The Asn9 variant of lipoprotein lipase is associated with the - 93G promoter mutation and an increased risk of coronary artery disease

Two mutations in the lipoprotein lipase (LPL) gene, a T to G transition at position -93 of the proximal promoter region and an Asp9Asn substitution in exon 2, were examined in 762 Dutch males with angiographically-diagnosed coronary artery disease (CAD) and 296 healthy normolipidemic Dutch males. The two mutations exhibited strong linkage disequilibrium (D' = 0.975). A significantly higher proportion of cases (4.86%) than controls (1.37%) carried the -93G/Asn9 allele (p = 0.008). In the combined sample of cases and controls, adjusted mean plasma total cholesterol (TC) levels were significantly higher in -93G/Asn9 carriers (6.20 ± 0.13 mmol/l) than in non-carriers (5.93 ± 0.03 mmol/l; p = 0.048), while mean high-density lipoprotein cholesterol (HDL-C) levels were lower in carriers (0.88 ± 0.03 mmol/l) than in non-carriers (0.98 ± 0.01 mmol/l; p = 0.002). There was a trend towards higher triglyceride (TG) levels in carriers (1.96 ± 0.14 mmol/l) compared with non-carriers (1.73 ± 0.03 mmol/l) (p = 0.08). Additionally, carrier frequencies in tertiles of TC, HDL-C, TG, and LPL activity, suggested an association of the -93G/Asn9 variant with higher TC and TG levels, and with lower HDL-C and LPL activity levels. Logistic regression revealed a significant odds ratio (OR) for the combined -93G/Asn9 genotype in CAD cases relative to controls (OR: 5.36; 95% CI: 1.57-18.24), with age, body mass index (BMI), smoking, and plasma total- and HDL-cholesterol levels included in the model. In conclusion, we show that the LPL Asp9Asn mutation is in non-random association with a T→G substitution at position -93 of the proximal promoter region and that the combined -93G/Asn9 genotype predisposes to decreased HDL-C levels and an increased risk of CAD.