In a model of myocardial ischemia-reperfusion injury, 30 min of ischemia followed by 24 h of reperfusion resulted in a significant decrease in the size of myocardial infarct in Nox1-, Nox2-, and Nox1/Nox2-deficient mice, but not in Nox4-deficient mice. The gene discussed is CYBB; the disease is myocardial ischemia.