BDNF and major depressive disorder: The results of the study showed that SNPs of eNOS, HSP70, FKBP5, miR-146a, ACE2, MAS1, SGK1, IL-4–589, IL-6–174, TNF-α–308, CRP–717, 5-HTTLPR, and BDNF genes are associated with the comorbidity of coronary heart disease and depression.