Clonal evolution in RUNX1 carriers. Asymptomatic carriers of pathogenic germ line RUNX1 variants develop early-onset clonal hematopoiesis (cumulative risk of 81% by age 50 years). As depicted in the model, this finding provides a rationale for testing the hypothesis that clonal hematopoiesis may provide a biomarker for early detection of disease progression in high-risk families.