L.A. Salazar

Seven DNA polymorphisms at the candidate genes of atherosclerosis in Brazilian women with angiographically documented coronary artery disease.

The possible association of genetic markers at the apolipoprotein E (HhaI polymorphism), apolipoprotein B (XbaI, EcoRI and Ins/Del polymorphisms), and low-density lipoprotein receptor (LDLR) (AvaII, HincII and PvuII polymorphisms) with coronary artery disease (CAD) was evaluated in 50 Brazilian women with CAD diagnosed by angiography and in 100 healthy women (controls). The frequency of E3/E4 genotype for HhaI polymorphism at the Apo E gene was significantly higher in CAD patients than in controls (40% vs. 14%, respectively, P<0.001). Similarly, the X-X- genotype for XbaI polymorphism was more frequent in CAD individuals than controls (42% vs. 12%, P<0.0001). The A+A+ and P1P1 genotypes for AvaII and PvuII polymorphisms at the LDLR locus were also higher in CAD subjects than controls (44% vs. 16%, P<0.001 and 64% vs. 39%, P<0.05, respectively). The estimated relative risks for CAD in women carrying the E3/E4, X-X-, A+A+ and P1P1 genotypes were 4.1 [95% confidence interval (CI), 3.0-5.6], 5.3 (95% CI, 3.8-7.5), 4.1 (95% CI, 3.0-5.5), and 2.8 (95% CI, 2.2-3.6), respectively. This study demonstrates that Apo E, Apo B and LDLR gene polymorphisms are associated with CAD in Brazilian Caucasian women.

Lipid-lowering response of the HMG-CoA reductase inhibitor fluvastatin is influenced by polymorphisms in the low-density lipoprotein receptor gene in Brazilian patients with primary hypercholesterolemia

Although the efficacy of fluvastatin (HMG‐CoA reductase inhibitor) in the treatment of primary hypercholesterolemia is well documented, a wide interindividual variation treatment response has been observed. We have studied the possible role of the AvaII (exon 13), HincII (exon 12), and PvuII (intron 15) polymorphisms at the low‐density lipoprotein receptor (LDLR) gene on lipid‐lowering response in 55 patients (36 to 70 years old) with primary hypercholesterolemia treated with fluvastatin for 16 weeks. LDLR genotypes were determined by PCR‐RFLP. The results indicate that the AvaII and PvuII polymorphisms influence the cholesterol‐lowering response of the HMG‐CoA reductase inhibitor Fluvastatin. Patients carrying A+A+ (AvaII) or P1P1 (PvuII) homozygous genotypes presented lower reduction in total cholesterol, LDL‐C and apolipoprotein B levels after 16 weeks of treatment with fluvastatin, when compared to other genotypes (P <0.05). Our data also support the previous assumption that the AvaII, HincII, and PvuII polymorphisms of the LDLR gene are associated with variation of serum cholesterol levels. Therefore, the identification of the LDLR genetic profile may provide better prediction of a patients clinical response to fluvastatin. J. Clin. Lab. Anal. 14:125–131, 2000.

Pvu II intron 15 polymorphism at the LDL receptor gene is associated with differences in serum lipid concentrations in subjects with low and high risk for coronary artery disease from Brazil.

Coronary artery disease (CAD) has a high prevalence in the Brazilian population. Nevertheless, studies of genetic risk factors for CAD in this country have not been sufficiently conducted. We used the Pvu II polymorphism (intron 15) at the low-density lipoprotein receptor (LDLR) gene to study the effect of variation at this locus in determining plasma lipid concentrations in 128 white subjects presenting a lipid profile suggesting high risk for CAD (HRG) and 100 white normolipidemic individuals (controls, CG). The Pvu II polymorphism was detected by PCR-RFLP. The P1P1 genotype for Pvu II polymorphism (homozygous for absence of restriction site) was greater in HRG individuals than in CG subjects (57% vs. 38%, P<0.05). Moreover, the P1P1 genotype was strongly associated with high concentrations of total cholesterol (P=0.0001), triglycerides (P=0. 0295), LDL-C (P=0.0001), and VLDL-C concentrations (P=0.0280) and lower HDL-C concentrations (P=0.0051) in HRG subjects. Similarly, the CG individuals with P1P1 genotype presented high concentrations of total cholesterol and LDL-C compared to other genotypes (P=0. 0001). This study demonstrates the influence of Pvu II polymorphism of the LDLR on serum lipid concentrations of individuals with low and high risk for CAD from Brazil.

Apolipoprotein B gene polymorphisms: prevalence and impact on serum lipid concentrations in hypercholesterolemic individuals from Brazil.

Genetic polymorphisms at the apolipoprotein B (apo B) have been associated with elevated plasma concentrations of low-density lipoprotein (LDL) cholesterol, atherosclerosis and increased risk for coronary artery disease (CAD). In the present study, four apo B gene polymorphisms (MspI, XbaI, Ins/Del and 3HVR) have been investigated to determine their frequencies and influence on the lipid profile of 177 hypercholesterolemic white Brazilian subjects (HG) and 100 control individuals (CG). The genotype distribution and allele frequency of MspI, XbaI and Ins/Del polymorphisms of apo B gene were similar between HG and CG groups. The frequency of the alleles smaller than 43 repeats (< or =43) of 3HVR polymorphism in the HG group was higher when compared to controls (16.4 vs. 8.5%, P<0.05). Moreover, these alleles were associated with higher total cholesterol concentrations in serum of hypercholesterolemic individuals (P<0.05). In addition, an association between Ins/Del and 3HVR polymorphism was observed. The alleles < or =43 and Del were more frequent in the HG when compared to the CG individuals (P<0.05). We concluded that 3HVR polymorphism at the apo B gene may be an important genetic marker to evaluate atherosclerotic disease risk.

Effects of Ava II and Hinc II polymorphisms at the LDL receptor gene on serum lipid levels of Brazilian individuals with high risk for coronary heart disease.

Coronary heart disease (CHD) has presented high prevalence in the Brazilian population. Nevertheless, studies of genetic risk factors for CHD in our country are insufficiently carried out. We have investigated the effects of Ava II (exon 13) and Hinc II (exon 12) polymorphisms at the low‐density lipoprotein receptor (LDLR) gene on circulating lipids of 170 white unrelated individuals presenting a lipid profile with high risk for CHD (HRG) and 130 controls (CG) from São Paulo City, Brazil. Ava II and Hinc II polymorphic regions at the LDLR gene were amplified by PCR and analyzed by enzymatic isotyping. The frequency of the genotypes A+A+ (Ava II) and H+H+ (Hinc II) was greater in HRG group compared to that of the controls (32 vs. 16% and 32 vs. 18%, respectively). Moreover, in the HRG group, A+A+ and H+H+ genotypes were associated with high concentrations of total cholesterol and LDL‐C in serum (P = 0.0001). Our results indicate that Ava II and Hinc II polymorphisms at the LDLR locus contribute to the variability of total cholesterol and LDL‐C levels in HRG individuals. These data suggest that the LDLR polymorphism remains a useful genetic marker for predicting CHD risk. J. Clin. Lab. Anal. 13:251–258, 1999.

Polymorphisms of the low-density lipoprotein receptor gene in Brazilian individuals with heterozygous familial hypercholesterolemia

Familial hypercholesterolemia (FH) is a metabolic disorder inherited as an autosomal dominant trait characterized by an increased plasma low-density lipoprotein (LDL) level. The disease is caused by several different mutations in the LDL receptor gene. Although early identification of individuals carrying the defective gene could be useful in reducing the risk of atherosclerosis and myocardial infarction, the techniques available for determining the number of the functional LDL receptor molecules are difficult to carry out and expensive. Polymorphisms associated with this gene may be used for unequivocal diagnosis of FH in several populations. The aim of our study was to evaluate the genotype distribution and relative allele frequencies of three polymorphisms of the LDL receptor gene, HincII(1773) (exon 12), AvaII (exon 13) and PvuII (intron 15), in 50 unrelated Brazilian individuals with a diagnosis of heterozygous FH and in 130 normolipidemic controls. Genomic DNA was extracted from blood leukocytes by a modified salting-out method. The polymorphisms were detected by PCR-RFLP. The FH subjects showed a higher frequency of A+A+ (AvaII), H+H+ (HincII(1773)) and P1P1 (PvuII) homozygous genotypes when compared to the control group (P<0.05). In addition, FH probands presented a high frequency of A+ (0.58), H+ (0.61) and P1 (0.78) alleles when compared to normolipidemic individuals (0.45, 0.45 and 0.64, respectively). The strong association observed between these alleles and FH suggests that AvaII, HincII(1773) and PvuII polymorphisms could be useful to monitor the inheritance of FH in Brazilian families.