The effect of ABCA1 gene polymorphisms on ischaemic stroke risk and relationship with lipid profile

ABCA1 Polymorphism R1587K in Chronic Hepatitis C Is Gender-Specific and Modulates Liver Disease Severity through Its Influence on Cholesterol Metabolism and Liver Function: A Preliminary Study

Chronic hepatitis C (CHC) progression is highly variable and can be influenced by lipid metabolism. The ATP-binding cassette transporter A1 (ABCA1) is involved in lipid metabolism and mediates cholesterol efflux from liver cells. ABCA1 gene polymorphism rs2230808 (R1587K) modulates lipid levels as it is located in an ABCA1 protein domain, which is essential for cholesterol efflux. We aimed to analyze the role of ABCA1 polymorphism R1587K (rs2230808) in modulating the biochemical parameters of lipid metabolism and liver function and its association with liver disease severity, according to gender. A total of 161 CHC patients were clinically, histologically, and biochemically evaluated. Genotyping was performed by melting-curve analysis and statistical analysis by SPSS 24.0. There were significant differences between ABCA1_rs2230808 genotypes and total cholesterol, γGT (γ-glutamyl-transpeptidase), and HCV-RNA. Gender differences: in females, ABCA1_rs2230808 (GG or GA) was associated with higher HCV-RNA serum levels; in males, ABCA1_rs2230808 (GG or GA) was associated with higher γGT, lower total cholesterol, increased risk for γGT ≥ 38 UI/L, and total cholesterol < 4.92 mmol/L. Only in the case of males were higher γGT and lower total cholesterol associated with severe fibrosis and steatosis. Total cholesterol < 4.92 mmol/L also associates with severe necroinflammation. We conclude that ABCA1_rs2230808 is gender-specific. ABCA1_rs2230808 Allele G was associated with different clinical and biochemical parameters, which are related to more severe liver disease.

The R219K Polymorphism of the ATP Binding Cassette Subfamily a Member 1 Gene and Susceptibility to Ischemic Stroke in Chinese Population

Stroke is the major cause of death and disability worldwide. ABCA1 R219K has been suggested as a risk factor for ischemic stroke, but the results remain inconclusive in the Chinese population. This study aimed to assess the association between ABCA1 R219K and ischemic stroke using meta-analysis. A systematic literature search was conducted to select eligible studies and the pooled odds ratio (OR) with 95% confidence interval (CI) was used to evaluate the strength of association. Fourteen studies containing 2865 cases and 3227 controls were included in the meta-analysis and the results suggested that there is a strong association between ABCA1 R219K and the ischemic stroke risks (K vs. R: OR = 0.837, 95% CI: 0.735- 0.954, p=0.008; KK vs. RR: OR = 0.689, 95% CI: 0.520-0.912, p=0.009; KK+RK vs. RR: OR = 0.782, 95% CI: 0.691-0.885, p<0.001). Subgroup analysis revealed that significant association was found for the 4 genetic models (p<0.05) in the Southern population, while in the northern population significant association was only found under the dominant model (KK+RK vs. RR: OR = 0.744, 95% CI: 0.583- 0.949, p<0.017). This meta-analysis suggested that ABCA1 R219K polymorphism might be a protective factor against developing IS, indicating this SNP may contribute to the pathogenesis of ischemic stroke and might be potentially used as a biomarker to predict the susceptibility to ischemic stroke.

The impact of APOA5, APOB, APOC3 and ABCA1 gene polymorphisms on ischemic stroke: Evidence from a meta-analysis

BACKGROUND AND AIMS

Genetic studies have been reported on the association between APOA5, APOB, APOC3 and ABCA1 gene polymorphisms and ischemic stroke, but results remain controversial. Hence, this meta-analysis aimed to infer the causal relationships of APOA5 (rs662799, rs3135506), APOB (rs693, rs1042031, rs1801701), APOC3 (rs4520, rs5128, rs2854116, rs2854117) and ABCA1 rs2230806 with ischemic stroke risk.

METHODS

A systematic review was performed for all the articles retrieved from multiple databases, up until March 2017. Data were extracted from all eligible studies, and meta-analysis was carried out using RevMan 5.3 and R package 3.2.1. The strength of association between each studied polymorphism and ischemic stroke risk was measured as odds ratios (ORs) and 95% confidence intervals (CIs), under fixed- and random-effect models.

RESULTS

A total of 79 studies reporting on the association between the studied polymorphisms and ischemic stroke risk were identified. The pooled data indicated that all genetic models of APOA5 rs662799 (ORs = 1.23-1.43), allelic and over-dominant models of APOA5 rs3135506 (ORs = 1.77-1.97), APOB rs1801701 (ORs = 1.72-2.13) and APOB rs1042031 (ORs = 1.66-1.88) as well as dominant model of ABCA1 rs2230806 (OR = 1.31) were significantly associated with higher risk of ischemic stroke. However, no significant associations were observed between ischemic stroke and the other five polymorphisms, namely ApoB (rs693) and APOC3 (rs4520, rs5128, rs2854116 and rs2854117), under any genetic model.

CONCLUSIONS

The present meta-analysis confirmed a significant association of APOA5 rs662799 CC, APOA5 rs3135506 CG, APOB rs1801701 GA, APOB rs1042031 GA and ABCA1 rs2230806 GG with increased risk of ischemic stroke.

Effect of ATP-binding Cassette Transporter A1 (ABCA1) Gene Polymorphisms on Plasma Lipid Variables and Common Demographic Parameters in Greek Nurses

Objective:

The present study is on line with our previous studies evaluating the influence of ATP-binding cassette transporter A1 (ABCA1) gene polymorphisms on the lipid variables of Greek student-nurses. The current study was undertaken to (1) estimate the influence of variant(s) such as rs2066715 (V825I), R219K, R1587K, I883M of ABCA1 gene on lipid variables and (2) evaluate the effect of all four ABCA1 polymorphisms on common demographic parameters.

Methods:

The study population involved 432 unrelated nurses (86 men) who were genotyped for ABCA1 polymorphisms and correlated according to lipid variables [total cholesterol (TC), triglycerides (TGs), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and apolipoprotein (apo) A] and demographic parameters (age, gender, BMI, waist circumference).

Results:

According to lipid variables concentration there was no difference between genotypes and alleles of V825I, R219K and I883M polymorphisms. The LDL-C concentration was 13% lower in RR compared with RK genotype (100.7 vs. 113.9 mg/dl, p=0.013) of R1587K gene polymorphism. In regression analysis the effects of age, gender and only R1587K gene polymorphism on LDL-C concentrations were proved significant. Additionally, LDL-C was increased (by 1.29 mg/dl on average) by every year of increase of age. Moreover, females had lower LDL-C concentrations as compared with males.

Conclusion:

Findings suggested that only R1587K polymorphism of ABCA1 gene was associated with lipid variables, age, and gender of Greek nurses. These findings may be helpful in assessing the risk factors for premature coronary heart disease and distinct individuals with lower/higher atherosclerotic burden.

Chromosome 9p21 and ABCA1 Genetic Variants and Their Interactions on Coronary Heart Disease and Ischemic Stroke in a Chinese Han Population

The single nucleotide polymorphisms (SNPs) related to both coronary heart disease (CHD) and ischemic stroke (IS) in Chinese individuals have not been identified definitely. This study was developed to evaluate the genetic susceptibility to CHD and IS on the chromosome 9p21 and the adenosine triphosphate (ATP)-binding cassette transporter A1 genes (ABCA1) in a Chinese Han population. Genotypes of the rs1333040, rs1333042, rs4977574, rs2066715 and rs2740483 SNPs were determined in 1134 unrelated patients (CHD, 565 and IS, 569) and 541 controls. The frequencies of the rs4977574 genotypes and alleles between CHD and control groups, and the rs2740483 genotypes and alleles between IS and control groups were different (p = 0.006–0.001). The subjects with rs1333042GG genotype and the carriers of the rs4977574G allele were associated with increased risk of CHD. The carriers of the rs4977574G allele were associated with increased risk of IS. However, the carriers of the rs2740483C allele had lower risk of IS than the non-carriers of the rs2740483C allele after controlling for potential confounders. The rs4977574GG-age (>60 year) interaction increased the risk of CHD (p = 0.022), whereas the rs2740483CG/CC-body mass index (>24 kg/m²) interaction decreased the risk of IS (p = 0.035). The interactions of rs1333040-rs1333042 on the risk of CHD and IS were relatively strong, whereas the interactions of rs1333040-rs1333042-rs2066715 and rs1333040-rs1333042-rs2066715-rs2740483 on the risk of CHD, and rs1333040-rs1333042-rs4977574 and rs1333040-rs1333042-rs4977574-rs2740483 on the risk of IS were relatively weak. These findings suggest that some common variants on the chromosome 9p21 and ABCA1 and their interactions may significantly modify the risk of CHD and IS independent of effects on serum lipid levels.

The impact of common polymorphisms in CETP and ABCA1 genes with the risk of coronary artery disease in Saudi Arabians

Background

Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Many genetic and environmental risk factors including atherogenic dyslipidemia contribute towards the development of CAD. Functionally relevant mutations in the dyslipidemia-related genes and enzymes involved in the reverse cholesterol transport system are associated with CAD and contribute to increased susceptibility of myocardial infarction (MI).

Method

Blood samples from 990 angiographically confirmed Saudi CAD patients with at least one event of myocardial infarction were collected between 2012 and 2014. A total of 618 Saudi controls with no history or family history of CAD participated in the study. Four polymorphisms, rs2230806, rs2066715 (ABCA1), rs5882, and rs708272 (CETP), were genotyped using TaqMan Assay.

Results

CETP rs5882 (OR = 1.45, P < 0.005) and ABCA1 rs2230806 (OR = 1.42, P = 0.017) polymorphisms were associated with increased risk of CAD. However, rs708272 polymorphism showed protective effect (B1 vs. B2: OR = 0.80, P = 0.003 and B2B2 vs. B1B1: OR = 0.68, P = 0.012) while the ABCA1 variant rs2066715 was not associated.

Conclusion

This study is the first to report the association of these polymorphisms with CAD in the population of the Eastern Province of Saudi Arabia. The rs5882 polymorphism (CETP) showed a significant association and therefore could be a promising marker for CAD risk estimation while the rs708272 polymorphism had a protective effect from CAD.

Association of ATP-binding cassette transporter A1 gene polymorphisms with plasma lipid variability and coronary heart disease risk

OBJECTIVE

Our study aimed to investigate the association of ABCA1 polymorphisms with plasma lipid variability and CHD risk in the Chinese Han population.

METHODS

754 CHD patients and 760 controls were included in this case-control study. Three SNPs (rs363717, rs4149339, and rs4149338) in ABCA1 3'UTR and one nonsynonymous SNP (rs2230808) in ABCA1 exon 35 were selected and genotyped. The analysis of genetic data was performed using the SNPstats program and the SPSS17.0 software.

RESULTS

Significant associations were observed between SNP rs363717 and CHD risk under different genetic models before or after Bonferroni corrections (codominant model: OR = 0.70, P = 0.003 for AG vs. AA; dominant model: OR = 0.71, P = 0.003 for GG + AG vs. AA). The nonsynonymous SNP rs2230808 was associated with higher total cholesterol levels (P = 0.047). The GCC haplotype (consisting of alleles of SNPs rs363717, rs4149339, and rs4149338) was associated with a decreased risk of CHD (OR = 0.8, P = 0.027). Three ABCA1 SNPs interacted with high triglyceride levels to increase CHD risk (P values of interactions were 0.010 for rs363717, 0.010 for rs4149339, and 0.020 for rs4149338, respectively).

CONCLUSIONS

Our results suggest that ABCA1 polymorphisms influence plasma lipid variability and CHD risk. ABCA1 polymorphisms could also modify the effects of plasma lipids on CHD risk.

Association of ATP-Binding Cassette Transporter A1 Gene Polymorphisms in Type 2 Diabetes Mellitus among Malaysians

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a complex polygenic disorder characterized by impaired insulin resistance, insulin secretion, and dysregulation of lipid and protein metabolism with environmental and genetic factors. ATP-binding cassette transporter A1 (ABCA1) gene polymorphisms are reported as the one of the genetic risk factors for T2DM in various populations with conflicting results. This study was conducted based on PCR-HRM to determine the frequency of ABCA1 gene by rs2230806 (R219K), rs1800977 (C69T), and rs9282541 (R230C) polymorphisms Malaysian subjects.

METHODS

A total of 164 T2DM and 165 controls were recruited and their genotypes for ABCA1 gene polymorphisms were determined based on the real time high resolution melting analysis.

RESULTS

There was a significant difference between the subjects in terms of age, BMI, FPG, HbA1c, HDL, LDL, and TG (P < 0.05). There was a significant association between HOM of R219K (P = 0.005), among Malaysian subjects; moreover, allele frequency revealed the significant difference in A allele of R219K (P = 0.003). But, there was no significant difference in genotypic and allelic frequencies of C69T and R230C polymorphism.

CONCLUSION

R219K polymorphism of ABCA1 gene can be considered as a genetic risk factor for T2DM subjects among Malaysians.

Increased risk of premature coronary artery disease in Egyptians with ABCA1 (R219K), CETP (TaqIB), and LCAT (4886C/T) genes polymorphism

BACKGROUND

Epidemiological studies have shown a strong inverse relationship between high-density lipoprotein (HDL) cholesterol (HDLc) levels and coronary artery disease (CAD), and a low concentration of plasma HDLc is considered an independent risk factor for premature atherosclerosis. Mutations in ATP-binding cassette A1 transporter (ABCA1), cholesteryl ester transfer protein (CETP), and lecithin: cholesterol acyltransferase (LCAT) reduce HDLc in humans.

OBJECTIVE

To date, no study had tested the association between these polymorphisms and premature CAD (PCAD) in the Egyptian population. Here we searched for ABCA1 (rs2230806), CETP (rs708272), and LCAT (rs5923) mutations in the Egyptian population and investigated the possible association between these gene polymorphisms and PCAD. We aimed to investigate the association between ABCA1, CETP, and LCAT gene polymorphisms and PCAD in Egyptians.

METHODS

A total of 235 Egyptians-116 with documented PCAD (PCAD group) and 119 controls-were enrolled in the study.

RESULTS

Mutation carriers with low HDLc had an elevated risk of PCAD (odds ratio [OR] = 11.38 for ABCA1 mutation carriers, P = .000; OR = 5.41 for CETP mutation carriers, P = .000; OR = 5.92 for LCAT mutation carriers, P = .000). Moreover, mutations in ABCA1, CETP, and LCAT were significantly associated with hyperlipidemia in this study.

CONCLUSION

These observations show that the R allele of ABCA1, the B1 allele of CETP, and the T allele LCAT genes are associated with PCAD in Egyptians. They have more considerable effect on patients with low HDLc.

ATP-binding cassette transporter A1 R219K polymorphism and ischemic stroke risk in the Chinese population: a meta-analysis

Recently, many studies have been focused on the association between the ATP-binding cassette transporter A1 (ABCA1) gene R219K polymorphism and ischemic stroke (IS). However, the study results have been inconsistent, especially in the Chinese population. Therefore, we performed a meta-analysis to better clarify the association between the ABCA1 gene and IS. All of the relevant studies used in our meta-analysis were identified using PubMed, OVID, Cochrane Library, Chinese Wan Fang database, Chinese VIP database, China National Knowledge Infrastructure (CNKI), and China Biological Medicine Database (CBM) up to May 2013. Statistical analysis was conducted with STATA software version 11.0. Odds ratios with 95% confidence intervals were applied to evaluate the strength of the association between ABCA1 gene R219K polymorphism and IS. Heterogeneity was evaluated using the Q-test and I(2) statistic. The funnel plots, Begg's and Egger's regression tests were used to assess the publication bias. Our meta-analysis showed the dominant genetic model (OR=0.92, 95% CI: 0.88-0.96), the recessive genetic model (OR=0.73, 95% CI: 0.51-1.05), the homozygote genetic model (OR=0.64, 95% CI: 0.44-0.94), the heterozygote genetic model (OR=0.81, 95% CI: 0.69-0.95), and the allelic genetic model (OR=0.83, 95% CI: 0.69-0.99). For R219K in IS, there were significant associations with these genetic models, but not with the recessive genetic model. Our meta-analysis indicated that the ABCA1 gene R219K polymorphism might be associated with IS and the K allele might be a protective factor in the Chinese population.

Promoter polymorphisms in the ATP binding cassette transporter gene influence production of cell-derived microparticles and are highly associated with susceptibility to severe malaria in humans

Microparticle (MP) efflux is known to be mediated by the ABCA1 protein, and the plasma level of these cell-derived MPs is elevated considerably during human malarial infection. Therefore, two polymorphisms at positions -477 and -320 in the promoter of the ABCA1 gene were genotyped and tested for association with the plasma MP level in four groups of malaria patients segregated according to the clinical severity, i.e., cerebral malaria (CM), multiorgan dysfunction (MOD), noncerebral severe malaria, and uncomplicated malaria (UM). The TruCount tube-based flow cytometric method was used for the exact quantification of different cell-derived MPs in patients. Polymorphisms in the ABCA1 gene promoter were analyzed by use of the PCR/two-primer-pair method, followed by restriction fragment length polymorphism, in 428 malaria patients. The level of circulating plasma MPs was significantly higher in febrile patients with Plasmodium falciparum infection, especially in CM patients compared to healthy individuals. The homozygous wild-type -477 and -320 genotype was observed to be significantly higher in patients with severe malaria. These patients also showed marked increases in the plasma MP numbers compared to UM patients. We report here for the first time an association of ABCA1 promoter polymorphisms with susceptibility to severe malaria, especially to CM and MOD, indicating the protective effect of the mutant variant of the polymorphism. We hypothesize that the -477T and -320G polymorphisms affect the downregulation of MP efflux and may be a predictor of organ complication during P. falciparum malarial infections.

Association studies of several cholesterol-related genes (ABCA1, CETP and LIPC) with serum lipids and risk of Alzheimer's disease

Objectives

Accumulating evidence suggested that dysregulation of cholesterol homeostasis might be a major etiologic factor in initiating and promoting neurodegeneration in Alzheimer’s disease (AD). ATP-binding cassette transporter A1 (ABCA1), hepatic lipase (HL, coding genes named LIPC) and cholesteryl ester transfer protein (CETP) are important components of high-density lipoprotein (HDL) metabolism and reverse cholesterol transport (RCT) implicated in atherosclerosis and neurodegenerative diseases. In the present study, we will investigate the possible association of several common polymorphisms (ABCA1R219K, CETPTaqIB and LIPC-250 G/A) with susceptibility to AD and plasma lipid levels.

Methods

Case–control study of 208 Han Chinese (104 AD patients and 104 non-demented controls) from Changsha area in Hunan Province was performed using the PCR-RFLP analysis. Cognitive decline was assessed using Mini Mental State Examination (MMSE) as a standardized method. Additionally, fasting lipid profile and the cognitive testing scores including Wechsler Memory Scale (WMS) and Wisconsin Card Sorting Test (WCST) were recorded.

Results and conclusions

We found significant differences among the genotype distributions of these three genes in AD patients when compared with controls. But after adjusting other factors, multivariate logistic regression analysis showed only ABCA1R219K (B = −0.903, P = 0.005, OR = 0.405, 95%CI:0.217-0.758) and LIPC-250 G/A variants(B = −0.905, P = 0.018, OR = 0.405, 95%CI:0.191-0.858) were associated with decreased AD risk. There were significantly higher levels of high-density lipoprotein cholesterol (HDL-C) and apolipoproteinA-I in the carriers of KK genotype and K allele (P < 0.05), and B2B2 genotype of CETP Taq1B showed significant association with higher HDL-C levels than other genotypes (F = 5.598, P = 0.004), while -250 G/A polymorphisms had no significant effect on HDL-C. In total population, subjects carrying ABCA1219K allele or LIPC-250A allele obtained higher MMSE or WMS scores than non-carriers, however, no significant association was observed in AD group or controls. Therefore, this preliminary study showed that the gene variants of ABCA1R219K and LIPC-250 G/A might influence AD susceptibility in South Chinese Han population, but the polymorphism of CETPTaq1B didn't show any association in despite of being a significant determinant of HDL-C.

Association of gender, ABCA1 gene polymorphisms and lipid profile in Greek young nurses

OBJECTIVE

One of the important proteins involved in lipid metabolism is the ATP-binding cassette transporter A1 (ABCA1) encoding by ABCA1 gene. In this study we evaluated the single nucleotide polymorphisms (SNPs) of ABCA1 gene. We analyzed SNPs in chromosome 9 such as rs2230806 (R219K) in the position 107620867, rs2230808 (R1587K) in the position 106602625 and rs4149313 (I883M) in the position 106626574 according to gender and lipid profile of Greek nurses.

METHODS

The study population consisted of 447 (87 men) unrelated nurses who were genotyped for ABCA1 gene polymorphisms. Additionally, lipid profile [total cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol (LDL-C) and apolipoprotein A1] was evaluated.

RESULTS

The distribution of all three studied ABCA1 gene polymorphisms did not differ according to gender. However, only R219K genotype distribution bared borderline statistical significance (p = 0.08) between the two studied groups. Moreover, allele frequencies of R219K, R1587K and I88M polymorphisms did not differ according to gender. In general, blood lipid levels did not seem to vary according to ABCA1 gene polymorphisms, when testing all subjects or when testing only men or only women. However, a significant difference of LDL-C distribution was detected in all subjects according to R1587K genotype, indicating lower LDL-C levels with KK polymorphism (p = 0.0025). The above difference was solely detected on female population (p = 0.0053).

CONCLUSIONS

The ABCA1 gene polymorphisms frequency, distribution and lipid profile did not differ according to gender. However, in the female population the KK genotype of R1587K gene indicated lower LDL-C levels. Further studies, involving a higher number of individuals, are required to clarify genes and gender contribution.

Cholesteryl Ester Transfer Protein and ATP-Binding Cassette Transporter A1 Genotype Alter the Atorvastatin and Simvastatin Efficacy

We compared the efficacy of atorvastatin with simvastatin according to cholesteryl ester transfer protein (CETP) and adenosine triphosphate-binding cassette transporter A1 ( ABCA1) genes. Patients treated with atorvastatin (n = 254) or simvastatin (n = 332) were genotyped for CETP (TaqIB and I405V) and ABCA1 (R219K) genetic variants. For genotype B1B2, atorvastatin compared with simvastatin treatment resulted in a greater decrease in total cholesterol (35.4% vs 31.6%, P = .035) and a lower increase in high-density lipoprotein cholesterol (2% vs 8%, P = .05). For genotype B2B2, atorvastatin compared with simvastatin treatment resulted in a lower decrease in low-density lipoprotein cholesterol (31.85 vs 42%, P = .029). For genotypes RR and KK, atorvastatin compared with simvastatin treatment resulted in a greater decrease of triglycerides (27% vs 17% and 35% vs 15%, respectively; P = .02 for all comparisons). The TaqIB and R219K (opposite to I405V) gene polymorphisms seem to modify the response to lipid-lowering therapy with simvastatin or atorvastatin treatment.

ATP-binding cassette transporter A1 gene polymorphisms and serum lipid levels in young Greek nurses

OBJECTIVE

The ATP-binding cassette transporter A1 (ABCA1) is essential protein involved in lipid metabolism. The present study was undertaken to detect the possible association of polymorphisms in the ABCA1 gene [rs2230806 (R219K) and rs2230808 (R1587K)] and lipid profile in Greek young nurses.

METHODS

The study population consisted of 308 unrelated nurses who were genotyped and the ABCA1 polymorphisms were detected. Additionally, lipid profile [total cholesterol (TC), triglycerides (TGs), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and apolipoprotein (apo) A] was evaluated.

RESULTS

There was no difference in the genotypic and allelic frequencies of the R219K polymorphism according to lipid profile. The R1587K genotypes differed significantly according to TC, LDL-C and TGs concentration (p = 0.023, p = 0.014 and p = 0.047, respectively). Particularly, significant difference in TC, LDL-C and TGs concentration was detected between RK and RR genotypes (p = 0.006, p = 0.004, p = 0.014, respectively). Women with RK genotype compared to RR genotype had higher concentration of TGs (134.25 mg/dl vs 108.89 mg/dl, p = 0.014, respectively), total cholesterol (207.41 mg/dl vs 187.69 mg/dl, p = 0.006, respectively), and LDL-C (110.6 mg/dl vs 96.9 mg/dl, p = 0.004, respectively).

CONCLUSIONS

These findings suggest that the R1587K polymorphism of ABCA1 gene was associated with lipid profile of Greek nurses. Women with RK genotype had higher TGs, total and LDL-C concentration compared to RR genotype. These observations may be significant in assessing the risk of CAD since a 1% change in LDL-C is associated with a 1% change of cardiovascular events. Also, TGs concentration were documented to play a significant role in women. However, this needs to be confirmed by larger studies.

Effect of ABCA1 variant on atherogenic dyslipidaemia in patients with Type 2 diabetes treated with rosiglitazone

AIMS

To investigate the effect of two common ATP-binding cassette transporter 1 (ABCA1) polymorphisms (rs4149263 and rs2020927) on atherogenic dyslipidaemia in Korean Type 2 diabetic patients who were treated with rosiglitazone.

PATIENTS AND METHODS

Two hundred and fifty-six patients with Type 2 diabetes who had never previously received peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonists or lipid-lowering treatment were treated with 4 mg of rosiglitazone daily for 12 weeks without any adjustment to their glucose-lowering regimen. The primary outcome was the change in atherogenic index of plasma (AIP), calculated as log [triglyceride (mmol/l)/high-density lipoprotein cholesterol (mmol/l)], before and after rosiglitazone treatment. The effect of rosiglitazone on the change in AIP was compared across the ABCA1 single nucleotide polymorphisms (SNPs) rs41429263 and rs2020927.

RESULTS

Before adjustment, the change in AIP at 12 weeks was significantly different across the rs4149263 genotypes [median (interquartile range): -0.05 (-0.21, 0.09) for TT; 0.02 (-0.09, 0.17) for TC; and 0.11 (0.03, 0.25) for CC; P = 0.003], but not across the rs2020927 [-0.04 (-0.18, 0.10) for TT; 0.03 (-0.17, 0.15) for TC; and -0.03 (-0.13, 0.10) for CC; P = 0.401]. After controlling for age, gender and duration of diabetes, the presence of the C-allele was significantly associated with an increase in AIP by 0.13 [95% confidence interval (CI), 0.04-0.21; P = 0.003]. This association did not change significantly when body mass index and pretreatment metabolic parameters were additionally controlled for (the change in AIP: 0.14; 95% CI, 0.04-0.24; P = 0.007).

CONCLUSIONS

The ABCA1 SNP rs4149263 may be associated with the change in atherogenic lipid profile in Type 2 diabetes treated with rosiglitazone.

Effect of ABCA1 mutations on risk for myocardial infarction

The adenosine triphosphate-binding cassette A1 (ABCA1) gene codes for a cellular phospholipid and cholesterol transporter that mediates the initial and essential step in high-density lipoprotein (HDL) biogenesis: the formation of nascent HDL particles. Mutations at the ABCA1 gene locus cause severe familial HDL deficiency and, in the homozygous form, cause Tangier disease. Several studies have investigated the influence of ABCA1 variation on lipid metabolism and coronary heart disease, but they have resulted in controversial and inconsistent results. Genetic variability at the ABCA1 gene has also been associated with increased risk of myocardial infarction. In one study, this association was independent of HDL cholesterol levels, raising the possibility that the measurement of HDL cholesterol levels may not provide adequate information on the functional roles of HDL particles. Nevertheless, genomic screening for complex diseases, such as coronary heart disease, and HDL deficiency in particular, may not add additional information to that gained from conventional global cardiovascular risk stratification.

The R219K polymorphism in the ATP-binding cassette transporter 1 gene has a protective effect on atherothrombotic cerebral infarction in Chinese Han ethnic population

The association of R219K and V825I polymorphisms of ABCA1 gene with cerebral infarction has been rarely reported. Here we wish to address this issue. A total of 476 subjects from Chinese Han ethnic population were investigated, including 152 control individuals and 324 patients with cerebral infarction. Genotyping of R219K and V825I were performed by PCR-RFLP analysis. Data were analyzed using a statistical package. The R219K genotype frequency distributions were significantly different between patients with atherothrombotic cerebral infarction (ACI) and control individuals, with fewer KK genotypes and more RR genotypes in ACI patients (chi(2)=9.89, P<0.01). The K allele is less frequent among ACI patients than in controls (chi(2)=9.16, P<0.005). A significant association of KK with decreased ACI risk was exhibited, especially in male patients, aged patients and individuals with hypertension. These results indicate that the K allele of R219K polymorphism is an independent protective factor against ACI. In addition, though there is no association of V825I with ACI, this polymorphism may have certain synergistic effect with hypertension in susceptibility to ACI.