A preliminary study of the association between the ABCA1 gene promoter DNA methylation and coronary artery disease risk

Coronary artery disease (CAD) is a common health problem in Iranian population. ATP binding cassette transporter A1 (ABCA1) plays central role in the efflux of the cholesterol from peripheral tissues back to liver. Inactivation of ABCA1 by epigenetic change such as DNA methylation may contribute to the development of CAD. The present study investigated the association between promoter DNA methylation status of ABCA1 with the development and severity of CAD. Our study population consisted of 110 angiographically documented CAD patients and 110 controls. The severity of CAD was determined based on the number of stenotic vessels showing more than 50% stenosis. Promoter DNA methylation status of ABCA1 was determined by methylation specific PCR. Lipid profile was determined by routine colorimetric methods. Results showed that the frequency of ABCA1 DNA methylation was significantly higher in CAD group as compared with control group (16.36% vs 5.45%; P=0.015). Also, the methylation frequency of ABCA1 gene was significantly higher in older CAD patients as compared with younger CAD patients (P=0.038). No association was seen between plasma lipid concentration and the promoter DNA methylation status of ABCA1 (P>0.05). Also, the association between the severity of CAD and methylation of ABCA1 gene was not significant (P>0.05). In conclusion the current study indicated ABCA1 DNA methylation as a significant risk factor for development but not severity of CAD. Also, predisposition to the development of CAD by ABCA1 gene DNA methylation was independent of plasma lipid concentration.