Analyses of longitudinal effects of gene-environment interactions on plasma C-reactive protein levels: the Hallym Aging Study

Identification of pleiotropic genetic variants affecting osteoporosis risk in a Korean elderly cohort

Pleiotropy has important implications for understanding the genetic basis and risk assessment of osteoporosis. Our aim was to identify pleiotropic genetic variants associated with the development of osteoporosis and predict osteoporosis risk by leveraging pleiotropic variants. We evaluated the effects of 21 conventional risk factors and 185 single-nucleotide polymorphisms (SNPs) in 63 inflammation- and metabolism-related genes on osteoporosis risk in a community-based Korean cohort study of 1025 participants, the Hallym Aging Study. Ten nongenetic factors, including sex (female) and hematocrit level, and 12 SNPs across ten genes showed evidence of association with incident osteoporosis in 270 initially osteoporosis-free subjects who completed a 6-year follow up. Three gene variants, rs1801282 (PPARG-Pro12Ala, hazard ratio (HR) = 3.26, P = 0.008), rs1408282 (near EPHA7, HR = 1.87, P = 0.002), and rs2076212 (PNPLA3-Gly115Cys, HR = 2.24, P = 0.024), were associated with significant differences in survival among the three genotype groups (P_diff = 0.042, 0.003, and 0.048, respectively). Individuals in the highest polygenic risk score tertile were 27.9 fold more likely to develop osteoporosis than those in the lowest tertile (P = 0.004). The PPARG gene in particular was a hub pleiotropic gene in the epistasis network. Our findings highlight pleiotropic modulations of metabolism- and inflammation-related genes in the development of osteoporosis and demonstrate the contribution of pleiotropic genetic variants in prediction of osteoporosis risk.

Genetic risk assessment for cardiovascular disease with seven genes associated with plasma C-reactive protein concentrations in Asian populations

Plasma C-reactive protein (CRP) level is a predictor of cardiovascular risk. We performed a meta-analysis on the effect of 12 single-nucleotide polymorphisms (SNPs) within 8 candidate loci in 36 752 Asians. In addition, we created weighted genetic risk scores (wGRSs) to evaluate the combined effects of genetic variants, which were suggested in the meta-analysis, for predicting the risks of elevated CRP levels as well as increased risks of hypertension and cardiovascular disease (CVD) in 748 Koreans. Nine SNPs located in seven genes, CRP, IL6R, GCKR, IL6, CYP17A1, HNF1A and APOE, were significantly associated with circulating CRP levels in this meta-analysis. Two SNPs, rs7310409 (HNF1A, P=3.4 × 10(-23)) and rs7553007 (CRP, P=3.4 × 10(-17)), had the most significant effects on CRP levels; and two SNPs, rs2097677 (IL6) and rs1004467 (CYP17A1) have never been found in the previous European meta-analysis. In Koreans, the subjects in the highest wGRS group had an ∼2.5-fold higher mean CRP level compared with those in the lowest wGRS group (P=2.1 × 10(-5)). We observed significant increases in the risks of hypertension (odds ratio=2.18, P=0.006) and CVD (odds ratio=9.59, P=3.2 × 10(-6)) among the subjects in the highest wGRS group. The wGRS models specific to Koreans may warrant further validation to be used as a proxy for the risk of CVD in Asians.