An integrated transcriptomic and epigenomic analysis identifies CD44 gene as a potential biomarker for weight loss within an energy-restricted program.

PURPOSE: The interindividual variable response to weight-loss treatments requires the search for new predictive biomarkers for improving the success of weight-loss programs. The aim of this study is to identify novel genes that distinguish individual responses to a weight-loss dietary treatment by using the integrative analysis of mRNA expression and DNA methylation arrays. METHODS: Subjects from Metabolic Syndrome Reduction in Navarra (RESMENA) project were classified as low (LR) or high (HR) responders depending on their weight loss. Transcriptomic (n = 24) and epigenomic (n = 47) patterns were determined by array-based genome-wide technologies in human white blood cells at the baseline of the treatment period. CD44 expression was validated by qRT-PCR and methylation degree of CpGs of the gene was validated by MassARRAY® EpiTYPER™ in a subsample of 47 subjects. CD44 protein levels were measured by ELISA in human plasma. RESULTS: Different expression and DNA methylation profiles were identified in LR in comparison to HR. The integrative analysis of both array data identified four genes: CD44, ITPR1, MTSS1 and FBXW5 that were differently methylated and expressed between groups. CD44 showed higher expression and lower DNA methylation levels in LR than in HR. Although differences in CD44 protein levels between LR and HR were not statistically significant, a positive association was observed between CD44 mRNA expression and protein levels. CONCLUSIONS: In summary, the combination of a genome-wide methylation and expression array dataset can be a useful strategy to identify novel genes that might be considered as predictors of the dietary response. CD44 gene transcription and methylation may be a possible candidate biomarker for weight-loss prediction.

LINE-1 and inflammatory gene methylation levels are early biomarkers of metabolic changes: association with adiposity.

We analyzed whether global and inflammatory genes methylation can be early predictors of metabolic changes and their associations with the diet, in a cross-sectional study (n = 40). Higher global methylation was associated to adiposity, insulin resistance, and lower quality of the diet. Methylation of IL-6, SERPINE1 and CRP genes was related to adiposity traits and macronutrients intake. SERPINE1 hypermethylation was also related to some metabolic alterations. CRP methylation was a better predictor of insulin resistance than CRP plasma concentrations. Global and inflammatory gene promoter hypermethylation can be good early biomarkers of adiposity and metabolic changes and are associated to the quality of the diet.

SH2B1 CpG-SNP is associated with body weight reduction in obese subjects following a dietary restriction program.

UNLABELLED: The objective of this study was to examine whether 7 SNPs previously associated with obesity-related traits that add or remove potential sites of DNA methylation are accompanied by differential DNA methylation and subsequently affect adiposity variables or body weight reduction in WBC from obese subjects under an energy-restricted program. MATERIAL AND METHODS: Anthropometric measurements were assessed in 47 volunteers recruited within the RESMENA study (Spain). At baseline, DNA from white blood cells was isolated and 7 obesity-related trait CpG-SNPs were genotyped by TaqMan-PCR. Then, methylation levels of CpG-SNP sites were quantified by MassArray® EpiTyper™ or MS-HRM approaches. RESULTS: Differential DNA methylation levels were observed by genotypes in all of the CpG-SNPs analyzed. The FTO and BDNF methylation levels were further correlated with baseline body weight and, BDNF mRNA levels and body weight change, respectively. Moreover, the rs7359397 (SH2B1) was associated with the body weight, body mass index, and truncal fat mass reduction. CONCLUSIONS: Our results reveal the interaction of epigenetic and genetic variations in CpG-SNPs, especially in BDNF and SH2B1 genes, and how allele-specific methylation may contribute to elucidate the possible molecular mechanisms as these SNPs are affecting the decrease of mRNA levels and contributing to a lower body weight reduction.

Differential DNA Methylation in Relation to Age and Health Risks of Obesity.

The aim of this study was to evaluate whether genome-wide levels of DNA methylation are associated with age and the health risks of obesity (HRO); defined according to BMI categories as "Low HRO" (overweight and class 1 obesity) versus "High HRO" (class 2 and class 3 obesity). Anthropometric measurements were assessed in a subsample of 48 volunteers from the Metabolic Syndrome Reduction in Navarra (RESMENA) study and 24 women from another independent study, Effects of Lipoic Acid and Eicosapentaenoic Acid in Human Obesity (OBEPALIP study). In the pooled population; the methylation levels of 55 CpG sites were significantly associated with age after Benjamini-Hochberg correction. In addition, DNA methylation of three CpG sites located in ELOVL2; HOXC4 and PI4KB were further negatively associated with their mRNA levels. Although no differentially methylated CpG sites were identified in relation to HRO after multiple testing correction; several nominally significant CpG sites were identified in genes related to insulin signaling; energy and lipid metabolism. Moreover, statistically significant associations between BMI or mRNA levels and two HRO-related CpG sites located in GPR133 and ITGB5 are reported. As a conclusion, these findings from two Spanish cohorts add knowledge about the important role of DNA methylation in the age-related regulation of gene expression. In addition; a relevant influence of age on DNA methylation in white blood cells was found, as well as, on a trend level, novel associations between DNA methylation and obesity.

Oxidative stress in susceptibility to breast cancer: study in Spanish population.

BACKGROUND: Alterations in the redox balance are involved in the origin, promotion and progression of cancer. Inter-individual differences in the oxidative stress regulation can explain a part of the variability in cancer susceptibility.The aim of this study was to evaluate if polymorphisms in genes codifying for the different systems involved in oxidative stress levels can have a role in susceptibility to breast cancer. METHODS: We have analyzed 76 single base polymorphisms located in 27 genes involved in oxidative stress regulation by SNPlex technology. First, we have tested all the selected SNPs in 493 breast cancer patients and 683 controls and we have replicated the significant results in a second independent set of samples (430 patients and 803 controls). Gene-gene interactions were performed by the multifactor dimensionality reduction approach. RESULTS: Six polymorphisms rs1052133 (OGG1), rs406113 and rs974334 (GPX6), rs2284659 (SOD3), rs4135225 (TXN) and rs207454 (XDH) were significant in the global analysis. The gene-gene interactions demonstrated a significant four-variant interaction among rs406113 (GPX6), rs974334 (GPX6), rs105213 (OGG1) and rs2284659 (SOD3) (p-value = 0.0008) with high-risk genotype combination showing increased risk for breast cancer (OR = 1.75 [95% CI; 1.26-2.44]). CONCLUSIONS: The results of this study indicate that different genotypes in genes of the oxidant/antioxidant pathway could affect the susceptibility to breast cancer. Furthermore, our study highlighted the importance of the analysis of the epistatic interactions to define with more accuracy the influence of genetic variants in susceptibility to breast cancer.

Gut microbiota produces biofilm-associated amyloids with potential for neurodegeneration.

Age-related neurodegenerative diseases involving amyloid aggregation remain one of the biggest challenges of modern medicine. Alterations in the gastrointestinal microbiome play an active role in the aetiology of neurological disorders. Here, we dissect the amyloidogenic properties of biofilm-associated proteins (BAPs) of the gut microbiota and their implications for synucleinopathies. We demonstrate that BAPs are naturally assembled as amyloid-like fibrils in insoluble fractions isolated from the human gut microbiota. We show that BAP genes are part of the accessory genomes, revealing microbiome variability. Remarkably, the abundance of certain BAP genes in the gut microbiome is correlated with Parkinson's disease (PD) incidence. Using cultured dopaminergic neurons and Caenorhabditis elegans models, we report that BAP-derived amyloids induce α-synuclein aggregation. Our results show that the chaperone-mediated autophagy is compromised by BAP amyloids. Indeed, inoculation of BAP fibrils into the brains of wild-type mice promote key pathological features of PD. Therefore, our findings establish the use of BAP amyloids as potential targets and biomarkers of α-synucleinopathies.

SERPINE1, PAI-1 protein coding gene, methylation levels and epigenetic relationships with adiposity changes in obese subjects with metabolic syndrome features under dietary restriction.

Plasminogen activator inhibitor 1 (PAI-1) has been associated with metabolic disorders, through different mechanisms, which could involve changes in DNA methylation. This work aimed to assess the potential relationships of the cytosine methylation levels within SERPINE1 gene transcriptional regulatory region, which codes for PAI-1, in peripheral white blood cells with anthropometrical, metabolic and inflammatory features. Forty-six obese subjects with metabolic syndrome features followed Control or Metabolic Syndrome Reduction in Navarra (RESMENA) energy-restricted (-30%E) diets for 8 weeks. SERPINE1 transcriptional regulatory region methylation at baseline was analyzed by a microarray technical. Both dietary strategies reduced anthropometric and biochemical parameters. The Control group significantly reduced plasma PAI-1 concentrations but not the RESMENA group. Participants from both nutritional interventions with higher SERPINE1 methylation levels at baseline showed significantly major reductions in body weight, total fat mass, android fat mass, total cholesterol and triglycerides, as compared with those with lower initial SERPINE1 methylation levels. In conclusion, the DNA methylation levels of SERPINE1 transcriptional regulatory region were associated with some metabolic and anthropometric changes in obese subjects with metabolic syndrome under energy restriction, suggesting a complex epigenetic network in the regulation of this recognized pro-inflammatory marker. (www.clinicaltrials.gov; NCT01087086).

LINE-1 methylation is positively associated with healthier lifestyle but inversely related to body fat mass in healthy young individuals.

With the goal of investigating if epigenetic biomarkers from white blood cells (WBC) are associated with dietary, anthropometric, metabolic, inflammatory and oxidative stress parameters in young and apparently healthy individuals. We evaluated 156 individuals (91 women, 65 men; age: 23.1±3.5 years; body mass index: 22.0±2.9 kg/m(2)) for anthropometric, biochemical and clinical markers, including some components of the antioxidant defense system and inflammatory response. DNA methylation of LINE-1, TNF-α and IL-6 and the expression of some genes related to the inflammatory process were analyzed in WBC. Adiposity was lower among individuals with higher LINE-1 methylation. On the contrary, body fat-free mass was higher among those with higher LINE-1 methylation. Individuals with higher LINE-1 methylation had higher daily intakes of calories, iron and riboflavin. However, those individuals who presented lower percentages of LINE-1 methylation reported higher intakes of copper, niacin and thiamin. Interestingly, the group with higher LINE-1 methylation had a lower percentage of current smokers and more individuals practicing sports. On the other hand, TNF-α methylation percentage was negatively associated with waist girth, waist-to-hip ratio and waist-to-stature ratio. Plasma TNF-α levels were lower in those individuals with higher TNF-α methylation. This study suggests that higher levels of LINE-1 and TNF-α methylation are associated with better indicators of adiposity status in healthy young individuals. In addition, energy and micronutrient intake, as well as a healthy lifestyle, may have a role in the regulation of DNA methylation in WBC and the subsequent metabolic changes may affect epigenetic biomarkers.

Higher Fruit Intake Is Related to TNF-α Hypomethylation and Better Glucose Tolerance in Healthy Subjects.

BACKGROUND/AIM: This study hypothesized an association between healthy dietary patterns, hypermethylation of the tumor necrosis factor-α (TNF-α) promoter and decreased risk of metabolic changes. METHODS: Forty normal-weight young women were involved in this cross-sectional study. DNA was isolated from white blood cells, and CpG site methylation in TNF-α was analyzed by Sequenom EpiTyper. The quality of the diet was assessed by Healthy Eating Index (HEI-2005). RESULTS: Contradicting our hypothesis, HEI-2005 score was negatively associated with CpG5 (r = -0.460, p = 0.003) and TNF-α total methylation (r = -0.355, p = 0.026). A higher intake of fruits was related to lower insulin, HOMA-IR, and TNF-α methylation. No other dietary pattern was related to TNF-α methylation. TNF-α total methylation correlated positively with systolic blood pressure (r = 0.323; p = 0.042) and CpG5 methylation with body mass index (r = 0.333, p = 0.036). Furthermore, fiber intake was negatively associated with the CpG5 (r = -0.324, p = 0.041) and TNF-α total methylation (r = -0.434, p = 0.005), whereas vitamin C intake was negatively associated with TNF-α total methylation (r = -0.411, p = 0.009). Intakes of apples and citrus fruits were negatively associated with TNF-α total methylation. CONCLUSION: A healthy dietary pattern and higher fruit intake (particularly apples and citrus fruits) were related to better glucose tolerance in healthy subjects, which could be mediated by lower TNF-α methylation.

Expression of inflammation-related miRNAs in white blood cells from subjects with metabolic syndrome after 8 wk of following a Mediterranean diet-based weight loss program.

OBJECTIVES: The aim of this study was to evaluate the influence of a dietary strategy for weight loss (the RESMENA [reduction of metabolic syndrome in Navarra, Spain] diet) on the expression of inflammation-related microRNAS (miRNAs) and genes in white blood cells (WBC) from individuals with metabolic syndrome (MetS). METHODS: The clinical, anthropometric, and biochemical characteristics of 40 individuals with MetS (20 men and 20 women; age: 48.84 ± 10.02 y; body mass index: 35.41 ± 4.42 kg/m(2)) were evaluated before and after an 8-wk hypocaloric diet based on the Mediterranean dietary pattern. Nutrient intake was assessed with a food frequency questionnaire and 48-h weighed food records. Total RNA was isolated from WBC and the expression of some inflammation-related miRNAs and mRNAs (IL-6, TNF-α, ICAM-1, IL-18, SERPINE1, VCAM-1, GAPDH) was assessed by quantitative polymerase chain reaction. RESULTS: The RESMENA nutritional intervention improved most anthropometric and biochemical features. The expression of miR-155-3p was decreased in WBC, whereas Let-7b was strongly upregulated as a consequence of the dietary treatment. However, they were not correlated with the expression of the proinflammatory genes in the same cells. The changes in the expression of let-7b, miR-125b, miR-130a, miR-132-3p, and miR-422b were significantly associated with changes in diet quality when assessed by the Healthy Eating Index. Moreover, low consumption of lipids and saturated fat (g/d) were associated with higher expression of let-7b after the nutritional intervention. CONCLUSIONS: The Mediterranean-based nutritional intervention was able to induce changes in the expression of let-7b and miR-155-3p in WBC from patients with MetS after 8 wk. Moreover, the quality of the diet has an important effect on the miRNAs expression changes. These results should be highlighted because these miRNAs have been associated with inflammatory gene regulation and important human diseases.

DNA Methylation and Hydroxymethylation Levels in Relation to Two Weight Loss Strategies: Energy-Restricted Diet or Bariatric Surgery.

BACKGROUND: Weight loss can be influenced by genetic factors and epigenetic mechanisms that participate in the regulation of body weight. This study aimed to investigate whether the weight loss induced by two different obesity treatments (energy restriction or bariatric surgery) may affect global DNA methylation (LINE-1) and hydroxymethylation profile, as well as the methylation patterns in inflammatory genes. METHODS: This study encompassed women from three differents groups: 1. control group (n = 9), normal weight individuals; 2. energy restriction group (n = 22), obese patients following an energy-restricted Mediterranean-based dietary treatment (RESMENA); and 3. bariatric surgery group (n = 14), obese patients underwent a hypocaloric diet followed by bariatric surgery. Anthropometric measurements and 12-h fasting blood samples were collected before the interventions and after 6 months. Lipid and glucose biomarkers, global hydroxymethylation (by ELISA), LINE-1, SERPINE-1, and IL-6 (by MS-HRM) methylation levels were assessed in all participants. RESULTS: Baseline LINE-1 methylation was associated with serum glucose levels whereas baseline hydroxymethylation was associated with BMI, waist circumference, total cholesterol, and triglycerides. LINE-1 and SERPINE-1 methylation levels did not change after weight loss, whereas IL-6 methylation increased after energy restriction and decreased in the bariatric surgery group. An association between SERPINE-1 methylation and weight loss responses was found. CONCLUSIONS: Global DNA methylation and hydroxymethylation might be biomarkers for obesity and associated comorbidities. Depending on the obesity treatment (diet or surgery), the DNA methylation patterns behave differently. Baseline SERPINE-1 methylation may be a predictor of weight loss values after bariatric surgery.

Common variants of the liver fatty acid binding protein gene influence the risk of type 2 diabetes and insulin resistance in Spanish population.

SUMMARY: The main objective was to evaluate the association between SNPs and haplotypes of the FABP1-4 genes and type 2 diabetes, as well as its interaction with fat intake, in one general Spanish population. The association was replicated in a second population in which HOMA index was also evaluated. METHODS: 1217 unrelated individuals were selected from a population-based study [Hortega study: 605 women; mean age 54 y; 7.8% with type 2 diabetes]. The replication population included 805 subjects from Segovia, a neighboring region of Spain (446 females; mean age 52 y; 10.3% with type 2 diabetes). DM2 mellitus was defined in a similar way in both studies. Fifteen SNPs previously associated with metabolic traits or with potential influence in the gene expression within the FABP1-4 genes were genotyped with SNPlex and tested. Age, sex and BMI were used as covariates in the logistic regression model. RESULTS: One polymorphism (rs2197076) and two haplotypes of the FABP-1 showed a strong association with the risk of DM2 in the original population. This association was further confirmed in the second population as well as in the pooled sample. None of the other analyzed variants in FABP2, FABP3 and FABP4 genes were associated. There was not a formal interaction between rs2197076 and fat intake. A significant association between the rs2197076 and the haplotypes of the FABP1 and HOMA-IR was also present in the replication population. CONCLUSIONS: The study supports the role of common variants of the FABP-1 gene in the development of type 2 diabetes in Caucasians.

Association between AT C573T polymorphism and cardiovascular risk factors in myocardial infarction.

BACKGROUND: Polymorphisms in the AT1 gene have been associated with various parameters related to the pathogenesis of cardiovascular diseases and to myocardial infarction. This study analyzed the relationship between two polymorphisms of the angiotensin II AT-1 receptor gene (AT1_1166 and AT1_573) and the risk of ischemic heart disease by studying their association with several cardiovascular risk factors. METHODS: The sample population comprised 356 subjects: 174 patients who had survived myocardial infarction (61.01 ± 8.15 years), and 182 age- and gender-matched controls (mean age of 60.25 ± 9.43). The polymorphisms of the angiotensin II AT1-receptor gene (C573T and A1166C) were studied by polymerase chain reaction and DNA restriction analysis. We compared the patients' genetic polymorphism with their risk of ischemic heart disease. RESULTS: The A1166C polymorphism did not show any significant differences between the groups. However, with respect to C573T, genotypes tended to differ significantly between cases and controls in the CC and TT types, remaining significant when the CC and CT+TT were grouped. Through analysis of the fit of various multivariate models, we found that the CC genotype is a risk factor for myocardial infarction. This risk remains significant after being adjusted for gender, age, homeostasis model assessment, and anthropometric variables. CONCLUSIONS: There is a relationship between the C573T polymorphism and the pathogenesis of myocardial infarction that seems to be due to its relationship with some risk factors. However, given the multifactorial nature of this pathology, further studies are needed to confirm the evidence that we report herein.

ELOVL6 genetic variation is related to insulin sensitivity: a new candidate gene in energy metabolism.

BACKGROUND: The elongase of long chain fatty acids family 6 (ELOVL6) is an enzyme that specifically catalyzes the elongation of saturated and monounsaturated fatty acids with 12, 14 and 16 carbons. ELOVL6 is expressed in lipogenic tissues and it is regulated by sterol regulatory element binding protein 1 (SREBP-1). OBJECTIVE: We investigated whether ELOVL6 genetic variation is associated with insulin sensitivity in a population from southern Spain. DESIGN: We undertook a prospective, population-based study collecting phenotypic, metabolic, nutritional and genetic information. Measurements were made of weight and height and the body mass index (BMI) was calculated. Insulin resistance was measured by homeostasis model assessment. The type of dietary fat was assessed from samples of cooking oil taken from the participants' kitchens and analyzed by gas chromatography. Five SNPs of the ELOVL6 gene were analyzed by SNPlex. RESULTS: Carriers of the minor alleles of the SNPs rs9997926 and rs6824447 had a lower risk of having high HOMA_IR, whereas carriers of the minor allele rs17041272 had a higher risk of being insulin resistant. An interaction was detected between the rs6824447 polymorphism and the intake of oil in relation with insulin resistance, such that carriers of this minor allele who consumed sunflower oil had lower HOMA_IR than those who did not have this allele (P = 0.001). CONCLUSIONS: Genetic variations in the ELOVL6 gene were associated with insulin sensitivity in this population-based study.

Dietary polyunsaturated fatty acids may increase plasma LDL-cholesterol and plasma cholesterol concentrations in carriers of an ABCG1 gene single nucleotide polymorphism: study in two Spanish populations.

BACKGROUND: ABCG1 mediates cellular cholesterol transport, but there is very little known about the influence of ABCG1 polymorphisms on human plasma lipoprotein cholesterol concentrations or on the interactions of these polymorphisms with diet. OBJECTIVE: Our objective was to investigate whether interactions between PUFA intake and ABCG1 polymorphisms modulate associations with plasma total cholesterol (TC), LDL- and HDL-cholesterol in two Spanish populations. METHODS: We grounded our investigation on two general population-based studies: the Hortega study (population A) and the Pizarra study (population B). Participants included 1178 individuals (50.0% women, age range 21-85 years) and 763 individuals (66% women, age range 23-73 years) from populations A and B, respectively, without lipid lowering drugs. Subjects were genotyped for ABCG1 variants. Biochemical measurements were taken by standard procedures. Dietary intakes were estimated with a validated questionnaire. RESULTS: In population A, the A allele homozygotes of SNP rs4148102 had higher TC and LDLc concentrations in subjects on a high PUFA diet than did the carriers of the G allele (242.1 ± 38.9 vs. 198.0 ± 36.0mg/dL, p = 0.003, and 149.8 ± 37.9 vs. 111.4 ± 32.1mg/dL, p = 0.005, respectively), and significant gene-diet interactions were observed (p=0.020 and p = 0.013, respectively). In population B, similar differences in TC and LDLc concentrations were also found in association with this SNP under a high PUFA diet (253.2±24.9 vs. 197.7 ± 39.9 mg/dL, p = 0.009, and 171.8 ± 20.5 vs. 120.4 ± 34.2mg/dL, p = 0.004, respectively), but the gene-diet interactions observed were not significant (p = 0.379 and p = 0.422, respectively). In the pooled populations, differences in the TC and LDLc concentrations increased (246.8 ± 32.9 vs. 198.0 ± 37.5, p = 6 × 10(-5), and 159.0±32.6 vs. 114.3 ± 33.1, p = 3 × 10(-5), respectively), and significant gene-diet interactions were maintained (p = 0.006 and p = 0.003, respectively). CONCLUSION: In two Spanish populations, the ABCG1 polymorphism rs4148102 was associated with variations in plasma lipoprotein cholesterol concentrations in subjects with high PUFA intakes. Carriers of the AA genotype consuming high PUFA diet showed higher plasma LDLc concentrations.

Genetic bases of urinary albumin excretion and related traits in hypertension.

Epidemiological as well as animal studies have recognized the potential role of genetic factors in the development of microalbuminuria and related traits (renal insufficiency, end-stage renal disease and nephroangiosclerosis) in hypertension. To unravel genetic variants of susceptibility, candidate gene, linkage and genome wide scan analysis has been used. In spite of the great efforts that have been made in the field, sound knowledge about the major genetic variants causing the susceptibility to develop renal damage in hypertension is scarce, since many associations were not replicated or only showed association in a certain subgroup of patients. Looking initially at genes of the most important physiological pathways of blood pressure regulation, linkage and genome wide scan have also detected genes of the lipid metabolism and protein components of the glomerular structures as potential candidate genes. Well designed large-scale genome-wide analysis and replication studies with large cohorts can help in the future to clarify the genetic bases of renal damage in hypertension. Combined strategies can contribute toward a better understanding of the genetic basis of urinary albumin excretion and renal damage in hypertension

Association of selected ABC gene family single nucleotide polymorphisms with postprandial lipoproteins: results from the population-based Hortega study.

The aim of the study was to determine the influence of twenty single nucleotide polymorphisms (SNPs) of the ABCA1, ABCG1, ABCG5 and ABCG8 genes on the plasmatic concentrations of total cholesterol (TC), HDL and LDL cholesterol (HDLc, LDLc) in the postprandial state with a representative Spanish Caucasian population (1473 individuals, 50.0% women, ages ranging 21-85 years). In men, subjects with the AA genotype of the ABCA1 rs2230806 (R219K) polymorphism were associated with increased plasma LDLc levels, while the ABCA1 haplotype, which included the rs2230806 A allele, was associated with higher TC and LDLc plasma concentrations. In women, significant relationships were found between rs1893590 polymorphisms (ABCG1 gene) and HDLc plasma concentrations (subjects with the AA genotype had lower HDLc levels). For the ABCG8 gene, the rs4148211 polymorphism was associated with higher plasma TC and LDLc concentrations in the total population. Moreover, an ABCG5-G8 haplotype, which included the rs6544718 T allele, was associated with higher HDLc plasma concentrations in women. In conclusion, different SNPs of the ABCA1, ABCG1 and ABCG5-ABCG8 genes were associated, some under gender-specific analysis, with variations in the plasma lipid levels under postprandial conditions in a representative Spanish population.

Analysis of sequence variations in the LDL receptor gene in Spain: general gene screening or search for specific alterations?

BACKGROUND: Familial hypercholesterolemia (FH) is a frequent form of autosomal-dominant hypercholesterolemia that predisposes to premature coronary atherosclerosis. FH is caused by sequence variations in the gene coding for the LDL receptor (LDLR). This gene has a wide spectrum of sequence variations, and genetic diagnosis can be performed by 2 strategies. METHODS: Point variations and large rearrangements were screened along all the LDLR gene (promoter, exons, and flanking intron sequences). RESULTS: We screened a sample of 129 FH probands from the Valencian Community, Spain, and identified 54 different LDLR sequence variations. The most frequent (10% of cases) was 111insA, and 60% of the variants had a frequency as low as 1%. A previously described method for detection of known sequence variations in the Spanish population by DNA array analysis allowed the identification of only approximately 50% of patients with a variant LDLR gene and approximately 40% of the screened samples. CONCLUSION: Our results indicate that the adequate procedure to identify LDLR sequence variations in outbreed populations should include screening of the entire gene.