Abstract P264: Association of D-dimer with Incident Cardiovascular Disease Events and F3 Gene Variants in African Americans: Results From the Jackson Heart Study

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Plasma D-dimer, a fibrin degradation product, is a biomarker of both coagulation and fibrinolysis and a risk factor for both arterial and venous thrombosis. African Americans (AAs) have increased risk of thrombosis and higher levels of D-dimer as compared to European populations, but little is known about the genetic architecture of D-dimer in AAs. D-dimer was assessed in 4163 AAs from the Jackson Heart Study (mean age 55 years, 62.1% female). We hypothesized that D-dimer levels would associate with incident cardiovascular disease events and with both coding and noncoding genetic variants. Median (interquartile range) D-dimer in the cohort was 0.40 (0.26-0.64) μg/ml. D-dimer was associated with increased risk of coronary heart disease (hazard ratio (HR) per standard deviation (SD)=1.26, p=0.012), stroke (HR=1.27, p=0.018), heart failure (HR=1.33, p=0.001), and mortality (HR=1.25, p<0.0001) in models adjusted for age, sex, BMI, current smoking, diabetes, hypertension, systolic blood pressure, and low-density lipoprotein cholesterol. Using data from the Affymetrix Genome-Wide Human SNP Array 6.0, imputation based on the 1000 Genomes project reference panel (Phase I, Version 3, March 2012 release) was completed using MACH 1.0 and minimac in 2709 participants with D-dimer. Associations were assessed using MACH2QTL v.1.13, with models adjusted for age, sex, and the first ten principal components for global ancestry calculated using EIGENSOFT. The most significant signal was for an intergenic locus near F3 (top variant rs2022030, p=5.71x10 -12 , minor allele frequency=10.6%, imputation r 2 =1). F3 codes for tissue factor, a necessary co-factor for factor VIIa in the initiation of the extrinsic blood coagulation pathway. The F3 locus had been previously associated with D-dimer levels in European populations but has not been reported for AAs. Data were also available from the Illumina HumanExome Beadchip, version 1.1, in 2502 individuals; single variant analyses and gene-based tests for nonsynonymous, splicing, and nonsense variants with a minor allele frequency <5% were performed using RAREMETAL, adjusted for age, sex, and the first ten principal components. For single variant analyses, a nonsynonymous variant in GPRASP1 (G protein-coupled receptor associated sorting protein 1, rs145805077, p= 1.84x10 -7 , minor allele frequency=0.3%) was significantly associated with decreased D-dimer. No gene-based test result met the strict multiple comparison significance threshold; the top gene-based result with the sequence kernel association test (SKAT) was for six variants in PPM1M (protein phosphatase, Mg2+/Mn2+ dependent, 1M, p=6.09x10 -6 ). These results highlight D-dimer as an important predictor of cardiovascular disease risk in AAs and that levels of this biomarker are associated with the F3 locus.