LIPG SNPs, their haplotypes and gene-environment interactions on serum lipid levels

Abstract

Background: Maonan nationality is a relatively conservative and isolated minority in the Southwest of China. Little is known about the association of endothelial lipase gene (LIPG) single nucleotide polymorphisms (SNPs) and serum lipid levels in the Chinese populations.

Methods: A total of 1280 subjects of Maonan nationality and 1218 participants of Han nationality were randomly selected from our previous stratified randomized samples. Genotypes of the four LIPG SNPs were determined by polymerase chain reaction-restriction fragment length polymorphism, and then confirmed by direct sequencing.

Results: Several SNPs were associated with high-density lipoprotein cholesterol (rs3813082, rs2000813 and rs2097055) in the both ethnic groups; total cholesterol and apolipoprotein (Apo) A1 (rs2000813) in Han nationality; and low-density lipoprotein cholesterol, ApoB, triglyceride (rs2097055) and ApoA1 (rs3819166) in Maonan minority (P < 0.0125 for all after Bonferroni correction). The commonest haplotype was rs3813082T-rs2000813C-rs2097055T-rs3819166A (Han, 44.2% and Maonan, 48.7%). The frequencies of the T-C-T-A, T-C-T-G, T-T-C-G and G-T-C-G haplotypes were different between the Maonan and Han populations (P < 0.05-0.001). The associations between haplotypes and dyslipidemia were also different in the Han and/or Maonan populations (P < 0.05-0.001).

Conclusions: The differences in serum lipid profiles between the two ethnic groups might partly be attributed to these LIPG SNPs, their haplotypes and gene-environmental interactions.

Trial registration: Retrospectively registered.

Keywords: Endothelial lipase; Environmental factor; Haplotype; Lipids; Single nucleotide polymorphism.

Fig. 1

Electrophoresis of polymerase chain reaction products of the samples. Lane M is the 100 bp marker ladder; lanes 1–6 are samples; the PCR products of a (rs3813082), b (rs2000813), c (rs2097055) and d (rs3919166) were 210-, 254-, 421- and 473-bp bands; respectively

Fig. 2

Genotyping of the four LIPG SNPs. Lane M is the 100 bp marker ladder; lanes 1–6 are samples. a (rs3813082): lanes 1 and 2, GG genotype (210 bp); lanes 3 and 4, TT genotype (117- and 93-bp); and lanes 5 and 6, GT genotype (210-, 117- and 93-bp); b (rs2000813): lanes 2 and 6, CC genotype (254-bp); lanes 3 and 4, CT genotype (254-, 217- and 37-bp); and lanes 1 and 5, TT genotype (254- and 217-bp); c (rs2097055): lanes 1 and 4, CC genotype (421-bp); lanes 2, 5 and 6, TT genotype (283- and 138-bp); and lane 3, CT genotype (421-, 283- and 138-bp); d (rs3819166): lanes 2 and 5, GG genotype (473-bp); lanes 3 and 4, AA genotype (307- and 166-bp); and lanes 1 and 6, AG genotype (473-, 307- and 166-bp). The bands less than 90-bp fragments were not visible in the gel owing to their fast migration speed

Fig. 3

A part of the nucleotide sequences of the four LIPG SNPs

Fig. 4

Linkage disequilibrium (LD) analyses of the four LIPG SNPs. LD status was shown in a (Han) and b (Maonan) among 1 (rs3813082), 2 (rs2000813), 3 (rs2097055) and 4 (rs3819166) SNPs. The LD status is expounded by the r²

Fig. 5

Association of single SNP and serum lipid levels. TC total cholesterol, TG triglyceride, HDL-C high-density lipoprotein cholesterol, LDL-C low-density lipoprotein cholesterol, Apo apolipoprotein. ^aP < 0.0125 (was considered statistically significant after the Bonferroni correction) and ^bP < 0.001

Fig. 6

Association of the haplotypes and serum lipid traits. TC total cholesterol, TG triglyceride, HDL-C high-density lipoprotein cholesterol, LDL-C low-density lipoprotein cholesterol, Apo apolipoprotein. ^aP < 0.0125 (was considered statistically significant after the Bonferroni correction) and ^bP < 0.001