The e4 isoform of apoE, which exhibits a higher affinity for the ABCA1/ABCG1 system, was associated with a moderate increase in the risk of ischemic heart disease, while the association with the e2 isoform (characterized by a lower affinity) is uncertain, probably because of its low frequency in the population [99,100,101,102]. The gene discussed is APOE; the disease is coronary artery disorder.