PPARG2 Pro12Ala and ADAMTS9 rs4607103 as "insulin resistance loci" and "insulin secretion loci" in Italian individuals. The GENFIEV study and the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 4.

We investigated cross-sectionally whether the type 2 diabetes (T2DM) risk alleles of rs1801282 (PPARG2) and rs4607103 (ADAMTS9) were associated with T2DM and/or insulin sensitivity (IS) and beta cell function (ßF) in Italians without and with newly diagnosed T2DM. In 676 nondiabetic subjects (336 NGR and 340 IGR) from the GENFIEV study and in 597 patients from the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS), we (1) genotyped rs1801282 and rs4607103, (2) assessed ßF by C-peptide/glucose modeling after OGTT, and (3) assessed IS by HOMA-IR in both studies and by euglycemic insulin clamp in VNDS only. Logistic, linear, and two-stage least squares regression analyses were used to test (a) genetic associations with T2DM and with pathophysiological phenotypes, (b) causal relationships of the latter ones with T2DM by a Mendelian randomization design. Both SNPs were associated with T2DM. The rs4607103 risk allele was associated to impaired ßF (p < 0.01) in the GENFIEV study and in both cohorts combined. The rs1801282 genotype was associated with IS both in the GENFIEV study (p < 0.03) and in the VNDS (p < 0.03), whereas rs4607103 did so in the VNDS only (p = 0.01). In a Mendelian randomization design, both HOMA-IR (instrumental variables: rs1801282, rs4607103) and ßF (instrumental variable: rs4607103) were related to T2DM (p < 0.03-0.01 and p < 0.03, respectively). PPARG2 and ADAMTS9 variants are both associated with T2DM and with insulin resistance, whereas only ADAMTS9 may be related to ßF. Thus, at least in Italians, they may be considered bona fide "insulin resistance genes".

Recommendations for the classification of diseases as CFTR-related disorders.

Several diseases have been clinically or genetically related to cystic fibrosis (CF), but a consensus definition is lacking. Here, we present a proposal for consensus guidelines on cystic fibrosis transmembrane conductance regulator (CFTR)-related disorders (CFTR-RDs), reached after expert discussion and two dedicated workshops. A CFTR-RD may be defined as "a clinical entity associated with CFTR dysfunction that does not fulfil diagnostic criteria for CF". The utility of sweat testing, mutation analysis, nasal potential difference, and/or intestinal current measurement for the differential diagnosis of CF and CFTR-RD is discussed. Algorithms which use genetic and functional diagnostic tests to distinguish CF and CFTR-RDs are presented. According to present knowledge, congenital bilateral absence of vas deferens (CBAVD), acute recurrent or chronic pancreatitis and disseminated bronchiectasis, all with CFTR dysfunction, are CFTR-RDs.

Upregulated expression of Toll-like receptor 4 in peripheral blood of ischaemic stroke patients correlates with cyclooxygenase 2 expression.

OBJECTIVES: An inflammatory process following stroke in human brains and systemic inflammatory responses after stroke in humans have been reported by numerous investigators. The aim of the study was to investigate if genes involved in the cyclooxygenase 2 (COX-2) pathway are upregulated at peripheral level in patients after transient ischaemic attack (TIA) and stroke. DESIGN OF STUDY: Blood samples were obtained from two groups of patients undergoing carotid endarterectomy. The first group included 25 patients who presented TIA or ischaemic stroke. The second group included 35 patients who had an asymptomatic internal carotid artery stenosis. Total RNA was isolated and the expression of Toll-like Receptor 4 (TLR4), COX-2, membrane-associated Prostaglandin E synthase (mPGES-1), Prostaglandin E2 receptors (EP3 and EP4) was analysed by real time RT-PCR. RESULTS: Expression of COX-2 and TLR4 were significantly increased in symptomatic patients (p < 0.001). Correlation analysis showed that TLR4 expression significantly correlated with COX-2 expression (R = 0.65; p < 0.01) in ischaemic stroke patients. This correlation was not observed in TIA and asymptomatic patients. CONCLUSIONS: Our results suggest that the peripheral mechanism of inflammatory injury after stroke may be mediated by TLR4 through a COX-2-dependent pathway.

Variants and haplotypes of TCF7L2 are associated with ß-cell function in patients with newly diagnosed type 2 diabetes: the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 1.

CONTEXT: Intronic variants of TCF7L2 are confirmed genetic risk factors for type 2 diabetes and are associated to alterations in beta cell function in nondiabetic individuals. OBJECTIVE: The objective of the study was to test whether TCF7L2 variability may affect ß-cell function also in patients with type 2 diabetes. DESIGN: This was a cross-sectional association study. SETTING: The study was conducted at a university hospital referral center for diabetes. PATIENTS: Patients included 464 (315 males and 149 females) glutamic acid decarboxylase-negative patients [age: median 59 yr (interquartile range: 52-65); body mass index: 29.3 kg/m(2) (26.5-32.9); fasting plasma glucose: 7.0 mmol/liter (6.1-8.0)] with newly diagnosed type 2 diabetes. INTERVENTION(S): Interventions included frequently sampled oral glucose tolerance test and euglycemic insulin clamp. MAIN OUTCOME MEASURE(S): ß-Cell function (derivative control and proportional control); insulin sensitivity; genotypes of the following TCF7L2 single-nucleotide polymorphisms: rs7901695, rs7903146, rs11196205, and rs12255372. RESULTS: Both rs7901695 and rs7903146 diabetes risk alleles were associated with reduced proportional control of ß-cell function (P = 0.019 and P = 0.022, respectively). Two low-frequency haplotypes were associated with extreme (best and worst) phenotypes of ß-cell function (P < 0.01). No associations between TCF7L2 genotypes and insulin sensitivity were detected. CONCLUSIONS: TCF7L2 diabetes risk variants, either as single-nucleotide polymorphisms or as haplotypes, detrimentally influence ß-cell function and might play a role in determining the metabolic phenotype of patients with newly diagnosed type 2 diabetes.

Consensus on the use and interpretation of cystic fibrosis mutation analysis in clinical practice.

It is often challenging for the clinician interested in cystic fibrosis (CF) to interpret molecular genetic results, and to integrate them in the diagnostic process. The limitations of genotyping technology, the choice of mutations to be tested, and the clinical context in which the test is administered can all influence how genetic information is interpreted. This paper describes the conclusions of a consensus conference to address the use and interpretation of CF mutation analysis in clinical settings. Although the diagnosis of CF is usually straightforward, care needs to be exercised in the use and interpretation of genetic tests: genotype information is not the final arbiter of a clinical diagnosis of CF or CF transmembrane conductance regulator (CFTR) protein related disorders. The diagnosis of these conditions is primarily based on the clinical presentation, and is supported by evaluation of CFTR function (sweat testing, nasal potential difference) and genetic analysis. None of these features are sufficient on their own to make a diagnosis of CF or CFTR-related disorders. Broad genotype/phenotype associations are useful in epidemiological studies, but CFTR genotype does not accurately predict individual outcome. The use of CFTR genotype for prediction of prognosis in people with CF at the time of their diagnosis is not recommended. The importance of communication between clinicians and medical genetic laboratories is emphasized. The results of testing and their implications should be reported in a manner understandable to the clinicians caring for CF patients.

Epidemiology and a novel procedure for large scale analysis of CFTR rearrangements in classic and atypical CF patients: a multicentric Italian study.

BACKGROUND: Mutation epidemiology in each ethnic group is a crucial step of strategies for cystic fibrosis (CF) diagnosis and counselling. To date, the scanning of the whole coding region of the cystic fibrosis transmembrane conductance regulator (CFTR) gene permits to identify about 90% of alleles from patients bearing CF and a lower percentage in patients bearing atypical CF. CFTR rearrangements in heterozygosis elude current techniques for molecular analysis, and some of them have been reported with a frequency up to 6% in various ethnic groups. METHODS: Using quantitative PCR analysis of all coding regions, we assessed the occurrence of CFTR rearrangements in 130 alleles from classic CF patients and in 198 alleles from atypical CF patients (all unrelated and from Italian descent) bearing unidentified mutations after the scanning of CFTR. RESULTS: Seven rearrangements (i.e., dele1, dele2, dele2_3, dele 14b_17b, dele17a_18, dele22_23, and dele22_24) were identified in 34/131 (26.0%) CF alleles bearing undetected mutations (which means about 2.5% of all CF alleles) and in none of the 198 alleles from atypical CF. The CFTR haplotype and the sequence analysis of the breakpoints confirmed the common origin of all the rearrangements. Thus, we set up a novel duplex PCR assay for the large-scale analysis of the seven rearrangements. The procedure was rapid (all PCR amplifications were obtained under the same conditions), costless and repeatable. CONCLUSIONS: It is useful to select the CFTR rearrangements more frequent in specific ethnic groups and to set up procedures for large-scale analysis. Their study can be performed in cases in which a high detection rate is required (i.e., partners of CF carriers/patients). On the contrary, the analysis of rearrangement is useless in atypical CF patients.

Two new highly polymorphic markers in the 3' UTR region of the PLA2G7 gene.

We described two new highly polymorphic markers located 31 bp downstream of the last nucleotide of exon 12 in the 3' UTR region of the gene PLA2G7: 1344 +31TG(n) AG(m). Eight and 14 alleles were observed for the AG and TG repeats, respectively. These two markers have the highest heterozygosity until now reported for PLA2G7 gene.

COX-2 promoter region polymorphisms in multiple sclerosis: lack of association of -765G>C with disease risk.

Cyclooxygenase-2 (COX-2) is extensively expressed in multiple sclerosis lesions suggesting that regulatory variants of the COX-2 gene could be implicated in multiple sclerosis (MS). Screening of the proximal 5' regulatory region and genotyping of -765G>C and -62C>G showed that polymorphisms in this COX-2 region are unlikely to be involved in MS susceptibility.

Chromosome 7p linkage and GPR154 gene association in Italian families with allergic asthma.

BACKGROUND: Several genome scans have reported linkage of markers on chromosome 7p with asthma and related phenotypes in different populations. A fine mapping in Finnish and French-Canadian populations has associated the GPR154 gene (also known as G-protein-coupled receptor for asthma susceptibility, GPRA) with elevated IgE or asthma. OBJECTIVE: To confirm chromosome 7p linkage and candidate gene association in Italian families with atopic asthma. METHODS: In a two-phase approach, we first performed a linkage analysis of chromosome 7, and then a family-based association study on the GPR154 gene for allergic asthma phenotypes in the Italian population. RESULTS: The screening of 117 families with 19 microsatellite markers showed potential linkage for elevated IgE (P<0.002 at 22 cM from p-ter), asthma (P<0.005 at 44 cM), or atopy (P<0.005 at 54 cM). In the second phase of the present study, candidate gene GPR154, which is located in the phase one-linked region, was investigated in 211 families with seven single nucleotide polymorphisms (SNPs) that tag most haplotype variability, by the pedigree disequilibrium test. Elevated IgE levels were associated with two GPR154 gene SNPs (SNP 546333, P=0.0046; rs740 347, P=0.006), and with haplotypes in the global test (P=0.013). Haplotype analysis performed in nuclear families having at least 1 asthmatic parent showed a significant association with asthma (P=0.0173), atopy (P=0.0058), SPT (P=0.0025), and bronchial hyper reactivity (P=0.0163). CONCLUSION: These results support a susceptibility locus for asthma and related phenotypes on chromosome 7, and are in agreement with recent reports suggesting that a common susceptibility factor for atopic manifestations in asthma is likely conferred by the locus containing the GPR154 gene.

Highly preferential association of NonF508del CF mutations with the M470 allele.

BACKGROUND: On the basis of previous findings on random individuals, we hypothesized a preferential association of CF causing mutations with the M allele of the M470V polymorphic site of the CFTR gene. METHODS: We have determined the M/V-CF mutation haplotype in a series of 201 North East Italian and 73 Czech CF patients who were not F508del homozygotes, as F508del was already known to be fully associated with the M allele. RESULTS: Out of 358 not F508del CF genes, 84 carried the V allele and 274 the less common M allele. In the N-E Italian population, MM subjects have a risk of carrying a CF causing mutation 6.9x greater than VV subjects when F508del is excluded and 15.4x when F508del is included. In the Czech population a similar, although less pronounced, association is observed. CONCLUSIONS: Besides the possible biological significance of this association, the possibility of exploiting it for a pilot screening program has been explored in a local North East Italian population for which CF patients were characterized for their CF mutation. General M470V genotyping followed by common CF mutation screening limited to couples in which each partner carries at least one M allele would need testing only 39% of the couples, which contribute 89% of the total risk, with a cost benefit.

ApoE epsilon2/epsilon3/epsilon4 polymorphism, ApoC-III/ApoE ratio and metabolic syndrome.

Triglyceride-rich lipoproteins contain both apolipoproteins E (ApoE) and C-III (ApoC-III), which show opposite functional properties. The relationships between the ApoE (epsilon2/epsilon3/epsilon4) gene polymorphism and ApoC-III/ApoE ratio has never been investigated. A large population (n=552) of cardiovascular patients, without diabetes and/or lipid-lowering therapy, with or without metabolic syndrome (MetSyn), was genotyped for epsilon2/epsilon3/epsilon4 polymorphism and their ApoCIII/ApoE ratio was evaluated. A second group of patients (n=76) with peripheral artery disease was also genotyped and their ApoC-III/ApoE ratios were measured in HDL and non-HDL fractions. Subjects with E2 had higher and E4 carriers lower TG,ApoE and ApoC-III levels, respectively. The ApoCIII/ ApoE ratio showed an opposite trend, gradually increasing from E2/E2 to E4/E4 subjects. MetSyn patients also had an elevated ApoC-III/ApoE ratio and E4 carriers were more frequent in MetSyn patients (OR 2.08 with a 95%CI 1.22-3.5). The distribution of ApoC-III/ApoE ratio was confirmed also in the second group, with lower values in E2/E3 and higher in E3/E4 subjects. Similar results were obtained for the concentrations measured in non-HDL fractions, but not in the HDL fractions. ApoE epsilon2/epsilon3/epsilon4 gene polymorphism is a determinant of the relative proportion of apolipoprotein C-III to E. Carriers of the unfavourable E4 allele present the highest ApoCIII/ApoE ratio and are twofold more frequent among individuals affected by MetSyn.

Interaction between metabolic syndrome and PON1 polymorphisms as a determinant of the risk of coronary artery disease.

The enzyme serum paraoxonase plays an important role in antioxidant defences and prevention of atherosclerosis. Metabolic syndrome (MS) is a clinical condition associated with increased oxidant stress and cardiovascular mortality. Two common polymorphisms of serum paraoxonase, PON1 Leu(55)Met and Gln(192)Arg, have been postulated to modulate the cardiovascular risk. We studied 915 subjects with angiographic documentation: 642 subjects with coronary atherosclerosis and 273 with normal coronary arteries. Two hundred and twenty-four subjects met the diagnostic criteria of MS. We found a significant interaction between MS and both the PON1 polymorphisms in determining the risk of coronary artery disease (P<0.05 by likelihood-ratio test). The 55Leu and the 192Arg alleles, associated with reduced protection against lipid peroxidation, were associated with coronary artery disease only in the MS subgroup. Subjects with MS and both 55Leu and 192Arg alleles had significantly increased risk (OR=9.38 with 95% CI=3.02-29.13 after adjustment by multiple logistic regression) as compared to subjects without MS and with 55Met/Met-192Gln/Gln genotype. No increased risk was found for subjects with MS and the 55Met/Met-192Gln/Gln genotype. This study highlights a potential example of genetic (paraoxonase polymorphisms)-clinical (MS) interaction influencing cardiovascular risk.

Interaction between smoking and PON2 Ser311Cys polymorphism as a determinant of the risk of myocardial infarction.

BACKGROUND: Increased oxidative stress is thought to play a role in the pathogenesis of the atherothrombotic process. Paraoxonases (PONs) are closely related antioxidant enzymes encoded by clustered genes on chromosome 7q. We evaluated three PON polymorphisms (PON1 Leu55Met and Gln192Arg; PON2 Ser311Cys) as possible risk factors for coronary atherosclerotic disease (CAD) and/or its main thrombotic complication, myocardial infarction (MI). MATERIALS AND METHODS: We studied 890 subjects with angiographic documentation of coronary vessels (272=CAD-free; 618=CAD). In the CAD group, 341 subjects had a previous MI. RESULTS: Frequencies of various genotypes were not significantly different between CAD-free subjects and the entire CAD population. In the latter group, there were more carriers of the PON2 311Cys variation among those who had suffered a MI than among those who had not (P<0.01 by chi2). The adjusted OR for MI among PON2 311Cys carriers was 1.5 (95%CI, 1.03-2.19). A gene-environmental interaction was found between PON2 Ser311Cys and smoking. Smoking by itself was associated with an increased MI risk. Among smokers, however, the MI risk was related to PON2 genotype: Cys/Cys homozygotes (OR=5.3; 95%CI, 1.7-16.4) and Ser/Cys heterozygotes (OR=2.1; 95%CI, 1.3-3.6) were at greater risk than Ser/Ser subjects (OR=1.2; 95%CI, 0.8-1.8). The PON2 polymorphism did not influence the MI risk among nonsmokers. CONCLUSIONS: In CAD subjects, a proportion of the risk of MI may be influenced by the interaction between smoking and a polymorphism in the antioxidant enzyme PON2.

No linkage or association of five polymorphisms in the interleukin-4 receptor alpha gene with atopic asthma in Italian families.

The literature contains conflicting reports on the association of common variants of the interleukin (IL)-4 receptor alpha (IL4RA) gene with atopic asthma. The purpose of the present study was to investigate the linkage and association of several gene polymorphisms with atopic asthma in a large series of well-characterized individuals. Analysis of five polymorphisms (I50V, E375A, C406R, S478P and Q551R) of the IL4RA gene was performed in 823 individuals from 182 families with atopic asthmatic children from north-east Italy. The subjects were tested for clinical asthma, total serum IgE level, skin prick test positivity to common aeroallergens, and bronchial hyperresponsiveness to methacholine. The frequency of the polymorphisms was similar to that reported for other populations. The 375, 406, 478 and 551 polymorphisms were in linkage disequilibrium, as previously reported. No linkage or transmission disequilibrium was observed in the families between any mutation and any of the phenotypes investigated. No multipoint haplotype was associated with any phenotype. In conclusion, the IL4RA gene does not seem to play an important role in genetic predisposition to atopic asthma in the population tested.

Tumour necrosis factor family genes in a phenotype of COPD associated with emphysema.

Genetic factors are believed to play a role in the individual susceptibility to chronic obstructive pulmonary disease (COPD). Tumour necrosis factor (TNF) family genes have been widely investigated but inconsistent results may lie either in the genetic heterogeneity of populations or in the poor phenotype definition. A genetic study was performed using a narrower phenotype of COPD. The authors studied 86 healthy smokers and 63 COPD subjects who were enrolled based on irreversible airflow obstruction (forced expiratory volume in one second/forced vital capacity <70% predicted) and a diffusing capacity for carbon monoxide <50% predicted (moderate-to-severe COPD associated with pulmonary emphysema). The following polymorphisms were investigated: TNF-308, the biallelic polymorphism located in the first intron of the lymphotoxin-alpha gene, and exon 1 and exon 6 of the TNF receptor 1 and 2 genes, respectively. No significant deviations were found concerning the four polymorphisms studied between the two populations. The authors confirm that the tumour necrosis factor family genes, at least for the polymorphisms investigated, are not major genetic risk factors for chronic obstructive pulmonary disease in Caucasians, either defined in terms of emphysema (this study) or airflow obstruction (previous studies). Nevertheless, the authors would like to emphasise the importance of narrowing the phenotype in the search for genetic risk factors in chronic obstructive pulmonary disease.

Myelin oligodendrocyte glycoprotein polymorphisms and multiple sclerosis.

A detailed analysis of the coding sequences of myelin oligodendrocyte glycoprotei (MOG) gene was performed in multiple sclerosis (MS) patients and in control individuals and three new polymorphisms are described: T636C, nt 571+77C-->T (IVS 4), and nt 710-44A-->G (IVS 6). Screening studies demonstrated that T636C was present in three MS patients and in no control individual and that polymorphisms nt 571+77C-->T (IVS 4), and nt 710-44A-->G (IVS 6), were present with no significant frequency differences in MS patients and control individuals. No mutations were found after sequencing the coding sequences of the extracellular domain of MOG gene in 20 MS patients and 20 control individuals. Screening studies were also performed for known polymorphisms: G15A, Val142Leu, nt 571+68A-->G (IVS 4), and 571+92C-->G (IVS 4). Polymorphism Val 142 Leu, which is linked to nt 571+68A-->G (IVS 4), resulted under-represented in MS patients.

A1298C methylenetetrahydrofolate reductase mutation and coronary artery disease: relationships with C677T polymorphism and homocysteine/folate metabolism.

5, 10-Methylenetetrahydrofolate reductase (MTHFR) is a crucial enzyme in homocysteine/methionine metabolism. The most-studied C677T polymorphism in the MTHFR gene results in a thermolabile variant with reduced activity, and is associated with increased levels of total plasma homocysteine, a risk factor for coronary artery disease. A new mutation in the MTHFR gene (A1298C) has also been reported to lower enzyme activity. Whether A1298C is a risk factor for coronary artery disease, separately or in combination with C677T, and/or relative to total plasma homocysteine and folate status, is unclear to date. We evaluated this hypothesis in 470 angiographically characterized subjects, 302 with coronary artery disease, and 168 with normal coronary arteries. The frequency of the 1298C allele was 0.33 and that of combined heterozygosity 0.315. No difference was found in the frequency of the genotypes or when analyzed for combined heterozygosity between patients with coronary artery disease and normals. Independent of folate status, the 1298C allele was not associated with increased total plasma homocysteine. No additional effect of A1298C on total plasma homocysteine was observed in 148 combined heterozygotes compared with 98 heterozygotes for the C677T alone. These findings do not support a major role for the A1298C mutation in homocysteine metabolism and emphasize the hypothesis that MTHFR genotypes may interfere with coronary artery disease risk only when an unbalanced nutritional status leads to raised total plasma homocysteine levels.

Linkage to atopy on chromosome 19 in north-eastern Italian families with allergic asthma.

BACKGROUND: Allergic asthma is a multifactorial disease for which there is a widely assessed, although poorly understood, genetic involvement. Genome-wide screens reported evidence for linkage of allergic asthma-related phenotypes to several chromosomal locations. Markers on chromosome 19 have been linked to allergic asthma phenotypes in different populations in independent studies. OBJECTIVE: The aim of this study was to perform a genetic linkage analysis on chromosome 19 to search for DNA markers linked to phenotypes related to allergic asthma. METHODS: Using non-parametric multipoint linkage analysis on a total of 22 random DNA markers in 2 stages, a sample of 111 families (542 subjects) from north-eastern Italy, recruited through an asthmatic allergic proband, was investigated. Phenotypes examined were: clinical asthma, total serum elevated IgE, skin prick test positivity, bronchial hyper-responsiveness, and atopy defined as skin prick test positivity and/or elevated IgE. Simulation studies were performed to confirm the significance of the results. RESULTS: A novel linkage of atopy and skin prick test positivity to marker D19S601 (19q13.3) was found. Modest evidence for linkage of atopy, skin prick test positivity, and IgE was also found to marker D19S591 (19p13.3). Simulation analysis for atopy gave an NPL-Z > 3.326 in 2 replicates out of 1000 (P = 0.002) for D19S601, and an NPL-Z > 2.56 in 16 replicates out of 1000 (P = 0.016) for D19S591. CONCLUSIONS: On chromosome 19, suggestive linkage of atopy and skin prick test positivity with marker D19S601 (19q13.3) and modest evidence of linkage of marker D19S591 (19p13.3) to the atopic phenotypes investigated were found. These results suggest that these regions may contain susceptibility loci associated to atopic phenotypes.

Predictive genetic testing -- new possibilities in determination of risk of complex diseases.

Predictive genetic testing offers the possibility to statistically determine the risk of inheriting a complex phenotype by establishing an individual s genotype for metabolic polymorphisms. Here we discuss the conditions under which a predictive test may be offered to a patient and the problems connected with it. Examples of predictive genetic testing for multifactorial diseases and drug responses are given. We describe in detail the association of the C677T polymorphism of methylentetrahydrofolate reductase gene with hyperhomocystinemia and folate levels, as an independent risk factor for cardiovascular disease, and the association of a polymorphism of the promoter of the 5-lipoxygenase gene and the response to leukotriene inhibitors in asthma. Prospective development of genomic medicine and its use in the study of complex traits will hopefully bring significant benefit to the population and enhance the prevention and therapy of common diseases.

Homozygosity for angiotensinogen 235T variant increases the risk of myocardial infarction in patients with multi-vessel coronary artery disease.

OBJECTIVE: Molecular variants of the angiotensinogen (AGT) and the angiotensin II type 1 receptor (ATR) genes have been associated with the risk of coronary artery disease (CAD) and myocardial infarction (MI), but data so far available are conflicting. The primary object of the paper is to verify this possible association by a rigorous, angiographically controlled study in a large sample of patients with or without multi-vessel CAD. DESIGN: We designed a large case-control study in Italian patients candidates for coronary artery bypass grafting, with angiographically documented multi-vessel CAD, compared to subjects with angiographically documented normal coronary arteries. METHODS AND RESULTS: AGT M235T and ATR A1166C gene polymorphisms were analysed in 699 subjects; 454 patients were candidates for coronary artery bypass grafting, having angiographically documented (mainly multi-vessel) CAD. An appropriate documentation of previous MI was obtained from 404/454 (89%, 247 with and 157 without MI). Subjects (n = 245) with angiographically documented normal coronary arteries, were included as control group (CAD-free group). CAD patients had a substantial burden of conventional risk factors as compared with controls free of coronary atherosclerosis. Age, gender, smoking habit and number of stenosed vessels were the only differences between patients with or without previous myocardial infarction, who were similarly exposed to the other conventional risk factors (including hypertension). AGT M235T and ATR A1166C allele and genotype frequencies were similar between CAD and CAD-free patients. In the CAD group, AGT 235T allele was found more frequently in subjects with a previous myocardial infarction (0.494 versus 0.414; P < or = 0.05). By logistic regression, homozygosity for AGT 235T variant appeared to confer 1.9-fold increased risk for MI in both the univariate and the multivariate (adjusted for age, gender, smoking habit and number of stenosed vessels) model. CONCLUSIONS: AGT 235 T homozygous patients with multivessel CAD have an increased risk of myocardial infarction as compared with subjects with clinically similar phenotype but different genotype.