The role of LTA4H and ALOX5AP polymorphism in asthma and allergy susceptibility

Background: Leukotrienes (LTs) have been identified as central mediators in asthma and allergy. Pharmacological inhibition of cysteinyl‐LT activity improves asthma symptoms and control. Accumulating evidence suggests a role for the dihydroxy leukotriene LTB₄ in airway disease. LTA₄ hydrolase and 5‐lipoxygenase activating protein have key roles in LTB₄ production. Single nucleotide polymorphism (SNPs) and haplotypes spanning the LTA4H and ALOX5AP genes have been associated with LTB₄ production and myocardial infarction (MI). Objective: To assess the contribution of LTA4H and ALOX5AP polymorphism to asthma and allergy susceptibility. Methods: Three hundred and forty‐one Caucasian families (two asthmatic siblings) were genotyped for eight SNPs spanning ALOX5AP and five SNPs spanning LTA4H. Association analyses of asthma and related phenotypes (total IgE, atopy, bronchial hyper‐responsiveness, FEV₁) were undertaken using the Family Based Association Test. Results: Single point analyses identified association (P < 0.05) between SNPs SG13S114, SG13S89, SG13S41 (ALOX5AP), rs1978331 (LTA4H) and asthma and/or related phenotypes. Haplotype analyses using all LTA4H SNPs identified a single key risk haplotype for the development of asthma (P = 0.006) and related phenotypes (P = 0.042–0.005). Haplotype analyses using all ALOX5AP SNPs identified several asthma and atopy risk and protective haplotypes. There was limited correlation with previously identified MI risk haplotypes in both genes. Carriers of both ALOX5AP SG13S41 and LTA4H rs1978331 alleles had an increased risk of developing asthma (OR 2.17, CI 1.41–3.32). Conclusions: These data provide evidence for the role of SNPs spanning the ALOX5AP and LTA4H genes in asthma and atopy susceptibility in the Caucasian population and support a role for LTB₄ in disease pathogenesis.     

Phosphodiesterase 4D Gene and Risk of Noncardiogenic Ischemic Stroke in a Korean Population

Recently published studies from different populations provide apparently conflicting evidence on the association between the phosphodiesterase 4D (PDE4D) gene and ischemic stroke. The relationship between a representative PDE4D genotype and ischemic stroke was explored in a case-control study of 205 consecutive Korean patients with noncardiogenic ischemic stroke and 103 healthy controls who were neurologically and radiologically proven to be stroke-free. We selected and genotyped a PDE4D single nucleotide polymorphism (SNP 41, rs152312) as a candidate marker for susceptibility to ischemic stroke because SNP 41 has shown the most significant association with stroke in both a meta-analysis and the original Icelandic study of the PDE4D gene. No significant difference was observed between the cases and controls in the distribution of the PDE4D SNP 41 genotypes. The results from the adjusted conditional logistic regression analysis (adjusted for age, hypertension, diabetes and smoking status) showed no significant association between PDE4D SNP 41 genotypes and an increased risk of noncardiogenic ischemic stroke. The PDE4D gene is not a major risk factor for noncardiogenic ischemic stroke in a Korean population, which supports the recent evidence suggesting that the causative genetic variants of ischemic stroke may differ across populations.     

No association of ALOX5AP polymorphisms with risk of MRI-defined brain infarcts

The arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene has been associated with stroke. The majority of the reported ALOX5AP associations have considered non-radiologically confirmed infarcts as the stroke phenotype. We assessed the association of genetic variants in ALOX5AP with stroke defined by the presence of infarcts on brain magnetic resonance imaging (MRI). We studied 202 persons with MRI-defined brain infarcts and 487 healthy individuals of Caribbean Hispanic ancestry. Another sample of European ancestry comprised 1823 persons with MRI-defined brain infarct and 7578 control subjects. Subjects were genotyped for the 4 single nucleotide polymorphisms (SNPs) that define ALOX5AP HapA haplotype. No association was found between SNPs and MRI-defined brain infarcts. Our data do not support the hypothesis that variants in ALOX5AP are associated with risk of MRI-defined brain infarcts.     

Variants of the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene and risk of ischemic stroke in Han Chinese of eastern China

Variants of the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene have been suggested to play an important role in the pathogenesis of atherosclerosis and ischemic stroke.This study was aimed to explore the association of ALOX5AP variants with ischemic stroke risk in Han Chinese of eastern China.A total of 690 ischemic stroke cases and 767 controls were recruited.The subjects were further subtyped according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria.On the basis of that,two polymorphisms of the ALOX5AP gene (rs10507391 and rs12429692) were determined by TaqMan genotyping assay.In addition,plasma leukotriene B4 (LTB4) levels were analyzed in these subjects.There was no evidence of association between the two variants of ALOX5AP and the risk of ischemic stroke or its TOAST-subtypes.Haplotype analysis and stratification analysis according to sex,age,body mass index,hypertension,and diabetes also showed negative association.Analysis of LTB4 levels in a subset of cases and controls revealed that LTB4 levels were significantly higher in ischemic stroke cases than in the controls (70.06±14.75 ng/L vs 57.34±10.93 ng/L;P=0.000) and carriers of the T allele of the rs10507391 variant were associated with higher plasma LTB4 levels (P=0.000).The present study suggests there is no association of the two polymorphisms in the ALOX5AP gene with ischemic stroke risk in Han Chinese of eastern China.     

Ischaemic stroke in hypertensive patients is associated with variations in the PDE4D genome region

Previous Icelandic studies reported that single nucleotide polymorphisms (SNPs) in the phosphodiesterase 4D (PDE4D) region and the 5-lipoxygenase activating protein ALOX5AP were associated with ischaemic stroke, whereas other studies reported ambiguous findings. We examined 932 ischaemic stroke patients from a Swedish population-based stroke register, and 396 control subjects. We assessed possible associations between ischaemic stroke and nine preselected SNPs in the chromosome regions of the PDE4D gene, including rs12188950 (SNP45) and rs3887175 (SNP39); the ALOX5AP gene, including rs17222814 (SG13S25) and the promoter region of the MHC class II transactivator, MHC2TA. The T allele of SNP45 showed negative association with ischaemic stroke (odds ratio, OR=0.72; 95% confidence interval (CI): 0.58-0.91; P=0.0055). Among hypertensive subjects, this influence of the T allele of SNP45, and the T allele of SNP39, were more pronounced (with OR=0.52; 95% CI: 0.37-0.73; P=0.0001 and OR=0.57; 95% CI: 0.41-0.79; P=0.0007, respectively). These SNPs also interacted with hypertension with a relative excess risk due to interaction of -1.66 (P=0.0002) for SNP45 and -1.65 (P=0.0005) for SNP39. The P-values remained significant after correction for multiple testing. Among nonhypertensives, the A allele of SG13S25 indicated increased stroke risk (OR=1.82; 95% CI: 1.21-2.74; P=0.0039; not significant after Bonferroni correction). SNP45 was associated with ischaemic stroke even when controlling for hypertension, diabetes, heart disease and smoking. Our meta-analysis of 13 studies (including ours) showed no overall influence of SNP45 on ischaemic stroke. However, the 13 studies may differ because of nonrandom causes, as suggested by the heterogeneity test (P=0.042). This might support previously undetected mechanisms causing fluctuating ischaemic stroke risk.European Journal of Human Genetics (2008) 16, 1117-1125; doi:10.1038/ejhg.2008.62; published online 9 April 2008.     

Analysis of polymorphic variants of <Emphasis Type="Italic">PDE4D</Emphasis> gene in patients with acute stroke from Moldavian population

The risk of the development of ischemic stroke is caused by both genetic predisposition and environmental factors. In recent investigations, the DeCode group discovered polymorphisms in the phosphodiesterase 4D (PDE4D) gene associated with the risk of the development of ischemic stroke. The aim of the present work was to investigate two polymorphisms in the PDE4D gene (SNP41 (rs52312) and SNP87 (rs2910829)) in patients with ischemic stroke and in the control sample from the Moldavian ethnic group. Statistically significant data about the association between ischemic stroke and studied polymorphisms were not detected.     

Association between ORMDL3, IL1RL1 and a deletion on chromosome 17q21 with asthma risk in Australia

Genome-wide association studies followed by replication provide a powerful approach to map genetic risk factors for asthma. We sought to search for new variants associated with asthma and attempt to replicate the association with four loci reported previously (ORMDL3, PDE4D, DENND1B and IL1RL1). Genome-wide association analyses of individual single nucleotide polymorphisms (SNPs), rare copy number variants (CNVs) and overall CNV burden were carried out in 986 asthma cases and 1846 asthma-free controls from Australia. The most-associated locus in the SNP analysis was ORMDL3 (rs6503525, P=4.8 × 10⁻⁷). Five other loci were associated with P<10⁻⁵, most notably the chemokine CXC motif ligand 14 (CXCL14) gene (rs31263, P=7.8 × 10⁻⁶). We found no evidence for association with the specific risk variants reported recently for PDE4D, DENND1B and ILR1L1. However, a variant in IL1RL1 that is in low linkage disequilibrium with that reported previously was associated with asthma risk after accounting for all variants tested (rs10197862, gene wide P=0.01). This association replicated convincingly in an independent cohort (P=2.4 × 10⁻⁴). A 300-kb deletion on chromosome 17q21 was associated with asthma risk, but this did not reach experiment-wide significance. Asthma cases and controls had comparable CNV rates, length and number of genes affected by deletions or duplications. In conclusion, we confirm the association between asthma risk and variants in ORMDL3 and identify a novel risk variant in IL1RL1. Follow-up of the 17q21 deletion in larger cohorts is warranted.     

A large-sample assessment of possible association between ischaemic stroke and rs12188950 in the PDE4D gene

Previous reports have shown ambiguous findings regarding the possible associations between ischaemic stroke (IS) and single nucleotide polymorphisms (SNPs) in the phosphodiesterase 4D (PDE4D) gene region. The SNP rs12188950 (or SNP45) has often been studied in this context. We performed a multi-centre study involving a large sample of 2599 IS patients and 2093 control subjects from the south and west regions of Sweden to replicate previous studies regarding IS risk and rs12188950. Subjects from Lund Stroke Register (LSR), Malmö Diet and Cancer Study (MDC) and Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS) were enroled. Subgroups of participants with hypertension and participants <55 years of age, as well as the TOAST subgroups large vessel disease, small vessel disease and cardioembolism, were also assessed. Univariate odds ratios (ORs) and ORs controlling for hypertension, diabetes and current smoking were calculated. We additionally performed a meta-analysis including 10 500 patients and 10 102 control subjects from 17 publications (including the present study). When assessing pooled data from LSR, MDC and SAHLSIS we obtained no association between IS and rs12188950 for all participants (OR=0.93; 95% confidence interval (CI): 0.83–1.05). Significant associations were not found for hypertensive participants or participants with age <55, or when separately evaluating patients from the three different TOAST subgroups. The meta-analysis showed no significant overall estimate (OR=0.96; 95% CI: 0.89–1.04) with significant heterogeneity for random effect (P=0.042). No effect from rs12188950 on IS was found from either our pooled multi-centre data or the performed meta-analysis. We did not find any association between the examined subgroups and rs12188950 either.     

The role of LTA4H and ALOX5AP genes in the risk for asthma in Latinos

Background Leukotrienes play an important role in allergic and inflammatory diseases, but reports on the involvement of arachidonate 5‐lipoxygenase‐activating protein (ALOX5AP) and leukotriene A₄ hydrolase (LTA4H) in asthma have been inconclusive. Objective To determine whether polymorphisms in ALOX5AP and LTA4H genes are risk factors for asthma in two different Latino groups: Mexicans and Puerto Ricans. Methods The LTA4H gene was sequenced in individuals from both groups to identify novel polymorphisms. Single‐nucleotide polymorphisms (SNPs) in the ALOX5AP and LTA4H genes were analysed for associations with asthma and asthma‐related phenotypes in 687 parent–child trios of Mexican and Puerto Rican origin. Results In LTA4H, five previously unknown polymorphisms were identified. Two SNPs within LTA4H (rs17525488 and rs2540493) were protective for asthma in Latinos (P=0.007 and 0.05, respectively). Among the Mexican patients, LTA4H polymorphisms were associated with baseline lung function and IgE levels. For ALOX5AP, the minor allele at SNP rs10507391 was associated with protection from asthma (odds ratio=0.78, P=0.02) and baseline lung function (P=0.018) in Puerto Ricans. A gene–gene interaction was identified between LTA4H (rs17525488) and ALOX5AP (rs10507391), (P=0.003, in the combined sample). Conclusion Our results support the role of LTA4H and ALOX5AP variants as risk factors for asthma in Latino populations. Cite this as: M. Via, A. De Giacomo, H. Corvol, C. Eng, M. A. Seibold, C. Gillett, J. Galanter, S. Sen, H. Tcheurekdjian, R. Chapela, J. R. Rodríguez‐Santana, W. Rodríguez‐Cintrón, S. Thyne, P. C. Avila, S. Choudhry and E. González Burchard on behalf of the Genetics of Asthma in Latino Americans (GALA) Study, Clinical & Experimental Allergy, 2010 (40) 582–589.     

Association of two polymorphisms in the FADS1/FADS2 gene cluster and the risk of coronary artery disease and ischemic stroke

Little is known about the association of the FADS1/FADS2 SNPs and serum lipid levels and the risk of coronary artery disease (CAD) and ischemic stroke (IS) in the Chinese southern population. The present study aimed to determine such association in the Chinese southern population. A total of 1,669 unrelated subjects (CAD, 534; IS, 553; and healthy controls, 582) were recruited in the study. Genotypes of the FADS1 rs174546 SNP and the FADS2 rs174601 SNP were determined by the SNaPshot Multiplex Kit. The T allele and TT genotype frequencies of the two SNPs were predominant in our study population. The T alleles were associated with increased risk of CAD and IS. Correspondingly, the C alleles were associated with reduced risk of CAD and IS. Haplotype analyses showed that the haplotype of T-T (rs174546-rs174601) was associated with an increased risk for IS, and the haplotype of C-C (rs174546-rs174601) was associated with a reduced risk for CAD and IS. The two SNPs were likely to influence serum lipid levels. The T allele carriers of the two SNPs and rs174601 TT genotype were associated with decreased serum HDL-C and ApoAI levels in the patient groups and with an increased risk of CAD and IS. The present study suggests that the FADS1 rs174546 SNP and the FADS2 rs174601 SNP are associated with the risk of CAD and IS, and are likely to influence serum lipid levels. However, further functional studies are needed to clarify how the two SNPs actually affect serum lipid levels and the risk of CAD and IS.     

Scavenger Receptor Class B Type 1 Gene rs5888 Single Nucleotide Polymorphism and the Risk of Coronary Artery Disease and Ischemic Stroke: A Case-Control Study

Background: Our previous studies have showed that the rs5888 single nucleotide polymorphism (SNP) in Scavenger receptor class B type 1 (SCARB1) gene is associated with serum lipid levels in the general Chinese populations. The present study was undertaken to detect the associations between rs5888 SNP and the risk of coronary artery disease (CAD) and ischemic stroke (IS).Methods: A total of 1,716 unrelated subjects (CAD, 601; IS, 533; and healthy controls, 582) were included in this study. Genotyping of the rs5888 SNP were determined by polymerase chain reaction and restriction fragment length polymorphism.Results: The genotypic frequencies of SCARB1 rs5888 SNP were different between CAD patients and controls, the subjects with TT genotype had high risk of CAD (OR = 1.76, P = 0.038 for TT vs. CC; and OR = 1.75, P = 0.036 for TT vs. CC/CT). There was no significant association between genotypes and the risk of IS. Further analysis showed that the subjects with TT genotype in the total population had lower levels of high-density lipoprotein cholesterol than the subjects with CC/CT genotypes (P < 0.05), the subjects with TT genotype in controls but not in CAD or IS patients had higher levels of serum LDL-C and ApoB than those with CC genotype (P < 0.05 for each).Conclusions: The present study suggests that the SCARB1 rs5888 SNP influences serum lipid levels, and is associated with the risk of CAD.     

Genetic variation in the lipoxygenase pathway and risk of colorectal neoplasia

Arachidonate lipoxygenase (ALOX) enzymes metabolize arachidonic acid to generate potent inflammatory mediators and play an important role in inflammation‐associated diseases. We investigated associations between colorectal cancer risk and polymorphisms in ALOX5, FLAP, ALOX12, and ALOX15, and their interactions with nonsteroidal anti‐inflammatory drug (NSAID) use. We genotyped fifty tagSNPs, one candidate SNP, and two functional promoter variable nucleotide tandem repeat (VNTR) polymorphisms in three US population‐based case‐control studies of colon cancer (1,424 cases/1,780 controls), rectal cancer (583 cases/775 controls), and colorectal adenomas (485 cases/578 controls). Individuals with variant genotypes of the ALOX5 VNTR had a decreased risk of rectal cancer, with the strongest association seen for individuals with one or more alleles of >5 repeats (wild type = 5, OR>5/≥5 = 0.42, 95% CI 0.20–0.92; P = 0.01). Four SNPs in FLAP (rs17239025), ALOX12 (rs2073438), and ALOX15 (rs4796535 and rs2619112) were associated with rectal cancer risk at P ≤ 0.05. One SNP in FLAP (rs12429692) was associated with adenoma risk. A false discovery rate (FDR) was applied to account for false positives due to multiple testing; the ALOX15 associations were noteworthy at 25% FDR. Colorectal neoplasia risk appeared to be modified by NSAID use in individuals with variant alleles in FLAP and ALOX15. One noteworthy interaction (25% FDR) was observed for rectal cancer. Genetic variability in ALOXs may affect risk of colorectal neoplasia, particularly for rectal cancer. Additionally, genetic variability in FLAP and ALOX15 may modify the protective effect of NSAID use against colorectal neoplasia. © 2013 Wiley Periodicals, Inc.     

Association analysis between polymorphisms in the dopamine D2 receptor (DRD2) and dopamine transporter (DAT1) genes with cocaine dependence

Genetic research on cocaine dependence (CD) may help clarify our understanding of the disorder as well as provide novel insights for effective treatment. Since dopamine neurotransmission has been shown to be involved in drug reward, related genes are plausible candidates for susceptibility to CD. The dopamine receptor D₂ (DRD2) protein and dopamine transporter (DAT1) protein play regulatory roles in dopamine neurotransmission. The TaqI A single-nucleotide polymorphism (SNP) in the DRD2 gene and the 3′ variable number tandem repeat (VNTR) polymorphism in the DAT1 gene have been implicated in psychiatric disorders and drug addictions. In this study, we hypothesize that these polymorphisms contribute to increased risk for CD. Cocaine-dependent individuals (n = 347) and unaffected controls (n = 257) of African descent were genotyped for the polymorphisms in the DRD2 and DAT1 genes. We observed no statistically significant differences or trends in allele or genotype frequencies between cases and controls for either of the tested polymorphisms. Our study suggests that there is no association between the DRD2 and DAT1 polymorphisms and CD. However, additional studies using larger sample sizes and clinically homogenous populations are necessary before confidently excluding these variants as contributing genetic risk factors for CD.     

ALOX5AP基因SG13S114A/T多态性与颈动脉粥样硬化斑块稳定性的相关性

目的 探讨花生四烯酸5-脂氧合酶激活蛋白(arachidonate 5-lipoxygenase acttvating protein,ALOX5AP)基因SG13S114 A/T的多态性与颈动脉粥样硬化斑块稳定程度的关系.方法 应用聚合酶链反应-限制性片段长度多态性分析法检测132例颈动脉易损斑块及152例稳定斑块的急性脑梗死者ALOX5AP基因SG13S114 A/T基因型,比较两组间该位点多态性的差异.结果 易损斑块组ALOX5AP基因SG13S114 AA基因型和A等位基因频率高于稳定斑块组,两组差异有统计学意义(P＜0.01),其中男性和女性上述基因型和等位基因频率的比较,易损斑块组均高于稳定斑块组,两组差异有统计学意义(P＜0.01).结论 ALOX5AP基因SG13S114 A/T多态性可能与动脉粥样斑块的稳定性有关,其中SG13S114 A等位基因可能是易损斑块的风险因素.     

Association of polymorphisms of innate immunity-related genes and tuberculosis susceptibility in Mongolian population

BackgroundsGenetic polymorphism of the toll-like receptor 2, 4 (TLR2, TLR4) and natural resistance-associated macrophage protein 1 (NRAMP1) genes may affect host immune response to Mycobacterium tuberculosis (Mtb) and lead to the variation of susceptibility to tuberculosis (TB) in humans. However, the association of single nucleotide polymorphisms (SNP) in these genes and the susceptibility to TB in Mongolian population has not been investigated.MethodsWe conducted a genetic association study including 197 Mongolian TB patients and 217 Mongolian healthy controls in Inner Mongolia, China. DNA of blood samples was extracted and genotyped for 5 SNPs in TLR4, 4 SNPs in TLR2 and 5 SNPs in NRAMP1 by next-generation sequencing. A logistic regression was performed and odds ratios (OR) with 95% confidence intervals (CI) were calculated to estimate the risk at TB by each SNP.ResultsThe most significant locus associated with the susceptibility to TB was TLR4 rs11536889. The frequency for allele C of TLR4 rs11536889 was 16.0% in TB patients and 23.5% in healthy controls, respectively. Rs11536889 C/C genotype of TLR4 was significantly associated with the low susceptibility against TB compared to G/G genotype in the dominant model (OR 0.62, 95% CI 0.41–0.94).ConclusionsThe TLR4 rs11536889 polymorphisms might be an indicative of the low susceptibility to TB in Mongolian population, which provides valuable information for the generation of effective strategy or measurement against TB in Mongolian population.     

Association of ALOX5AP gene single nucleotide polymorphisms and cerebral infarction in the Han population of northern China

ABSTRACT: BACKGROUND: To explore the association of ALOX5AP single nucleotide polymorphisms (SNPs) and haplotype with the occurrence of cerebral infarction in the Han population of northern China. METHODS: Blood samples were collected from 236 patients of Han ancestry with a history of cerebral infarction and 219 healthy subjects of Han ancestry with no history of cerebral infarction or cardiovascular disease. Applied Biosystems(R) TaqMan(R) SNP Genotyping Assays for SNP genotyping were used to determine the genotypes of 7 ALOX5AP SNP alleles (rs4073259, rs4769874, rs9315050, rs9551963, rs10507391, rs9579646, and rs4147064). RESULTS: One SNP allele (A) of rs4073259 was significantly associated with development of cerebral infarction (P = 0.049). In comparison to control groups, haplotype rs9315050&rs9551963 AAAC [OR (95 % CI) =1.53 (1.02-2.29)], and genotypes rs4147064 CT [OR (95 % CI) =1.872 (1.082-3.241)], and rs9551963 AC [OR (95 % CI) = 2.015 (1.165-3.484)] increased the risk of cerebral infarction in patients with hypertension. Genotype rs9579646 GG [OR (95 % CI) = 2.926 (1.18-7.251)] increased the risk of, while rs4073259 GG [OR (95 % CI) = 0.381 (0.157-0.922)] decreased the risk of cerebral infarction in patients with diabetes. CONCLUSION: These results suggest the ALOX5AP SNP A allele in rs4073259 and genotype rs9579646 GG, rs9551963 AC, and haplotype rs9315050 & rs9551963 AAAC were associated with an increased risk of ischemic stroke in the Han population, while rs4073259 GG was associated with a decreased risk.     

Male specific association between the 5-HTR6 gene 267C/T SNP and suicide in the Portuguese population

Serotonergic system dysfunction has been implicated in the etiology of suicide. A large number of genetic studies have focused on the potential involvement of genes coding for components of serotonergic system in suicidal behavior. However, other genes belonging to this system remain to be investigated or have been poorly studied, as is the case of the 5-HT6 receptor (5-HTR6) gene. In this study, we investigated the potential association between the 5-HTR6 gene 267C/T SNP and suicide in a Portuguese population. Blood samples were collected from 179 suicide victims and 189 controls. Genotypes for the 5-HTR6 gene 267C/T SNP were obtained with the restriction enzyme Rsa I. A tendency was found for genotype association between this polymorphism and suicide, but the differences were not statistically significant (χ² = 5.374, df = 2, p = 0.068). However, a gender-specific association was detected when comparing the genotype distribution between male suicide victims and male controls (χ² = 6.988, df = 2, p = 0.030), suggesting that this SNP might have a role in the etiology of suicide in male subjects in the Portuguese population.     

Association of variants in CELSR2-PSRC1-SORT1 with risk of serum lipid traits,coronary artery disease and ischemic stroke

Recent genome-wide association studies (GWAS) have identified genetic variants associated with coronary artery disease (CAD), ischemic stroke (IS) and serum lipid traits in different ethnic groups. Some loci were found to affect the risk of CAD and IS. However, there were no data in the southern Chinese populations. Our study was to assess the association of CELSR2-PSRC1-SORT1 rs599839, rs464218 and rs6698443 SNPs and serum lipid levels and the risk of CAD and IS. The genotypes of 3 SNPs were detected in 561 CAD and 527 IS patients, and in 590 healthy controls. The genotypic and allelic frequencies of the rs599839 SNP were different between the controls and IS patients (P < 0.05). The minor G alleles of rs599839 and rs464218 SNPs were associated with higher high-density lipoprotein cholesterol concentrations in CAD and IS patients (P < 0.05); respectively. No association was found between the SNPs of rs599839, rs464218 and rs6698843 at the CELSR2-PSRC1-SORT1 and the risk of CAD or IS. These results will be replicated in the other Chinese populations.     

Genome-wide association of sleep and circadian phenotypes

Background

Numerous studies suggest genetic influences on sleepiness and circadian rhythms. The Sleep Heart Health Study collected questionnaire data on sleep habits and sleepiness from 2848 Framingham Heart Study Offspring Cohort participants. More than 700 participants were genotyped using the Affymetrix 100K SNP GeneChip, providing a unique opportunity to assess genetic linkage and association of these traits.

Methods

Sleepiness (defined as the Epworth Sleepiness Scale score), usual bedtime and usual sleep duration were assessed by self-completion questionnaire. Standardized residual measures adjusted for age, sex and BMI were analyzed. Multipoint variance components linkage analysis was performed. Association of SNPs to sleep phenotypes was analyzed with both population-based and family-based association tests, with analysis limited to 70,987 autosomal SNPs with minor allele frequency ≥10%, call rate ≥80%, and no significant deviation from Hardy-Weinberg equilibrium (p ≥ 0.001).

Results

Heritability of sleepiness was 0.29, bedtime 0.22, and sleep duration 0.17. Both genotype and sleep phenotype data were available for 749 subjects. Linkage analysis revealed five linkage peaks of LOD >2: four to usual bedtime, one to sleep duration. These peaks include several candidate sleep-related genes, including CSNK2A2, encoding a known component of the circadian molecular clock, and PROK2, encoding a putative transmitter of the behavioral circadian rhythm from the suprachiasmatic nucleus. Association tests identified an association of usual bedtime with a non-synonymous coding SNP in NPSR1 that has been shown to encode a gain of function mutation of the neuropeptide S receptor, whose endogenous ligand is a potent promoter of wakefulness. Each copy of the minor allele of this SNP was associated with a 15 minute later mean bedtime. The lowest p value was for association of sleepiness with a SNP located in an intron of PDE4D, which encodes a cAMP-specific phosphodiesterase widely expressed in human brain. Full association results are posted at http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000007.

Conclusion

This analysis confirms prior reports of significant heritability of sleepiness, usual bedtime, and usual sleep duration. Several genetic loci with suggestive linkage to these traits are identified, including linkage peaks containing circadian clock-related genes. Association tests identify NPSR1 and PDE4D as possible mediators of bedtime and sleepiness.