P2RX7 and coronary artery disorder: The study genotyped SNPs in the P2RX7 gene in 1244 patients with ischemic heart disease and 5969 individuals with cardiovascular risk factors as well as 2488 control subjects, and detailed analysis supports that the 1513A>C polymorphism or the loss-of-function E496A mutation may reduce the risk of ischemic heart disease in smokers.