The circadian rhythm regulates various physiological mechanisms, and its disruption can promote many disorders. Disturbance of endogenous circadian rhythms enhances the chance of myocardial infarction (MI), showing that circadian clock genes could have a crucial function in the onset of the disease. This case-control study was performed on 1057 participants. It was hypothesized that the polymorphisms of one nucleotide (SNP) in three circadian clock genes (CLOCK, ARNTL, and PER2) could be associated with MI. Statistically significant differences, estimated by the Chi-square test, were found in the distribution of alleles and genotypes between MI and no-MI groups of the CLOCK (rs6811520 and rs13124436) and ARNTL (rs3789327 and rs12363415) genes. According to the results of the present study, the polymorphisms in the CLOCK and ARNTL genes could be related to MI.

The growing body of evidence shows a significant difference in the circadian rhythm of cardiovascular disease based on biological sex. The incidence of cardiovascular disease varies between women and men. Additionally, biological sex is vital for the timely application of therapy—chronotherapy, which benefits both sexes. This study aimed to examine the potential difference of single nucleotide polymorphisms (SNPs) of the circadian rhythm genes ARNTL, CLOCK, CRY2 and PER2 in women and men with myocardial infarction. A cross-sectional study was conducted, including 200 patients with myocardial infarction. Altogether, ten single nucleotide polymorphisms in the ARNTL, CLOCK, CRY2 and PER2 genes were analyzed. The Chi-square test yielded statistically significant differences in CLOCK gene rs11932595 polymorphism in a recessive genotype model between women and men with a p-value of 0.03 and an odds ratio 2.66, and a corresponding 95% confidence interval of 1.07 to 6.66. Other analyzed polymorphisms of the circadian rhythm genes ARNTL, CRY2, and PER2 did not significantly differ between the sexes. According to the study’s current results, the CLOCK gene’s genetic variability might affect myocardial infarction concerning biological sex.