Single nucleotide polymorphisms in the proximal promoter region of apolipoprotein M gene (apoM) confer the susceptibility to development of type 2 diabetes in Han Chinese

OBJECTIVE: Dyslipidemia correlating to insulin resistance is one of the key features in type 2 diabetes (T2D). Recent studies have demonstrated that apolipoprotein M (apoM) is important for the formation of prebeta-high-density lipoprotein (HDL) and cholesterol (CHO) efflux in macrophages to HDL. In the present study, we investigated the potential association of apoM genetic variation with the development of T2D. METHODS: Single nucleotide polymorphisms (SNPs) C-1065A, T-855C and T-778C in the proximal promoter region of apoM gene were validated to represent in Han Chinese. Further genotyping experiments in 170 T2D patients and 156 non-diabetic control subjects were performed with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Single marker analysis for SNP T-778C indicated that T2D patients had increased frequency of C allele in comparison with non-diabetic controls (10.6% versus 5.8%, P = 0.026, OR = 1.934). In non-diabetic controls, the carriers with CT and CC genotypes had higher plasma CHO (221.7 versus 204.2 mg/dL, P = 0.033) and fasting plasma glucose (FPG) (92.6 versus 89.7 mg/dL, P = 0.041) levels than the subjects with TT genotype. Further analysis with adjustment for age, BMI, SBP, DBP, CHO and TG demonstrated that this SNP was strongly associated with T2D (P = 0.013, OR = 2.287). Haplotype analysis for those three SNPs, however, indicated that the common haplotypes were less informative than studying the role of the T-778C variant independently of the haplotype context. CONCLUSION: The present study provided the first evidence that SNP T-778C in the proximal promoter region of apoM gene was associated with the levels of plasma CHO and FPG and also conferred the risk in the development of T2D among Han Chinese.