The PCSK9 gene E670G polymorphism affects low-density lipoprotein cholesterol levels but is not a risk factor for coronary artery disease in ethnic Chinese in Taiwan

Background: An E670G polymorphism of the exon 12 of the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene was recently found to be associated with increased plasma low-density lipoprotein cholesterol (LDL-C) levels and severity of coronary atherosclerosis. This case-control study tested for a possible link between this PCSK9 polymorphism and the risk of coronary artery disease (CAD) in an ethnic Chinese population in Taiwan. Methods: The subjects included 202 CAD patients and 614 unrelated controls. Genotypes were determined via polymerase chain reaction, restriction mapping with MboII, and gel electrophoresis. Results: Contradictory to the results of a previous report, a significantly lower level of LDL-C was noted in 670G carriers than in non-carriers (2.78±0.82 mmol/L vs. 3.02±0.85 mmol/L; p=0.029) among controls, after adjusting for age, gender, smoking, hypertension, diabetes mellitus, body mass index, and use of lipid-lowering agents. The 670G carrier was identified less frequently in patients with CAD than in controls (9.9% vs. 11.9%), but the difference was not significant in a multivariable logistic regression analysis (odds ratio=0.73; 95% CI=0.24-2.22; p=0.575). The G allele also occurred at similar frequencies in the two groups (5.0% vs. 6.0%; p=0.421). Conclusions: These results indicate that the E670G polymorphism of the PCSK9 gene modulates plasma LDL-C levels, but that it is not a risk variant for CAD in ethnic Chinese in Taiwan.