Coronary artery ectasia is associated with the c.894G>T (Glu298Asp) polymorphism of the endothelial nitric oxide synthase gene.

Coronary artery ectasia (CAE) is characterized by inappropriate dilation of the coronary vasculature. The underlying mechanisms of CAE formation are not yet entirely known. A polymorphism in the endothelial nitric oxide synthase (eNOS) gene, which reduces eNOS activity, might be a risk factor for coronary heart diseases. However, its role in CAE is unknown. One of the most studied eNOS gene polymorphisms is a c.894G>T polymorphism that results in the conversion of Glu (GAG) to Asp (GAT) at position 298. In this study, we investigated the potential association between the c.894G>T (Glu298Asp) polymorphism and CAE. The present study included 84 subjects from 2,980 consecutive patients in whom elective diagnostic coronary angiography was performed. Forty patients with isolated CAE and 44 subjects with normal coronary arteries were enrolled. The frequencies of the G allele were 78.4% in the control and 57.5% in CAE patients. The TT genotype was more frequent in patients with CAE than that in the controls (20% vs. 4.5%, p = 0.013). Furthermore, the risk of developing CAE in the presence of the homozygous TT genotype was significantly higher in the patients than that in the controls (OR = 7.7, 95% CI = 1.44-41.3). The presence of an 894T allele increased the risk of CAE 2.8-fold (95% CI = 1.15-6.73; p = 0.027). The frequencies of the T allele were 65% in CAE patients and 38.6% in the controls. In conclusion, the c.894G>T polymorphism in the eNOS gene may be a risk factor for CAE.

Angiotensin-converting enzyme gene polymorphism in arrhythmogenic right ventricular dysplasia: is DD genotype helpful in predicting syncope risk?

INTRODUCTION: Arrhythmogenic right ventricular dysplasia (ARVD) is a heritable disorder characterised by fibrofatty replacement of right ventricular myocytes and increased risk of ventricular arrhythmias and sudden cardiac death. Angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism affects myocardial ACE levels. DD genotype favours myocardial fibrosis and is associated with malignant ventricular tachycardia. The aim of this study was to explore ACE gene polymorphism in ARVD patients. METHODS: Twenty-nine patients with ARVD and 24 controls were included. All ARVD patients had documented sustained ventricular tachycardia. Thirteen patients had syncopal episodes. Six patients were resuscitated from sudden cardiac death. ACE gene polymorphism was identified by polymerase chain reaction technique. RESULTS: There was no significant difference in DD genotype frequency between ARVD patients and controls (44.8% vs. 45.8%, p=0.94). However, DD genotype frequency was significantly higher in ARVD patients with syncopal episodes compared to those without syncope (69.2% vs. 25.0%, p=0.017, odds ratio:6.750, 95% confidence interval: 1.318-34.565). DD genotype was detected in higher frequency also in patients with a family history of sudden cardiac death (66.7% vs. 39.1%,p=0.36). CONCLUSION: High prevalence of DD genotype in ARVD patients with syncope suggests that ACE I/D polymorphism might be useful in identifying high-risk patients for syncope.