Copy number variation of the Lipoprotein(a) (LPA) gene is associated with coronary artery disease in a southern Han Chinese population.

Abstract

Copy number variations (CNVs), genomic duplication or deletion events occurring at larger than 1 kb scale, contribute to the complex diseases substantially. Lipoprotein(a) [Lp(a)] is a major inherited risk factor for atherosclerosis and coronary artery disease (CAD). We investigated the association between a CNV of the Lp(a) (LPA) gene and CAD. The case-control study included 271 CAD patients and 207 controls diagnosed by coronary angiography. A taqman real-time fluorescence PCR based technique was developed according to the 2 × 2(-ΔΔCt±SD) calculation method. We detected LPA CNVs with a range of 1, 2 and 3. The 1 copy number carriers had a significantly reduced risk of CAD compared with those with 2 copy number after adjusting for the confounding factors (P < 0.001, OR = 0.38, 95% CI 0.23-0.64). Further stratified analyses suggested a significant protective effect of the 1 copy number in the elderly population (P = 0.008), females (P = 0.007) as well as in populations with non-hyperlipidemia (P = 0.003), hypertension (P = 0.001), non-smoking (P < 0.001) and high Lp(a) (≥ 0.3 g/L) levels (P = 0.001). The 1 copy number of the LPA gene may be an independent protective factor of CAD in a southern Han Chinese population, particularly in females and the elderly.