Shared genetic susceptibility to ischemic stroke and coronary artery disease: a genome-wide analysis of common variants

BACKGROUND AND PURPOSE

Ischemic stroke (IS) and coronary artery disease (CAD) share several risk factors and each has a substantial heritability. We conducted a genome-wide analysis to evaluate the extent of shared genetic determination of the two diseases.

METHODS

Genome-wide association data were obtained from the METASTROKE, Coronary Artery Disease Genome-wide Replication and Meta-analysis (CARDIoGRAM), and Coronary Artery Disease (C4D) Genetics consortia. We first analyzed common variants reaching a nominal threshold of significance (P<0.01) for CAD for their association with IS and vice versa. We then examined specific overlap across phenotypes for variants that reached a high threshold of significance. Finally, we conducted a joint meta-analysis on the combined phenotype of IS or CAD. Corresponding analyses were performed restricted to the 2167 individuals with the ischemic large artery stroke (LAS) subtype.

RESULTS

Common variants associated with CAD at P<0.01 were associated with a significant excess risk for IS and for LAS and vice versa. Among the 42 known genome-wide significant loci for CAD, 3 and 5 loci were significantly associated with IS and LAS, respectively. In the joint meta-analyses, 15 loci passed genome-wide significance (P<5×10(-8)) for the combined phenotype of IS or CAD and 17 loci passed genome-wide significance for LAS or CAD. Because these loci had prior evidence for genome-wide significance for CAD, we specifically analyzed the respective signals for IS and LAS and found evidence for association at chr12q24/SH2B3 (PIS=1.62×10(-7)) and ABO (PIS=2.6×10(-4)), as well as at HDAC9 (PLAS=2.32×10(-12)), 9p21 (PLAS=3.70×10(-6)), RAI1-PEMT-RASD1 (PLAS=2.69×10(-5)), EDNRA (PLAS=7.29×10(-4)), and CYP17A1-CNNM2-NT5C2 (PLAS=4.9×10(-4)).

CONCLUSIONS

Our results demonstrate substantial overlap in the genetic risk of IS and particularly the LAS subtype with CAD.

Pharmacogenetics in cardiovascular disease: the challenge of moving from promise to realization: concepts discussed at the Canadian Network and Centre for Trials Internationally Network Conference (CANNeCTIN), June 2009

Pharmacogenetics in cardiovascular medicine brings the potential for personalized therapeutic strategies that improve efficacy and reduce harm. Studies evaluating the impact of genetic variation on pharmacologic effects have been undertaken for most major cardiovascular drugs, including antithrombotic agents, β-adrenergic receptor blockers, statins, and angiotensin-converting enzyme inhibitors. Across these drug classes, many polymorphisms associated with pharmacodynamic, pharmacokinetic, or surrogate outcomes have been identified. However, their impact on clinical outcomes and their ability to improve clinical practice remains unclear. This review will examine the current clinical evidence supporting pharmacogenetic testing in cardiovascular medicine, provide clinical guidance based on the current evidence, and identify further steps needed to determine the utility of pharmacogenetics in cardiovascular care.

Two chromosome 9p21 haplotype blocks distinguish between coronary artery disease and myocardial infarction risk

BACKGROUND

Variants at the 9p21 locus associate with the risk of coronary artery disease (CAD) or myocardial infarction (MI). However, atherosclerotic plaque deposition is distinct from MI (plaque rupture and thrombosis), and recent studies showed no association between these variants and MI in patients with preexisting CAD. We performed haplotype analysis at the 9p21 locus to test whether haplotypes at distinct linkage disequilibrium blocks predict these phenotypes.

METHODS AND RESULTS

Using 24 single-nucleotide polymorphisms genotyped in white patients without diabetes mellitus, we reconstructed haplotypes at the 9p21 locus. Patients with angiograhic CAD/MI had ≥1 epicardial stenosis >50% (n=2352), whereas controls were asymptomatic and over the age of 60 years (n=2116). For CAD patients, regression models examined the association of haplotypes with initial age of symptomatic CAD, number of diseased vessels, and history of MI. In the case-control study, only haplotypes at 1 block tagged by rs1333049 associated with CAD more so than MI. These haplotypes also associated with early onset of CAD (β=-0.13; P=1.37×10(-4)) and disease severity (β=0.1823; P=0.006) but not with prevalent MI among patients with CAD. In contrast, haplotypes at another block tagged by rs518394 associated with prevalent MI (β=0.239; P=2.05×10(-4)), but remarkably these are inversely associated with disease severity (β=-0.196; P=0.003). This MI association was replicated in the Cleveland Clinic GeneBank premature CAD cohort (n=1385; β=0.207; P=0.019).

CONCLUSIONS

Variants/haplotypes at 2 blocks are distinguished at 9p21; those at 1 block predispose to atherosclerosis, whereas those at the other predispose to MI among patients with preexisting CAD.

Neurologic safety event rates in the SENTIS trial control population

BACKGROUND

Adverse event (AE) rates for interventional stroke trials are not well established.

AIMS

We prospectively evaluated control arm AEs from a randomized stroke trial to establish expected rates of neurologic AEs.

METHODS

Control data from the Safety and Efficacy of NeuroFlo Technology in Ischemic Stroke (SENTIS) Trial were evaluated. Patients were ≥ 18 years with National Institutes of Health Stroke Scale (NIHSS) scores 5-18 within 14 h of stroke onset. Follow-up was 90 days. Neurological AEs and serious AEs (SAEs) were adjudicated and the following defined times used to determine treatment relatedness: 24-h imaging for intracranial hemorrhage (ICnH) including hemorrhagic transformation, 7 days each for cerebral edema and neurologic worsening/stroke progression, and 30 days for new ischemic strokes.

RESULTS

The control group included 257 patients, 49.4% female, mean age of 68.3 years, and median NIHSS of 10. Neurologic AEs occurred at the following rates: ICnH 27.6%, cerebral edema 6.6%, neurologic worsening 18.3%, and new stroke 4.7%. Most of these events occurred within the defined times: ICnH 74.6%, cerebral edema 94.1%, neurologic worsening 87.2%, and new stroke 83.3%.

CONCLUSIONS

SENTIS Trial control arm neurologic events provide estimates of expected AE rates and defined times that can be used for future stroke trial's safety assessments.

Assessment of the 9p21.3 locus in severity of coronary artery disease in the presence and absence of type 2 diabetes

BACKGROUND

The 9p21.3 locus is strongly associated with the risk of coronary artery disease (CAD) and with type 2 diabetes (T2D). We investigated the association of 9p21.3 variants with severity of CAD (defined by the number of vessel diseased [VD]) in the presence and absence of T2D.

METHODS

We tested 11 9p21.3-variants for association in a white Italian study (N = 2,908), and carried out replication in 2 independent white populations, a German study (N = 2,028) and a Canadian Study (N=950). SNP association and permutation analyses were conducted.

RESULTS

We identified two 9p21.3-variants, rs4977574 (P < 4×10(-4)) and rs2383207 (P < 1.5×10(-3)) that were associated with severity of CAD in subjects without T2D. Association of rs4977574 with severity of CAD was confirmed in the Canadian Study. Results from subgroup analysis among patients with T2D showed an interaction between rs10738610 and T2D with P = 4.82×10(-2). Further investigation showed that rs10738610 (P < 1.99×10(-2)) was found to be significantly associated with severity of CAD in subjects with T2D.

CONCLUSIONS

The 9p21.3 locus is significantly associated with severity of CAD. The number of associations of 9p21.3 variants with severity of CAD is variable to the presence and absence of T2D. In a CAD-susceptible region of 115 kb, there is only one variant associated with the severity of coronary vessel disease in the presence of type 2 diabetes.

Large-scale association analysis identifies new risk loci for coronary artery disease

Coronary artery disease (CAD) is the commonest cause of death. Here, we report an association analysis in 63,746 CAD cases and 130,681 controls identifying 15 loci reaching genome-wide significance, taking the number of susceptibility loci for CAD to 46, and a further 104 independent variants (r(2) < 0.2) strongly associated with CAD at a 5% false discovery rate (FDR). Together, these variants explain approximately 10.6% of CAD heritability. Of the 46 genome-wide significant lead SNPs, 12 show a significant association with a lipid trait, and 5 show a significant association with blood pressure, but none is significantly associated with diabetes. Network analysis with 233 candidate genes (loci at 10% FDR) generated 5 interaction networks comprising 85% of these putative genes involved in CAD. The four most significant pathways mapping to these networks are linked to lipid metabolism and inflammation, underscoring the causal role of these activities in the genetic etiology of CAD. Our study provides insights into the genetic basis of CAD and identifies key biological pathways.

Allergic Rhinitis and its Impact on Asthma (ARIA): achievements in 10 years and future needs

Allergic rhinitis (AR) and asthma represent global health problems for all age groups. Asthma and rhinitis frequently coexist in the same subjects. Allergic Rhinitis and its Impact on Asthma (ARIA) was initiated during a World Health Organization workshop in 1999 (published in 2001). ARIA has reclassified AR as mild/moderate-severe and intermittent/persistent. This classification closely reflects patients' needs and underlines the close relationship between rhinitis and asthma. Patients, clinicians, and other health care professionals are confronted with various treatment choices for the management of AR. This contributes to considerable variation in clinical practice, and worldwide, patients, clinicians, and other health care professionals are faced with uncertainty about the relative merits and downsides of the various treatment options. In its 2010 Revision, ARIA developed clinical practice guidelines for the management of AR and asthma comorbidities based on the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system. ARIA is disseminated and implemented in more than 50 countries of the world. Ten years after the publication of the ARIA World Health Organization workshop report, it is important to make a summary of its achievements and identify the still unmet clinical, research, and implementation needs to strengthen the 2011 European Union Priority on allergy and asthma in children.

Acute generalised exanthematous pustulosis secondary to cotrimoxazole or tenofovir

Cutaneous adverse drug reactions are a common complication of antiretroviral therapy and of drugs used to treat opportunistic infections. We present a rare case of acute generalised exanthematous pustulosis secondary to cotrimoxazole or tenofovir.

Clinical and genetic association of serum paraoxonase and arylesterase activities with cardiovascular risk

OBJECTIVE

Diminished serum paraoxonase and arylesterase activities (measures of paraoxonase-1 [PON-1] function) in humans have been linked to heightened systemic oxidative stress and atherosclerosis risk. The clinical prognostic use of measuring distinct PON-1 activities has not been established, and the genetic determinants of PON-1 activities are not known.

METHODS AND RESULTS

We established analytically robust high-throughput assays for serum paraoxonase and arylesterase activities and measured these in 3668 stable subjects undergoing elective coronary angiography without acute coronary syndrome and were prospectively followed for major adverse cardiovascular events (MACE= death, myocardial infarction, stroke) over 3 years. Low serum arylesterase and paraoxonase activities were both associated with increased risk for MACE, with arylesterase activity showing greatest prognostic value (quartile 4 versus quartile 1; hazard ratio 2.63; 95% CI, 1.97-3.50; P<0.01). Arylesterase remained significant after adjusting for traditional risk factors, C-reactive protein, and creatinine clearance (hazard ratio, 2.20; 95% CI, 1.60-3.02; P<0.01), predicted future development of MACE in both primary and secondary prevention populations, and reclassified risk categories incrementally to traditional clinical variables. A genome-wide association study identified distinct single nucleotide polymorphisms within the PON-1 gene that were highly significantly associated with serum paraoxonase (1.18×10(-303)) or arylesterase (4.99×10(-116)) activity but these variants were not associated with either 3-year MACE risk in an angiographic cohort (n=2136) or history of either coronary artery disease or myocardial infarction in the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis consortium (n≈80 000 subjects).

CONCLUSIONS

Diminished serum arylesterase activity, but not the genetic determinants of PON-1 functional measures, provides incremental prognostic value and clinical reclassification of stable subjects at risk of developing MACE.

Severe chronic allergic (and related) diseases: a uniform approach--a MeDALL--GA2LEN--ARIA position paper

Concepts of disease severity, activity, control and responsiveness to treatment are linked but different. Severity refers to the loss of function of the organs induced by the disease process or to the occurrence of severe acute exacerbations. Severity may vary over time and needs regular follow-up. Control is the degree to which therapy goals are currently met. These concepts have evolved over time for asthma in guidelines, task forces or consensus meetings. The aim of this paper is to generalize the approach of the uniform definition of severe asthma presented to WHO for chronic allergic and associated diseases (rhinitis, chronic rhinosinusitis, chronic urticaria and atopic dermatitis) in order to have a uniform definition of severity, control and risk, usable in most situations. It is based on the appropriate diagnosis, availability and accessibility of treatments, treatment responsiveness and associated factors such as comorbidities and risk factors. This uniform definition will allow a better definition of the phenotypes of severe allergic (and related) diseases for clinical practice, research (including epidemiology), public health purposes, education and the discovery of novel therapies.

Plasma HDL cholesterol and risk of myocardial infarction: a mendelian randomisation study

BACKGROUND

High plasma HDL cholesterol is associated with reduced risk of myocardial infarction, but whether this association is causal is unclear. Exploiting the fact that genotypes are randomly assigned at meiosis, are independent of non-genetic confounding, and are unmodified by disease processes, mendelian randomisation can be used to test the hypothesis that the association of a plasma biomarker with disease is causal.

METHODS

We performed two mendelian randomisation analyses. First, we used as an instrument a single nucleotide polymorphism (SNP) in the endothelial lipase gene (LIPG Asn396Ser) and tested this SNP in 20 studies (20,913 myocardial infarction cases, 95,407 controls). Second, we used as an instrument a genetic score consisting of 14 common SNPs that exclusively associate with HDL cholesterol and tested this score in up to 12,482 cases of myocardial infarction and 41,331 controls. As a positive control, we also tested a genetic score of 13 common SNPs exclusively associated with LDL cholesterol.

FINDINGS

Carriers of the LIPG 396Ser allele (2·6% frequency) had higher HDL cholesterol (0·14 mmol/L higher, p=8×10(-13)) but similar levels of other lipid and non-lipid risk factors for myocardial infarction compared with non-carriers. This difference in HDL cholesterol is expected to decrease risk of myocardial infarction by 13% (odds ratio [OR] 0·87, 95% CI 0·84-0·91). However, we noted that the 396Ser allele was not associated with risk of myocardial infarction (OR 0·99, 95% CI 0·88-1·11, p=0·85). From observational epidemiology, an increase of 1 SD in HDL cholesterol was associated with reduced risk of myocardial infarction (OR 0·62, 95% CI 0·58-0·66). However, a 1 SD increase in HDL cholesterol due to genetic score was not associated with risk of myocardial infarction (OR 0·93, 95% CI 0·68-1·26, p=0·63). For LDL cholesterol, the estimate from observational epidemiology (a 1 SD increase in LDL cholesterol associated with OR 1·54, 95% CI 1·45-1·63) was concordant with that from genetic score (OR 2·13, 95% CI 1·69-2·69, p=2×10(-10)).

INTERPRETATION

Some genetic mechanisms that raise plasma HDL cholesterol do not seem to lower risk of myocardial infarction. These data challenge the concept that raising of plasma HDL cholesterol will uniformly translate into reductions in risk of myocardial infarction.

FUNDING

US National Institutes of Health, The Wellcome Trust, European Union, British Heart Foundation, and the German Federal Ministry of Education and Research.

Not hysteria: ovarian teratoma-associated anti-N-methyl-D-aspartate receptor encephalitis

We report a case of a 33-year-old nulliparous woman who, following a short prodromal illness, experienced a series of psychiatric and behavioural symptoms. These included states of terror, insomnia, delirium, self-harm and suicidal ideation, facial dyskinesias, verbigeration, cognitive impairment, reduced responsiveness, violence and paranoia. A diagnosis of anti-N-methyl-d-aspartate (NMDAR) encephalitis was made 50 days after symptom onset. Early tumour removal is associated with an improved prognosis and a laparoscopic oophorectomy was performed following detection of a dermoid cyst. Within 24 hours of the operation there was marked improvement in cognitive function and appetite.