The expression of mRNAs of PPP3CB (MR, n = 13, aortic valve disease, n = 6; 14.45±0.35 vs. 17.13±0.49, P = 0.001), MEF2C (MR, n = 14, aortic valve disease, n = 7; 15.67±0.56 vs. 17.37±0.34, P = 0.037) and PLCE1 (MR, n = 13, aortic valve disease, n = 7; 15.68±0.42 vs. 17.10±0.34, P = 0.043) in the left atrial free wall was significantly up-regulated in the MR patients compared to patients with aortic valve disease (Fig 5). The gene discussed is PLCE1; the disease is aortic valve disorder.