We found that the average methylation status of DDAH2 promoter was significantly higher in CAD patients than in controls (P < 0.05, Figure 3C).Consistent with the hypermethylation of DDAH2 promoter in EPCs from CAD patients, real-time PCR analysis showed that DDAH2 mRNA level in EPCs from CAD patients was markedly reduced compared with controls (P < 0.01, Figure 3D). Here, DDAH2 is linked to coronary artery disorder.