CH associated with shorter overall survival (OS) (hazard ratio [HR] 1.36, 95% CI 1.04-1.77, P = 0.023); specifically, <i>TET2</i> mutations independently predicted inferior OS (HR 1.62, 95% CI 1.15-2.28, P = 0.01) after adjusting for age and for CLL-related prognostic biomarkers, namely IGHV and <i>TP53</i> status. The gene discussed is TET2; the disease is B-cell chronic lymphocytic leukemia.