The genotype and allele frequencies in healthy controls and in groups A and B are presented in Table 1. The genotype distribution in the control group fitted the Hardy-Weinberg equilibrium (p = 1.0 c2 = 0.099).

There was a tendency for an increase in frequency of the TNFA1 allele and a decrease in frequency of the TNFA2 allele in Group A (p = 0.06) compared with the control group. The distribution of the genotypes and alleles between group B and the controls did not differ significantly. The comparison of two study groups showed that the TNFA1/2 genotype and TNFA2 allele frequencies in Group B were significantly higher than in Group A, whereas those of TNFA1/1 genotype and TNFA1 allele were lower. OR for the TNFA1/2 genotype and TNFA2 allele were 2.09 and 1.68, respectively.

Table 1. Genotype and allele frequencies of the –308 (G®A) polymorphism of the TNF-a gene in myocardial infarction patients (group A), sudden cardiac death individuals (group B) and healthy controls from Ufa, Bashkortostan, Russia.