Influence of functional polymorphism in MIF promoter on sudden cardiac death in Chinese populations

Sudden cardiac death (SCD) is defined as an unexpected natural death without any obvious non-cardiac causes that occurs within 1 h with witnessed symptom onset or within 24 h without witnessed symptom onset. Genetic studies conducted during the past decade have markedly illuminated the genetic basis of the cardiac disorders associated with SCD. Macrophage migration inhibitory factor (MIF) is an upstream immunoregulatory cytokine associated with the pathogenesis of many inflammatory diseases including atherosclerosis and myocardial infarction. Previous studies have reported that the functional -794(CATT)_5-8 polymorphism in MIF is unrelated to sudden infant death syndrome susceptibility. However, there are no reports concerning the association between the polymorphism and adult SCD susceptibility. In the current study, we investigated the association between the -794(CATT)_5-8 polymorphism and adult SCD susceptibility using 79 adult SCD cases and 313 healthy controls. All samples were analysed using a conventional polymerase chain reaction (PCR) technique. We found that CATT₆ and 5-6 were the most common allele and genotype in both groups, respectively, while no significant association was found between the -794(CATT)_5-8 polymorphism and SCD susceptibility. We also summarized the allele frequencies of -794(CATT)_5-8 in cohorts of healthy people from different countries and found that the allele frequency distributions of the polymorphism in Chinese populations were quite different from that of American and European populations (P = 0.005, P = 0.0001, respectively), but similar to Japanese populations (P = 0.827). In conclusion, this study indicates that the -794(CATT)_5-8 polymorphism may not be associated with adult SCD susceptibility in Chinese populations. Different allele frequency distributions of the polymorphism in multiple populations may provide a useful reference for further genetic association studies.