Association Of Several Genetic Polymorphisms And Dyslipidemia In The Guangxi Mulao Population

Background:Atherosclerotic cardiovascular disease (ASCVD) has been an increasing disease burden worldwide. The modification of serum lipids plays an essential role in the reduction of CVD risk. Although lipid modification has been focused mainly on reducing the low-density lipoprotein cholesterol (LDL-C) level, in recent years, lowering both triglyceride (TG) and LDL-C levels has found to be more beneficial than lowering LDL-C alone. Hence, several researchattentions have been paid to regulate or control the serum TG levels. It is well established that the serum lipid levelsareco-modulated by the genetic and environmental factors. Numerous evidences have been shown that approximately40-70%of lipid trait is heritable. Thus, the familial resemblance in plasma lipids and lipoproteins is mainly determined by the genetic factors. Serum TG concentration is a complex polygenic trait that is determined by environmental and genetic factors including common and rare variants in various genes. Therefore, identification of the genes related to TG metabolism could provide a clue to search for novel pathway in lipid regulation, and thereby discoveringnoval therapeutic or preventive methods for CAD. With the rapid progress in genome-wide association studies (GWAS), a great number of TG-related loci have been reported. As the frequency of the susceptible等位基因s and their effect size on serum lipid levels may vary across world populations or between hyperlipidemic and normolipidemic populations, replication of GWAS signals across diverse ethnic groups and assessment of their association with the risk of hyperlipidemia have become fundamental in validation of these signals. Recently, three studies have found a genome-wide significant association between single nucleotide polymorphisms (SNPs) in the BUD13homolog (BUD13)/zinc finger protein259(ZNF259) genes and one or more serum lipid traits in the European populations. However, such association remains elusive in the Chinese populations.Part Ⅰ:Associations of Polymorphisms in the BUD13and ZNF259Genes and Serum Lipid Levels in the Mulao and Han PopulationsObjective:This study’s objective was to detect the association between5SNPs (BUD13rs10790162c.237+1741T> C, rs17119975c.323-575A> G, and rs11556024c.*147C> T and ZNF259rs2075290c.1093-336G> A,and rs964184c.*365+359C> G) in the BUD13and ZNF259genes and environmental factors with serum lipid levels in the Chinese Mulao and Han populations.Methods:This study comprised of825of Mulao and781of Han participants. Genotyping of5SNPs in the BUD13and ZNF259genes was performed with the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) combined with gel electrophoresis, andthen confirmed by direct sequencing. Results:The genotype and allele frequencies of ZNF259rs2015290and rs964184and BUD13rs10790162were different between the Mulao and Han populations (P<0.001for all). After the Bonferroni P values correction, in the Mulao population,the levels of TG(ZNF259rs2075290and rs964184and BUD13rs10790162) among the genotypes were significantly different (P<0.01-0.001for all); whereas in the Han population, the levels of TG(BUD13rs10790162), ApoA1(BUD13rs11556024) and the ApoA1/ApoB ratio(BUD13rs10790162and ZNF259rs964184) among the genotypes were different (P<0.01-0.001for all). Significant linkage disequilibrium (LD) was noted betwee ZNF259rs2075290and rs964184, ZNF259rs2075290and BUD13rs10790162, and ZNF259rs964184and BUD13rs10790162(r2>0.50, P<0.001). The A-C-G-A-C (among the ZNF259rs2075290and rs964184, and BUD13rs10790162, rs17119975and rs11556024SNPs) haplotype accounted for over half of the%haplotype of each ethnic group. Significant difference in the frequencies of the A-C-G-A-C and G-G-A-A-C haplotypes between the two ethnic groups was detected (P<0.01). On multiple linear regression analyses, a significant correlation between the serum lipid parameters and numerous environmental factors including age, gender, height, weight, waist circumference, body mass index, smoking, alcohol consumption, blood pressure, and fasting blood glucose levels was noted in both ethnic groups (P<0.05-0.001).Conclusions:The BUD13and ZNF259SNPs were associated with different serum lipid parameters in the two ethnic groups, suggesting that the association of these variants with serum lipid levels might have ethnic specificity. Part II:Sex Specific Associations of Polymorphisms in the BUD13and ZNF259Genes and Serum Lipid Levels between the Mulao and Han populationsObjective:This aim of the current study was to detect the association of the BUD13and ZNF259SNPs and environmental factors with serum lipid levels between males and females in the Mulao and Han populations.Methods:The study population composed of788(346males/442females) of Mulao and778(307males/471females) of Han participants.Genotypes of5SNPs (BUD13rs10790162, rs17119975, and rs11556024and ZNF259rs2075290, and rs964184) were determined by polymerase chain reaction(PCR) and restriction fragment length polymorphism(RFLP) combined with gel electrophoresis, and then confirmed by direct sequencing.Results:In the Mulaoethnic group, male population had higher levels of serum TG and ApoB, but lower HDL-C and ApoAl/ApoB ratio than the female population (P<0.05-0.01). Inthe Hangroup, males had higher levels of TC, TG, LDL-C and ApoB, but lower ApoAl/ApoB ratio than the females (P<0.05-0.001). The genotype frequency of ZNF259rs2075290and allele frequency of ZNF259rs964184differed significantly between the gendersin the Han population (P<0.05-0.001for all) but not in the Mulao population (P>0.05). Serum levels of TG(BUD13rs10790162and rs17119975) and ApoB (BUD13rs17119975) in Mulao males, the levels of TC and TG (ZNF259rs2075290and rs964184, and BUD13rs10790162) in Mulao females were different between the genotypes (P<0.01-0.001). On the other hand, the levels of HDL-C and ApoA1(BUD13rs10790162and rs11556024), and ApoA1/B (ZNF259rs964184and BUD13rs10790162) in Han males, and the levels of TC (ZNF259rs964184) and TG (ZNF259rs2075290and rs964184, and BUD13rs10790162) in Han females were different between the genotypes (P<0.01-0.001). The trend of association is that compared to the major homozygous genotype, the minor homozygous genotype and heterozygous genotype was associated with the higher lipid levels. This trend was consistent for all the SNPs except BUD13rs17119975, which showed a reverse-trend in males but not in females.Conclusions:The BUD13/ZNF259SNPs are associated with the different serum lipid parameters between males and females in the Mulao and Han ethnic groups. These findings imply that the correlation between the BUD13/ZNF259SNPs and serum lipid levels might have sex-specificity. Part III:Association of the Variants in the BUD13and ZNF259Genes and their haplotypes with the Risk of DyslipidemiaObjectives:Our objectives were1) to detect the association between the BUD13/ZNF259SNPs and serum lipid levels in the hypercholesterolemia (HCH)/hypertriglyceridemia (HTG) populations,2) to evaluate the association betweenthe BUD13/ZNF259haplotypes and the risk of HCH and HTG, and3) to explore the possible interactions among the BUD13/ZNF259SNPs.Methods:Genotypes of5SNPs (BUDI3rs120790162, rs17119975, and rs11556024and ZNF259rs2075290, and rs964184) in634hyperlipidemic and547normolipidemic subjects were determined by polymerase chain reaction (PCR)and restriction fragment length polymorphism (RFLP) combined with gel electrophoresis, and then confirmed by direct sequencing. GMDR (generalized multifactor dimensionalityreduction) software Beta0.9was used for construction of gene-gene interaction model and the accuracy of possible association model was tested.Results:The genotype frequency of the BUD13rs10790162SNP and the allele frequencies of the ZNF259rs964184, BUD13rs10790162and BUD13rs17119975SNPs significantly differed between the HCH and non-HCH populations (P<0.05-0.01). On the other hand, the genotypic and allelic frequencies of the ZNF259rs2075290, ZNF259rs964184and BUD13rs10790162SNPs and the allelic frequency of the BUD13rs11556024SNP significantly differed between the HTG and non-HTG groups (P<0.001for each). Significant linkage disequilibrium (LD) was noted among the ZNF259rs2075290, ZNF259rs964184and BUD13rs10790162SNPs (r2>0.5, P<0.001).The ZNF259rs2075290, ZNF259rs964184and BUD13rs10790162SNPs were significantly associated with serum lipid levels in both HCH and non-HCH populations(P<0.008-0.001). On single locus analysis, only BUD13rs10790162was associated with HCH (odd ration, OR:2.23,95%CI:1.05to4.75,P=0.015). The remaining4SNPs did not reachstatistically significant association levelwith either HCH or HTG risk (P>0.05). The G-G-A-A-C haplotype, carrying rs964184-G-allele, was associated with increased in HCH risk (OR:1.35,95%CI:1.10,1.66, P=0.005) and HTG (OR:1.75,95%CI:1.39to2.21, P=0.000). The A-C-G-G-C and A-C-A-G-T haplotypes, carrying rs964184-C-allele, were associated with decreased in HCH risk (OR:0.77,95%CI:0.61,0.99, P=0.039and OR:0.66,95%CI:0.47to0.94, P=0.021, respectively). On multi-locus analyses, the two-to-three locus models showed a significant association with HCH and HTG (P<0.01-0.001).Conclusions:The BUD13/ZNF259SNPs, which were significant in the European populations, are also replicable in the Guangxihyperlipidemic and normolipidemic populations. Moreover, inter-locus interactions may exist among these SNPs. However, further functional analysis is required to clarify how these SNPs and genes actually affect the serum lipid levels.