Association of four-locus gene interaction with aspirin-intolerant asthma in Korean asthmatics

Association of Extracellular Signal-Regulated Kinase Genes With Myopia: A Longitudinal Study of Chinese Children

Objective

The present study was designed to investigate whether the extracellular signal-regulated kinase (ERK) signaling pathway, a downstream component of dopamine signaling, is involved in myopia among Chinese children.

Methods

During a 3.5-year follow-up, 488 primary school students were enrolled in this study. Non-cycloplegic spherical equivalent refraction (SE) and other ocular parameters were assessed. Four variants of four genes in the ERK signaling pathway were selected: RASGRF1 rs6495367, PTPN5 rs1550870, PTPRR rs11178469, and PDGFRA rs6554163. SNPscan was used to genotype single-nucleotide polymorphisms (SNPs). PLINK software was used to assess the associations of the genetic variants with the occurrence or development of myopia, SE, and other ocular parameters. We created a protein-protein interaction (PPI) network and microRNA (miRNA)-gene network using String and Cytoscape and conducted enrichment analyses on the genes in these networks.

Results

In total, 426 children (baseline age: 7.28 ± 0.26 years; 236 (55.4%) boys and 190 girls) wereenrolled. After adjusting for confounding factors with 10,000 permutations, children with the CT or TT genotype of PTPN5 rs1550870 were more susceptible to myopia than those with the CC genotype (adjusted p = 0.011). Additionally, PTPN5 rs1550870 was correlated with significant myopic shift and increasing axial length (AL) and lens thickness (LT) but had a negative effect on central corneal thickness (CCT). RASGRF1 rs6495367 was negatively associated with myopic shift (additive: adjusted p = 0.034; dominant: adjusted p = 0.020), myopic SE and AL. PDGFRA rs6554163 TA or AA was negatively associated with increasing LT (adjusted p = 0.033). Evaluation of the effects of SNP-SNP combinations on incident myopia revealed a statistically significant one-locus model: PTPN5 rs1550870 [cross-validation consistency (CVC) = 10/10, adjusted p = 0.0107]. The genes in the PPI and miRNA-gene interaction networks were subjected to enrichment analyses, which suggested that these genes are involved mainly in eye development and dopaminergic synapse-related processes.

Conclusion

We identified genetic variants of crucial ERK signaling pathway genes that were significantly correlated with myopia and ocular parameter alterations in Chinese children. A combination of gene and miRNA functional analyses with enrichment analyses highlights the regulatory effects associated with ocular development and dopamine biological functions. This study offers novel clues to understand the role of dopamine in the molecular mechanisms of myopia.

NSAID-Exacerbated Respiratory Disease (NERD): From Pathogenesis to Improved Care

Nonsteroidal antiinflammatory drug (NSAID)-exacerbated respiratory disease (NERD) is characterized by moderate-to-severe asthma and a higher prevalence of chronic rhinosinusitis/nasal polyps, but is a highly heterogeneous disorder with various clinical manifestations. Two major pathogenic mechanisms are: (1) overproduction of cysteinyl leukotrienes with dysregulation of arachidonic acid metabolism and (2) increased type 2 eosinophilic inflammation affected by genetic mechanisms. Aspirin challenge is the gold standard to diagnose NERD, whereas reliable in vitro biomarkers have yet not been identified. Therapeutic approaches have been done on the basis of disease severity with the avoidance of culprit and cross-reacting NSAIDs, and when indicated, aspirin desensitization is an effective treatment option. Biologic approaches targeting Type 2 cytokines are emerging as potential therapeutic options. Here, we summarize the up-to-date evidence of pathophysiologic mechanisms and diagnosis/management approaches to the patients with NERD with its phenotypic classification.

Potential Biomarkers for NSAID-Exacerbated Respiratory Disease

Asthma is a common chronic disease with several variant phenotypes and endotypes. NSAID-exacerbated respiratory disease (NERD) is one such endotype characterized by asthma, chronic rhinosinusitis (CRS) with nasal polyps, and hypersensitivity to aspirin/cyclooxygenase-1 inhibitors. NERD is more associated with severe asthma than other asthma phenotypes. Regarding diagnosis, aspirin challenge tests via the oral or bronchial route are a standard diagnostic method; reliable in vitro diagnostic tests are not available. Recent studies have reported various biomarkers of phenotype, diagnosis, and prognosis. In this review, we summarized the known potential biomarkers of NERD that are distinct from those of aspirin-tolerant asthma. We also provided an overview of the different NERD subgroups.

Novel genetic associations and gene-gene interactions of chemokine receptor and chemokine genetic polymorphisms in HIV/AIDS

OBJECTIVE

To investigate the influence of candidate polymorphisms on chemokine receptor/ligand genes on HIV infection and AIDS progression (HIV/AIDS).

DESIGN

Fifteen polymorphisms of the CCR3, CCR4, CCR5, CCR6, CCR8, CXCR3, CXCR6, CCL20, CCL22 and CXCL10 genes were analysed in 206 HIV-positive patients classified as rapid progressors (n = 40), or nonrapid progressors (n = 166), and in 294 HIV-seronegative patients.

METHODS

The polymorphisms were genotyped using minisequencing. Genetic models were tested using binomial logistic regression; nonparametric multifactor dimensionality reduction (MDR) was used to detect gene-gene interactions.

RESULTS

The CCR3 rs3091250 [TT, adjusted odds ratio (AOR): 2.147, 95% confidence interval (CI) 1.076-4.287, P = 0.030], CCR8 rs2853699 (GC/CC, AOR: 1.577, 95% CI 1.049-2.371, P = 0.029), CXCL10 rs56061981 (CT/TT, AOR: 1.819, 95% CI 1.074-3.081, P = 0.026) and CCL22 rs4359426 (CA/AA, AOR: 1.887, 95% CI 1.021-3.487, P = 0.043) polymorphisms were associated with susceptibility to HIV infection. The CCL20 rs13034664 (CC, OR: 0.214, 95% CI 0.063-0.730, P = 0.014) and CCL22 rs4359426 (CA/AA, OR: 2.685, 95% CI 1.128-6.392, P = 0.026) variants were associated with rapid progression to AIDS. In MDR analyses revealed that the CXCL10 rs56061981 and CCL22 rs4359426 combination was the best model, with 57% accuracy (P = 0.008) for predicting susceptibility to HIV infection.

CONCLUSION

Our results provide new insights into the influence of candidate chemokine receptor/ligand polymorphisms and significant evidence for gene-gene interactions on HIV/AIDS susceptibility.

Integrative information theoretic network analysis for genome-wide association study of aspirin exacerbated respiratory disease in Korean population

BACKGROUND

Aspirin Exacerbated Respiratory Disease (AERD) is a chronic medical condition that encompasses asthma, nasal polyposis, and hypersensitivity to aspirin and other non-steroidal anti-inflammatory drugs. Several previous studies have shown that part of the genetic effects of the disease may be induced by the interaction of multiple genetic variants. However, heavy computational cost as well as the complexity of the underlying biological mechanism has prevented a thorough investigation of epistatic interactions and thus most previous studies have typically considered only a small number of genetic variants at a time.

METHODS

In this study, we propose a gene network based analysis framework to identify genetic risk factors from a genome-wide association study dataset. We first derive multiple single nucleotide polymorphisms (SNP)-based epistasis networks that consider marginal and epistatic effects by using different information theoretic measures. Each SNP epistasis network is converted into a gene-gene interaction network, and the resulting gene networks are combined as one for downstream analysis. The integrated network is validated on existing knowledgebase of DisGeNET for known gene-disease associations and GeneMANIA for biological function prediction.

RESULTS

We demonstrated our proposed method on a Korean GWAS dataset, which has genotype information of 440,094 SNPs for 188 cases and 247 controls. The topological properties of the generated networks are examined for scale-freeness, and we further performed various statistical analyses in the Allergy and Asthma Portal (AAP) using the selected genes from our integrated network.

CONCLUSIONS

Our result reveals that there are several gene modules in the network that are of biological significance and have evidence for controlling susceptibility and being related to the treatment of AERD.

Recent advance in investigation of gene polymorphisms in Japanese patients with aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) is a complex clinical syndrome characterised by severe asthmatic attack upon treatment with aspirin and/or non-steroidal anti-inflammatory drugs (NSAIDs). Genetic predisposition has been considered as a crucial determinant and candidate genes have concentrated especially on cysteinyl leukotrienes (LTs)-related genes as the inhibitory action of aspirin and NSAIDs on cyclooxygenase activity may cause overproduction of cysteinyl LTs. However, conflicting results have been reported, in parallel with replication studies in different ethnic groups. Thus, future areas of investigations need to focus on comprehensive approaches towards the discovery of other genetic biomarkers. Unfortunately, few papers have been reported about gene polymorphisms in Japanese patients with AERD. Here, we described on our recent genetic investigations on B2ADR, IL-13, IL-17A, CYP2C19, TBXA2R, CRTH2 and HSP70. This review indicates potential genetic biomarkers contributing to the early diagnosis of AERD, which may include CYP2C19 and HSP70 gene polymorphisms, and future validation studies in independent population are required to provide reassurance about our findings.

Polymorphisms in catechol-O-methyltransferase modify treatment effects of aspirin on risk of cardiovascular disease

OBJECTIVE

Catechol-O-methyltransferase (COMT), a key enzyme in catecholamine metabolism, is implicated in cardiovascular, sympathetic, and endocrine pathways. This study aimed to confirm preliminary association of COMT genetic variation with incident cardiovascular disease (CVD). It further aimed to evaluate whether aspirin, a commonly used CVD prevention agent, modified the potential association of COMT with incident CVD.

APPROACH AND RESULTS

We examined COMT polymorphism rs4680 (MAF [minor allele frequency], 0.47), encoding a nonsynonymous methionine-to-valine substitution, in the Women's Genome Health Study (WGHS), a large population-based cohort of women with randomized allocation to aspirin or vitamin E when compared with placebo and 10-year follow-up. Rs4680 effects were confirmed with COMT polymorphism rs4818 and also examined in Coronary ARtery DIsease Genome-wide Replication and Meta-analysis/The Coronary Artery Disease Genetics Consortium, consortia for genome-wide association studies of coronary artery disease. Among WGHS women allocated to placebo (135 events/n=5811), the rs4680 valine allele was protective against incident CVD relative to the methionine (hazard ratio [HR; 95% confidence interval {CI}], 0.66 [0.51-0.84]; P=0.0007); an association also observed in Coronary ARtery DIsease Genome-wide Replication and Meta-analysis and The Coronary Artery Disease Genetics Consortium (combined P=2.4×10(-5)). In the WGHS, the rs4680 association was abolished by randomized allocation to aspirin, such that valine/valine women experienced higher CVD rates with aspirin allocation when compared with placebo (HR [95% CI], 1.85 [1.05-3.25]; P=0.033), whereas methionine/methionine women experienced lower rates (HR [95% CI], 0.60 [0.39-0.93]; P=0.023). Allocation to vitamin E also conferred higher but nonsignificant CVD rates on valine/valine (HR [95% CI], 1.50 [0.83-2.70]; P=0.180) when compared with significantly lower rates on methionine/methionine (HR [95% CI], 0.53 [0.34-0.84]; P=0.006) women. Rs4818 results were similar.

CONCLUSIONS

Common COMT polymorphisms were associated with incident CVD, and this association was modified by randomized allocation to aspirin or vitamin E. Replication of these findings is required.

CC chemokine receptor-3 as new target for age-related macular degeneration

CC chemokine receptor-3 (CCR3) is involved in angiogenic processes. Recently, CCR3 was accounted to participate in choroidal neovascularization (CNV) and CCR3 targeting was reported to be superior to standard antivascular endothelial growth factor-A (VEGF-A) administration when tested in an artificially induced CNV in animals. As human CCR3 studies are lacking in age-related macular degeneration (AMD) patients we sought to determine if CCR3 has any association with inflammatory processes that occur in CNV. A total of 176 subjects were included on the basis of inclusion criteria. Real time PCR was used to analyze the single nucleotide polymorphism in CCR3 of AMD (115) and normal controls (n=61). Genotype frequency was adjusted for possible confounders like cigarette smoking, alcohol, meat consumption and other risk factors. Chi-square test was used for analysis of polymorphism. The genotype distribution of CCR3 (rs3091250) polymorphism was significantly different in AMD patients in the Indian population. GT (heterozygous) and TT (homozygous) at the rs3091250 SNP increased risk of AMD as compared to the GG genotypes (OR=4.8, CI 95%=2.2-10.8 and OR=4.1, CI 95%=1.6-10.1 respectively). Subgroup analysis of AMD patients in wet and dry revealed no significant differences. There was no significant difference for rs3091312 in AMD and control group. A significant association between AMD and CCR3 (rs3091250) polymorphism localized on chromosome 3p21.3 was detected. The results suggest the possible contribution of rs3091250, a new predisposing allele in AMD.

Genetics of hypersensitivity to aspirin and nonsteroidal anti-inflammatory drugs

Various hypersensitivity reactions have been reported with aspirin and nonsteroidal anti-inflammatory drugs. Hypersensitivity can occur regardless of a chemical drug structure or its therapeutic potency. Allergic conditions include aspirin-exacerbated respiratory disease (AERD or aspirin-induced asthma), aspirin-induced urticaria/angioedema (AIU), and anaphylaxis. Several genetic studies on aspirin hypersensitivity have been performed to discover the genetic predisposition to aspirin hypersensitivity and to gain insight into the phenotypic diversity. This article updates data on the genetic mechanisms that govern AERD and AIU and summarizes recent findings on the molecular genetic mechanism of aspirin hypersensitivity.

Current view on nasal polyps management in Samter's triad patients

The nasal polyps associated with Samter's triad are often very extensive, difficult to treat, with great tendency to recurrence. In this paper the current opinion on nasal polyps management in aspirin triad patients was presented.

PATHOGENESIS

Opinions on pathogenesis of these disease was remembered as well as its epidemiology.

DIAGNOSTIC METHODS

The available diagnostic methods were presented. Treatment options: The available preservative treatment options was analyzed including aspirin desensitization. The role of surgical treatment, functional endoscopic sinus surgery was analyzed.

Perinatal gene-gene and gene-environment interactions on IgE production and asthma development

Atopic asthma is a complex disease associated with IgE-mediated immune reactions. Numerous genome-wide studies identified more than 100 genes in 22 chromosomes associated with atopic asthma, and different genetic backgrounds in different environments could modulate susceptibility to atopic asthma. Current knowledge emphasizes the effect of tobacco smoke on the development of childhood asthma. This suggests that asthma, although heritable, is significantly affected by gene-gene and gene-environment interactions. Evidence has recently shown that molecular mechanism of a complex disease may be limited to not only DNA sequence differences, but also gene-environmental interactions for epigenetic difference. This paper reviews and summarizes how gene-gene and gene-environment interactions affect IgE production and the development of atopic asthma in prenatal and childhood stages. Based on the mechanisms responsible for perinatal gene-environment interactions on IgE production and development of asthma, we formulate several potential strategies to prevent the development of asthma in the perinatal stage.

Flow Cytometry-Assisted Basophil Activation Test as a Safe Diagnostic Tool for Aspirin/NSAID Hypersenstivity

Purpose

Aspirin and non-steroidal anti-inflammatory drugs (ASA/NSAIDs) are common causes of drug hypersensitivity. An oral provocation test is the only definitive diagnostic test. This study assessed the reliability of a flow cytometry-assisted basophil activation test (FAST) as a safe diagnostic method for ASA/NSAID-induced hypersensitivity, as its high sensitivity and specificity have been demonstrated for many other drugs.

Methods

Eighteen patients and 11 controls were enrolled. Using a Flow-CAST kit® (Bühlmann Laboratories AG, Schönenbuch, Switzerland), 29 analyses with aspirin, ibuprofen, and diclofenac were performed by flow cytometry to detect double-positive staining of anti-IgE and anti-CD63. The stimulation index was defined as the activated basophil percentage after drug stimulation/basally active basophil percentage. A stimulation index≥2 and an absolute activated basophil percentage≥5 were considered positive.

Results

Patients with hypersensitivity to ASA/NSAIDs were predominantly female, and the prevalence of atopy was higher in patients than in controls. A sensitivity of 61%, specificity of 91%, positive predictive value of 92%, and negative predictive value of 59% were achieved.

Conclusions

FAST is a useful additional method for diagnosis of hypersensitivity reactions to ASA/NSAIDs. Further development is required to increase the sensitivity of the test.

Arg16Gly β2-adrenergic receptor gene polymorphism in Japanese patients with aspirin-exacerbated respiratory disease

BACKGROUND

There has been no report that investigated β(2)-adrenergic receptor (ADRB2) gene polymorphism in patients with aspirin-exacerbated respiratory disease (AERD).

METHODS

DNA in the specimens in three groups of study subjects classified patients with AERD, patients with aspirin-tolerant asthma (ATA) and normal controls was extracted, and the target DNA sequence of the ADRB2 was amplified using a set of primers to generate an amplicon of 219 bp in length. Allelic discrimination assay for single nucleotide polymorphisms relating to the ADRB2 gene expression was carried out by using a previously described single nucleotide polymorphism detective system, sequence-specific thermal-elution chromatography.

RESULTS

The frequency of the Gly variant allele in patients with AERD was significantly lower than that in patients with ATA (p = 0.007), and the odds ratio (OR) of AERD to ATA associated with wild-type ArgArg homozygote was 3.300. Frequencies of wild-type ArgArg homozygote are significantly higher than those of variant-type ArgGly/GlyGly genotype in patients with AERD compared with those with ATA (p < 0.001, OR = 3.153). In patients with AERD, frequencies of wild-type ArgArg homozygote in both female and male patients are significantly higher than those of variant-type ArgGly/GlyGly genotype in male patients compared with those with ATA (p < 0.001, OR = 5.128 and p = 0.007, OR = 4.367, respectively). Also, in patients with AERD, frequencies of wild-type ArgArg homozygote in female patients are significantly higher than those of variant-type ArgGly/GlyGly genotype in female patients compared with those with ATA (p = 0.002, OR = 2.825).

CONCLUSIONS

We were the first to analyze Arg16Gly ADRB2 gene polymorphism in Japanese patients with AERD, and showed that Arg16Gly ADRB2 gene polymorphism in Japanese patients with AERD is different from that in the patients with ATA.

Genetic mechanisms in aspirin-exacerbated respiratory disease

Aspirin-exacerbated respiratory disease (AERD) refers to the development of bronchoconstriction in asthmatics following the exposure to aspirin or other nonsteroidal anti-inflammatory drugs. The key pathogenic mechanisms associated with AERD are the overproduction of cysteinyl leukotrienes (CysLTs) and increased CysLTR1 expression in the airway mucosa and decreased lipoxin and PGE2 synthesis. Genetic studies have suggested a role for variability of genes in disease susceptibility and the response to medication. Potential genetic biomarkers contributing to the AERD phenotype include HLA-DPB1, LTC4S, ALOX5, CYSLT, PGE2, TBXA2R, TBX21, MS4A2, IL10, ACE, IL13, KIF3A, SLC22A2, CEP68, PTGER, and CRTH2 and a four-locus SNP set composed of B2ADR, CCR3, CysLTR1, and FCER1B. Future areas of investigation need to focus on comprehensive approaches to identifying biomarkers for early diagnosis.

Update on recent advances in the management of aspirin exacerbated respiratory disease

Aspirin intolerant asthma (AIA) is frequently characterized as an aspirin (ASA)-exacerbated respiratory disease (AERD). It is a clinical syndrome associated with chronic severe inflammation in the upper and lower airways resulting in chronic rhinitis, sinusitis, recurrent polyposis, and asthma. AERD generally develops secondary to abnormalities in inflammatory mediators and arachidonic acid biosynthesis expression. Upper and lower airway eosinophil infiltration is a key feature of AERD; however, the exact mechanisms of such chronic eosinophilic inflammation are not fully understood. Cysteinyl leukotriene over-production may be a key factor in the induction of eosinophilic activation. Genetic studies have suggested a role for variability of genes in disease susceptibility and response to medication. Potential genetic biomarkers contributing to the AERD phenotype include HLA-DPB1*301, LTC4S, ALOX5, CYSLT, PGE2, TBXA2R, TBX21, MS4A2, IL10 -1082A > G, ACE -262A > T, and CRTH2 -466T > C; the four-locus SNP set was composed of B2ADR 46A > G, CCR3 -520T > G, CysLTR1 -634C > T, and FCER1B -109T > C. Management of AERD is an important issue. Aspirin ingestion may result in significant morbidity and mortality, and patients must be advised regarding aspirin risk. Leukotriene receptor antagonists (LTRA) that inhibit leukotriene pathways have an established role in long-term AERD management and rhinosinusitis. Aspirin desensitization may be required for the relief of upper and lower airway symptoms in AERD patients. Future research should focus on identification of biomarkers for a comprehensive diagnostic approach.

Analysis of interactions between genetic variants of BMP4 and environmental factors with nonsyndromic cleft lip with or without cleft palate susceptibility

A hospital-based case-control study was conducted to identify interactions between the 538(T-->C) polymorphic site of bone morphogenetic protein 4 gene (BMP4T538C) and exposures in pregnancy with nonsyndromic cleft lip, with or without cleft palate (nsCL/P). Associations between offspring polymorphism of BMP4T538C, paternal smoking, paternal high-risk drinking, maternal passive smoking, and maternal multivitamin supplement with nsCL/P were analyzed by logistic regression analysis. BMP4T538C polymorphism, maternal passive smoking exposures and maternal multivitamin use were associated with the risk of nsCL/P but paternal smoking and paternal high-risk drinking were not. Gene-environment interactions were analyzed using the multifactor dimensionality reduction (MDR) method. The two-factor model including maternal passive smoking and BMP4T538C, was the best for predicting nsCL/P risk with a maximum cross-validation consistency (10/10) and a maximum average testing accuracy(0.605; P<0.0001). The findings suggested that: BMP4T538C could be used as a genetic susceptibility marker for nsCL/P; maternal passive smoking exposure is a risk factor for nsCL/P; maternal multivitamin supplements are a protective factor; the synergistic effect of BMP4T538C and maternal passive smoking could provide a new tool for identifying individuals at high risk of nsCL/P, and provides additional evidence that nsCL/P is determined by genetic and environmental factors.

Leukotriene C4 synthase and ischemic cardiovascular disease and obstructive pulmonary disease in 13,000 individuals

Ischemic cardiovascular disease and obstructive pulmonary disease involve inflammation. Leukotrienes may be important pro-inflammatory mediators. We tested the hypothesis that the (-1072)G > A and (-444)A > C promoter polymorphisms of leukotriene C4 synthase confer risk of transient ischemic attack (TIA), ischemic stroke, ischemic heart disease (IHD), asthma, and chronic obstructive pulmonary disease (COPD). We genotyped individuals from the Danish general population, the Copenhagen City Heart Study, and Danish patients with IHD/coronary atherosclerosis, the Copenhagen Ischemic Heart Disease Study. We used prospective (n = 10,386), cross-sectional (n = 10,386), and case-control (n = 2392 + 5012) designs. Allele frequency was 0.07 for (-1072)A and 0.29 for (-444)C. Cumulative incidence for TIA was higher for (-1072)AA versus GG genotype (log-rank: p < 0.001), and lower for (-444)CC versus AA genotype (log-rank: p = 0.03). Cumulative incidence for ischemic stroke was also lower for (-444)CC versus AA genotype (log-rank: p = 0.04). Multifactorially adjusted hazard ratios for TIA were 5.2(95% CI:1.9-14) for (-1072)AA versus GG genotype, and 0.4(0.2-1.0) for (-444)CC versus AA genotype. Corresponding values were 1.9 (0.7-5.2) and 0.7 (0.5-1.0) for ischemic stroke, and 0.8 (0.4-1.6) and 1.0 (0.9-1.2) for IHD. In the case-control study, corresponding multifactorially adjusted odds ratios for IHD/coronary atherosclerosis were 0.5 (0.2-1.3) and 1.2 (1.0-1.5). These genotypes were not associated with risk of asthma or COPD. Leukotriene C4 synthase promoter genotypes influence risk of TIA and ischemic stroke, but not risk of IHD/coronary atherosclerosis, asthma, or COPD.

Genetic susceptibility to schizophrenia: role of dopaminergic pathway gene polymorphisms

Aim: We investigated 16 polymorphisms from three genes, dopamine receptor D2 (DRD2), catechol-O-methyl transferase (COMT) and brain derived neurotrophic factor (BDNF), which are involved in the dopaminergic pathways, and have been reported to be associated with susceptibility to schizophrenia and response to antipsychotic therapy. Materials & methods: Single-locus association analyses of these polymorphisms were carried out in 254 patients with schizophrenia and 225 controls, all of southern Indian origin. Additionally, multifactor-dimensionality reduction analysis was performed in 422 samples (243 cases and 179 controls) to examine the gene–gene interactions and to identify combinations of multilocus genotypes associated with either high or low risk for the disease. Results: Our results demonstrated initial significant associations of two SNPs for DRD2 (rs11608185, genotype: χ2 = 6.29, p-value = 0.043; rs6275, genotype: χ2 = 8.91, p-value = 0.011), and one SNP in the COMT gene (rs4680, genotype: χ2 = 6.67, p-value = 0.035 and allele: χ2 = 4.75, p-value = 0.029; odds ratio: 1.33, 95% confidence interval: 1.02–1.73), but not after correction for multiple comparisons indicating a weak association of individual markers of DRD2 and COMT with schizophrenia. Multifactor-dimensionality reduction analysis suggested a two locus model (rs6275/DRD2 and rs4680/COMT) as the best model for gene–gene interaction with 90% cross-validation consistency and 42.42% prediction error in predicting disease risk among schizophrenia patients. Conclusion: The present study thus emphasizes the need for multigene interaction studies in complex disorders such as schizophrenia and to understand response to drug treatment, which could lead to a targeted and more effective treatment.

What do we know about the genetics of aspirin intolerance?

Although acetylsalicylic acid is prescribed for a broad range of diseases, it can induce a wide array of clinically recognized hypersensitivity reactions, including aspirin-intolerant asthma (AIA) with rhinitis and aspirin-intolerant urticaria (AIU) with anaphylaxis. Altered eicosanoid metabolism is the generally accepted mechanism of aspirin intolerance; the overproduction of cysteinyl leucotrienes has been suggested to play a causative role in both AIA and AIU. Genetic markers suggested for AIA include HLA-DPBI*0301, leucotriene C4 synthase (LTC4S), ALOX5, CYSLT, PGE2, TBXA2R and TBX21. Similarly, HLA-DB1*0609, ALOX5, FCER1A and HNMT have been identified as possible genetic markers for AIU. An additional low-risk genetic marker for AIA is MS4A2, which encodes the beta-chain of FCER1. Other single and sets of two or more interacting genetic markers are currently being investigated. Analyses of the genetic backgrounds of patients with AIA and AIU will promote the development of early diagnostic and therapeutic interventions, which may reduce the incidence of AIA and AIU.