The common genetic variants within the CYP2C19 gene, the loss-of-function hepatic CYP2C19*2 (rs4244285) and *3 (rs4986893) polymorphisms were found to be dominantly associated with a lower clopidogrel responsiveness [14]–[16] and a higher risk of adverse cardiac events such as the occurrence of stent thrombosis and recurrent myocardial infarction [17]–[19]. The gene discussed is CYP2C19; the disease is myocardial infarction.