OBJECTIVES:Apolipoprotein M (apoM) is important for the formation of pre-beta-high-density lipoprotein (HDL) and cholesterol efflux in macrophages. It is demonstrated that single-nucleotide polymorphism (SNP) T-778C of apoM gene is related to type 2 diabetes in Han Chinese. In the present study, we investigated the possible association of apoM polymorphism in relation to coronary artery disease (CAD) in Han Chinese. DESIGN AND METHODS:This case-controlled study consisted of 118 CAD patients who were diagnosed angiographically to have at least 30% stenosis, and 255 unrelated subjects who were used as control. ApoM gene polymorphism in the proximal promoter region was analyzed by PCR-RFLP and serum lipid levels were also measured. RESULTS:It is indicated that CAD patients had increased frequency of C allele on apoM T-778C compared to the controls (14.8% vs. 6.9%, P=0.0008). Multivariable logistic regression analysis indicated that odds ratios (ORs) for all subjects with apoM CC+CT genotypes and C allele were 1.9 (95% CI=1.1-2.9, P<0.0001) and 1.9 (95% CI=1.3-3.2, P<0.0001), respectively. The plasma total cholesterol (TC) levels were significantly higher in individuals with CC or CT genotype than those with TT genotype in both CAD patients and controls. CONCLUSIONS:The present findings suggest that the C allele at nucleotide -778 in the apoM gene is a risk factor for genetic susceptibility to CAD and is also associated with TC levels in Han Chinese.