Objective: Elevated HDL cholesterol and its principal carrier protein apolipoprotein a1 [apo(a1)] are associated with reduced risk of coronary heart disease (CHD). No studies are available on the impact of the -75-bp and/or +83-bp polymorphisms of the apo(a1) gene on HDL cholesterol and apo(a1) levels in patients with type 2 diabetes.
Research design and methods: We determined the prevalence of the: -75-bp and +83-bp polymorphisms of the apo(a1) gene by restriction fragment length polymorphism analysis among 308 unrelated nondiabetic subjects with CHD and among 251 unrelated patients with type 2 diabetes with CHD and in randomly selected 82 healthy men (CHD-).
Results: The rare M1- and M2- allele frequencies of the apo(a1) gene were 23 and 1.8%, respectively, among control subjects; 20 and 1.5%, respectively, among nondiabetic subjects with CHD; and 22 and 2.6%, respectively, among patients with type 2 diabetes and CHD (NS). Nonsmoking nondiabetic subjects with CHD having the M2+- genotype had higher HDL cholesterol (1.48 +/- 0.19 vs. 1.23 +/- 0.02 mmol/l, P < 0.01) and apo(a1) (1.43 +/- 0.10 vs. 1.36 +/- 0.02 g/l, P < 0.05) levels than subjects with the M2++ genotype, even after adjustment for confounding factors. This association was not found among patients with type 2 diabetes and CHD.
Conclusions: We conclude that the +83-bp polymorphism of the apo(a1) gene is associated with elevated HDL cholesterol and apo(a1) levels in Finnish nondiabetic subjects but not in patients with type 2 diabetes.