Apolipoprotein A5-1131T>C polymorphism, but not APOE genotypes, increases susceptibility for dyslipidemia in children and adolescents

Association between apolipoprotein gene polymorphisms and hyperlipidemia: a meta-analysis

BACKGROUND

Hyperlipidemia plays an important role in the etiology of cardio-cerebrovascular disease. Over recent years, a number of studies have explored the impact of apolipoprotein genetic polymorphisms in hyperlipidemia, but considerable differences and uncertainty have been found in their association with different populations from different regions.

RESULTS

A total of 59 articles were included, containing in total 13,843 hyperlipidemia patients in the case group and 15,398 healthy controls in the control group. Meta-analysis of the data indicated that APOA5-1131 T > C, APOA1 -75 bp, APOB XbaI, and APOE gene polymorphisms were significantly associated with hyperlipidemia, with OR values of 1.996, 1.228, 1.444, and 1.710, respectively. All P-values were less than 0.05.

CONCLUSIONS

Meta-analysis of the data indicated that the C allele of APOA5 1131 T > C, the A allele at APOA1-75 bp, the APOB XbaI T allele, and the ε2 and ε4 allele of APOE were each a risk factor for susceptibility for hyperlipidemia.

Association of apoE gene polymorphisms with lipid metabolism in renal diseases

BACKGROUND AND OBJECTIVES

Apolipoprotein E (apoE) plays a central role in the metabolism and homeostasis of lipids. ApoE gene encodes three major isoforms: ε2, ε3 a nd ε4 forming six phenotypes: E2E2, E2E3, E2E4, E3E3, E3E3 and E4E4. Disorders of the lipid metabolism and the homeostasis are frequently coexist in renal diseases. The association between gene polymorphisms of apoE and lipid metabolism were not consistent. This meta-analysis was performed to assess the association between gene polymorphisms of apoE and lipid metabolism in renal diseases.

METHODS

A pre-defined literatures search and selection of eligible relevant investigations were performed to extract and collect data from electronic databases.

RESULTS

Sixteen articles were enrolled for the analysis of association between apoE gene polymorphisms and lipid metabolism. Subjects with E3E4 had a higher total cholesterol (TC) than those with E3E3, and subjects with E2E3 had a lower TC than those with E3E3. Subjects with ε2, had a lower TC than those with ε3 or ε4, and subjects with ε4 had a higher TC than those with, ε3. Subjects with E2E2, E2E3 or E4E4 had a higher triglyceride (TG) than those with E3E3. Subjects with ε4 had a higher TG than those with ε3. Subjects with ε2, had a higher level of TG than those with non-ε2. Subjects with E3E4 had a slightly lower high-density lipoprotein (HDL) than those with E3E3. E3E4 appeared to be associated with lower levels of HDL. Subjects with E2E2, E2E3 had a notably lower low-density lipoprotein (LDL) than those with E3E3. Subjects with ε2, had a lower LDL than those with ε3 or ε4 ApoE gene polymorphisms were not associated with very low-density lipoprotein, and lipoprotein (a) [Lp(a)]. Subjects with E2E3 or E2E4 had higher apoE levels than those with E3E3, and subjects with E4E4 had lower apoE levels than those with E3E3.

CONCLUSION

ApoE gene polymorphisms are associated with the expression of TC, TG HDL, LDL, Lp(a) or apoE.

The APOA5-rs662799 Polymorphism Is a Determinant of Dyslipidemia in Vietnamese Primary School Children

Apolipoprotein A-V encoded by apolipoprotein 5 (APOA5) gene plays an important role in lipid metabolism, especially in the regulation of plasma triglycerol levels. The study aimed to evaluate the association of the APOA5-rs662799 polymorphism with dyslipidemia in Vietnamese children and the potential modification of obesity-related traits (body mass index, waist circumference, hip circumference, and waist-to-hip ratio) on this association. A case-control study was conducted with a total of 154 dyslipidemia cases and 389 controls at the age of 6 to 10 recruited at 31 primary schools in Hanoi city of Vietnam. Genotype for APOA5-rs662799 polymorphism was determined by the restriction fragment length polymorphism analysis. The association of APOA5-rs662799 polymorphism with dyslipidemia adjusting for age, sex, residence, and obesity-related traits was analyzed by binary logistic regression analysis. The results showed that in comparison with T/T and T/C carriers, the C/C carriers had a higher concentration of serum TAG in cases (p =0.049). Carriers of the C allele (C/C + T/C) had higher risk for developing dyslipidemia and hypertriglyceridemia than subjects with T/T genotype (odds ratio, OR = 1.7, p =0.0062 and OR = 1.6, p = 0.026, respectively). The association remained significant after adjusting for age, gender, residence, and obesity status (OR = 1.75, p = 0.006 and OR = 1.53, p = 0.049, respectively) or other obesity-related traits. The study suggested that the APOA5-rs662799 polymorphism may be a determinant of dyslipidemia and hypertriglyceridemia in Vietnamese children, independent of obesity-related traits.

Analysis of apolipoprotein E genetic polymorphism in a large ethnic Hakka population in southern China

There is currently no data about the genetic variations of APOE in Hakka population in China. The aim of this study was to analyze the allelic and genotypic frequencies of APOE gene polymorphisms in a large ethnic Hakka population in southern China. The APOE genes of 6,907 subjects were genotyped by the gene chip platform. The allele and genotype frequencies were analyzed. Results showed that the ∊3 allele had the greatest frequency (0.804) followed by ∊2 (0.102), and ∊4 (0.094), while genotype ∊3/∊3 accounted for 65.43% followed by ∊2/∊3 (15.85%), ∊3/∊4 (14.13%), ∊2/∊4 (3.01%), ∊4/∊4 (0.84%), and ∊2/∊2 (0.74%) in all subjects. The frequencies of the ∊4 allele in Chinese populations were lower than Mongolian and Javanese, while the frequencies of the ∊2 allele were higher and ∊4 allele lower than Japanese, Koreans, and Iranian compared with the geographically neighboring countries. The frequencies of ∊2 and ∊4 alleles in Hakka population were similar to the Vietnamese, Chinese-Shanghai, Chinese-Kunming Han and Chinese-Northeast, and French. The frequency of ∊2 in Hakka population was higher than Chinese-Dehong Dai and Chinese-Jinangsu Han. The low frequency of the APOE ∊4 allele may suggest a low genetic risk of Hakka population for cardiovascular disease, Alzheimer's disease, and other diseases.

Apolipoprotein status in type 2 diabetes mellitus and its complications (Review)

Dyslipidaemia in type 2 diabetes mellitus (T2DM) is characterized by high plasma triglyceride concentrations, reduced high‑density lipoprotein concentrations and increased small density low‑density lipoprotein concentrations. Dyslipidaemia may lead to cardiovascular disease (CVD) and other complications. Apolipoproteins mainly comprise six species, apolipoprotein (apo)A, apoB, apoC, apoD, apoE and apoM, which are important components of plasma lipoproteins that carry lipids and stabilize the structure of lipoproteins. Complex metabolic disorders of apolipoproteins are present in T2DM, such as high plasma apoB, apoC‑II, apoC‑III and apoE concentrations, and low plasma apoA‑I and apoM concentrations, which are associated with dyslipidaemia and interrelated complications. Plasma concentrations of some apolipoproteins are also altered in T2DM with CVD or other complications. Several apolipoprotein polymorphisms are associated with diabetes susceptibility and/or lipid metabolism. The present review described the metabolic disorders of apolipoproteins in T2DM and its complications, and the relationship between each major apolipoprotein and T2DM, as well as the effects of apolipoprotein polymorphisms on diabetic susceptibility.

Association of APOA5 Gene Promoter Region -1131T>C Polymorphism (rs662799) to Plasma Triglyceride Level in Patients with Type 2 Diabetic Nephropathy

INTRODUCTION

Diabetic Nephropathy (DN), a serious complication of Type 2 Diabetic Mellitus (T2DM), is progressive and susceptibility to DN varies among T2DM patients. ApoA5-1131T>C polymorphism revealed that is strongly associated with triglyceride levels and proposed as a predisposing factor for DN.

AIM

The purpose of this study was to investigate the association -1131T>C ApoA5 gene polymorphism with serum lipids levels in Type 2 diabetic (DM) patients with or without DN in north of Iran (Mazandaran province).

MATERIALS AND METHODS

This study comprised patients with established T2DM (n=161) and controls (n=58). Genotyping of APOA5 -1131T>C polymorphisms was performed by PCR-RFLP. Diabetic patients were divided into two groups: with nephropathy (DN+, n = 90) and without nephropathy (DN-, n = 71). Lipids and lipoproteins were assessed by enzymatic methods.

RESULTS

The genotype frequencies were 63.8 % TT, 31 % TC, 5.2 % CC in controls, 33.8% TT, 52.1 % TC, 14.1 % CC in DN- and 44.4 % TT, 36.7 % TC, 18.9 % CC in DN+ patients. The TC genotype and the CC genotype were overexpressed among DN+ and DN-population in comparison to the control group. The highest and the lowest TG levels in both diabetic patients and controls belonged to CC+TC and TT genotypes, respectively. Furthermore in both patients TG increased with this order: TT< TC<CC.

CONCLUSION

These results suggest that APOA5 -1131T>C polymorphisms influence lipid levels in type 2 diabetic patients.

Novel mutations in the GPIHBP1 gene identified in 2 patients with recurrent acute pancreatitis

BACKGROUND

Glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) has been demonstrated to be essential for the in vivo function of lipoprotein lipase (LPL), the major triglyceride (TG)-hydrolyzing enzyme involved in the intravascular lipolysis of TG-rich lipoproteins. Recently, loss-of-function mutations of GPIHBP1 have been reported as the cause of type I hyperlipoproteinemia in several patients.

METHODS

Two unrelated patients were referred to our Lipid Units because of a severe hypertriglyceridemia and recurrent pancreatitis. We measured LPL activity in postheparin plasma and serum ApoCII and sequenced LPL, APOC2, and GPIHBP1.

RESULTS

The 2 patients exhibited very low LPL activity not associated with mutations in LPL gene or with ApoCII deficiency. The sequence of GPIHBP1 revealed 2 novel point mutations. One patient (proband 1) was found to be homozygous for a C>A transversion in exon 3 resulting in the conversion of threonine to lysine at position 80 (p.Thr80Lys). The other patient (proband 2) was found to be homozygous for a G>T transversion in the third base of the ATG translation initiation codon in exon 1, resulting in the conversion of methionine to isoleucine (p.Met1Ile).

CONCLUSION

In conclusion, we have identified 2 novel GPIHBP1 missense mutations in 2 unrelated patients as the cause of their severe hypertriglyceridemia.

Distribution of APOE polymorphism in the "Paisa" population from northwest Colombia (Antioquia)

BACKGROUND

The apolipoprotein E (APOE) gene plays a pivotal role in cholesterol metabolism. Since the discovery of the APOE*2 and APOE*4 as the major susceptibility alleles for several diseases including dyslipidemia, atherosclerosis, coronary heart disease, late-onset and early Alzheimer's disease, the APOE genotype might be considered as a potential predictive factor for both epidemiological research and diagnosis.

AIM

The aim of this study is to report on the polymorphism of the APOE gene in the "Paisa" population from northwest Colombia (Antioquia) to obtain a population baseline of the existing variation in this locus.

METHOD

One thousand and one healthy voluntaries were genotyped for the APOE polymorphism using polymerase chain reaction-restriction fragment length polymorphism technique.

RESULTS

The APOE*3/*3 genotype presented the highest frequency (66.33%) and the APOE*4/*4 had the lowest frequency (1.89%). Genotype frequencies comply with Hardy-Weinberg expectations. Allele frequencies obtained for APOE*2, APOE*3 and APOE*4 were 0.075 ± 0.005 (95% CI = 0.063-0.086), 0.814 ± 0.009 (0.797-0.831) and 0.111 ± 0.007 (0.098-0.125), respectively.

CONCLUSION

Although globally the high-to-low APOE frequency follows the E*3 > E*4 > E*2 trend, the present APOE frequency data is in disagreement with some reports from South-American countries.

Relationship between apolipoprotein E gene polymorphism and total cholesterol level in patients with kidney diseases

AIM: To evaluate the association between apolipoprotein E (apoE) gene polymorphism and total cholesterol (TC) level in patients with kidney diseases.

METHODS: A predefined literature search was performed to collect data from the electronic databases of PubMed, Embase and the Cochrane Library and eligible relevant studies reporting the association of apoE gene polymorphism with TC level in patients with kidney diseases were recruited for meta-analysis.

RESULTS: Twenty-one studies were identified for the analysis of association between apoE gene polymorphism and TC level in patients with kidney disease. Subjects with E3E4 had a higher TC than those with E3E3 [weighted mean differences (WMD) = 2.14, P = 0.01] and subjects with E2E3 had a lower TC than those with E3E3 (WMD = -1.93, P = 0.01). Subjects with ε2 had a lower TC than those with ε3 (ε2 vs ε3: WMD = -1.23, P = 0.002; ε2 vs ε4: WMD = -2.77, P ﹤0.0001) and subjects with 3 had a lower TC than those with 4 (WMD = -0.79, P = 0.03).

CONCLUSION: Subjects with apoE E3E4 and ε4 had a higher TC level and subjects with apoE E2E3 and ε2 had a higher TC level in patients with kidney disease. However, more well-designed studies should be performed in the future to confirm these findings.

Relationship between apolipoprotein E gene polymorphism with triglyceride level in patients with renal diseases

Apolipoprotein E (apoE), one of the major plasma lipoproteins, plays a major role in the transport and metabolism of lipids by acting as a ligand. apoE gene contains three potential alleles: ϵ2, ϵ3 and ϵ4, forming six genotypes: E2E2, E2E3, E2E4, E3E3, E3E3 and E4E4. Association between apoE gene polymorphism and triglyceride (TG) is still controversial. There was not any meta-analysis to explore the association of apoE gene polymorphism with triglyceride level, and this meta-analysis was performed to evaluate the association between apoE gene polymorphism and triglyceride in patients with renal diseases. A predefined literature search and selection of eligible relevant studies were performed to collect data from electronic databases. Twenty-four articles were identified for the analysis of association between apoE gene polymorphism and triglyceride level. Subjects with E2E3 or E3E4 had a higher TG than those with E3E3. Subjects with ϵ4 had a higher TG than those with ϵ3. Subjects with ϵ2 had a slightly higher TG than those with ϵ3, although there was no statistical difference. Interestingly, subjects with ϵ4 had a much higher TG than those with ϵ2. In conclusion, E2E3, E3E4 or ϵ4 was associated with higher level of TG. However, more studies should be performed in the future.

The polymorphism -1131T>C in apolipoprotein A5 gene is associated with dyslipidemia in Brazilian subjects

BACKGROUND

Polymorphisms in apolipoprotein A5 gene (APOA5) have been associated with higher triglyceride levels in many populations. The aim of the study was to determine the allelic and genotypic distribution of the APOA5 -1131T>C polymorphism and to identify the association of the genetic variant and the risk for dyslipidemia.

METHODS

We genotyped 109 dyslipidemic subjects and 107 controls. The total cholesterol, triglycerides and HDL-c were determined enzymatically. Comparison of means among groups was calculated by ANOVA. Significant differences among groups were evaluated by Student-Newman-Keuls test.

RESULTS

The minor allele C was more frequent in dyslipidemic subjects than controls (p=0.019) and confers an increased individual risk for dyslipidemia (OR=1.726, CI 95%=1.095-2.721). The genotype analysis by gender showed that this allele was more frequent in dyslipidemic males (p=0.037; OR=2.050, CI 95%=1.042-4.023). When participants were analyzed according to genotypes TT and TC/CC, C-carriers presented higher cholesterol and triglycerides levels than TT homozygous (p=0.046 and 0.049, respectively).

CONCLUSIONS

The allele C confers higher total cholesterol and triglycerides levels in dyslipidemic adults. The APOA5 -1131T>C polymorphism is associated with dyslipidemia in male subjects.

-1131T>C and SW19 polymorphisms in APOA5 gene and lipid levels in type 2 diabetic patients

Type 2 diabetes mellitus is a metabolic, vascular, and neuropathic disease with a high risk of atherosclerotic events due to dyslipidemic states. Polymorphisms in Apolipoprotein A5 gene (APOA5) have been associated with increased triglyceride levels in many different populations. This study aimed to identify the frequencies of the APOA5 -1131T>C and SW19 polymorphisms and evaluate their effects on lipid levels in patients with type 2 diabetes. Genotyping of APOA5 -1131T>C and SW19 polymorphisms was performed by PCR-RFLP in 146 diabetic patients and in controls (n = 173), from 30 to 80 years of age. Diabetic patients were divided into two groups: patients not treated with lipid lowering drugs (group G1; n = 62) and those treated with lipid lowering drugs (group G2, n = 84). Lipids and lipoproteins were determined enzymatically. Among participants not treated with lipid-lowering drugs (diabetics G1 and controls; n = 235), the -1131C was associated with lower LDLc levels (p = 0.015). In the diabetic patients, the 19W allele was associated with higher triglyceride levels (p = 0.004). In G1 diabetic patients, the combined analysis of APOA5 -1131T>C and SW19 polymorphisms showed that [TC or CC] + SS carriers presented lower total cholesterol levels than did other genotype combinations (p = 0.049). It could therefore be concluded that APOA5 -1131T>C and SW19 polymorphisms influence lipid levels in type 2 diabetic patients.