Bst-1 RFLP at the human lipoprotein lipase (LPL) gene locus

Associations of the ABCA1 and LPL Gene Polymorphisms With Lipid Levels in a Hyperlipidemic Population

We conducted a cross-sectional study to investigate the effects of the adenosine triphosphate-binding cassette transporter 1 (ABCA1) I883M and lipoprotein lipase (LPL) HindIII polymorphisms on lipid levels in patients with hyperlipidemia. A total of 533 patients were enrolled. Serum lipid parameters were determined by an automatic biochemistry analyzer. Genotyping of the ABCA1 I883M and LPL HindIII was carried out using the polymerase chain reaction-restriction fragment length polymorphism technique. Multiple linear regression analysis was used to estimate the associations between serum lipid levels and the genetic polymorphisms. The frequency distribution of the ABCA1 I883M and LPL HindIII polymorphisms did not deviate from Hardy-Weinberg equilibrium. The major finding of our regression analysis showed that neither the ABCA1 I883M nor the LPL HindIII polymorphism was associated with baseline serum lipid levels in the total population. However, among patients with elevated alanine aminotransferase (ALT) levels (ALT ≥ 40 U/L), carriers of the M allele of the ABCA1 gene had lower levels of high-density lipoprotein cholesterol (HDL-C) and higher levels of low-density lipoprotein cholesterol (LDL-C) after adjusting for age, sex, smoking status, alcohol consumption, education level, occupation, and work intensity ( P < .05 for both). A test on interaction terms between the ABCA1 I833M polymorphism and ALT on HDL-C and LDL-C levels also remained significant ( P = .001 and P = .014, respectively). Our data suggest that there are significant interactive effects between ABCA1 I883M and ALT levels on HDL-C and LDL-C levels. However, the LPL HindIII polymorphism did not influence lipid levels.

DNA polymorphism of Pvu II site in the lipoprotein lipase gene in patients with non-insulin dependent diabetes mellitus

We studied the effect of variation at the lipoprotein lipase (LPL) gene locus on the susceptibility of individuals with non-insulin dependent diabetes mellitus (NIDDM) in a population of 110 NIDDM patients and 91 controls. Our objective was to study the relationship between the LPL-Pvu II polymorphism and NIDDM and lipid metabolism. PCR-RFLP was used to determine the DNA polymorphism of the sixth intron of the LPL gene. The frequencies of the genotypes in case and control groups were 29.1 and 30.8% for P+/P+; 45.5 and 36.3% for P+/P-; 25.5 and 33% for P-/P- respectively. There was no significant difference in frequencies of genotypes between the two groups. Logistic regression analysis revealed that triacylglycerol (TAG) and apolipoprotein E levels were associated with NIDDM, whereas Pvu II genotypes were not found as independent risk factors for the disease. Overall this study demonstrates the role of the Pvu II polymorphism in the LPL gene in modulating plasma lipid/lipoprotein levels in patients with NIDDM.

Lipoprotein Lipase Gene Polymorphism and Lipid Profile in Coronary Artery Disease

Context.—Lipoprotein lipase (LPL) plays a central role in lipid metabolism, hydrolyzing triglyceride in chylomicrons and very-low-density lipoproteins. The PvuII polymorphic variant of LPL gene is common and might affect risk of coronary artery disease (CAD).

Objective.—Our aim was to determine whether LPL– PvuII polymorphism can be considered to be an independent risk factor or a predictor for CAD in Turkish subjects.

Design.—We used polymerase chain reaction and restriction enzyme digestion to determine the distribution of the previously described C→T transition that causes a PvuII polymorphism in intron 6 among healthy blood donors of Turkish origin and among angiographically confirmed CAD patients with comparable ethnic backgrounds.

Results.—For the PvuII genotypes, within the CAD group (n = 80), the +/− genotype was found in 39 individuals (48.8%), whereas 25 (31.3%) carried the +/+ genotype, and 14 (17.5%) carried the −/− genotype. Within the control group (n = 49), the −/− genotype was found in 19 individuals (38.8%), 16 (32.7%) carried the +/− genotype, and 14 (28.6%) carried the +/+ genotype. The genotype frequency distribution was significantly different (P = .049) in the CAD and control study groups. The most frequent genotype among CAD patients was +/−; this genotype was more frequent in patients than in control subjects. However, the −/− genotype was more prevalent in the control group. Lipoprotein lipase–PvuII polymorphism was found to be associated with fasting total cholesterol and low-density lipoprotein cholesterol levels. The +/+ genotype was found to have higher levels of total cholesterol and low-density lipoprotein cholesterol in both the CAD and control groups.

Conclusion.—There was a difference in the distribution of LPL–PvuII genotypes between the healthy subjects and the patients with CAD. Lipoprotein lipase–PvuII polymorphisms were not detected as independent risk factors for CAD in this study group, but had associations with lipid levels.

Genetic polymorphisms and mutations of the lipoprotein lipase gene in Japanese schoolchildren with hypoalphalipoproteinemia

Lipoprotein lipase (LPL) is an important enzyme for the hydrolysis of TG on lipoproteins, and its activity is positively correlated with the plasma levels of high density lipoprotein cholesterol (HDL-C). To investigate the association between the LPL gene and low HDL-C levels, we studied two polymorphisms (Hind III and Pvu II) and three mutations (Asn291Ser, Gly188Glu and LPL(Arita)) of the LPL gene in 114 children with low HDL-C levels (<40 mg/dl) and 194 control children using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques (PCR-RFLP). The frequency of the Pvu II +/+ genotype was significantly higher in the children with low-HDL/high-TG (TG>100 mg/dl, 90th percentile level among Japanese schoolchildren) than in the other children (vs the low-HDL/normal-TG children, chi2 = 7.49, p < 0.01; vs control children, chi2 = 7.23, p < 0.01). Pvu II+ allele of the LPL gene was associated with elevated TG levels in low HDL-C groups. In addition, we found one heterozygote of LPL(Arita) (deletion of G at base 916 in exon 5, the most common mutation of LPL deficiency in Japanese), among the low-HDL/high-TG subjects. The other two variants were not detected in either the low-HDL children or control children. LPL Asn291Ser and Gly188Glu have been presumed to be rare in the Japanese population. In conclusion, our results suggest that hypoalphalipoproteinemia with elevated TG level may be associated with genetic variations of the LPL gene.

Common variation in the lipoprotein lipase gene: effects on plasma lipids and risk of atherosclerosis

The importance of the enzyme lipoprotein lipase (LPL) in the development of dyslipidaemia and atherosclerosis is increasingly recognised. Variations in the LPL gene which are common in the general population have been shown to be associated with alterations in plasma lipids. D9N and N291S both occur at carrier frequencies of up to about 5% and have been associated with increased plasma triacylglycerol and decreased high density lipoprotein cholesterol concentrations, effects which seem to be magnified in more obese individuals. S447X carrier frequency is approximately 20%, but unlike carriers of N9 or S291, X447 carriers appear to have a more favourable lipid profile. A transition within the LPL promoter at position-93 may lead to increased LPL activity and have a beneficial effect on plasma lipids. Greater knowledge of the underlying mechanisms of these variations within the LPL gene may be of considerable importance in understanding genetic predisposition to atherosclerosis and heart disease.

Molecular pathobiology of the human lipoprotein lipase gene

Lipoprotein lipase (LPL; E.C. 3.1.1.34) is a key enzyme in the metabolism of lipids. Many diseases, including obesity, coronary heart disease, chylomicronemia (pancreatitis), and atherosclerosis, appear to be directly or indirectly related to abnormalities in LPL function. Human LPL is a member of a superfamily of lipases that includes hepatic lipase and pancreatic lipase. These lipases are characterized by extensive homology, both at the level of the gene and the mature protein, suggesting that they have a common evolutionary origin. A large number of natural mutations have been discovered in the human LPL gene, which are located at different sites in the gene and affect different functions of the mature protein. There is a high prevalence of two of these mutations (207 and 188) in the Province of Québec, and one of them (207) is almost exclusive to the French-Canadian population. A study of these and other naturally occurring mutant LPL molecules, as well as those created in vitro by site-directed mutagenesis, indicate that the sequence of LPL is organized into multiple structural and functional units that act in concert in the normal enzyme. In this review, we discuss the interrelationships of LPL structure and its function, the molecular etiology of abnormal LPL in humans, and the clinical and therapeutic aspects of LPL deficiency.

Polymorphisms in the lipoprotein lipase gene and their associations with plasma lipid concentrations in 40-year-old Danish men

BACKGROUND

In some previous studies, HindIII and Pvu II restriction fragment length polymorphisms (RFLPs) in the lipoprotein lipase (LPL) gene were associated with coronary heart disease and plasma concentrations of HDL cholesterol and triglycerides. However, the populations studied were relatively small and heterogeneous in regard to age, sex, and ethnic background.

METHODS AND RESULTS

Associations of a HindIII (intron 8) and a Pvu II (intron 6) RFLP in the LPL gene with plasma concentrations of cholesterol, HDL cholesterol, non-HDL cholesterol, and triglycerides were studied in 457 randomly selected 40-year-old Danish men. The HindIII and the Pvu II sites were in strong linkage disequilibrium. The frequencies of the H+ and P+ alleles (+ denotes presence of cutting site) were 0.717 and 0.464, respectively. In multivariate analysis, there was a clear gene dosage effect of the H+ allele on HDL. The lowest HDL cholesterol concentration was in the H+H+ group, the highest concentration was in the H-H- group, and the H+H- group had intermediate HDL concentrations (P = .03). There was a similar, but not statistically significant gene dosage effect on triglyceride concentrations, with the highest value seen in the H+H+ group. There were no other associations between LPL RFLPs and lipoprotein components. In males reporting family history of premature ischemic heart disease, the H+H+ genotype was overrepresented (odds ratio, 2.75; 95% confidence interval, 1.37 to 5.53).

CONCLUSIONS

The results suggest that genetic variation in or near the LPL gene plays a role in interindividual differences in HDL cholesterol concentration and in risk of atherosclerosis and ischemic heart disease in men.