However, we found that KN-93 treatment did not reduce atrial SR Ca2+ leak in RyR2-S2808D+/+ or RyR2-R2474S+/− atrial cardiomyocytes, suggesting that direct oxidation of atrial RyR2, but not phosphorylation by oxidized CaMKII, is the main factor inducing atrial SR Ca2+ leak and AF. The gene discussed is RYR2; the disease is atrial fibrillation.