EDN1 and coronary artery disorder: A significant difference (p-value = 0.0168) in plasma ET-1 levels was found between the allelic group 3A/3A homozygous and 3A/4A heterozygous in the study group of CHD cases (Fig. 3a), this difference being marginally more significant (p-value = 0.0482) in cyanotic than in acyanotic group (p-value = 0.2646; Fig. 3b).