We studied DNA samples from 306 male patients with MI (191 Russians aged 45.5 ± 0.5 years, and 115 Tatars aged 45.03 ± 0.6), attending the Republic Cardiac Center and Republic Clinical Hospital in Ufa. The MI was diagnosed on the basis of clinical, enzymatic, electrocardio­graphic and echocardiographic criteria. All of the following criteria were necessary to confirm this diagnosis: typical chest pain for longer than 30 minutes, an increase in creatine kinase of more than twice the baseline level, characteristic electrocardiographic changes with Q-wave and zone of hypokinesiasia or akinesia. The control group consisted of 245 unrelated healthy male blood donors (116 Russians aged 38.6 ± 0.8, and 129 Tatars aged 39.7 ± 0.7).

      Genomic DNA was extracted from whole venous blood by phenol-chloroform extraction [10]. Genotyping was performed by polymerase chain reaction (PCR). The primers 5'-GTT GTC ATC AGA CTT TGA CC-3' and 5'-TTC AGT TCA TAT GGA CCA GA-3' were used to amplify a DNA fragment of 249 bp containing the polymorphic TaqI site [11]. The PCR procedure consisted of three cycles of denaturation at 97°C for 90 seconds, 55°C for 90 seconds and 74°C for 60 seconds, 32 cycles of denaturation at 97°C for 30 seconds, annealing at 55°C for 30 seconds, extension at 74°C for 30 seconds, and a final extension at 72°C for 10 min. [11]. This polymorphism is characterized by a T→C transition. The allele containing C at position +3953 and digested by TaqI restrictase is designated as allele E1. Another allele that was not digested by TaqI (T at position +3953), was named allele E2. The PCR products were analyzed after electrophoresis on a polyacrylamide gel stained with ethi­dium bromide. The E1 allele gave fragments of 135 and 114 bp, and the E2 allele gave a 249 bp fragment.

      Genotype frequencies were checked for deviation from the Hardy-Weinberg equilibrium by the λ² test, using the Rows x Columns program [12]. The confidence interval (CI) of genotype frequencies were obtained on the basis of Fisher’s distribution. Pair-wise comparison of genotypes and alleles was done with Fisher’s two-side exact test [13]. The strength of association between the alleles and genotypes was estimated by the odds ratio (OR) [14]. Differences were considered significant at a value of p<0.05.