ABCG1 and coronary artery disorder: We have noticed that the CHD-associated ABCG1 CpG sites in the prospective study are variable from the case–control study, which may be attributed to the limited sample size, and may also own to the processing of the CHD since the methylation of ABCG1 was examined at pre-clinical which is in average 2 years before the events of CHD.