Association of the GALNT2 gene polymorphisms and several environmental factors with serum lipid levels in the Mulao and Han populations

Abstract

Background: The association of UDP-N-acetyl-alpha-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase 2 gene (GALNT2) single nucleotide polymorphisms (SNPs) and serum lipid profiles in the general population is not well known. The present study was undertaken to detect the association of GALNT2 polymorphisms and several environmental factors with serum lipid levels in the Guangxi Mulao and Han populations.

Method: A total of 775 subjects of Mulao nationality and 699 participants of Han nationality were randomly selected from our stratified randomized cluster samples. Genotyping of the GALNT2 rs2144300 and rs4846914 SNPs was performed by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing.

Results: There were no significant differences in the genotypic and allelic frequencies of both SNPs between the two ethnic groups, or between the males and females. The subjects with TT genotype of rs2144300 in Mulao had lower serum triglyceride (TG) levels than the subjects with CC genotype in females (P < 0.01). The participants with CT/TT genotype of rs2144300 in Han had lower TG and apolipoprotein (Apo) B levels, and higher high-density lipoprotein cholesterol (HDL-C), ApoA1 levels and the ratio of ApoA1 to ApoB in males; and higher low-density lipoprotein cholesterol (LDL-C) and ApoB levels in females than the participants with CC genotype (P < 0.05-0.001). The individuals with GA/AA genotype of rs4846914 in Mulao had higher total cholesterol (TC) and LDL-C levels than the individuals with GG genotype in males (P < 0.05 for each). The subjects with AA genotype of rs4846914 in Han had higher LDL-C and ApoB levels, and lower HDL-C levels and the ratio of ApoA1 to ApoB than the subjects with GG genotype (P < 0.05 for each). The levels of TC in Mulao were correlated with the genotypes of rs4846914 in males (P < 0.05). The levels of ApoA1 in Han were correlated with the genotypes of both SNPs, and the levels of HDL-C and ApoB and the ratio of ApoA1 to ApoB were associated with the genotypes of rs2144300 in males (P < 0.05-0.001). The levels of LDL-C in Han were correlated with the genotypes of rs4846914 in females (P < 0.05). Serum lipid parameters were also correlated with several enviromental factors.

Conclusions: The associations of both GALNT2 rs2144300 and rs4846914 SNPs and serum lipid levels are different in the Mulao and Han populations. These discrepancies might partly result from different GALNT2 gene-enviromental interactions.

Figure 1

Electrophoresis of PCR products of the samples. (A) GALNT2 rs2144300. Lane M, 100 bp marker ladder; lanes 1-5, samples. The 208 bp bands are the PCR products. (B) GALNT2 rs4846914. Lane M, 100 bp marker ladder; lanes 1-5, samples. The 192 bp bands are the PCR products.

Figure 2

Genotyping of the GALNT2 rs2144300 and rs4846914 polymorphisms. (A) GALNT2 rs2144300. Lane M, 100 bp marker ladder; lanes 1 and 2, CC genotype (208 bp); lanes 3 and 4, CT genotype (208-, 181- and 27-bp); and lanes 5 and 6, TT genotype (181- and 27-bp). (B) GALNT2 rs4846914. Lane M, 100 bp marker ladder; lanes 1 and 2, AA genotype (126- and 66-bp); lanes 3 and 4, GA genotype (126-, 107-, 66- and 19-bp); and lanes 5 and 6, GG genotype (107-, 66- and 19-bp). The 27- and 19-bp fragments were invisible in the gel owing to their fast migration speed.

Figure 3

A part of the nucleotide sequences of GALNT2 rs2144300 and rs4846914 SNPs. (A) GALNT2 rs2144300 SNP: (1) CC genotype, (2) CT genotype, (3) TT genotype. (B) GALNT2 rs4846914 SNP: (1) GG genotype, (2) GA genotype, (3) AA genotype.