The apolipoprotein A5 (APOA5) gene predisposes Caucasian children to elevated triglycerides and vitamin E (Four Provinces Study)

Abstract

Objective Apolipoprotein A-V plays an important role in lipid metabolism regulation, particularly modulating triglyceride levels, as has been shown by many association studies in adults. The aim of this study was to analyse the effect of APOA5 on lipid profiles and fat-soluble vitamins (due to its strong relationship with triglyceride metabolism) in children. Methods We determined polymorphisms −1131T>C and S19W in the APOA5 gene in 964 6–8-year-old participants of the 4P study and analysed the influence of the APOA5 gene on plasma lipid levels (total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides), apolipolipoproteins (apo A-I and apo B) and fat-soluble antioxidant vitamin (α-tocopherol, γ-tocopherol, lycopene, α-carotene, β-carotene and retinol) levels. Results The allele frequencies of both polymorphisms were comparable to those described in adult Caucasian populations (0.08 and 0.07 for −1131T>C and S19W, respectively). Boys carrying the −1131C allele have a 12% increase in circulating triglyceride levels ( p = 0.016) and a 7% decrease in HDL phospholipid levels ( p = 0.016). Linked to its effect on triglycerides, boys with the −1131C allele also have a 5% increase in plasma α-tocopherol levels ( p = 0.032). This effect was not observed in female participants. Boys carrying the rare allele for the S19W polymorphism have a 4% increase in circulating cholesterol levels ( p = 0.045), whereas girls have a 9% increase in circulating triglyceride levels ( p = 0.029). Linked to its effect on triglycerides, female carriers of the rare allele for S19W also have a 6% increase in α-tocopherol levels ( p = 0.009). Conclusion In children, the effect of APOA5 gene variants on triglyceride levels is related to gender, and because of the strong relationship between lipid metabolism and fat-soluble antioxidant vitamins, it also involves a significant elevation in α-tocopherol concentrations.