Billions of peripheral white blood cells are produced every day by the regular divisions of hematopoietic stem cells and their descendants in the bone marrow. Under normal circumstances, thousands of stem cells contribute progeny to the blood at any given time, making white blood cells a group with diverse ancestry.
Clonal hematopoiesis is a common age-related condition in which the descendants of one of these hematopoietic stem cells begin to dominate substantial portions of the blood. Genome-wide analyses have determined that clonal hematopoiesis is frequently driven by recurrent genetic alterations that confer a competitive advantage to specific hematopoietic stem cells, thus giving them the ability to expand disproportionately.