No abstract

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.

We assessed the effect of two common mutations in the lipoprotein lipase gene (LPL), D9N and N291S, which have been shown to modulate plasma lipids in a wide spectrum of patients. A total of 1114 men and 1 144 women from the Framingham Offspring Study (FOS) were analyzed for these two LPL variants. Subsequently, the association with fasting plasma lipids and risk of coronary artery disease (CHD) was determined. We extended our study by calculating weighed means of lipids and lipoproteins in carriers and non-carriers for these LPL mutations in patients with genetic dyslipidemias, CHD patients and healthy controls. In the FOS sample, the D9N and N291S alleles were associated with lower high-density lipoprotein-cholesterol (HDL-C) (delta = - 0.07 mmol/ 1, p = 0.03) and a trend towards increased triglycerides (delta = 0.25 mmol/ 1, p = 0.07). In women, a trend towards the high triglyceride, low HDL-C phenotype was evident (delta = - 0.02 mmol/1 for HDL-C and delta = 0.14 mmol/l for triglycerides, respectively). Cumulative analysis of other studies of male carriers of the D9N and N291S revealed higher levels of triglycerides (D291N; 2.60(1.85) mmol/l vs. 1.62(1.18) mmol/l: p < 0.0001) (D9N; 1.94 (1.19) mmol/l vs. 1.74(1.17) mmol/l: p < 0.001) and lower HDL-C (N291S; 1.04(0.32) mmol/l vs. 1.15(0.28) mmol/l: p < 0.0001) (D9N; 1.08(0.24) mmol/l vs. 1.16(0.28) mmol/l: p < 0.0001). In females, results differed with higher TG levels (N291S; 1.70(0.99) mmol/l vs. 1.10(0.63) mmol/l: p < 0.001) (D9N; 1.08(0.76) mmol/l vs. 0.96(0.51) mmol/l: p < 0.01) and lower HDL-C levels (N291S; 1.27(0.33) mmol/l vs. 1.51(0.32) mmol/l: p < 0.0001); however, the HDL-C levels for D9N carriers were similar to non-carriers (D9N; 1.52(0.29) mmol/l vs. 1.53(0.35) mmol/l: p = 0.83). Our data provide evidence that common variants of the LPL gene are significant modulators of lipid and lipoprotein levels in both men and women.