Genome-Wide Association Study Highlights <i>APOH</i> as a Novel Locus for Lipoprotein(a) Levels—Brief Report
Mary Hoekstra, Hao Yu Chen, Jian Rong, Line Dufresne, Jie Yao, Xiuqing Guo, Michael Y. Tsai, Sotirios Tsimikas, Wendy S. Post, Ramachandran S. Vasan, Jerome I. Rotter, Martin G. Larson, George Thanassoulis, James C. Engert
Abstract
Objective: Lp(a) (lipoprotein[a]) is an independent risk factor for cardiovascular diseases and plasma levels are primarily determined by variation at the LPA locus. We performed a genome-wide association study in the UK Biobank to determine whether additional loci influence Lp(a) levels. Approach and Results: We included 293 274 White British individuals in the discovery analysis. Approximately 93 095 623 variants were tested for association with natural log-transformed Lp(a) levels using linear regression models adjusted for age, sex, genotype batch, and 20 principal components of genetic ancestry. After quality control, 131 independent variants were associated at genome-wide significance (P ≤5×10 -8 ). In addition to validating previous associations at LPA , APOE , and CETP , we identified a novel variant at the APOH locus, encoding β2GPI (beta2-glycoprotein I). The APOH variant rs8178824 was associated with increased Lp(a) levels (β [95% CI] [ln nmol/L], 0.064 [0.047–0.081]; P =2.8×10 -13 ) and demonstrated a stronger effect after adjustment for variation at the LPA locus (β [95% CI] [ln nmol/L], 0.089 [0.076–0.10]; P =3.8×10 -42 ). This association was replicated in a meta-analysis of 5465 European-ancestry individuals from the Framingham Offspring Study and Multi-Ethnic Study of Atherosclerosis (β [95% CI] [ln mg/dL], 0.16 [0.044–0.28]; P =0.0071). Conclusions: In a large-scale genome-wide association study of Lp(a) levels, we identified APOH as a novel locus for Lp(a) in individuals of European ancestry. Additional studies are needed to determine the precise role of β2GPI in influencing Lp(a) levels as well as its potential as a therapeutic target.