and were subsequently followed for the development of PAD, defined by occurrence of a PAD-related hospitalization, through 2012. Cox proportional hazard models were performed to determine the association of Lp-PLA2 levels and PLA2G7 gene variants with incident PAD. Results During a median follow-up of 14.9 years, we identified 756 incident cases of PAD. In analyses adjusting for age, race, and sex, each standard deviation increment in Lp-PLA2 activity (62 nmol/ml/min) was associated with a higher risk of developing PAD (hazard ratio (HR) 1.17; 95% confidence interval (CI) 1.09, 1.26). This association remained significant after additional adjustment for risk factors, other cardiovascular disease, and medication use, but was strongly attenuated (HR: 1.09; 95% CI 1.00, 1.20). PLA2G7 variants were not associated with a lower risk of PAD in both white carriers (HR: 1.21; 95% CI: 0.17–8.56) and African-American carriers (HR: 0.83; 95% CI: 0.41–1.67), although statistical power was quite limited for this analysis, particularly in whites. Conclusions While higher Lp-PLA2 activity was associated with an increased risk for incident PAD, it is likely a risk marker largely represented by traditional risk factors.

Several studies have found associations between higher pancreatic fat content and adverse health outcomes, such as diabetes and the metabolic syndrome, but investigations into the genetic contributions to pancreatic fat are limited. This genome-wide association study, comprised of 804 participants with MRI-assessed pancreatic fat measurements, was conducted in the ethnically diverse Multiethnic Cohort-Adiposity Phenotype Study (MEC-APS). Two genetic variants reaching genome-wide significance, rs73449607 on chromosome 13q21.2 (Beta = -0.67, P = 4.50x10-8) and rs7996760 on chromosome 6q14 (Beta = -0.90, P = 4.91x10-8) were associated with percent pancreatic fat on the log scale. Rs73449607 was most common in the African American population (13%) and rs79967607 was most common in the European American population (6%). Rs73449607 was also associated with lower risk of type 2 diabetes (OR = 0.95, 95% CI = 0.89–1.00, P = 0.047) in the Population Architecture Genomics and Epidemiology (PAGE) Study and the DIAbetes Genetics Replication and Meta-analysis (DIAGRAM), which included substantial numbers of non-European ancestry participants (53,102 cases and 193,679 controls). Rs73449607 is located in an intergenic region between GSX1 and PLUTO, and rs79967607 is in intron 1 of EPM2A. PLUTO, a lncRNA, regulates transcription of an adjacent gene, PDX1, that controls beta-cell function in the mature pancreas, and EPM2A encodes the protein laforin, which plays a critical role in regulating glycogen production. If validated, these variants may suggest a genetic component for pancreatic fat and a common etiologic link between pancreatic fat and type 2 diabetes.

Whole-genome sequencing (WGS) can improve assessment of low-frequency and rare variants, particularly in non-European populations that have been underrepresented in existing genomic studies. The genetic determinants of C-reactive protein (CRP), a biomarker of chronic inflammation, have been extensively studied, with existing genome-wide association studies (GWASs) conducted in >200,000 individuals of European ancestry. In order to discover novel loci associated with CRP levels, we examined a multi-ancestry population (n = 23,279) with WGS (∼38× coverage) from the Trans-Omics for Precision Medicine (TOPMed) program. We found evidence for eight distinct associations at the CRP locus, including two variants that have not been identified previously (rs11265259 and rs181704186), both of which are non-coding and more common in individuals of African ancestry (∼10% and ∼1% minor allele frequency, respectively, and rare or monomorphic in 1000 Genomes populations of East Asian, South Asian, and European ancestry). We show that the minor (G) allele of rs181704186 is associated with lower CRP levels and decreased transcriptional activity and protein binding in vitro, providing a plausible molecular mechanism for this African ancestry-specific signal. The individuals homozygous for rs181704186-G have a mean CRP level of 0.23 mg/L, in contrast to individuals heterozygous for rs181704186 with mean CRP of 2.97 mg/L and major allele homozygotes with mean CRP of 4.11 mg/L. This study demonstrates the utility of WGS in multi-ethnic populations to drive discovery of complex trait associations of large effect and to identify functional alleles in noncoding regulatory regions.

Background— The correlation of null alleles with human phenotypes can provide insight into gene function in humans. In individuals of African ancestry, we set out to identify null and damaging missense variants, and test these variants for association with a range of cardiovascular phenotypes. Methods and Results— We performed whole-exome sequencing in 3223 black individuals from the Jackson Heart Study and found a total of 729 666 variant sites with minor allele frequency −7 ). Null and damaging missense variants in PCSK9 were associated with 36 mg/dL lower low-density lipoprotein cholesterol ( P =3×10 −21 ). Three individuals in their 50s with complete PCSK9 deficiency (each compound heterozygote for PCSK9 p.Y142X and p.C679X) were identified, with one having a coronary artery calcification score in the 83rd percentile despite a low-density lipoprotein cholesterol of 32 mg/dL. A damaging missense variant in HBQ1 (p.G52A) was associated with a 2 pg/cell lower mean corpuscular hemoglobin ( P =9×10 −13 ) and rare damaging missense variants in VPS13A with higher red blood cell distribution width ( P =9.9×10 –8 ). Conclusions— A limited number of null/damaging alleles with a large effect on cardiovascular traits were detectable in ≈3000 black individuals.

Neutrophils are a key component of innate immunity. Individuals with low neutrophil count are susceptible to frequent infections. Linkage and association between congenital neutropenia and a single rare missense variant in TCIRG1 have been reported in a single family. Here, we report on nine rare missense variants at evolutionarily conserved sites in TCIRG1 that are associated with lower absolute neutrophil count (ANC; p = 0.005) in 1,058 participants from three cohorts: Atherosclerosis Risk in Communities (ARIC), Coronary Artery Risk Development in Young Adults (CARDIA), and Jackson Heart Study (JHS) of the NHLBI Grand Opportunity Exome Sequencing Project (GO ESP). These results validate the effects of TCIRG1 coding variation on ANC and suggest that this gene may be associated with a spectrum of mild to severe effects on ANC.

Platelet production, maintenance, and clearance are tightly controlled processes indicative of platelets' important roles in hemostasis and thrombosis. Platelets are common targets for primary and secondary prevention of several conditions. They are monitored clinically by complete blood counts, specifically with measurements of platelet count (PLT) and mean platelet volume (MPV). Identifying genetic effects on PLT and MPV can provide mechanistic insights into platelet biology and their role in disease. Therefore, we formed the Blood Cell Consortium (BCX) to perform a large-scale meta-analysis of Exomechip association results for PLT and MPV in 157,293 and 57,617 individuals, respectively. Using the low-frequency/rare coding variant-enriched Exomechip genotyping array, we sought to identify genetic variants associated with PLT and MPV. In addition to confirming 47 known PLT and 20 known MPV associations, we identified 32 PLT and 18 MPV associations not previously observed in the literature across the allele frequency spectrum, including rare large effect (FCER1A), low-frequency (IQGAP2, MAP1A, LY75), and common (ZMIZ2, SMG6, PEAR1, ARFGAP3/PACSIN2) variants. Several variants associated with PLT/MPV (PEAR1, MRVI1, PTGES3) were also associated with platelet reactivity. In concurrent BCX analyses, there was overlap of platelet-associated variants with red (MAP1A, TMPRSS6, ZMIZ2) and white (PEAR1, ZMIZ2, LY75) blood cell traits, suggesting common regulatory pathways with shared genetic architecture among these hematopoietic lineages. Our large-scale Exomechip analyses identified previously undocumented associations with platelet traits and further indicate that several complex quantitative hematological, lipid, and cardiovascular traits share genetic factors.

White blood cells play diverse roles in innate and adaptive immunity. Genetic association analyses of phenotypic variation in circulating white blood cell (WBC) counts from large samples of otherwise healthy individuals can provide insights into genes and biologic pathways involved in production, differentiation, or clearance of particular WBC lineages (myeloid, lymphoid) and also potentially inform the genetic basis of autoimmune, allergic, and blood diseases. We performed an exome array-based meta-analysis of total WBC and subtype counts (neutrophils, monocytes, lymphocytes, basophils, and eosinophils) in a multi-ancestry discovery and replication sample of ∼157,622 individuals from 25 studies. We identified 16 common variants (8 of which were coding variants) associated with one or more WBC traits, the majority of which are pleiotropically associated with autoimmune diseases. Based on functional annotation, these loci included genes encoding surface markers of myeloid, lymphoid, or hematopoietic stem cell differentiation (CD69, CD33, CD87), transcription factors regulating lineage specification during hematopoiesis (ASXL1, IRF8, IKZF1, JMJD1C, ETS2-PSMG1), and molecules involved in neutrophil clearance/apoptosis (C10orf54, LTA), adhesion (TNXB), or centrosome and microtubule structure/function (KIF9, TUBD1). Together with recent reports of somatic ASXL1 mutations among individuals with idiopathic cytopenias or clonal hematopoiesis of undetermined significance, the identification of a common regulatory 3' UTR variant of ASXL1 suggests that both germline and somatic ASXL1 mutations contribute to lower blood counts in otherwise asymptomatic individuals. These association results shed light on genetic mechanisms that regulate circulating WBC counts and suggest a prominent shared genetic architecture with inflammatory and autoimmune diseases.

Background: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the US with differential risk across race/ethnicity groups and increases lung cancer risk. In the Multiethnic Cohort (MEC), an ethnically diverse prospective cohort (>215,000) established in the early 1990’s in California and Hawaii, we found COPD prevalence was highest in African Americans, followed by European Americans, Native Hawaiians, Latinos and Japanese Americans. Family history and smoking are strong risk factors for COPD with heritability estimates ranging from 20-40%. However, large scale genomic studies (GWAS) have primarily focused on Europeans. Thus, ethnic-specific calibration of polygenic risk scores (PRS) for predicting COPD has the potential to identify those with greatest need for recommended screening and targeted prevention. Methods: Incident COPD case status was identified from linkage to Medicare claims files which followed a total of 17,291 for PRS analyses from 1998-2014. We performed Cox regression accounting for pack-years smoked and duration quit at two time points of 3,917 COPD cases with genetic data. Genotyped data from MEC individuals from multiple SNP arrays were imputed to the Haplotype Reference Consortium panel (~39 million SNPs). From this repository, we extracted 82 independent risk loci identified from the largest (250,000 European individuals) lung function/COPD GWAS to date from the UK Biobank. To calculate the COPD PRS, we matched imputed dosages to the 82 reported UK Biobank risk allele by locus and summed MEC genotypes under a standard additive general linear model. We compared two Cox regression models 1) not including PRS and 2) including PRS. Results: From epidemiologic analysis, we find that smoking is highly predictive of COPD risk (as expected) and that even after adjusting for pack-years of smoking and years quit racial disparities are evident, with African Americans (Hazard Ratio (HR): 1.25, p=3.7 × 10−6) and Japanese Americans (HR: 1.14, p=0.017) having slightly increased risk of disease compared to European Americans; whereas, Native Hawaiians have similar risk as European Americans (HR=0.95, p=0.48) and Latinos have decreased risk (HR: 0.75, p=2.43 × 10−8). Testing the PRS, we found an 8% increase risk per standard deviation (HR:1.08, p=5.41 × 10−6) while ethnic group differences in risk remained quite similar after adjustment for the PRS. Testing for interaction between pack-years and PRS, we found a suggestive increase of the smoking effect for those with the highest levels of PRS (p=0.09). Conclusion: Based on the racial disparities present from our COPD findings, particularly the increased risks among African Americans and Japanese Americans, we will examine the excess relative risk over a lifetime and within 5-year age intervals. We are currently expanding our MEC genotyped repository which should double our sample size, improve ability to detect PRS-smoking interactions, as well as test PRS for lung cancer. Citation Format: Linda M. Polfus, Meng Lin, S. Lani Park, David Conti, Jackie Porcel, Veronica W. Setiawan, Lynne Wilkens, Christopher A. Haiman, Loïc Le Marchand, Daniel O. Stram. Multiethnic polygenic risk scores and smoking interactions for chronic obstructive lung disease [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr C048.

Background: Phthalates (Phth), known endocrine-disruptors, may play a role in breast carcinogenesis. Low-molecular-weight phthalates (LMWPhth) are commonly found in personal care products while high MWPhth (HMWPhth) are used primarily as plasticizers. Individual Phth may disrupt normal mammary gland development and promote tumorigenesis by binding to and activating the estrogen receptor (ER). Methods: We prospectively examined the association between pre-diagnostic urinary levels of Phth metabolites and breast cancer risk in a case-control study nested within the Multiethnic Cohort (MEC). We measured 11 Phth metabolites and phthalic acid from overnight/first morning urine samples of 798 women with invasive breast cancer (355 Japanese Americans, 218 Whites, 125 Native Hawaiians, 62 Latinos, and 38 African Americans; the latter three groups were combined due to small numbers) and 796 matched controls using an ultrasensitive isotope dilution orbitrap LCMS assay after hydrolysis from conjugation, extraction, and concentration. Average time between urine collection and breast cancer diagnosis was 5.5 years (SD=3.3). Cases and controls were 1:1 matched on area (Hawaii or California), birth year (± 1 year), race/ethnicity, urine type (overnight or first morning), and date of urine collection (± 1 year). Association of LMWPhth (MBP, MiBP, MEP, MMP), HMWPhth (MBzP, MEHP, MEHHP, MEOHP, MECPP, MCMHP, MCHP), and total Phth exposure (LMWPhth + HMWPhth), and phthalic acids with breast cancer risk were examined using conditional logistic regression. All models were adjusted for creatinine levels, demographics, and potential confounders (e.g., education and established breast cancer risk factors). Stratified analyses were conducted by race/ethnicity and ER and progesterone receptor (PR) status. Results: Women in the highest tertile (T3) of total Phth exposure showed a significant increased risk of breast cancer compared to women in the lowest tertile (T1) (HR=1.36, 95% CI: 1.02-1.82). The association was suggested across race/ethnicity with a statistically significant positive association observed in the three smaller groups combined (Native Hawaiians, Latinos, and African Americans) with HR for T2=2.29 (95% CI: 1.27-4.41) and HR for T3=2.42 (95% CI: 1.25-4.70); Ptrend=0.006. By ERPR status, risk associations tended to be stronger for ER-PR- (n=96 cases) (HR=1.13, 95% CI: 0.89-1.45) than for ER+PR+ (n=694 cases) (HR=1.06, 95% CI: 0.94-1.19) breast tumors. Among the three smaller groups combined, total Phth exposure was associated with a significant increased risk of ER-PR- breast cancer (n=38 cases) (P=0.045). Conclusion: This is one of the first studies of Phth exposure and breast cancer to include large numbers of diverse populations in a single study. Risk patterns were stronger among the combined group of Native Hawaiians, Latinos, and African American and for ER-PR- breast cancer. Better understanding of these differences in risk associations by race/ethnicity and ERPR status is needed. This abstract is also being presented as Poster D100. Citation Format: Anna H. Wu, Adrian A. Franke, Chiuchen Tseng, Shannon M. Conroy, Yuqing S. LI, Mindy DeRouen, Linda Polfus, Christian Caberto, Daniel Stram, Chris Haiman, Lynne R. Wilkens, Loic Le Marchand, Iona Cheng. Exposure to phthalates and risk of invasive breast cancer: The Multiethnic Cohort Study [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr PR06.

Lipoprotein-associated phospholipase A2 (LpPLA2) activity was associated with higher CHD risk in a meta-analysis, which was partly dependent on circulating lipid levels. Apolipoprotein C3 loss-of-function (ApoC3 LOF) mutations were related with reduced postprandial lipemia and CHD risk. However, the association of LpPLA2 activity with ApoC3 LOF is not known.We examined the association of LpPLA2 activity and ApoC3 LOF mutations and incident cardiovascular disease (CVD) (defined as coronary heart disease [CHD] plus ischemic stroke) and all-cause mortality in the biracial longitudinal Atherosclerosis Risk In Communities (ARIC) study.The mean LpPLA2 activity was 229.3 nmol/min/mL and was higher in men and whites. LpPLA2 activity correlated positively with atherogenic dyslipidemia. ApoC3 LOF carriers had lower LpPLA2 activity levels compared to non-carriers, and there was inverse association between LpPLA2 activity and ApoC3 LOF mutations in whites. In a fully adjusted model, greater LpPLA2 activity was independently associated with incident CVD (HR 1.35, 1.09-1.68 for highest vs. lowest quintile), which was mainly explained by its association with CHD, and was also associated with all-cause mortality (HR 1.65, 1.38-1.98).Greater LpPLA2 activity was associated with increased CHD and all-cause mortality in both whites and African-Americans in the ARIC study. The inverse relation between LpPLA2 activity and ApoC3 LOF mutations suggests that delayed lipoprotein clearance may at least in part explain the observed association of LpPLA2 activity with increased CVD risk.

A typical human exome harbors dozens of loss-of-function (LOF) variants1, which can lower disease risk factor levels and affect drug efficacy2. We hypothesized that LOF variants are enriched in genes influencing risk factor levels and the onset of common chronic diseases, such as cardiovascular disease and diabetes. To test this hypothesis, we sequenced the exomes of 8,554 individuals and analyzed the effects of predicted LOF variants on 20 chronic disease risk factor phenotypes. Analysis of this sample as discovery and replication strata of equal size verified two relationships in well-studied genes (PCSK9 and APOC3) and identified eight new loci. Previously unknown relationships included elevated fasting glucose in carriers of heterozygous LOF variation in TXNDC5, which encodes a biomarker for type 1 diabetes progression, and apparent recessive effects of C1QTNF8 on serum magnesium levels. These data demonstrate the utility of functional-variant annotation within a large sample of deeply phenotyped individuals for gene discovery.

Aims Darapladib, a potent inhibitor of lipoprotein-associated phospholipase A

The primary risk factor for lung cancer (second most common cancer in men and women in the U.S.) is tobacco smoking. Prior GWAS have identified variants in the CHRNA5-CHRNA3-CHRNB4 cluster (chr 15q25) to be associated with smoking. Total nicotine equivalents (TNE) measured from urine represents the sum of nicotine, cotinine, and trans-3′-hydroxycotinine and its glucuronides, as well as nicotine N-oxide, and is a biomarker of nicotine uptake and, when adjusted for cigarettes smoked per day (CPD), a biomarker of smoking intensity. In addition to smoking status, genetic variation is likely to influence smoking behavior (e.g., number of cigarettes, number of puffs, depth of inhalation) and, thus, one's internal exposure to nicotine and tobacco carcinogens. We conducted a genome-wide association study of TNE (i.e. smoking dose) among 2,239 cancer-free, current smokers from the Multiethnic Cohort, comprised of 5 ethnic groups. TNE was measured using liquid chromatography-tandem mass spectrometry analysis in overnight or first morning urine samples. Genotyping was conducted utilizing the Illumina 1M array and the data were imputed to the 1000 Genomes reference panel, for a total of 11.9 million SNPs and indels. Linear regression models were conducted in all subjects combined and each ethnic group using the log transformed TNE measurement, adjusted for age, BMI, sex, and the first ten principle components (Model 1). A separate model additionally adjusted for log transformed cigarettes per day (Model 2). Genome-wide significant associations with TNE for Model 1 included the chr 15q25 region, specifically, intronic common SNPs in CHRNB4 (rs17487223) and CHRNA3 (rs55676755) with P=7.37x10-9 (Beta (SE) = 0.21 (0.04)) and P=2.22x10-8 (Beta (SE) = 0.19 (0.03)), respectively. Ethnic specific analyses pointed to European American, African American, and Hispanic individuals mainly contributing to the signal. Nicotinic receptors, as ligand-gated channels consist of five subunits and are the primary targets for nicotine and initiate the brain responses to smoking. Our findings with nicotine uptake confirm previous reports that these biologically plausible genes influence smoking behavior. For Model 2 in all pooled ethnicities combined, three intronic SNPs were near genome-wide significance (with lowest P=7.13x10-8 for rs55934265) in the beta-1,3-galactosyltransferase (B3GALT1) gene, Beta (SE) = -0.57 (0.10). The B3GALT1 signal was primarily driven by the African American data (N=364) with ethnic specific results at P=5.3x10-4, Beta (SE) = -0.47 (0.13). B3GALT1 is expressed exclusively in the brain and is involved in the biosynthesis of glycolipids. Next steps include constructing a genetic risk score (GRS) of TNE, and evaluating the GRS in association with lung cancer risk independent of self-reported levels of smoking. Citation Format: Linda M. Polfus, S. Lani Park, Yesha M. Patel, Sharon E. Murphy, David Conti, Christopher Haiman, Daniel O. Stram, Loïc Le Marchand. Genome-wide association study (GWAS) of total nicotine equivalents: A composite biomarker of nicotine uptake [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 232.

Neutrophils are a key component of innate immunity. Individuals with low neutrophil count are susceptible to frequent infections. Linkage and association between congenital neutropenia and a single rare missense variant in TCIRG1 have been reported in a single family. Here, we report on nine rare missense variants at evolutionarily conserved sites in TCIRG1 that are associated with lower absolute neutrophil count (ANC)(p=0.005) in 1058 participants from three cohorts: the Atherosclerosis Risk in Communities (ARIC), Coronary Artery Risk Development in Young Adults (CARDIA) and Jackson Heart (JHS) studies of the NHLBI Grand Opportunity Exome Sequencing Project (GO ESP). These results validate the effects of TCIRG1 coding variation on ANC and suggest that this gene may be associated with a spectrum of mild to severe effects on ANC.

Among over 6300 participants in the Atherosclerosis Risk in Communities study, participants with genetic variants associated with reduced lipoprotein-associated phospholipase A2 activity did not have an accompanying decreased risk of cardiovascular morbidity or mortality.

Background: Chronic immune thrombocytopenia (ITP) is a complex autoimmune disease characterized by antibody mediated platelet destruction and impaired production. Sustained autoimmunity in chronic ITP appears to be due to generalized immune dysregulation including altered T cell balance with a shift toward immune activation (increased Th1/Th2 ratio) as well as decreased number and impaired function of regulatory T cells (Treg). The cause of these abnormalities has not been fully elucidated and is likely multifactorial, but genetic factors may be involved in ITP pathogenesis. Improved understanding of genetic influences could lead to novel therapeutic approaches. Aim: To identify genetic variants that may be involved in chronic ITP susceptibility and severity. Methods: Whole exome sequencing (WES) was performed on 262 samples with robust phenotype data on children with chronic ITP from the North American Chronic ITP Registry (NACIR, n= 173) and the Platelet Disorders Center at the Weill-Cornell Medical Center (n=89). All but three patients were ≤19 years old at diagnosis; 83% had primary ITP, 10% had Evans syndrome, 7% had other autoimmune disorders. Sequencing data for ITP cases of European American (EA) ancestry were compared to EA controls with platelets >150 x 109/L sequenced in the Atherosclerosis Risk in Communities (ARIC) Study (N=5664) to identify candidate genes associated with ITP susceptibility. Analyses filtered variants on a minor allele frequency (MAF) 150 x 109/L (N=5664). Results: Several damaging variants identified in genes involved in cellular immunity had a significantly increased frequency in the EA ITP cohort (Table). The most significant associations were detected in the IFNA17 gene, which is involved in TGF-β secretion and could affect number and function of the Treg compartment. IFNA17 rs9298814 (9:21227622 A>C) was identified in 26% of cases in the EA ITP cohort compared to Conclusion: Damaging variants in genes associated with cellular immunity have an increased frequency in children with chronic ITP compared to controls, providing further evidence for the role of T cell abnormalities in the pathophysiology of ITP. The IFNA17 and IFNLR1 genes maintained significance when the ITP cohort was stratified according to disease severity, and may be important candidate genes involved in immune regulation and sustained autoimmunity associated with chronic ITP. Table. Genes identified through WES analysis of children with chronic ITP. Gene Function Relevant to ITP Pathophysiology Minor Allele Count (MAC)Cases Controls p value EA Chronic ITP vs. EA ARIC (non-ITP) controls N=172 N=5664 IFNA17 Treg, TGF-β signaling 91 17 3.97x10-13 DGCR14 IL-17 induction 14 3 1.27x10-10 SMAD2 TGF-β signaling 1 0 5.62x10-22 CD83 Th17/Treg balance 2 3 1.67x10-6 EA Chronic ITP requiring Second Line Therapy vs. EA ARIC (non-ITP) controls N=139 N=5664 IFNLR1 Class II cytokine receptor 2 1 3.95x10-15 IFNA17 Treg, TGF-β signaling 75 17 3.40x10-7 REL T and B cell function, inflammation 2 0 1.39x10-14 Disclosures Off Label Use: Off-label use of CliniMACS purified CD34+ cells. Lambert:GSK: Consultancy; NovoNordisk: Honoraria; Hardin Kundla McKeon & Poletto: Consultancy. Recht:Baxalta: Research Funding; Kedrion: Consultancy. Bussel:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; protalex: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; rigel: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cangene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.