GWAS of QRS duration identifies new loci specific to Hispanic/Latino populations

Background The electrocardiographically quantified QRS duration measures ventricular depolarization and conduction. QRS prolongation has been associated with poor heart failure prognosis and cardiovascular mortality, including sudden death. While previous genome-wide association studies (GWAS) have identified 32 QRS SNPs across 26 loci among European, African, and Asian-descent populations, the genetics of QRS among Hispanics/Latinos has not been previously explored. Methods We performed a GWAS of QRS duration among Hispanic/Latino ancestry populations (n = 15,124) from four studies using 1000 Genomes imputed genotype data (adjusted for age, sex, global ancestry, clinical and study-specific covariates). Study-specific results were combined using fixed-effects, inverse variance-weighted meta-analysis. Results We identified six loci associated with QRS (P<5x10-8), including two novel loci: MYOCD, a nuclear protein expressed in the heart, and SYT1, an integral membrane protein. The top SNP in the MYOCD locus, intronic SNP rs16946539, was found in Hispanics/Latinos with a minor allele frequency (MAF) of 0.04, but is monomorphic in European and African descent populations. The most significant QRS duration association was with intronic SNP rs3922344 (P = 1.19x10-24) in SCN5A/SCN10A. Three other previously identified loci, CDKN1A, VTI1A, and HAND1, also exceeded the GWAS significance threshold among Hispanics/Latinos. A total of 27 of 32 previously identified QRS duration SNPs were shown to generalize in Hispanics/Latinos. Conclusions Our QRS duration GWAS, the first in Hispanic/Latino populations, identified two new loci, underscoring the utility of extending large scale genomic studies to currently under-examined populations

Predicting risk of bacterial vaginosis: the role of race, smoking and corticotropin-releasing hormone-related genes

Bacterial vaginosis (BV) is one of the most prevalent vaginal disorders in adult women and is associated with adverse pregnancy outcomes such as pre-term birth. Genetic factors, particularly in genes involved in inflammation and infection, are associated with this condition. Additionally, environmental risk factors including stress and smoking are associated with BV. The purpose of this study was to identify genetic variants in stress-related genes such as corticotropin-releasing hormone (CRH), receptor 1, receptor 2 and binding protein (CRH-BP) that associate with BV. Also gene–environment effects with smoking are determined. BV was quantified using the Nugent score in 82 white and 65 black women in the first trimester of pregnancy. Associations between Nugent score, genotype and smoking were analyzed using Kruskal–Wallis and Wilcoxon rank sum non-parametric tests. In white women, non-smokers with the CT genotype at CRH-BP + 17487 have lower Nugent scores (median: 0, range: 0–0) than non-smokers with the TT genotype (median: 2, range: 0–8) (P = 0.002); whereas smokers with the CT genotype have higher Nugent scores (median: 6, range: 0–10) than smokers with the TT genotype (median: 1, range: 0–10) (P = 0.021). In black women, the AG genotype at CRH + 3362 or CRH − 1667 is associated with lower Nugent scores (median for both: 3, range: 0–10) compared with the homozygous genotypes (median for each homozygous genotype: 8, range: 0–10). Also, in black women, models remain significant after adjusting for smoking (P = 0.04 for both). These data indicate that susceptibility to BV is affected by patterns of genetic variation in stress-related genes and smoking plays an important role

Ethnic differences in the relationship between birth weight and type 2 diabetes mellitus in postmenopausal women

AimThe objective of this study is to examine the relationship between self-reported birth weight and the adult occurrence of type 2 diabetes mellitus in a large multi-ethnic population of women.MethodsBaseline data from the Women's Health Initiative Observational Study [n=75,993] was used to examine the association between participant birth weight category and prevalent type 2 diabetes mellitus. Models were adjusted for age, ethnicity, body mass index and other pertinent risk factors. Sub-analyses were performed stratifying by ethnicity.ResultsThere was a strong inverse association between birth weight and type 2 diabetes mellitus with a birth weight of <6 pounds (lbs) (OR: 1.16, 95% CI: 1.01, 1.33) significantly associated with an increased risk of type 2 diabetes mellitus and a birth weight of ≥10 lbs (OR: 0.72, 95% CI: 0.57, 0.92) associated with a decreased risk of type 2 diabetes mellitus compared to women who reported their birth weight between 7 and 8 lbs 15 ounces (oz). Stratifying by ethnicity, the inverse association between birth weight and type 2 diabetes mellitus was only apparent in White women, but not Black, Hispanic or Asian women.ConclusionLower birth weight was associated with increased T2D risk in American White and Black post-menopausal women

Association of low-frequency and rare coding-sequence variants with blood lipids and coronary heart disease in 56,000 whites and blacks

Low-frequency coding DNA sequence variants in the proprotein convertase subtilisin/kexin type 9 gene (PCSK9) lower plasma low-density lipoprotein cholesterol (LDL-C), protect against risk of coronary heart disease (CHD), and have prompted the development of a new class of therapeutics. It is uncertain whether the PCSK9 example represents a paradigm or an isolated exception. We used the "Exome Array" to genotype >200,000 low-frequency and rare coding sequence variants across the genome in 56,538 individuals (42,208 European ancestry [EA] and 14,330 African ancestry [AA]) and tested these variants for association with LDL-C, high-density lipoprotein cholesterol (HDL-C), and triglycerides. Although we did not identify new genes associated with LDL-C, we did identify four low-frequency (frequencies between 0.1% and 2%) variants (ANGPTL8 rs145464906 [c.361C>T; p.Gln121-], PAFAH1B2 rs186808413 [c.482C>T; p.Ser161Leu], COL18A1 rs114139997 [c.331G>A; p.Gly111Arg], and PCSK7 rs142953140 [c.1511G>A; p.Arg504His]) with large effects on HDL-C and/or triglycerides. None of these four variants was associated with risk for CHD, suggesting that examples of low-frequency coding variants with robust effects on both lipids and CHD will be limited