RNF213 Variants, Vasospastic Angina, and Risk of Fatal Myocardial Infarction.

Importance: Vasospastic angina (VSA) is vasospasm of the coronary artery and is particularly prevalent in East Asian populations. However, the specific genetic architecture for VSA at genome-wide levels is not fully understood. Objective: To identify genetic factors associated with VSA. Design, Setting, and Participants: This was a case-control genome-wide association study of VSA. Data from Biobank Japan (BBJ; enrolled patients from 2002-2008 and 2013-2018) were used, and controls without coronary artery disease (CAD) were enrolled. Patients from the BBJ were genotyped using arrays or a set of arrays. Patients recruited between 2002 and 2005 were classified within the first dataset, and those recruited between 2006 and 2008 were classified within the second dataset. To replicate the genome-wide association study in the first and second datasets, VSA cases and control samples from the latest patients in the BBJ recruited between 2013 and 2018 were analyzed in a third dataset. Exposures: Single-nucleotide variants associated with VSA. Main Outcomes and Measures: Cases with VSA and controls without CAD. Results: A total of 5720 cases (mean [SD] age, 67 [10] years; 3672 male [64.2%]) and 153 864 controls (mean [SD] age, 62 [15] years; 77 362 male [50.3%]) in 3 datasets were included in this study. The variants at the RNF213 locus showed the strongest association with VSA across the 3 datasets (odds ratio [OR], 2.34; 95% CI, 1.99-2.74; P = 4.4 × 10-25). Additionally, rs112735431, an Asian-specific rare deleterious variant (p.Arg4810Lys) experimentally shown to be associated with reduced angiogenesis and a well-known causal risk for Moyamoya disease was the most promising candidate for a causal variant explaining the association. The effect size of rs112735431 on VSA was distinct from that of other CADs. Furthermore, homozygous carriers of rs112735431 showed an association with VSA characterized by a large effect estimate (OR, 18.34; 95% CI, 5.15-65.22; P = 7.0 × 10-6), deviating from the additive model (OR, 4.35; 95% CI, 1.18-16.05; P = .03). Stratified analyses revealed that rs112735431 exhibited a stronger association in males (χ21 = 7.24; P = .007) and a younger age group (OR, 3.06; 95% CI, 2.24-4.19), corresponding to the epidemiologic features of VSA. In the registry, carriers without CAD of the risk allele rs112735431 had a strikingly high mortality rate due to acute myocardial infarction during the follow-up period (hazard ratio, 2.71; 95% CI, 1.57-4.65; P = 3.3 × 10-4). As previously reported, a possible overlap between VSA and Moyamoya disease was not found. Conclusions and Relevance: Results of this study suggest that vascular cell dysfunction mediated by variants in the RNF213 locus may promote coronary vasospasm, and the presence of the risk allele could serve as a predictive factor for the prognosis.

Prinzmetal angina in a child with actin gene ACTC1 mutation.

Prinzmetal angina is a rare cause of intermittent chest pain in paediatrics. Here, we report the case of a 2-year-old female who presented with episodic chest pain, malaise, diaphoresis, fatigue, and poor perfusion on exam. During her hospitalisation, these episodes were associated with significant low cardiac output as evidenced by lactic acidosis and low mixed venous oxygen saturations. Her workup revealed an actin alpha cardiac muscle 1 (ACTC1) gene mutation and associated left ventricular non-compaction with decreased systolic function. She was started on oral heart failure medications as well as a calcium channel blocker but continued to have episodes which were found to promptly resolve with nitroglycerine. She was ultimately listed for cardiac transplant given her perceived risk of sudden death.

T786C Mutation in the Endothelial Nitric Oxide Synthase Gene in Patients With Primary Osteonecrosis.

Mutations in the T786C endothelial nitric oxide synthase gene (eNOS) are associated with osteonecrosis and Prinzmetal's angina. Nitric oxide is necessary for bone health and ameliorates Prinzmetal's angina. This study compared mutations of T786C eNOS in 146 patients with primary osteonecrosis, 114 patients with Prinzmetal's angina, and 83 normal control subjects. Patients with osteonecrosis had more mutant eNOS alleles than control subjects (42% vs 22%, respectively; P<.0001) but had the same number of mutant alleles as patients with Prinzmetal's angina (42% vs 41%, respectively; P=.7), who in turn had more mutant eNOS alleles than control subjects (41% vs 22%, respectively; P=.0001). Of 146 patients with primary osteonecrosis, 65 (45%) had none of the 5 thrombophilias (Factor V Leiden heterozygosity, high levels of Factors VIII and XI, anticardiolipin antibody immunoglobulin M, and homocysteine) that otherwise distinguished patients with osteonecrosis from control subjects (P<.05). No associations were found between eNOS hetero-homozygosity and the 5 major thrombophilias in primary osteonecrosis. Of the 65 patients who had osteonecrosis but no major thrombophilias, for 41 (28% of the total sample of 146), eNOS hetero-homozygosity was the only abnormality. Normalization of nitric oxide levels with l-arginine 9 g/d or l-citrulline 800 mg/d, both of which relieve vasospastic angina in Prinzmetal's angina, which has the same eNOS genotype as primary osteonecrosis, may slow or stop the progression of osteonecrosis. Placebo-controlled trials of patients with primary osteonecrosis who are hetero-homozygous for the T786C eNOS mutation and have no major thrombophilias are needed to assess the safety and efficacy of this treatment. [Orthopedics. 2017; 40(5):e898-e903.].

The endothelial nitric oxide synthase T-786c mutation, a treatable etiology of Prinzmetal's angina.

We assessed to what degree the endothelial nitric oxide synthase (eNOS) T-786C polymorphism, leading to reduced nitric oxide (NO) production-coronary artery spasm, was reversibly associated with Prinzmetal's variant angina (PVA). ENOS T-786C PCR analyses were done in 19 women, 8 men, 26 Caucasian, 1 African-American, median age 53, with well-documented PVA and in 72 healthy controls who did not differ by race or gender. Of the 27 cases, 7 (26%) were homozygous for wild-type normal eNOS (CC), 13 (48%) were T-786C heterozygotes (CT), and 7 (26%) were T-786C homozygotes (TT) vs controls, 44 (61%) CC, 27 (38%) TC, and 1 (1%) TT, P < 0.0001. The mutant eNOS T-786C allele frequency in PVA patients was 27/54 (50%) vs 29/144 (20%) in controls, P < 0.0001. On oral L-arginine (9.2 g/d) to increase production of NO for a median of 4.7 months in 16 PVA patients with symptomatic angina despite conventional nitrate-calcium channel blockers, using the Seattle Angina Questionnaire, satisfaction with symptom remission rose (median) from 50% to 100% (P = 0.004), satisfaction with angina frequency reduction rose from 65% to 80% (P = 0.02), satisfaction with treatment for symptoms rose from 38% to 88% (P = 0.001), and perception of overall life status rose from 25 to 71% (P = 0.0002). On L-arginine (median 4.7 months), in 20 patients, none had worsening of angina, and of 7 patients whose angina totally resolved, eNOS T-786C homozygosity was over-represented, P = 0 .04. The eNOS T-786C mutation appears to be a reversible etiology of PVA in patients whose angina may be ameliorated by L-arginine.

A Becker myotonia patient with compound heterozygosity for CLCN1 mutations and Prinzmetal angina pectoris.

Becker myotonia is a recessive muscle disease with prevalence of > 1:50,000. It is caused by markedly reduced function of the chloride channel encoded by CLCN1. We describe a Polish patient with severe myotonia, transient weakness, and muscle cramps who only responds to lidocaine. In addition, the patient has Prinzmetal angina pectoris and multiple lipomatosis. He is compound heterozygeous for a novel p.W303X and a frequent p.R894X CLCN1 mutation. CLCN1 exon number variation was excluded by MLPA. His son with latent myotonia was heterozygeous for p.R894X. We discuss the potential relations of the three rare diseases and the inheritance of p.R894X.

Endothelial nitric oxide synthase T-786C mutation, a reversible etiology of Prinzmetal's angina pectoris.

Because the endothelial nitric oxide synthase (eNOS) T-786C polymorphism is associated with reduced nitric oxide production and coronary artery spasm in Japanese patients, we speculated that it might be reversibly associated with Prinzmetal's variant angina in white Americans. Polymerase chain reaction analyses of eNOS T-786C and stromelysin 5A6A polymorphisms were done in 31 women and 12 men (42 white and 1 black American, median age 50 years), with well-documented Prinzmetal's variant angina. We matched each case with 1 healthy control by race and gender. Of the 43 cases, 21 (49%) were homozygous for wild-type normal eNOS, 19 (44%) were T-786C heterozygotes, and 3 (7%) were T-786C homozygotes. Of the 43 controls, 31 (72%) were homozygous for wild-type normal eNOS, 12 (28%) were T-786C heterozygotes, and 0 (0%) were T-786C homozygotes (p = .013). The mutant eNOS T-786C allele frequency in patients was 25 (29%) of 86 vs 12 (14%) of 86 in the controls (p = 0.016). Patients did not differ from controls for the distribution of the stromelysin 6A mutation (p = 0.66) or for the mutant 6A allele frequency (53% in cases, 50% in controls; p = 0.65). Nineteen patients took nitric oxide-elevating l-arginine (9.2 g/day, orally). Of these 19 patients, 10 (53%) became free of angina, 3 (16%) were improved but not angina free, and 6 (32%) had no change in their angina. Using l-arginine, the physical ability score (Seattle Angina Questionnaire) increased from a median of 42 to 72 of a total possible score of 100 (p = 0.011), satisfaction with symptom reduction increased from 53 to 61 (p = 0.004), and the perception of quality of life as acceptable increased from 29 to 50 (p = 0.001). In conclusion, the eNOS T-786C mutation appears to be a reversible etiology of Prinzmetal's variant angina in white Americans whose angina might be ameliorated by l-arginine.

Association of the manganese superoxide dismutase polymorphism with vasospastic angina pectoris.

BACKGROUND: Vasospastic angina (VSA) is closely related to endothelial dysfunction caused by oxidative damage. Manganese superoxide dismutase (MnSOD) is an antioxidant enzyme that functions in mitochondria. There are two genetic variants of MnSOD arising from a substitution of an alanine for a valine in the signal peptide. We previously reported that the valine allele of MnSOD decreases the mitochondrial MnSOD (mtMnSOD) activity. Here, we investigated the association of the MnSOD polymorphism (Ala16Val) with VSA. METHODS AND RESULTS: Blood samples were collected from 618 healthy subjects who did not have any symptoms or other evidence suggesting angina pectoris, and 228 patients who underwent coronary angiography on suspicion of angina, and were diagnosed to have VSA by acetylcholine test. MnSOD genotype of each subject was determined by real-time polymerase chain reaction. The valine allele frequency was higher in the VSA patients (0.890) than in the healthy subjects (0.839) [odds ratio (OR)=1.55, p=0.0085]. In healthy subjects the MnSOD genotype distribution was as follows: alanine/alanine 1.9%, alanine/valine 28.3%, and valine/valine 69.8%, and in VSA patients the prevalence was: alanine/alanine 1.3%, alanine/valine 19.3%, and valine/valine 79.4%. Thus, the valine allele was closely associated with VSA (p=0.019). Multivariate logistic regression analysis showed valine/valine homozygosity to be an independent risk factor for VSA (OR=2.02, 95% CI 1.43, 2.85; p=0.0012). CONCLUSION: The valine variant of MnSOD signal peptide increases the risk of VSA.

Mutation of ARHGAP9 in patients with coronary spastic angina.

Coronary artery spasm has an important function in the etiology of variant angina and other acute coronary syndromes. Abnormal activation of Rho-family GTPases has been observed in cardiovascular disorders, but the function of genetic variability in Rho-family GTPases remains to be evaluated in cardiovascular disorders. We examined the genetic variability of Rho-family GTPases and their regulators in coronary artery spasm. We performed a comprehensive candidate gene analysis of 67 single nucleotide polymorphisms with amino-acid substitution in Rho-family GTPases and their regulators in 103 unrelated Japanese patients with acetylcholine-induced coronary artery spasm and 102 control Japanese subjects without acetylcholine-induced coronary artery spasm. We noted an association of the single nucleotide polymorphism of ARHGAP9 (rs11544238, Ala370Ser) with coronary artery spasm (odds ratio =2.67). We found that ARHGAP9 inactivated Rac as RacGAP and that the mRNA level of ARHGAP9 was strongly detected in hematopoietic cells. ARHGAP9 negatively regulated cell migration. The Ala370Ser polymorphism counteracted ARHGAP9-reduced cell migration, spreading and adhesion. The Ala370Ser polymorphism in the ARHGAP9 gene is associated with coronary artery spasm. These data suggest that the polymorphism of ARHGAP9 has a critical function in the infiltration of hematopoietic cells into the endothelium and inflammation leading to endothelial dysfunction.

Association of endothelin-1 gene polymorphisms with variant angina in Korean patients.

BACKGROUND: The incidence of variant angina in oriental patients is higher than in patients from the Western world. Endothelin-1 (ET-1) seems to be associated with coronary vasospasm in variant angina, suggesting that ET-1 gene variants may be important in coronary vasospasm in variant angina. We wanted to assess potential association between Korean variant angina and three polymorphisms of the ET-1 gene, which include the +138delA polymorphism in exon 1, G8002A polymorphism in intron 4 and Lys198Asn polymorphism in exon 5. METHOD: A total of 97 patients with variant angina and 111 healthy controls were studied. Analyses of the +138delA, G8002A and Lys198Asn polymorphisms were carried out by polymerase chain reaction-restriction fragment length polymorphism and haplotype techniques. RESULTS: The frequency of mutant 138delA allele was lower in the angina group than in controls [p=0.003, odds ratio (OR)=0.42] and the frequencies of A8002 or Asn198 were significantly higher in the variant angina group than in controls (p=0.005, OR=2.17 or p=0.009, OR=1.75, respectively). According to haplotype analysis, 4A/A8002/Asn198 haplotype was significantly associated with the disease (p=0.0162, OR=2.33) and 3A/G8002/Lys198 haplotype was protective against the disease (p=0.0043, OR=0.54). CONCLUSIONS: The ET-1 gene polymorphisms, such as +138delA, G8002A and Lys198Asn polymorphisms, seem to be associated with variant angina in Korean patients.

PPARgamma gene C161T substitution is associated with reduced risk of coronary artery disease and decreased proinflammatory cytokine expression.

BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPARgamma) is a transcription factor implicated in the expression of proinflammatory cytokines in atheroma-associated cells, and the expression of proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-alpha) and matrix metalloproteinases (MMPs), represents a critical step in atherogenesis and atherosclerosis. In this study, we test the hypothesis of whether a polymorphism corresponding to C161T substitution in exon 6 of the PPARgamma gene may affect the expression of proinflammatory cytokines and the onset of coronary artery diseases (CADs) in a Chinese population. METHODS: We have studied distribution of the PPARgamma C161T substitution at exon 6 in 247 patients with CAD and 214 patients with chest pain syndrome. The plasma concentrations of MMP-9 and TNF-alpha were measured by enzyme-linked immunosorbent assay. RESULTS: The results showed that the frequencies of the CC, CT, and TT genotypes were 61.9%, 34.0%, and 4.1% in CAD, and 51.4%, 45.3%, and 3.3% in chest pain syndrome, respectively. There was a significant association between the PPARgamma C161T polymorphism and CAD. The T allele carriers (CT + TT) had significantly reduced CAD risk compared with the CC homozygotes (odds ratio 0.547, 95% CI 0.327-0.831, P = .012) in a logistic regression model after controlling known independent factors for CAD. The CC homozygotes also had increased MMP-9 and TNF-alpha levels compared with T allele carriers. Moreover, the CC homozygotes were more susceptible to acute coronary syndrome than T allele carriers. CONCLUSIONS: PPARgamma C161T polymorphism was associated with angiographically documented CAD in a Chinese population. The T allele of the PPARgamma gene might have a protective effect on the progression of CAD and reduce the onset of acute coronary syndrome, which might be associated with the decreased expression of MMP-9 and TNF-alpha in patients with CAD.

Klotho gene polymorphism may be a genetic risk factor for atherosclerotic coronary artery disease but not for vasospastic angina in Japanese.

BACKGROUND: The klotho gene, originally identified by insertional mutagenesis in mice, suppresses multiple aging phenotypes, including atherosclerosis. We tested the hypothesis that the G-395A polymorphism of the klotho gene is associated with increased risk for 2 types of ischemic heart disease in Japanese. METHODS: The study population consisted of 197 patients with coronary heart disease (CAD) who had >75% luminal diameter narrowing, 77 patients with vasospastic angina (VSA) without significant fixed coronary artery disease, and 331 healthy control subjects. RESULTS: The frequency of the A allele carriers of the klotho gene was significantly higher in the CAD group than in the control group (29.9% vs. 19.0%). The unadjusted odds ratio for CAD in the A allele carriers compared with the control group was 1.82 (p=0.004) and a traditional risk-adjusted logistic regression model revealed that the A allele was an independent predictor of CAD (odds ratio, 1.76; p=0.03). In contrast, the frequency of the A allele carriers was not significantly different in the VSA group (23.4%; adjusted odds ratio, 1.18. CONCLUSIONS: The -395A polymorphism of the human klotho gene may be a genetic risk factor for IHD and not for VSA.

Common adrenergic receptor polymorphisms as novel risk factors for vasospastic angina.

BACKGROUND: Sympathetic activity mediated by adrenergic receptors (ARs) appears to play an important role in controlling the vasomotor tone and, thus, may be associated with vasospastic angina (VA). We investigated the association of the common functional polymorphisms of the AR gene and VA. The candidates were alpha2CDel322-325, beta1Gly389Arg, beta2Arg16Gly, and beta2Gln27Glu polymorphisms. METHODS: Eighty-two patients with VA, confirmed by coronary angiography with or without ergonovine provocation test, and 114 apparently healthy control subjects were investigated for genotype of 4 AR polymorphisms and established risk factors of ischemic heart disease. RESULTS: The minor alleles were alpha2CDel322-325, beta1Gly389, beta2Gly16, and beta2Glu27 and their frequencies were 7%, 18%, 42%, and 29%, respectively, in the control subjects of this Korean population, which were different from those of other ethnic groups. On univariate analysis, age, smoking, male sex, alpha2CDel322-325 allele carrier state, and beta2Gln27 homozygote state were significant risk factors for VA. After multivariate analysis using multiple logistic regression model, age (odds ratio [OR] 1.809, CI 1.046-1.135, P < .0001), smoking (OR 4.902, CI 2.105-11.416, P = .0002), alpha2CDel322-325 allele carrier state (OR 5.132, CI 2.094-12.578, P = .0003), and beta2Gln27 allele homozygosity (OR 3.152, CI 1.364-7.285, P = .0072) remained as independent risk factors. In the combined genotype analysis, the effect of beta2Gln27 allele was evident only when the alpha2CDel322-325 allele was absent. CONCLUSIONS: The alpha2CDel322-325 allele carrier state and beta2Gln27 allele homozygote state were identified as novel risk factors of VA in this Korean population. This result suggests the importance of the adrenergic stimuli and the genetic background in the pathogenesis of the VA.

Vasospastic angina and microvascular angina are differentially influenced by PON1 A632G polymorphism in the Japanese.

BACKGROUND: Ethnicity and smoking are well-known risk factors for the pathogenesis of coronary vasospasm. Oxidative stress induced by smoking plays a crucial role in coronary vasospasm, but is not enough to account for the pathogenesis of coronary vasospasm, indicating that genetic factors are strongly involved. METHODS AND RESULTS: The study group comprised 162 vasospastic angina patients (VSAs), 61 microvascular angina patients (MVAs) and 61 non-responders (NRs) diagnosed by acetylcholine provocation test. Four polymorphisms of the oxidative stress related genes, cytochrome b-245, alpha polypeptide gene (CYBA) C242T and A640G, paraoxonase 1 gene (PON1) A632G, phospholipase A2 group VII gene (PLA2G7) G994T were genotyped. Allele frequency of PON1 632-G was significantly higher in both the VSA with dominant fashion and the MVA with recessive fashion compared with NR. This association was strongly influenced by gender in the MVA only. There were no significant associations between the other polymorphisms and coronary vasospasm. In addition, the allele frequency of PON1 632-G in the Japanese was higher than in Caucasians. CONCLUSIONS: There was a significant association between PON1 A632G polymorphism and MVA as well as VSA, but the impact of this on VSA and MVA is different in the Japanese.

Absence of Kir6.1/KCNJ8 mutations in Italian patients with abnormal coronary vasomotion.

The disturbances in coronary vasomotor tone have been extensively analyzed, but the exact molecular mechanisms underlying abnormal coronary vasomotion remain to be elucidated. It has been suggested that impaired coronary vasoreactivity can be the expression of a defect in vascular smooth muscle cells. A mouse model of human variant (vasospastic) angina has been recently obtained by disruption of Kir6.1/Kcnj8, a gene coding for a small pore-forming inward rectifier potassium channel. A phenotype resembling variant angina was also reported in mice lacking Sur2, the partner protein of Kir6.1. To better define the role of the smooth muscular ATP-sensitive potassium channels in the pathogenesis of abnormal coronary vasomotion, a complete mutational analysis of Kir6.1/KCNJ8 gene was performed in a series of 18 Italian patients with impaired coronary vasomotility. Polymerase chain reaction and direct sequencing of PCR products were done. No mutations were detected in the sample analyzed, thus suggesting that Kir6.1/KCNJ8 aberrations are not a common cause of abnormal coronary vasomotion in Italians. To the best of our knowledge, this study represents the first mutational analysis of Kir6.1/KCNJ8 gene in humans. Since major racial differences in the prevalence of abnormal coronary vasomotion have been described, further mutation screenings of Kir6.1/KCNJ8 gene are required to assess its role in the pathogenesis of impaired coronary vasomotility among various ethnic groups.

Episodic coronary artery vasospasm and hypertension develop in the absence of Sur2 K(ATP) channels.

K(ATP) channels couple the intracellular energy state to membrane excitability and regulate a wide array of biologic activities. K(ATP) channels contain a pore-forming inwardly rectifying potassium channel and a sulfonylurea receptor regulatory subunit (SUR1 or SUR2). To clarify the role of K(ATP) channels in vascular smooth muscle, we studied Sur2 gene-targeted mice (Sur2(-/-)) and found significantly elevated resting blood pressures and sudden death. Using in vivo monitoring, we detected transient, repeated episodes of coronary artery vasospasm in Sur2(-/-) mice. Focal narrowings in the coronary arteries were present in Sur2(-/-) mice consistent with vascular spasm. We treated Sur2(-/-) mice with a calcium channel antagonist and successfully reduced vasospastic episodes. The intermittent coronary artery vasospasm seen in Sur2(-/-) mice provides a model for the human disorder Prinzmetal variant angina and demonstrates that the SUR2 K(ATP) channel is a critical regulator of episodic vasomotor activity.

Mouse model of Prinzmetal angina by disruption of the inward rectifier Kir6.1.

The inwardly rectifying K(+) channel Kir6.1 forms K(+) channels by coupling with a sulfonylurea receptor in reconstituted systems, but the physiological roles of Kir6.1-containing K(+) channels have not been determined. We report here that mice lacking the gene encoding Kir6.1 (known as Kcnj8) have a high rate of sudden death associated with spontaneous ST elevation followed by atrioventricular block as seen on an electrocardiogram. The K(+) channel opener pinacidil did not induce K(+) currents in vascular smooth-muscle cells of Kir6.1-null mice, and there was no vasodilation response to pinacidil. The administration of methylergometrine, a vasoconstrictive agent, elicited ST elevation followed by cardiac death in Kir6.1-null mice but not in wild-type mice, indicating a phenotype characterized by hypercontractility of coronary arteries and resembling Prinzmetal (or variant) angina in humans. The Kir6.1-containing K(+) channel is critical in the regulation of vascular tonus, especially in the coronary arteries, and its disruption may cause Prinzmetal angina.

Brugada syndrome: a case report of an unusual association with vasospastic angina and coronary myocardial bridging.

This report describes a case of an unusual association between vasospastic angina, coronary myocardial bridging, and Brugada syndrome. The patient complained of chest pain followed by rhythmic palpitation and syncope. Brugada syndrome ECG markers were documented with transient ST-segment elevation in lateral leads. A coronary angiogram showed a myocardial bridging in the left anterior descending artery and coronary vasospasm was reproduced after intracoronary ergonovine injection in the circumflex coronary artery. Ventricular fibrillation was induced by programmed electrical stimulation. The described association can be important because interaction between ischemia and Brugada syndrome electrophysiological substrate could modulate individual susceptibility to life-threatening ventricular tachyarrhythmias.

Variant angina is not associated with angiotensin I converting enzyme gene polymorphism but rather with smoking.

BACKGROUND: Angiotensin converting enzyme (ACE) perhaps plays roles in regulating coronary vasomotor tone by producing angiotensin II and degrading bradykinin. OBJECTIVES: We sought to investigate the role of ACE gene polymorphism in the pathogenesis of variant angina and to compare it with that of other clinical risk factors for male patients with variant angina and age-matched and sex-matched control subjects. METHODS: We studied 78 male patients with variant angina who exhibited spontaneous or provoked coronary spasms during coronary angiography and compared prevalences of ACE gene genotype (deletion D and insertion I) and other risk factors between this group of patients with variant angina and age-matched and sex-matched control subjects whose angiograms were normal and in whom the ergonovine test did not cause spasms (n = 80). RESULTS: Smokers were more prevalent in the group of patients with variant angina (P < 0.05). Genotype and allele prevalences of the group of patients with variant angina (0.14, 0.53 and 0.33 for DD, DI and II and 0.41 and 0.59 for D and I, respectively) were no different from those of the control group (0.16, 0.49 and 0.35 for DD, DI and II and 0.40 and 0.60 for D and I). Multiple logistic regression analysis showed that smoking was a significant risk factor for variant angina (odds ratio 2.61, 95% confidence interval 1.03-6.66) whereas ACE genotype was not. CONCLUSIONS: Variant angina is associated with an environmental factor, such as smoking, rather than a genetic factor, such as ACE gene polymorphism.