The important role of APOAV gene variants in determination of plasma triglyceride levels has been shown in many population studies. Recently, an influence of APOAV T-1131>C polymorphism on C-reactive protein (CRP) in young Korean males has been reported. We have therefore analyzed a putative association between T-1131>C, Ser19>Trp and Val153>Met APOAV variants (PCR and restriction analysis) and CRP concentrations in 1119 Caucasian males, aged between 28 and 67 years (49.2±10.8 years). The frequency of C allele carriers was lower in Caucasians than in Koreans (15.5 % vs. 46.2 %). CRP levels did not differ between T/T homozygotes (n=946, 1.61±2.05 mg/l) and carriers of the C allele (n=173, 1.67±1.95 mg/l). Thus, in contrast to Korean males, T-1131>C APOAV variant has no effect on plasma concentrations of CRP in a large group of Caucasian males. Other APOAV variants (Ser19>Trp and Val153>Met) did not also influence plasma concentrations of CRP. APOAV variants are unlikely to be an important genetic determinant of plasma CRP concentrations in Caucasian males.
The frequencies of the alleles of Xbal polymorphism in the apolipoprotein B gene were determined in two groups of children, 82 with high (HCG) and 86 with low (LCG) cholesterol levels. A slightly higher incidence of the X2X2 genotype in HCG was found, but the differences were not statistically significant. No relations were found between the Xbal polymorphic site and the levels of serum lipids and lipoproteins. Common Xbal polymorphism in the apolipoprotein B gene does not determine significantly the plasma cholesterol levels in childhood.
ABCG5 and ABCG8 transporters play an important role in the absorption and excretion of sterols. Missence polymorphisms (Gln604Glu in the ABCG5 and Asp19His, Tyr54Cys, Thr400Lys, and Ala632Val in the ABCG8) in these genes have been described. In 131 males and 154 females whose dietary composition markedly changed and lipid parameters decreased over an 8-year follow-up study (total cholesterol decreased from 6.21±1.31 mmol/l in 1988 to 5.43±1.06 mmol/l in 1996), these polymorphisms were investigated using PCR. Plasma lipid levels and changes in plasma lipid levels were independent of the Gln604Glu polymorphism in ABCG5 and Asp19His and the Ala632Val polymorphisms in ABCG8. The Tyr54Cys polymorphism influenced the degree of reduction in total plasma cholesterol (D –0.49 mmol/l in Tyr54 homozygotes vs. D +0.12 mmol/l in Cys54 homozygotes, p<0.04) and LDL-cholesterol (D –0.57 mmol/l in Tyr54 homozygotes vs. D +0.04 mmol/l in Cys54 homozygotes, p<0.03) levels between 1988 and 1996 in females, but not in males. Male Thr400 homozygotes exhibited a greater decrease in total cholesterol (D –0.90 mmol/l vs. D –0.30 mmol/l, p<0.02) and LDL-cholesterol (D –0.62 mmol/l vs. D –0.19 mmol/l, p<0.04) than Lys400 carriers. No such association was observed in females. We conclude that Tyr54Cys and Thr400Lys variations in the ABCG8 gene may play a role in the genetic determination of plasma cholesterol levels and could possibly influence the gender-specific response of plasma cholesterol levels after dietary changes. These polymorphisms are of potential interest as genetic variants that may influence the lipid profile.