Characterized by the age-associated expansion of hematopoietic stem cell clones harboring somatic mutations-most commonly in TET2, DNMT3A, ASXL1, and JAK2-CHIP affects over 10% of individuals older than 70 years and confers a 1.5- to 2-fold increased risk of coronary heart disease and all-cause mortality, independent of traditional cardiovascular risk factors. The gene discussed is TET2; the disease is coronary artery disorder.