Investigation of associations between apolipoprotein A5 and C3 gene polymorphisms with plasma triglyceride and lipid levels

SUMMARY OBJECTIVE: The aim of this study was to determine frequency and associations between APOA5 c.56C>G, −1131T>C, c.553G>T, and APOC3 −482C>T and SstI gene polymorphisms with hypertriglyceridemia. METHODS: Under a case-control study model, 135 hypertriglyceridemic and 178 normotriglyceridemic control participants were recruited. Polymerase chain reaction and restriction fragment length polymorphism methods were utilized for genotyping. Statistical calculations were performed by comparing allele and genotype frequencies between groups. Clinical characteristics were compared between groups and intra-group genotypes. RESULTS: APOC3 gene −482C>T and SstI polymorphic genotypes and allele frequencies were significantly higher in hypertriglyceridemic group (genotype frequencies, p=0.035, p=0.028, respectively). Regression analysis under unadjusted model confirmed that APOC3 −482C>T and SstI polymorphisms were significantly contributing to have hypertriglyceridemia (p=0.02, odds ratio [OR]=1.831 (95% confidence interval [CI] 1.095-3.060); p=0.04, OR=1.812 (1.031-3.183), respectively). APOA5 c.56C>G was in complete linkage disequilibrium with APOA5 c.553G>T polymorphism (D'=1). CONCLUSION: For the first time in a population sample from Turkey, among the five polymorphisms of APOA5 and APOC3 genes investigated, APOC3 −482C>T and SstI polymorphisms were associated with elevated serum TG levels, while APOA5 c.56C>G, −1131T>C, and c.553G>T polymorphisms were not.

Apolipoprotein A5 3'-UTR variants and cardiometabolic traits in Koreans: results from the Korean genome and epidemiology study and the Korea National Health and Nutrition Examination Survey

BACKGROUND/OBJECTIVES: This study aimed to test the association between APOA5 3'-UTR variants (rs662799) and cardiometabolic traits in Koreans. SUBJECTS/METHODS: For this study, epidemiological data, Apolipoprotein A5 (APOA5) genotype information, and lymphoblastoid cell line (LCL) biospecimens from a subset of the Ansung-Ansan cohort within the Korean Genome and Epidemiology study (KoGES-ASAS; n = 7,704) as well as epidemiological data along with genomic DNA biospecimens of participants from a subset of the Korea National Health and Nutrition Examination Survey (KNHANES 2011-12; n = 2,235) were obtained. APOA5 mRNA expression was also measured. RESULTS: APOA5 rs662799 genotype distributions in both the KoGES-ASAS and KNHANES groups were 50.6% for TT, 41.3% for TC, and 8.1% for CC, which are similar to those in previous reports. In both groups, minor C allele carriers, particularly subjects with CC homozygosity, had lower high-density lipoprotein (HDL) cholesterol and higher triglyceride levels than TT homozygotes. Linear regression analysis showed that the minor C allele significantly contributed to reduction of circulating HDL cholesterol levels [β = −2.048, P < 0.001; β = −2.199, P < 0.001] as well as elevation of circulating triglyceride levels [β = 0.053, P < 0.001; β = 0.066, P < 0.001] in both the KoGES-ASAS and KNHANES groups. In addition, higher expression levels of APOA5 in LCLs of 64 healthy individuals were negatively associated with body mass index (r = −0.277, P = 0.027) and circulating triglyceride level (r = −0.340, P = 0.006) but not significantly correlated with circulating HDL cholesterol level. On the other hand, we observed no significant difference in the mRNA level of APOA5 according to APOA5 rs662799 polymorphisms. CONCLUSIONS: The C allele of APOA5 rs662799 was found to be significantly associated with cardiometabolic traits in a large Korean population from the KoGES-ASAS and KNHANES. The effect of this genotype may be associated with post-transcriptional regulation, which deserves further experimental confirmation.

Lack of Evidence of the Role of APOA5 3’UTR Polymorphisms in Iranian Children and Adolescents with Metabolic Syndrome

BACKGROUND: Metabolic syndrome (MetS) is a complex and multifactorial disorder characterized by insulin resistance, dyslipidaemia, hyperglycemia, abdominal obesity, and elevated blood pressure. The apolipoprotein A5 (APOA5) gene variants have been reported to correlate with two major components of MetS, including low levels of high density lipoprotein cholesterol (HDL-C) and high levels of triglyceride. In the present study, we explored the associations between five single nucleotide polymorphisms (SNPs) of APOA5 gene and the MetS risk. METHODS: In a case-control design, 120 Iranian children and adolescents with/without MetS were genotyped by polymerase chain reaction-sequencing for these SNPs. Then, we investigated the association of SNPs, individually or in haplotype constructs, with MetS risk. RESULTS: The rs34089864 variant and H1 haplotype (harboring the two major alleles of rs619054 and rs34089864) were associated with HDL-C levels. However, there was no significant association between different haplotypes/individual SNPs and MetS risk. CONCLUSION: These results presented no association of APOA5 3’UTR SNPs with MetS. Further studies, including other polymorphisms, are required to investigate the involvement of APOA5 gene in the genetic susceptibility to MetS in the pediatric age group.

A preliminary report of apoA5 gene novel receptor-binding domain mutation in a patient with severe hypertriglyceridemia / 中华内科杂志

Objective To find novel variants and explore potential mechanism of triglyceride metabolism by resequencing apoA5 gene in patients with severe hypertriglyceridemia.MethodsThe apoA5 gene in the patients with severe hypertriglyceridemia were resequenced,who had been excluded with variants in LPL or apoC Ⅱ.With constructed apoA5 cDNA cxpression vectors,transiently expression was observed in vitro and the protein expression was detected by Western blot and 35S-labeled immunoprecipitation.Results The mutations of T184S and V153M werc found in a patient with heterozygous variants in apoA5,and T184S was not reported before. Both mutant and wild type apoA5 cDNA expression vectors were constructed successfully.Wcstcru blot and immunoprecipitation showed they can be expressed in the cell and the mutational apoA5 can be secreted from the cell as well as wild type. Conclusion A novel mutation in apoA5 was found in a patient with severe hypertriglyceridemia,which has the potential damaging effect for the function of this protein but not the secretion function.It need further study on the intcraction of apoA5 and other related proteins.